The concrete mix design available on this site are for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors. These are just to show you how to calculate and we are thankful to all the members who have emailed us these mix designs so that these could be shared with civil engineers worldwide.
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Here is the summary of links of all the mix designs we have till date:-
Mix Design For M20 Grade Of Concrete
Mix Design For M35 Grade Of Concrete
Mix Design For M40 Grade Of Concrete
Mix Design For M50 Grade Of Concrete
Mix Design For M60 Grade Of Concrete
In case you want the complete theory of Mix Design, Go here What is Concrete Mix Design
We will add more soon. You can help us do this fast, just email us any mix design you have.
Mix Design M-50 Grade
The mix design M-50 grade (Using Admixture –Sikament) provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.
Parameters for mix design M50
Grade Designation = M-50
Type of cement = O.P.C-43 grade
Brand of cement = Vikram ( Grasim )
Admixture = Sika [Sikament 170 ( H ) ]
Fine Aggregate = Zone-II
Sp. Gravity
Cement = 3.15
Fine Aggregate = 2.61
Coarse Aggregate (20mm) = 2.65
Coarse Aggregate (10mm) = 2.66
Minimum Cement (As per contract) =400 kg / m3
Maximum water cement ratio (As per contract) = 0.45
Mix Calculation: -
1. Target Mean Strength = 50 + ( 5 X 1.65 ) = 58.25 Mpa
2. Selection of water cement ratio:-
Assume water cement ratio = 0.35
3. Calculation of water: -
Approximate water content for 20mm max. Size of aggregate = 180 kg /m3 (As per Table No. 5 , IS : 10262 ). As plasticizer is proposed we can reduce water content by 20%.
Now water content = 180 X 0.8 = 144 kg /m3
4. Calculation of cement content:-
Water cement ratio = 0.35
Water content per cum of concrete = 144 kg
Cement content = 144/0.35 = 411.4 kg / m3
Say cement content = 412 kg / m3 (As per contract Minimum cement content 400 kg / m3 )
Hence O.K.
5. Calculation for C.A. & F.A.: [ Formula's can be seen in earlier posts]-
Volume of concrete = 1 m3
Volume of cement = 412 / ( 3.15 X 1000 ) = 0.1308 m3
Volume of water = 144 / ( 1 X 1000 ) = 0.1440 m3
Volume of Admixture = 4.994 / (1.145 X 1000 ) = 0.0043 m3
Total weight of other materials except coarse aggregate = 0.1308 + 0.1440 +0.0043 = 0.2791 m3
Volume of coarse and fine aggregate = 1 – 0.2791 = 0.7209 m3
Volume of F.A. = 0.7209 X 0.33 = 0.2379 m3 (Assuming 33% by volume of total aggregate )
Volume of C.A. = 0.7209 – 0.2379 = 0.4830 m3
Therefore weight of F.A. = 0.2379 X 2.61 X 1000 = 620.919 kg/ m3
Say weight of F.A. = 621 kg/ m3
Therefore weight of C.A. = 0.4830 X 2.655 X 1000 = 1282.365 kg/ m3
Say weight of C.A. = 1284 kg/ m3
Considering 20 mm: 10mm = 0.55: 0.45
20mm = 706 kg .
10mm = 578 kg .
Hence Mix details per m3
Increasing cement, water, admixture by 2.5% for this trial
Cement = 412 X 1.025 = 422 kg
Water = 144 X 1.025 = 147.6 kg
Fine aggregate = 621 kg
Coarse aggregate 20 mm = 706 kg
Coarse aggregate 10 mm = 578 kg
Admixture = 1.2 % by weight of cement = 5.064 kg.
Water: cement: F.A.: C.A. = 0.35: 1: 1.472: 3.043
Observation: -
A. Mix was cohesive and homogeneous.
B. Slump = 120 mm
C. No. of cube casted = 9 Nos.
7 days average compressive strength = 52.07 MPa.
28 days average compressive strength = 62.52 MPa which is greater than 58.25MPa
Hence the mix accepted.
Mix Design M-40 Grade
The mix design M-40 grade for Pier (Using Admixture – Fosroc) provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.
Parameters for mix design M40
Grade Designation = M-40
Type of cement = O.P.C-43 grade
Brand of cement = Vikram ( Grasim )
Admixture = Fosroc ( Conplast SP 430 G8M )
Fine Aggregate = Zone-II
Sp. Gravity Cement = 3.15
Fine Aggregate = 2.61
Coarse Aggregate (20mm) = 2.65
Coarse Aggregate (10mm) = 2.66
Minimum Cement (As per contract) = 400 kg / m3
Maximum water cement ratio (As per contract) = 0.45
Mix Calculation: -
1. Target Mean Strength = 40 + (5 X 1.65) = 48.25 Mpa
2. Selection of water cement ratio:-
Assume water cement ratio = 0.4
3. Calculation of cement content: -
Assume cement content 400 kg / m3
(As per contract Minimum cement content 400 kg / m3)
4. Calculation of water: -
400 X 0.4 = 160 kg Which is less than 186 kg (As per Table No. 4, IS: 10262)
Hence o.k.
5. Calculation for C.A. & F.A.: - As per IS : 10262 , Cl. No. 3.5.1
V = [ W + (C/Sc) + (1/p) . (fa/Sfa) ] x (1/1000)
V = [ W + (C/Sc) + {1/(1-p)} . (ca/Sca) ] x (1/1000)
Where
V = absolute volume of fresh concrete, which is equal to gross volume (m3) minus the volume of entrapped air ,
W = mass of water ( kg ) per m3 of concrete ,
C = mass of cement ( kg ) per m3 of concrete ,
Sc = specific gravity of cement,
(p) = Ratio of fine aggregate to total aggregate by absolute volume ,
(fa) , (ca) = total mass of fine aggregate and coarse aggregate (kg) per m3 of
Concrete respectively, and
Sfa , Sca = specific gravities of saturated surface dry fine aggregate and Coarse aggregate respectively.
As per Table No. 3 , IS-10262, for 20mm maximum size entrapped air is 2% .
Assume F.A. by % of volume of total aggregate = 36.5 %
0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.365 ) ( Fa / 2.61 )] ( 1 /1000 )
=> Fa = 660.2 kg
Say Fa = 660 kg.
0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.635 ) ( Ca / 2.655 )] ( 1 /1000 )
=> Ca = 1168.37 kg.
Say Ca = 1168 kg.
Considering 20 mm : 10mm = 0.6 : 0.4
20mm = 701 kg .
10mm = 467 kg .
Hence Mix details per m3
Cement = 400 kg
Water = 160 kg
Fine aggregate = 660 kg
Coarse aggregate 20 mm = 701 kg
Coarse aggregate 10 mm = 467 kg
Admixture = 0.6 % by weight of cement = 2.4 kg.
Recron 3S = 900 gm
Water: cement: F.A.: C.A. = 0.4: 1: 1.65: 2.92
Observation: -
A. Mix was cohesive and homogeneous.
B. Slump = 110mm
C. No. of cube casted = 12 Nos.
7 days average compressive strength = 51.26 MPa.
28 days average compressive strength = 62.96 MPa which is greater than 48.25MPa
Hence the mix is accepted.
Concrete Mix Design - M 20 Grade Of Concrete
1. REQUIREMENTS
a) Specified minimum strength = 20 N/Sq mm
b) Durability requirements
i) Exposure Moderate
ii) Minimum Cement Content = 300 Kgs/cum
c) Cement
(Refer Table No. 5 of IS:456-2000)
i) Make Chetak (Birla)
ii) Type OPC
iii) Grade 43
d) Workability
i) compacting factor = 0.7
e) Degree of quality control Good
Concrete Mix Design M-60
CONCRETE MIX DESIGN (GRADE M60)
(a) DESIGN STIPULATION:-
Target strength = 60Mpa
Max size of aggregate used = 12.5 mm
Specific gravity of cement = 3.15
Specific gravity of fine aggregate (F.A) = 2.6
Specific gravity of Coarse aggregate (C.A) = 2.64
Dry Rodded Bulk Density of fine aggregate = 1726 Kg/m3
Dry Rodded Bulk Density of coarse aggregate = 1638 Kg/m3
Saturday, July 4, 2009
Plate Girder In Buildings
or greatest resistance to bending, as much of a plate girder cross section as practicable should be concentrated in the flanges, at the greatest distance from the neutral axis. This
might require, however, a web so thin that the girder would fail by web buckling before it reached its bending capacity.
To preclude this, the AISC specification limits h/t.
For an unstiffened web, this ratio should not exceed.
h / t = 14,000 / (F Y (F y + 16.5) ) ½
where F y = yield strength of compression flange, ksi (MPa).
Larger values of h/t may be used, however, if the web is stiffened at appropriate intervals.
For this purpose, vertical angles may be fastened to the web or vertical plates welded to it. These transverse stiffeners are not required, though, when h/t is less than the value
computed from the preceding equation or Table 9.4.
Critical h/t for Plate Girders in Buildings should be taken from the codes
With transverse stiffeners spaced not more than 1.5 times the girder depth apart, the web clear-depth/thickness ratio may be as large as
h / t = 2000 / ( F y ) ½
If, however, the web depth/thickness ratio h/t exceeds 760 / (F b ) ½ , where F b , ksi (MPa), is the allowable bending stress in the compression flange that would ordinarily apply, this stress should be reduced to F ‘ b , given by the following equations:
F ‘ b = R P G R e F ¬b
R P G = [ 1 – 0.0005 ( A w / A f ) ( h/t – 760 / ( F b )) ½ ] ? 1.0
R e = [ ( 12 + ( A w /A f ) (3a – a 3 ) ) / ( 12 + 2 (A w / A f ) ] ? 1.0
Where A w = web area , in 2 (mm 2 )
A f = area of compression flange, in 2 (mm 2 )
a = 0.6 F y w / F b ? 1.0
F y w = minimum specified yield stress, ksi, (MPa), of web steel
In a hybrid girder, where the flange steel has a higher yield strength than the web, the preceding equation protects against excessive yielding of the lower strength web in the vicinity of the higher strength flanges. For nonhybrid girders, R e = 1.0.
might require, however, a web so thin that the girder would fail by web buckling before it reached its bending capacity.
To preclude this, the AISC specification limits h/t.
For an unstiffened web, this ratio should not exceed.
h / t = 14,000 / (F Y (F y + 16.5) ) ½
where F y = yield strength of compression flange, ksi (MPa).
Larger values of h/t may be used, however, if the web is stiffened at appropriate intervals.
For this purpose, vertical angles may be fastened to the web or vertical plates welded to it. These transverse stiffeners are not required, though, when h/t is less than the value
computed from the preceding equation or Table 9.4.
Critical h/t for Plate Girders in Buildings should be taken from the codes
With transverse stiffeners spaced not more than 1.5 times the girder depth apart, the web clear-depth/thickness ratio may be as large as
h / t = 2000 / ( F y ) ½
If, however, the web depth/thickness ratio h/t exceeds 760 / (F b ) ½ , where F b , ksi (MPa), is the allowable bending stress in the compression flange that would ordinarily apply, this stress should be reduced to F ‘ b , given by the following equations:
F ‘ b = R P G R e F ¬b
R P G = [ 1 – 0.0005 ( A w / A f ) ( h/t – 760 / ( F b )) ½ ] ? 1.0
R e = [ ( 12 + ( A w /A f ) (3a – a 3 ) ) / ( 12 + 2 (A w / A f ) ] ? 1.0
Where A w = web area , in 2 (mm 2 )
A f = area of compression flange, in 2 (mm 2 )
a = 0.6 F y w / F b ? 1.0
F y w = minimum specified yield stress, ksi, (MPa), of web steel
In a hybrid girder, where the flange steel has a higher yield strength than the web, the preceding equation protects against excessive yielding of the lower strength web in the vicinity of the higher strength flanges. For nonhybrid girders, R e = 1.0.
Deflections of Bents and Shear Walls
Horizontal deflections in the planes of bents and shear walls can be computed on the assumption that they act as cantilevers. Deflections of braced bents can be calculated
by the dummy-unit-load method or a matrix method. Deflections of rigid frames can be computed by adding the drifts of the stories, as determined by moment distribution
or a matrix method.
For a shear wall (Fig) the deflection in its plane induced by a load in its plane is the sum of the flexural
Figure showing Building frame resists lateral forces with (a) wind bents or (g) shear walls or a combination of the two. Bents may be braced in any of several ways, including (b) X bracing, (c) K bracing, (d) inverted V bracing, (e) knee bracing, and (f) rigid connections.
deflection as a cantilever and the deflection due to shear. Thus, for a wall with solid rectangular cross section, the deflection at the top due to uniform load is
? = 1.5 wH / Et [ ( H / L ) 3 + H / L]
where w = uniform lateral load
H = height of the wall
E = modulus of elasticity of the wall material
t = wall thickness
L = length of wall
For a shear wall with a concentrated load P at the top, the deflection at the top is
? c = ( 4 P / Et ) [ ( H / L ) 3 + 0.75 H / L ]
If the wall is fixed against rotation at the top, however, the deflection is
? f = ( P / Et ) [ ( H / L ) 3 + 3 H / L ]
Units used in these equations are those commonly applied in United States Customary System (USCS) and the System International (SI) measurements, that is, kip (kN), lb /in 2 (MPa), ft (m), and in (mm).
Where shear walls contain openings, such as those for doors, corridors, or windows, computations for deflection and rigidity are more complicated. Approximate methods, however, may be used.
Combined Axial Compression Or Tension And Bending
The AISC specification for allowable stress design for buildings includes three interaction formulas for combined axial compression and bending.
When the ratio of computed axial stress to allowable axial stress f /F a exceeds 0.15, both of the following equations must be satisfied:
( f a / F a ) + ( C m x f b x ) / (1– f a /F ‘ e x ) F b x + C m y f b y / (1 – f a / F ‘ e y ) F b y ? 1
f a / 0.60F y + f b x /F b x + f b y / F b y ? 1
when f a /F a ? 0.15, the following equation may be used instead of the preceding two:
f a / F a + f b x / F b x + f b y / F b y ? 1
In the preceding equations, subscripts x and y indicate the axis of bending about which the stress occurs, and
In the preceding equations, subscripts x and y indicate the axis of bending about which the stress occurs, and
F a = axial stress that would be permitted if axial force alone existed, ksi (MPa)
F b = compressive bending stress that would be permitted if bending moment alone existed, ksi (MPa)
F ‘ e = 149,000 / ( Kl b / r b ) 2 , ksi (MPa); as for F a , F b , and 0.6F y , F ‘ e may be increased one-third for wind and seismic loads
Lb = actual unbraced length in plane of bending, in (mm)
r b = radius of gyration about bending axis, in (mm)
K = effective-length factor in plane of bending
f a = computed axial stress, ksi (MPa)
f b = computed compressive bending stress at point under consideration, ksi (MPa)
C m = adjustment coefficient
When the ratio of computed axial stress to allowable axial stress f /F a exceeds 0.15, both of the following equations must be satisfied:
( f a / F a ) + ( C m x f b x ) / (1– f a /F ‘ e x ) F b x + C m y f b y / (1 – f a / F ‘ e y ) F b y ? 1
f a / 0.60F y + f b x /F b x + f b y / F b y ? 1
when f a /F a ? 0.15, the following equation may be used instead of the preceding two:
f a / F a + f b x / F b x + f b y / F b y ? 1
In the preceding equations, subscripts x and y indicate the axis of bending about which the stress occurs, and
In the preceding equations, subscripts x and y indicate the axis of bending about which the stress occurs, and
F a = axial stress that would be permitted if axial force alone existed, ksi (MPa)
F b = compressive bending stress that would be permitted if bending moment alone existed, ksi (MPa)
F ‘ e = 149,000 / ( Kl b / r b ) 2 , ksi (MPa); as for F a , F b , and 0.6F y , F ‘ e may be increased one-third for wind and seismic loads
Lb = actual unbraced length in plane of bending, in (mm)
r b = radius of gyration about bending axis, in (mm)
K = effective-length factor in plane of bending
f a = computed axial stress, ksi (MPa)
f b = computed compressive bending stress at point under consideration, ksi (MPa)
C m = adjustment coefficient
WEBS UNDER CONCENTRATED LOADS
Criteria for Buildings
The AISC specification for ASD for buildings places a limit on compressive stress in webs to prevent local web yielding. For a rolled beam, bearing stiffeners are required at a concentrated load if the stress f a , ksi (MPa), at the toe of the web fillet exceeds F a = 0.66F y w , where F y w is the minimum specified yield stress of the web steel, ksi (MPa). In the calculation of the stressed area, the load may be assumed distributed over the distance indicated in Fig. 9.4.
For a concentrated load applied at a distance larger than the depth of the beam from the end of the beam:
F a = R / f w ( N + 5K )
where R = concentrated load of reaction, kip (kN)
t w = web thickness, in (mm)
N = length of bearing, in (mm), (for end reaction, not less than k)
K = distance, in (mm), from outer face of flange to web toe of fillet
For a concentrated load applied close to the beam end:
f a = R / t w ( N + 2.5 k )
To prevent web crippling, the AISC specification requires that bearing stiffeners be provided on webs where concentrated loads occur when the compressive force
exceeds R, kip (kN), computed from the following:
For a concentrated load applied at a distance from the beam end of at least d/2, where d is the depth of beam:
R = 67.5 t 2 w [ 1 + 3 ( N / d ) ( t w / t f ) 1.5 ] (F y w t f / t w ) ½
where t f = flange thickness, in (mm)
For a concentrated load applied closer than d/2 from the beam end:
R = 34r 2 w [ 1 + 3 ( N / d ) ( t w / t f ) 1.5 ] ( F y w t f / t w ) ½
If stiffeners are provided and extend at least one-half of the web, R need not be computed.
Another consideration is prevention of sidesway web buckling. The AISC specification requires bearing stiffeners when the compressive force from a concentrated load
exceeds limits that depend on the relative slenderness of web and flange r w f and whether or not the loaded flange is restrained against rotation:
r w f = ( d c / t w ) / ( l / b f )
where l = largest unbraced length, in (mm), along either top or bottom flange at point of application of load
b = flange width, in (mm)
d c = web depth clear of fillets = d – 2k
Stiffeners are required if the concentrated load exceeds R, kip (kN), computed from
R = 6800 t 3 w / h ( 1 + 0.4 r 3 w f )
where h = clear distance, in (mm), between flanges, and r w f
is less than 2.3 when the loaded flange is restrained against rotation. If the loaded flange is not restrained and r w f is less than 1.7,
R = 0.4 r 3 w f ( 6800 t 3 w / h )
R need not be computed for larger values of r w f ..
The AISC specification for ASD for buildings places a limit on compressive stress in webs to prevent local web yielding. For a rolled beam, bearing stiffeners are required at a concentrated load if the stress f a , ksi (MPa), at the toe of the web fillet exceeds F a = 0.66F y w , where F y w is the minimum specified yield stress of the web steel, ksi (MPa). In the calculation of the stressed area, the load may be assumed distributed over the distance indicated in Fig. 9.4.
For a concentrated load applied at a distance larger than the depth of the beam from the end of the beam:
F a = R / f w ( N + 5K )
where R = concentrated load of reaction, kip (kN)
t w = web thickness, in (mm)
N = length of bearing, in (mm), (for end reaction, not less than k)
K = distance, in (mm), from outer face of flange to web toe of fillet
For a concentrated load applied close to the beam end:
f a = R / t w ( N + 2.5 k )
To prevent web crippling, the AISC specification requires that bearing stiffeners be provided on webs where concentrated loads occur when the compressive force
exceeds R, kip (kN), computed from the following:
For a concentrated load applied at a distance from the beam end of at least d/2, where d is the depth of beam:
R = 67.5 t 2 w [ 1 + 3 ( N / d ) ( t w / t f ) 1.5 ] (F y w t f / t w ) ½
where t f = flange thickness, in (mm)
For a concentrated load applied closer than d/2 from the beam end:
R = 34r 2 w [ 1 + 3 ( N / d ) ( t w / t f ) 1.5 ] ( F y w t f / t w ) ½
If stiffeners are provided and extend at least one-half of the web, R need not be computed.
Another consideration is prevention of sidesway web buckling. The AISC specification requires bearing stiffeners when the compressive force from a concentrated load
exceeds limits that depend on the relative slenderness of web and flange r w f and whether or not the loaded flange is restrained against rotation:
r w f = ( d c / t w ) / ( l / b f )
where l = largest unbraced length, in (mm), along either top or bottom flange at point of application of load
b = flange width, in (mm)
d c = web depth clear of fillets = d – 2k
Stiffeners are required if the concentrated load exceeds R, kip (kN), computed from
R = 6800 t 3 w / h ( 1 + 0.4 r 3 w f )
where h = clear distance, in (mm), between flanges, and r w f
is less than 2.3 when the loaded flange is restrained against rotation. If the loaded flange is not restrained and r w f is less than 1.7,
R = 0.4 r 3 w f ( 6800 t 3 w / h )
R need not be computed for larger values of r w f ..
DESIGN OF STIFFENERS UNDER LOADS
AISC requires that fasteners or welds for end connections of beams, girders, and trusses be designed for the combined effect of forces resulting from moment and shear induced by the rigidity of the connection. When flanges or moment connection plates for end connections of beams and girders are welded to the flange of an I- or H-shape column, a pair of column-web stiffeners having a combined cross-sectional area A s t not less than that calculated from the following equations must be provided whenever the calculated value of A s t is positive:
A s t = ( P b f – F y c t w c ( t b + 5k ) ) / F y s t
where F y c = column yield stress, ksi (MPa)
F y s t = stiffener yield stress, ksi (MPa)
K = distance, in (mm), between outer face of column flange and web toe of its fillet, if column is rolled shape, or equivalent distance if column is welded shape
P b f = computed force, kip (kN), delivered by flange of moment-connection plate multi plied by 5/3 , when computed force is due to live and dead load only, or by 4/3, when computed force is due to live and dead load in conjunction with wind or earthquake forces
T w c = thickness of column web, in (mm)
T b = thickness of flange or moment-connection plate delivering concentrated force, in (mm)
Notwithstanding the preceding requirements, a stiffener or a pair of stiffeners must be provided opposite the beam compression flange when the column-web depth clear of fillets d c is greater than
d c = ( 4100 t 3 w c ( F y e ) ½ ) / P b f
and a pair of stiffeners should be provided opposite the tension flange when the thickness of the column flange t f is less than
t f = 0.4 ( P b f ) ½ / F y c
Stiffeners required by the preceding equations should comply with the following additional criteria:
1. The width of each stiffener plus half the thickness of the column web should not be less than one-third the width of the flange or moment-connection plate delivering the concentrated force.
2. The thickness of stiffeners should not be less than t b /2.
3. The weld-joining stiffeners to the column web must be sized to carry the force in the stiffener caused by unbalanced moments on opposite sides of the column.
A s t = ( P b f – F y c t w c ( t b + 5k ) ) / F y s t
where F y c = column yield stress, ksi (MPa)
F y s t = stiffener yield stress, ksi (MPa)
K = distance, in (mm), between outer face of column flange and web toe of its fillet, if column is rolled shape, or equivalent distance if column is welded shape
P b f = computed force, kip (kN), delivered by flange of moment-connection plate multi plied by 5/3 , when computed force is due to live and dead load only, or by 4/3, when computed force is due to live and dead load in conjunction with wind or earthquake forces
T w c = thickness of column web, in (mm)
T b = thickness of flange or moment-connection plate delivering concentrated force, in (mm)
Notwithstanding the preceding requirements, a stiffener or a pair of stiffeners must be provided opposite the beam compression flange when the column-web depth clear of fillets d c is greater than
d c = ( 4100 t 3 w c ( F y e ) ½ ) / P b f
and a pair of stiffeners should be provided opposite the tension flange when the thickness of the column flange t f is less than
t f = 0.4 ( P b f ) ½ / F y c
Stiffeners required by the preceding equations should comply with the following additional criteria:
1. The width of each stiffener plus half the thickness of the column web should not be less than one-third the width of the flange or moment-connection plate delivering the concentrated force.
2. The thickness of stiffeners should not be less than t b /2.
3. The weld-joining stiffeners to the column web must be sized to carry the force in the stiffener caused by unbalanced moments on opposite sides of the column.
FASTENERS IN BUILDINGS
The AISC specification for allowable stresses for buildings specifies allowable unit tension and shear stresses on the cross-sectional area on the unthreaded body area of bolts and threaded parts. (Generally, rivets should not be used in direct tension.) When wind or seismic load are combined with gravity loads, the allowable stresses may be increased one-third.
Most building construction is done with bearing-type connections. Allowable bearing stresses apply to both bearing-type and slip-critical connections. In buildings, the allowable bearing stress F p , ksi (MPa), on projected area of fasteners is
F p = 1.2 F
where F u is the tensile strength of the connected part, ksi (MPa). Distance measured in the line of force to the nearest edge of the connected part (end distance) should be at least 1.5d, where d is the fastener diameter. The center-to-center spacing of fasteners should be at least 3d.
Most building construction is done with bearing-type connections. Allowable bearing stresses apply to both bearing-type and slip-critical connections. In buildings, the allowable bearing stress F p , ksi (MPa), on projected area of fasteners is
F p = 1.2 F
where F u is the tensile strength of the connected part, ksi (MPa). Distance measured in the line of force to the nearest edge of the connected part (end distance) should be at least 1.5d, where d is the fastener diameter. The center-to-center spacing of fasteners should be at least 3d.
COMPOSITE CONSTRUCTION
In composite construction, steel beams and a concrete slab are connected so that they act together to resist the load on the beam. The slab, in effect, serves as a cover plate. As a result, a lighter steel section may be used.
Construction In Buildings
There are two basic methods of composite construction.
Method 1. The steel beam is entirely encased in the concrete. Composite action in this case depends on the steel-concrete bond alone. Because the beam is completely braced laterally, the allowable stress in the flanges is 0.66F y , where F y is the yield strength, ksi (MPa), of the steel. Assuming the steel to carry the full dead load and the composite section to carry the live load, the maximum unit stress, ksi (MPa), in the steel is
F s = ( M D / S S ) + ( M L / S t r ) ? 0.66F y
where M D = dead-load moment, in-kip (kN-mm)
M L = live-load moment, in-kip (kN-mm)
S s = section modulus of steel beam, in 3 (mm 3 )
S t r = section modulus of transformed composite section, in 3 (mm 3 )
An alternative, shortcut method is permitted by the AISC specification. It assumes that the steel beam carries both live and dead loads and compensates for this by permitting
a higher stress in the steel:
f s = M D + M L / S s ? 0.76 F y
Method 2. The steel beam is connected to the concrete slab by shear connectors. Design is based on ultimate load and is independent of the use of temporary shores to support the steel until the concrete hardens. The maximum stress in the bottom flange is
F s = M D + M L / S t r £ 0.66 F y
To obtain the transformed composite section, treat the concrete above the neutral axis as an equivalent steel area by dividing the concrete area by n, the ratio of modulus of elasticity of steel to that of the concrete. In determination of the transformed section, only a portion of the concrete slab over the beam may be considered effective in resisting compressive flexural stresses (positive-moment regions). The width of slab on either side of the beam centerline that may be considered effective should not exceed any of the following:
1. One-eighth of the beam span between centers of sup- ports
2. Half the distance to the centerline of the adjacent beam
3. The distance from beam centerline to edge of slab
Construction In Buildings
There are two basic methods of composite construction.
Method 1. The steel beam is entirely encased in the concrete. Composite action in this case depends on the steel-concrete bond alone. Because the beam is completely braced laterally, the allowable stress in the flanges is 0.66F y , where F y is the yield strength, ksi (MPa), of the steel. Assuming the steel to carry the full dead load and the composite section to carry the live load, the maximum unit stress, ksi (MPa), in the steel is
F s = ( M D / S S ) + ( M L / S t r ) ? 0.66F y
where M D = dead-load moment, in-kip (kN-mm)
M L = live-load moment, in-kip (kN-mm)
S s = section modulus of steel beam, in 3 (mm 3 )
S t r = section modulus of transformed composite section, in 3 (mm 3 )
An alternative, shortcut method is permitted by the AISC specification. It assumes that the steel beam carries both live and dead loads and compensates for this by permitting
a higher stress in the steel:
f s = M D + M L / S s ? 0.76 F y
Method 2. The steel beam is connected to the concrete slab by shear connectors. Design is based on ultimate load and is independent of the use of temporary shores to support the steel until the concrete hardens. The maximum stress in the bottom flange is
F s = M D + M L / S t r £ 0.66 F y
To obtain the transformed composite section, treat the concrete above the neutral axis as an equivalent steel area by dividing the concrete area by n, the ratio of modulus of elasticity of steel to that of the concrete. In determination of the transformed section, only a portion of the concrete slab over the beam may be considered effective in resisting compressive flexural stresses (positive-moment regions). The width of slab on either side of the beam centerline that may be considered effective should not exceed any of the following:
1. One-eighth of the beam span between centers of sup- ports
2. Half the distance to the centerline of the adjacent beam
3. The distance from beam centerline to edge of slab
NUMBER OF CONNECTORS REQUIRED FOR BUILDING CONSTRUCTION
The total number of connectors to resist V h is computed from V h / q, where q is the allowable shear for one connector, kip (kN). Values of q for connectors in buildings are given in structural design guides.
The required number of shear connectors may be spaced uniformly between the sections of maximum and zero moment. Shear connectors should have at least 1 in (25.4 mm) of concrete cover in all directions; and unless studs are located directly over the web, stud diameters may not exceed 2.5 times the beam-flange thickness.
With heavy concentrated loads, the uniform spacing of shear connectors may not be sufficient between a concentrated load and the nearest point of zero moment. The number of shear connectors in this region should be at least
N 2 = N 1 [ ( M b / M m a x ) - 1] / ( b - 1 )
where M = moment at concentrated load, ft kip (kN-m)
M max = maximum moment in span, ft kip (kN-m)
N 1 = number of shear connectors required between M m a x and zero moment
b = S t r / S s or S e f f / S s , as applicable
S e f f = effective section modulus for partial composite action, in 3 (mm 3 )
Shear on Connectors
The total horizontal shear to be resisted by the shear connectors in building construction is taken as the smaller of the values given by the following two equations:
V h = 0.85 f ‘ c A c / 2
V h = A s F y / 2
where V h = total horizontal shear, kip (kN), between maximum positive moment and each end of steel beams (or between point of maximum positive moment and point of contraflexure in continuous beam)
f ‘ c = specified compressive strength of concrete at 28 days, ksi (MPa)
A c = actual area of effective concrete flange, in 2 (mm 2 )
A s = area of steel beam, in 2 (mm 2 )
In continuous composite construction, longitudinal reinforcing steel may be considered to act compositely with the steel beam in negative-moment regions. In this case, the total horizontal shear, kip (kN), between an interior support and each adjacent point of contraflexure should be taken as
V h = A s r F y r / 2
where A s r = area of longitudinal reinforcement at support within effective area, in 2 (mm 2 ); and F y r = specified minimum yield stress of longitudinal reinforcement, ksi (MPa).
The required number of shear connectors may be spaced uniformly between the sections of maximum and zero moment. Shear connectors should have at least 1 in (25.4 mm) of concrete cover in all directions; and unless studs are located directly over the web, stud diameters may not exceed 2.5 times the beam-flange thickness.
With heavy concentrated loads, the uniform spacing of shear connectors may not be sufficient between a concentrated load and the nearest point of zero moment. The number of shear connectors in this region should be at least
N 2 = N 1 [ ( M b / M m a x ) - 1] / ( b - 1 )
where M = moment at concentrated load, ft kip (kN-m)
M max = maximum moment in span, ft kip (kN-m)
N 1 = number of shear connectors required between M m a x and zero moment
b = S t r / S s or S e f f / S s , as applicable
S e f f = effective section modulus for partial composite action, in 3 (mm 3 )
Shear on Connectors
The total horizontal shear to be resisted by the shear connectors in building construction is taken as the smaller of the values given by the following two equations:
V h = 0.85 f ‘ c A c / 2
V h = A s F y / 2
where V h = total horizontal shear, kip (kN), between maximum positive moment and each end of steel beams (or between point of maximum positive moment and point of contraflexure in continuous beam)
f ‘ c = specified compressive strength of concrete at 28 days, ksi (MPa)
A c = actual area of effective concrete flange, in 2 (mm 2 )
A s = area of steel beam, in 2 (mm 2 )
In continuous composite construction, longitudinal reinforcing steel may be considered to act compositely with the steel beam in negative-moment regions. In this case, the total horizontal shear, kip (kN), between an interior support and each adjacent point of contraflexure should be taken as
V h = A s r F y r / 2
where A s r = area of longitudinal reinforcement at support within effective area, in 2 (mm 2 ); and F y r = specified minimum yield stress of longitudinal reinforcement, ksi (MPa).
PONDING CONSIDERATIONS IN BUILDINGS
Flat roofs on which water may accumulate may require analysis to ensure that they are stable under ponding conditions. A flat roof may be considered stable and an analysis does not need to be made if both of the following two equations are satisfied:
C p + 0.9 C s £ 0.25
I d ³ 25S 4 / 10 6
Where C p = 32 L s L 4 p / 10 7 I p
C s = 32 SL 4 s / 10 7 s
L p = length, ft (m), of primary member or girder
L s = length, ft (m), of secondary member or purlin
S = spacing, ft (m), of secondary members
I p = moment of inertia of primary member, in 4
(mm 4 )
I s = moment of inertia of secondary member, in 4
(mm 4 )
I d = moment of inertia of steel deck supported on secondary members, in 4 /ft (mm 4 /m)
For trusses and other open-web members, I s should be decreased 15 percent. The total bending stress due to dead loads, gravity live loads, and ponding should not exceed 0.80F y , where F y is the minimum specified yield stress for the steel.
C p + 0.9 C s £ 0.25
I d ³ 25S 4 / 10 6
Where C p = 32 L s L 4 p / 10 7 I p
C s = 32 SL 4 s / 10 7 s
L p = length, ft (m), of primary member or girder
L s = length, ft (m), of secondary member or purlin
S = spacing, ft (m), of secondary members
I p = moment of inertia of primary member, in 4
(mm 4 )
I s = moment of inertia of secondary member, in 4
(mm 4 )
I d = moment of inertia of steel deck supported on secondary members, in 4 /ft (mm 4 /m)
For trusses and other open-web members, I s should be decreased 15 percent. The total bending stress due to dead loads, gravity live loads, and ponding should not exceed 0.80F y , where F y is the minimum specified yield stress for the steel.
LOW COST HOUSING
Low Cost Housing is a new concept which deals with effective budgeting and following of techniques which help in reducing the cost construction through the use of locally available materials along with improved skills and technology without sacrificing the strength, performance and life of the structure.There is huge misconception that low cost housing is suitable for only sub standard works and they are constructed by utilizing cheap building materials of low quality.The fact is that Low cost housing is done by proper management of resources.Economy is also achieved by postponing finishing works or implementing them in phases.
Building Cost
The building construction cost can be divided into two parts namely:
Building material cost : 65 to 70 %
Labour cost : 65 to 70 %
Now in low cost housing, building material cost is less because we make use of the locally available materials and also the labour cost can be reduced by properly making the time schedule of our work. Cost of reduction is achieved by selection of more efficient material or by an improved design.
Areas from where cost can be reduced are:-
1) Reduce plinth area by using thinner wall concept.Ex.15 cms thick solid concrete block wall.
2) Use locally available material in an innovative form like soil cement blocks in place of burnt brick.
3) Use energy efficiency materials which consumes less energy like concrete block in place of burnt brick.
4) Use environmentally friendly materials which are substitute for conventional building components like use R.C.C. Door and window frames in place of wooden frames.
5) Preplan every component of a house and rationalize the design procedure for reducing the size of the component in the building.
6) By planning each and every component of a house the wastage of materials due to demolition of the unplanned component of the house can be avoided.
7) Each component of the house shall be checked whether if it’s necessary, if it is not necessary, then that component should not be used.
Cost reduction through adhoc methods
Foundation
Normally the foundation cost comes to about 10 to 15% of the total building and usually foundation depth of 3 to 4 ft. is adopted for single or double store building and also the concrete bed of 6″(15 Cms.) is used for the foundation which could be avoided.
It is recommended to adopt a foundation depth of 2 ft.(0.6m) for normal soil like gravely soil, red soils etc., and use the uncoursed rubble masonry with the bond stones and good packing. Similarly the foundation width is rationalized to 2 ft.(0.6m).To avoid cracks formation in foundation the masonry shall be thoroughly packed with cement mortar of 1:8 boulders and bond stones at regular intervals.
It is further suggested adopt arch foundation in ordinary soil for effecting reduction in construction cost up to 40%.This kind of foundation will help in bridging the loose pockets of soil which occurs along the foundation.
In the case black cotton and other soft soils it is recommend to use under ream pile foundation which saves about 20 to 25% in cost over the conventional method of construction.
Plinth
It is suggested to adopt 1 ft. height above ground level for the plinth and may be constructed with a cement mortar of 1:6. The plinth slab of 4 to 6″ which is normally adopted can be avoided and in its place brick on edge can be used for reducing the cost. By adopting this procedure the cost of plinth foundation can be reduced by about 35 to 50%.It is necessary to take precaution of providing impervious blanket like concrete slabs or stone slabs all round the building for enabling to reduce erosion of soil and thereby avoiding exposure of foundation surface and crack formation.
Walling
Wall thickness of 6 to 9″ is recommended for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is suggested to use burnt bricks which are immersed in water for 24 hours and then shall be used for the walls
Rat - trap bond wall
It is a cavity wall construction with added advantage of thermal comfort and reduction in the quantity of bricks required for masonry work. By adopting this method of bonding of brick masonry compared to traditional English or Flemish bond masonry, it is possible to reduce in the material cost of bricks by 25% and about 10to 15% in the masonry cost. By adopting rat-trap bond method one can create aesthetically pleasing wall surface and plastering can be avoided.
Concrete block walling
In view of high energy consumption by burnt brick it is suggested to use concrete block (block hollow and solid) which consumes about only 1/3 of the energy of the burnt bricks in its production. By using concrete block masonry the wall thickness can be reduced from 20 cms to 15 Cms. Concrete block masonry saves mortar consumption, speedy construction of wall resulting in higher output of labour, plastering can be avoided thereby an overall saving of 10 to 25% can be achieved.
Soil cement block technology
It is an alternative method of construction of walls using soil cement blocks in place of burnt bricks masonry. It is an energy efficient method of construction where soil mixed with 5% and above cement and pressed in hand operated machine and cured well and then used in the masonry. This masonry doesn’t require plastering on both sides of the wall. The overall economy that could be achieved with the soil cement technology is about 15 to 20% compared to conventional method of construction.
Doors and windows
It is suggested not to use wood for doors and windows and in its place concrete or steel section frames shall be used for achieving saving in cost up to 30 to 40%.Similiarly for shutters commercially available block boards, fibre or wooden practical boards etc., shall be used for reducing the cost by about 25%.By adopting brick jelly work and precast components effective ventilation could be provided to the building and also the construction cost could be saved up to 50% over the window components.
Lintals and Chajjas
The traditional R.C.C. lintels which are costly can be replaced by brick arches for small spans and save construction cost up to 30 to 40% over the traditional method of construction. By adopting arches of different shapes a good architectural pleasing appearance can be given to the external wall surfaces of the brick masonry.
Roofing
Normally 5″(12.5 cms) thick R.C.C. slabs is used for roofing of residential buildings. By adopting rationally designed insitu construction practices like filler slab and precast elements the construction cost of roofing can be reduced by about 20 to 25%.
Filler slabs
They are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc.These filler materials are so placed as not to compromise structural strength, result in replacing unwanted and nonfunctional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster.
For more on filler materials check Filler Materials Used in Concrete
Jack arch roof/floor
They are easy to construct, save on cement and steel, are more appropriate in hot climates. These can be constructed using compressed earth blocks also as alternative to bricks for further economy.
Ferrocement channel/shell unit
Provide an economic solution to RCC slab by providing 30 to 40% cost reduction on floor/roof unit over RCC slabs without compromising the strength. These being precast, construction is speedy, economical due to avoidance of shuttering and facilitate quality control.
Finishing Work
The cost of finishing items like sanitary, electricity, painting etc., varies depending upon the type and quality of products used in the building and its cost reduction is left to the individual choice and liking.
Conclusion
The above list of suggestion for reducing construction cost is of general nature and it varies depending upon the nature of the building to be constructed, budget of the owner, geographical location where the house is to be constructed, availability of the building material, good construction management practices etc. However it is necessary that good planning and design methods shall be adopted by utilizing the services of an experienced engineer or an architect for supervising the work, thereby achieving overall cost effectiveness to the extent of 25% in actual practice.
Building Cost
The building construction cost can be divided into two parts namely:
Building material cost : 65 to 70 %
Labour cost : 65 to 70 %
Now in low cost housing, building material cost is less because we make use of the locally available materials and also the labour cost can be reduced by properly making the time schedule of our work. Cost of reduction is achieved by selection of more efficient material or by an improved design.
Areas from where cost can be reduced are:-
1) Reduce plinth area by using thinner wall concept.Ex.15 cms thick solid concrete block wall.
2) Use locally available material in an innovative form like soil cement blocks in place of burnt brick.
3) Use energy efficiency materials which consumes less energy like concrete block in place of burnt brick.
4) Use environmentally friendly materials which are substitute for conventional building components like use R.C.C. Door and window frames in place of wooden frames.
5) Preplan every component of a house and rationalize the design procedure for reducing the size of the component in the building.
6) By planning each and every component of a house the wastage of materials due to demolition of the unplanned component of the house can be avoided.
7) Each component of the house shall be checked whether if it’s necessary, if it is not necessary, then that component should not be used.
Cost reduction through adhoc methods
Foundation
Normally the foundation cost comes to about 10 to 15% of the total building and usually foundation depth of 3 to 4 ft. is adopted for single or double store building and also the concrete bed of 6″(15 Cms.) is used for the foundation which could be avoided.
It is recommended to adopt a foundation depth of 2 ft.(0.6m) for normal soil like gravely soil, red soils etc., and use the uncoursed rubble masonry with the bond stones and good packing. Similarly the foundation width is rationalized to 2 ft.(0.6m).To avoid cracks formation in foundation the masonry shall be thoroughly packed with cement mortar of 1:8 boulders and bond stones at regular intervals.
It is further suggested adopt arch foundation in ordinary soil for effecting reduction in construction cost up to 40%.This kind of foundation will help in bridging the loose pockets of soil which occurs along the foundation.
In the case black cotton and other soft soils it is recommend to use under ream pile foundation which saves about 20 to 25% in cost over the conventional method of construction.
Plinth
It is suggested to adopt 1 ft. height above ground level for the plinth and may be constructed with a cement mortar of 1:6. The plinth slab of 4 to 6″ which is normally adopted can be avoided and in its place brick on edge can be used for reducing the cost. By adopting this procedure the cost of plinth foundation can be reduced by about 35 to 50%.It is necessary to take precaution of providing impervious blanket like concrete slabs or stone slabs all round the building for enabling to reduce erosion of soil and thereby avoiding exposure of foundation surface and crack formation.
Walling
Wall thickness of 6 to 9″ is recommended for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is suggested to use burnt bricks which are immersed in water for 24 hours and then shall be used for the walls
Rat - trap bond wall
It is a cavity wall construction with added advantage of thermal comfort and reduction in the quantity of bricks required for masonry work. By adopting this method of bonding of brick masonry compared to traditional English or Flemish bond masonry, it is possible to reduce in the material cost of bricks by 25% and about 10to 15% in the masonry cost. By adopting rat-trap bond method one can create aesthetically pleasing wall surface and plastering can be avoided.
Concrete block walling
In view of high energy consumption by burnt brick it is suggested to use concrete block (block hollow and solid) which consumes about only 1/3 of the energy of the burnt bricks in its production. By using concrete block masonry the wall thickness can be reduced from 20 cms to 15 Cms. Concrete block masonry saves mortar consumption, speedy construction of wall resulting in higher output of labour, plastering can be avoided thereby an overall saving of 10 to 25% can be achieved.
Soil cement block technology
It is an alternative method of construction of walls using soil cement blocks in place of burnt bricks masonry. It is an energy efficient method of construction where soil mixed with 5% and above cement and pressed in hand operated machine and cured well and then used in the masonry. This masonry doesn’t require plastering on both sides of the wall. The overall economy that could be achieved with the soil cement technology is about 15 to 20% compared to conventional method of construction.
Doors and windows
It is suggested not to use wood for doors and windows and in its place concrete or steel section frames shall be used for achieving saving in cost up to 30 to 40%.Similiarly for shutters commercially available block boards, fibre or wooden practical boards etc., shall be used for reducing the cost by about 25%.By adopting brick jelly work and precast components effective ventilation could be provided to the building and also the construction cost could be saved up to 50% over the window components.
Lintals and Chajjas
The traditional R.C.C. lintels which are costly can be replaced by brick arches for small spans and save construction cost up to 30 to 40% over the traditional method of construction. By adopting arches of different shapes a good architectural pleasing appearance can be given to the external wall surfaces of the brick masonry.
Roofing
Normally 5″(12.5 cms) thick R.C.C. slabs is used for roofing of residential buildings. By adopting rationally designed insitu construction practices like filler slab and precast elements the construction cost of roofing can be reduced by about 20 to 25%.
Filler slabs
They are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc.These filler materials are so placed as not to compromise structural strength, result in replacing unwanted and nonfunctional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster.
For more on filler materials check Filler Materials Used in Concrete
Jack arch roof/floor
They are easy to construct, save on cement and steel, are more appropriate in hot climates. These can be constructed using compressed earth blocks also as alternative to bricks for further economy.
Ferrocement channel/shell unit
Provide an economic solution to RCC slab by providing 30 to 40% cost reduction on floor/roof unit over RCC slabs without compromising the strength. These being precast, construction is speedy, economical due to avoidance of shuttering and facilitate quality control.
Finishing Work
The cost of finishing items like sanitary, electricity, painting etc., varies depending upon the type and quality of products used in the building and its cost reduction is left to the individual choice and liking.
Conclusion
The above list of suggestion for reducing construction cost is of general nature and it varies depending upon the nature of the building to be constructed, budget of the owner, geographical location where the house is to be constructed, availability of the building material, good construction management practices etc. However it is necessary that good planning and design methods shall be adopted by utilizing the services of an experienced engineer or an architect for supervising the work, thereby achieving overall cost effectiveness to the extent of 25% in actual practice.
ABOUT CIVIL ENGINEERING
Engineering is a term applied to the profession in which a knowledge of the mathematical and natural sciences, gained by study, experience, and practice, is applied to the efficient use of the materials and forces of nature. Engineers are the ones who have received professional training in pure and applied science.Before the middle of the 18th century, large-scale construction work was usually placed in the hands of military engineers. Military engineering involved such work as the preparation of topographical maps, the location, design, and construction of roads and bridges; and the building of forts and docks; see Military Engineering below. In the 18th century, however, the term civil engineering came into use to describe engineering work that was performed by civilians for nonmilitary purposes.
Civil engineering is the broadest of the engineering fields. Civil engineering focuses on the infrastructure of the world which include Water works, Sewers, Dams, Power Plants, Transmission Towers/Lines, Railroads, Highways, Bridges, Tunnels, Irrigation Canals, River Navigation, Shipping Canals, Traffic Control, Mass Transit, Airport Runways, Terminals, Industrial Plant Buildings, Skyscrapers, etc. Among the important subdivisions of the field are construction engineering, irrigation engineering, transportation engineering, soils and foundation engineering, geodetic engineering, hydraulic engineering, and coastal and ocean engineering.
Civil engineers build the world’s infrastructure. In doing so, they quietly shape the history of nations around the world. Most people can not imagine life without the many contributions of civil engineers to the public’s health, safety and standard of living. Only by exploring civil engineering’s influence in shaping the world we know today, can we creatively envision the progress of our tomorrows.
Civil engineering is the broadest of the engineering fields. Civil engineering focuses on the infrastructure of the world which include Water works, Sewers, Dams, Power Plants, Transmission Towers/Lines, Railroads, Highways, Bridges, Tunnels, Irrigation Canals, River Navigation, Shipping Canals, Traffic Control, Mass Transit, Airport Runways, Terminals, Industrial Plant Buildings, Skyscrapers, etc. Among the important subdivisions of the field are construction engineering, irrigation engineering, transportation engineering, soils and foundation engineering, geodetic engineering, hydraulic engineering, and coastal and ocean engineering.
Civil engineers build the world’s infrastructure. In doing so, they quietly shape the history of nations around the world. Most people can not imagine life without the many contributions of civil engineers to the public’s health, safety and standard of living. Only by exploring civil engineering’s influence in shaping the world we know today, can we creatively envision the progress of our tomorrows.
Friday, July 3, 2009
Construction Equipment
DUMP TRUCK
Dump trucks or production trucks are those that are used for transporting loose material such as sand, dirt, and gravel for construction. The typical dump truck is equipped with a hydraulically operated open box bed hinged at the rear, with the front being able to be lifted up to allow the contents to fall out on the ground at the site of delivery.Dump trucks come in many different configurations with each one specified to accomplish a specific task in the construction chain.
Standard dump truck
The standard dump truck is a full truck chassis with the dump body mounted onto the frame. The dump body is raised by a hydraulic ram lift that is mounted forward of the front bulkhead, normally between the truck cab and the dump body. The standard dump truck also has one front axle, and one or more rear axles which normally has dual wheels on each side. The common configurations for standard dump trucks include the six wheeler and ten wheeler.
Transfer dump truck
For the amount of noise made when transferring, the transfer dump truck is easy to recognize. It’s a standard dump truck that pulls a separate trailer which can be loaded with sand, asphalt, gravel, dirt, etc. The B box or aggregate container on the trailer is
powered by an electric motor and rides on wheels and rolls off of the trailer and into the main dump box. The biggest advantage with this configuration is to maximize payload capacity without having to sacrifice the maneuverability of the short and nimble dump truck standards.
Semi trailer end dump truck
The semi end dump truck is a tractor trailer combination where the trailer itself contains the hydraulic hoist. The average semi end dump truck has a 3 axle tractor that pulls a 2 axle semi trailer. The advantage to having a semi end dump truck is rapid unloading.
Semi trailer bottom dump truck
A bottom dump truck is a 3 axle tractor that pulls a 2 axle trailer with a clam shell type dump gate in the belly of the trailer. The biggest advantage of a semi bottom dump truck is the ability to lay material in a wind row. This type of truck is also maneuverable in reverse as well, unlike the double and triple trailer configurations.
Double and triple trailer
The double and triple bottom dump trucks consist of a 2 axle tractor pulling a semi axle semi trailer and an additional trailer. These types of dump trucks allow the driver to lay material in wind rows without having to leave the cab or stop the truck. The biggest disadvantage is the difficulty in going in reverse.
Side dump trucks
Side dump trucks consist of a 3 axle trailer pulling a 2 axle semi trailer. It offers hydraulic rams that tilt the dump body onto the side, which spills the material to the left or right side of the trailer. The biggest advantages with these types of dump trucks are that they allow rapid unloading and carry more weight than other dump trucks.
In addition to this, side dump trucks are almost impossible to tip over while dumping, unlike the semi end dump trucks which are very prone to being upset or tipped over. The length of these trucks impede maneuverability and limit versatility.
Off road dump trucks
Off road trucks resemble heavy construction equipment more than they do highway dump trucks. They are used strictly for off road mining and heavy dirt hauling jobs, such as excavation work. They are very big in size, and perfect for those time when you need to dig out roads and need something to haul the massive amounts of dirt to another location.
FRONT LOADER
Also known as a front end loader, bucket loader, scoop loader, or shovel, the front loader is a type of tractor that is normally wheeled and uses a wide square tilting bucket on the end of movable arms to lift and move material around.The loader assembly may be a removable attachment or permanently mounted on the vehicle. Often times, the bucket can be replaced with other devices or tools, such as forks or a hydraulically operated bucket.
Larger style front loaders, such as the Caterpillar 950G or the Volvo L120E, normally have only a front bucket and are known as front loaders, where the small front loaders are often times equipped with a small backhoe as well and called backhoe loaders or loader backhoes.Loaders are primarily used for loading materials into trucks, laying pipe, clearing rubble, and also digging. Loaders aren’t the most efficient machines for digging, as they can’t dig very deep below the level of their wheels, like the backhoe can.
The deep bucket on the front loader can normally store around 3 - 6 cubic meters of dirt, as the bucket capacity of the loader is much bigger than the bucket capacity of a backhoe loader. Loaders aren’t classified as excavating machinery, as their primary purpose is other than moving dirt.In construction areas, mainly when fixing roads in the middle of the city, front loaders are used to transport building materials such as pipe, bricks, metal bars, and digging tools. Front loaders are also very useful for snow removal as well, as you can use their bucket or as a snow plow. They can clear snow from the streets and highways, even parking lots.They will sometimes load the snow into dump trucks which will then haul it away.
Unlike the bulldozer, most loaders are wheeled and not tracked. The wheels will provide better mobility and speed and won’t damage paved roads near as much as tracks, although this will come at the cost of reduced traction. Unlike backhoes or tractors fitted with a steel bucket, large loaders don’t use automotive steering mechanisms, as they instead steer by a hydraulically actuated pivot point set exactly between the front and rear axles.This is known as articulated steering and will allow the front axle to be solid, therefore allowing it to carry a heavier weight.
Articulated steering will also give a reduced turn in radius for a given wheelbase. With the
front wheels and attachment rotating on the same axis, the operator is able to steer his load in an arc after positioning the machine, which can come in quite handy. The problem is that when the machine is twisted to one side and a heavy load is lifted high in the air, it has a bigger risk of turning over.
FORKLIFT
Sometimes called a forklift truck, the forklift is a powerful industrial truck that is used to lift and transport material by steel forks that are inserted under the load. Forklifts are commonly used to move loads and equipment that is stored on pallets. The forklift was developed in 1920, and has since become a valuable piece of equipment in many manufacturing and warehousing operations.
Types of Forklifts
The most common type of design with forklifts is the counter balance. Other types of designs include the reach truck and side loader, both of which are used in environments where the space is at a minimum.
Control and capability
Forklifts are available in many types and different load capacities. In the average warehouse setting,most forklifts have load capacities of around five tons. Along with the control to raise and lower the forks, you can also tilt the mast to compensate for the tendency of the load to angle the blades towards the ground and risk slipping it off the forks. The tilt will also provide a limited ability to operate on ground that isn’t level.There are some variations that allow you to move the forks and backrest laterally, which allows easier placement of a load. In addition to this, there are some machines that offer hydraulic control to move the forks together or further apart, which removes the need for you to get out of the cab to manually adjust for a different size load.
Another forklift variation that is sometimes used in manufacturing facilities, will utilize forklifts with a clamp attachment that you can open and close around a load, instead of having to use forks. Products such as boxes, cartons, etc., can be moved with the clamp attachment.
Safety
Forklifts are rated for loads at a specified maximum weight and a specified forward type center of gravity. All of this information is located on a nameplate that is provided by the manufacturer and the loads cannot exceed these specifications. One of the most important aspects of operating a forklift is the rear wheel steering. Even though this helps to increase maneuverability in tight cornering situations, it differs from the traditional experience of a driver with other wheeled vehicles as there is no caster action. Another critical aspect of the forklift is the instability. Both the forklift and the load must be considered a unit, with a varying center of gravity with every movement of the load.You must never negotiate a turn with a forklift at full speed with a raised load, as this can easily tip the forklift over.
VARIOUS TYPES OF CRANES:
A crane is a tower or derrick that is equipped with cables and pulleys that are used to lift and lower material. They are commonly used in the construction industry and in the manufacturing of heavy equipment. Cranes for construction are normally temporary
structures, either fixed to the ground or mounted on a purpose built vehicle.
They can either be controlled from an operator in a cab that travels along with the crane, by a push button pendant control station, or by radio type controls. The crane operator is ultimately responsible for the safety of the crews and the crane.
Mobile Cranes
The most basic type of crane consists of a steel truss or telescopic boom mounted on a mobile platform, which could be a rail, wheeled, or even on a cat truck. The boom is hinged at the bottom and can be either raised or lowered by cables or hydraulic cylinders.
Telescopic Crane
This type of crane offers a boom that consists of a number of tubes fitted one inside of the other. A hydraulic mechanism extends or retracts the tubes to increase or decrease the length of the boom.
Tower Crane
The tower crane is a modern form of a balance crane. When fixed to the ground, tower cranes will often give the best combination of height and lifting capacity and are also used when constructing tall buildings.
Truck Mounted Crane
Cranes mounted on a rubber tire truck will provide great mobility. Outriggers that extend vertically or horizontally are used to level and stabilize the crane during hoisting.
Rough Terrain Crane
A crane that is mounted on an undercarriage with four rubber tires, designed for operations off road. The outriggers extend vertically and horizontally to level and stabilize the crane when hoisting. These types of cranes are single engine machines where the same engine is used for powering the undercarriage as it is for powering the crane. In these types of cranes, the engine is normally mounted in the undercarriage rather than
in the upper portion.
Loader Crane
A loader crane is a hydraulically powered articulated arm fitted to a trailer, used to load equipment onto a trailer. The numerous sections can be folded into a small space when the crane isn’t in use.
Overhead Crane
Also refered to as a suspended crane, this type is normally used in a factory, with some of them being able to lift very heavy loads. The hoist is set on a trolley which will move in one direction along one or two beams, which move at angles to that direction along elevated or ground level tracks, often mounted along the side of an assembly area.
In the excavation world, cranes are used to move equipment or machinery. Cranes can quickly and easily move machinery into trenches or down steep hills, or even pipe. There are many types of cranes available, serving everything from excavation to road work.
Cranes are also beneficial to building bridges or construction. For many years, cranes have proven to be an asset to the industry of construction and excavating. Crane operators make really good money, no matter what type of crane they are operating.
COMPACT EXCAVATOR:
The compact hydraulic excavator can be a tracked or wheeled vehicle with an approximate operating weight of 13,300 pounds.Normally, it includes a standard backfill blade and features an independent boom swing. The compact hydraulic excavator is also known as a mini excavator.
A compact hydraulic excavator is different from other types of heavy machinery in the sense that all movement and functions of the machine are accomplished through the transfer of hydraulic fluid.The work group and blade are activated by hydraulic fluid acting upon hydraulic cylinders.The rotation and travel functions are also activated by hydraulic fluid powering hydraulic motors.
Most types of compact hydraulic excavators have three assemblies - house, undercarriage, and the work group
House
The house structure contains the compartment for the operator, engine compartment, hydraulic pump and also the distribution components. The house structure is attached to the top of the undercarriage via swing bearing. Along with the work group, them house is able to rotate upon the undercarriage without limit due to a hydraulic distribution valve that supplies oil to the undercarriage components.
Undercarriage
The undercarriage of compact excavators consists of rubber or steel tracks, drive sprockets, rollers,idlers, and associated components and structures.The undercarriage is also home to the house structure and the work group.
Work group
The work group consists of the boom, dipper or arm, and attachment. It is connected to the front of the house structure via a swinging frame that allows the work group to be hydraulically pivoted left or right in order to achieve offset digging for trenching parallel with the tracks.
Independent boom swing
The purpose of the boom swing is for offset digging around obstacles or along foundations,
walls, and forms. Another use is for cycling in areas that are too narrow for cab rotation. Another major advantage of the compact excavator is the independent boom swing.
Backfill blade
The backfill blade on compact excavators are used for grading, leveling, backfilling, trenching, and general dozer work. The blade can also be used to increase the dumping height and digging depth depending on it’s position in relation to the workgroup.
The most common place you’ll find compact excavators is in residential dwellings. When digging phone lines or other things, these pieces of equipment are very common for getting between houses. Due to their small size, they can fit almost anywhere.Over the years, the capabilities for compact excavators have expanded far beyond the tasks of excavation. With hydraulic powered attachments such as breakers, clamps, compactors and augers, the compact excavator is used with many other applications and serves as an effective attachment tool as well. Serving many purposes, the compact excavator is a great addition to any job that requires the use of machinery.
BULLDOZER:
The bulldozer is a very powerful crawler that is equipped with a blade. The term bulldozer is often used to mean any type of heavy machinery, although the term actually refers to a tractor that is fitted with a dozer blade. Often times, bulldozers are large and extremely powerful tracked vehicles. The tracks give them amazing ground mobility and hold through very rough terrain. Wide tracks on the other hand, help to distribute the weight of the dozer over large areas, therefore preventing it from sinking into sandy or muddy ground.
Bulldozers have great ground hold and a torque divider that’s designed to convert the power of the engine into dragging ability, which allows it to use its own weight to push heavy objects and even remove things from the ground. Take the Caterpillar D9 for example, it can easily tow tanks that weight more than 70 tons. Due to these attributes,bulldozers are used to clear obstacles, shrubbery and remains of structures and buildings.
The blade on a bulldozer is the heavy piece of metal plate that is installed on the front. The
blade pushes things around. Normally, the blade comes in 3 varieties:
1. A straight blade that is short and has no lateral curve, no side wings, and can be used
only for fine grading.
2. A universal blade, or U blade, which is tall and very curved, and features large side wings to carry more material around.
3. A combination blade that is shorter,offers less curvature, and smaller side wings.
Modifications
Over time, bulldozers have been modified to evolve into new machines that are capable of things the original bulldozers weren’t. A good example is that loader tractors were created by removing the blade and substituting a large volume bucket and hydraulic arms which will raise and lower the bucket, therefore making it useful for scooping up the earth and loading it into trucks.Other modifications to the original bulldozer include making it smaller to where it can operate in small working areas where movement is very limited, such as mining caves and tunnels. Very small bulldozers are known as calfdozers.
History
The first types of bulldozers were adapted from farm tractors that were used to plough fields. In order to dig canals, raise earth dams, and partake in earthmoving jobs, the tractors were equipped with a thick metal plate in the front. Later on, this thick metal plate earned the name blade.
The blade of the bulldozer peels layers of soil and pushes it forward as the tractor advances.The blade is the heart and soul of the bulldozer, as it was the first accessory to make full use for excavation type jobs. As the years went by, when engineers needed equipment to complete larger jobs, companies such as CAT, Komatsu, John Deere, Case, and JCB started to manufacture large tracked earthmoving equipment.They were very loud, very large, and very powerful and therefore earned the nickname “bulldozer”.Over the years, the bulldozers got bigger, more powerful, and even more sophisticated. The important improvements include better engines,more reliable drive trains, better tracks, and even hydraulic arms that will enable more precise manipulation of the blade and automated controls.As an added option, bulldozers can come equipped with a rear ripping claw to break up pavement or loosen rocky soil.The best known manufacturer of bulldozer is CAT,which has earned a vast reputation for making
tough and durable, yet reliable machines.Even though the bulldozer started off a modified farmtractor, it rapidly became one of the most useful pieces of equipment with excavating and construction.
BACKHOE LOADER
Also referred to as a loader backhoe, the backhoe loader is an engineering and excavation vehicle that consists of a tractor, front shovel and bucket and a small backhoe in the rear end. Due to the small size and versatility, backhoe loaders are common with small construction projects and excavation type work.Originally invented in Burlington Iowa back in 1857, the backhoe loader is the most common variation of the classic farm tractor.As the name implies, it has a loader assembly on the front and a backhoe attachment on the back.
Anytime the loader and backhoe are attached it is never referred to as a tractor, as it is not normally used for towing and doesn’t normally have a PTO.When the backhoe is permanently attached, the machine will normally have a seat that can swivel to the rear to face the backhoe controls.Any type of removable backhoe attachments will normally have a seperate seat on the attachment itself.Backhoe loaders are common and can be used for many tasks, which include construction, light transportation of materials, powering building equipment, digging holes and excavating, breaking asphalt, and even paving roads.You can often replace the backhoe bucket with other tools such as a breaker for breaking and smashing concrete and rock. There are some loader buckets that offer a retractable bottom, which enable it to empty the load more quickly and efficiently.
The retractable bottom loader buckets are often times used for grading and scratching off sand.The front assembly on a backhoe may be either removable or permanently attached. Often times,the bucket can be replaced with other tools or devices. In order to mount different attachments to the loader, it must be equipped with a tool coupler. The coupler consists of two hydraulic cylinders on the end of the arm assembly, which can expand and retract to allow different tools to be attached to the unit. There are several types of backhoe loader brands,including New Holland, John Deere, and Case. Some will offer you cabs, while others won’t. The newer types of backhoe loaders even offer you air conditioning, radios, and other accessories that make you feel like you are working with luxury.Common with excavating jobs, the backhoe can serve many purposes. It can haul equipment and supplies in the loader bucket.Another great use is to cover up dirt when filling in trench lines or covering up pipe that was just put in the ground.The backhoe attachment at the rear is ideal for digging water pipes and sewer pipes.The best thing about the backhoe loader is the fact that they are easy to operate. You don’t need to be a rocket scientist to fully operate this nifty piece of equipment.
Dump trucks or production trucks are those that are used for transporting loose material such as sand, dirt, and gravel for construction. The typical dump truck is equipped with a hydraulically operated open box bed hinged at the rear, with the front being able to be lifted up to allow the contents to fall out on the ground at the site of delivery.Dump trucks come in many different configurations with each one specified to accomplish a specific task in the construction chain.
Standard dump truck
The standard dump truck is a full truck chassis with the dump body mounted onto the frame. The dump body is raised by a hydraulic ram lift that is mounted forward of the front bulkhead, normally between the truck cab and the dump body. The standard dump truck also has one front axle, and one or more rear axles which normally has dual wheels on each side. The common configurations for standard dump trucks include the six wheeler and ten wheeler.
Transfer dump truck
For the amount of noise made when transferring, the transfer dump truck is easy to recognize. It’s a standard dump truck that pulls a separate trailer which can be loaded with sand, asphalt, gravel, dirt, etc. The B box or aggregate container on the trailer is
powered by an electric motor and rides on wheels and rolls off of the trailer and into the main dump box. The biggest advantage with this configuration is to maximize payload capacity without having to sacrifice the maneuverability of the short and nimble dump truck standards.
Semi trailer end dump truck
The semi end dump truck is a tractor trailer combination where the trailer itself contains the hydraulic hoist. The average semi end dump truck has a 3 axle tractor that pulls a 2 axle semi trailer. The advantage to having a semi end dump truck is rapid unloading.
Semi trailer bottom dump truck
A bottom dump truck is a 3 axle tractor that pulls a 2 axle trailer with a clam shell type dump gate in the belly of the trailer. The biggest advantage of a semi bottom dump truck is the ability to lay material in a wind row. This type of truck is also maneuverable in reverse as well, unlike the double and triple trailer configurations.
Double and triple trailer
The double and triple bottom dump trucks consist of a 2 axle tractor pulling a semi axle semi trailer and an additional trailer. These types of dump trucks allow the driver to lay material in wind rows without having to leave the cab or stop the truck. The biggest disadvantage is the difficulty in going in reverse.
Side dump trucks
Side dump trucks consist of a 3 axle trailer pulling a 2 axle semi trailer. It offers hydraulic rams that tilt the dump body onto the side, which spills the material to the left or right side of the trailer. The biggest advantages with these types of dump trucks are that they allow rapid unloading and carry more weight than other dump trucks.
In addition to this, side dump trucks are almost impossible to tip over while dumping, unlike the semi end dump trucks which are very prone to being upset or tipped over. The length of these trucks impede maneuverability and limit versatility.
Off road dump trucks
Off road trucks resemble heavy construction equipment more than they do highway dump trucks. They are used strictly for off road mining and heavy dirt hauling jobs, such as excavation work. They are very big in size, and perfect for those time when you need to dig out roads and need something to haul the massive amounts of dirt to another location.
FRONT LOADER
Also known as a front end loader, bucket loader, scoop loader, or shovel, the front loader is a type of tractor that is normally wheeled and uses a wide square tilting bucket on the end of movable arms to lift and move material around.The loader assembly may be a removable attachment or permanently mounted on the vehicle. Often times, the bucket can be replaced with other devices or tools, such as forks or a hydraulically operated bucket.
Larger style front loaders, such as the Caterpillar 950G or the Volvo L120E, normally have only a front bucket and are known as front loaders, where the small front loaders are often times equipped with a small backhoe as well and called backhoe loaders or loader backhoes.Loaders are primarily used for loading materials into trucks, laying pipe, clearing rubble, and also digging. Loaders aren’t the most efficient machines for digging, as they can’t dig very deep below the level of their wheels, like the backhoe can.
The deep bucket on the front loader can normally store around 3 - 6 cubic meters of dirt, as the bucket capacity of the loader is much bigger than the bucket capacity of a backhoe loader. Loaders aren’t classified as excavating machinery, as their primary purpose is other than moving dirt.In construction areas, mainly when fixing roads in the middle of the city, front loaders are used to transport building materials such as pipe, bricks, metal bars, and digging tools. Front loaders are also very useful for snow removal as well, as you can use their bucket or as a snow plow. They can clear snow from the streets and highways, even parking lots.They will sometimes load the snow into dump trucks which will then haul it away.
Unlike the bulldozer, most loaders are wheeled and not tracked. The wheels will provide better mobility and speed and won’t damage paved roads near as much as tracks, although this will come at the cost of reduced traction. Unlike backhoes or tractors fitted with a steel bucket, large loaders don’t use automotive steering mechanisms, as they instead steer by a hydraulically actuated pivot point set exactly between the front and rear axles.This is known as articulated steering and will allow the front axle to be solid, therefore allowing it to carry a heavier weight.
Articulated steering will also give a reduced turn in radius for a given wheelbase. With the
front wheels and attachment rotating on the same axis, the operator is able to steer his load in an arc after positioning the machine, which can come in quite handy. The problem is that when the machine is twisted to one side and a heavy load is lifted high in the air, it has a bigger risk of turning over.
FORKLIFT
Sometimes called a forklift truck, the forklift is a powerful industrial truck that is used to lift and transport material by steel forks that are inserted under the load. Forklifts are commonly used to move loads and equipment that is stored on pallets. The forklift was developed in 1920, and has since become a valuable piece of equipment in many manufacturing and warehousing operations.
Types of Forklifts
The most common type of design with forklifts is the counter balance. Other types of designs include the reach truck and side loader, both of which are used in environments where the space is at a minimum.
Control and capability
Forklifts are available in many types and different load capacities. In the average warehouse setting,most forklifts have load capacities of around five tons. Along with the control to raise and lower the forks, you can also tilt the mast to compensate for the tendency of the load to angle the blades towards the ground and risk slipping it off the forks. The tilt will also provide a limited ability to operate on ground that isn’t level.There are some variations that allow you to move the forks and backrest laterally, which allows easier placement of a load. In addition to this, there are some machines that offer hydraulic control to move the forks together or further apart, which removes the need for you to get out of the cab to manually adjust for a different size load.
Another forklift variation that is sometimes used in manufacturing facilities, will utilize forklifts with a clamp attachment that you can open and close around a load, instead of having to use forks. Products such as boxes, cartons, etc., can be moved with the clamp attachment.
Safety
Forklifts are rated for loads at a specified maximum weight and a specified forward type center of gravity. All of this information is located on a nameplate that is provided by the manufacturer and the loads cannot exceed these specifications. One of the most important aspects of operating a forklift is the rear wheel steering. Even though this helps to increase maneuverability in tight cornering situations, it differs from the traditional experience of a driver with other wheeled vehicles as there is no caster action. Another critical aspect of the forklift is the instability. Both the forklift and the load must be considered a unit, with a varying center of gravity with every movement of the load.You must never negotiate a turn with a forklift at full speed with a raised load, as this can easily tip the forklift over.
VARIOUS TYPES OF CRANES:
A crane is a tower or derrick that is equipped with cables and pulleys that are used to lift and lower material. They are commonly used in the construction industry and in the manufacturing of heavy equipment. Cranes for construction are normally temporary
structures, either fixed to the ground or mounted on a purpose built vehicle.
They can either be controlled from an operator in a cab that travels along with the crane, by a push button pendant control station, or by radio type controls. The crane operator is ultimately responsible for the safety of the crews and the crane.
Mobile Cranes
The most basic type of crane consists of a steel truss or telescopic boom mounted on a mobile platform, which could be a rail, wheeled, or even on a cat truck. The boom is hinged at the bottom and can be either raised or lowered by cables or hydraulic cylinders.
Telescopic Crane
This type of crane offers a boom that consists of a number of tubes fitted one inside of the other. A hydraulic mechanism extends or retracts the tubes to increase or decrease the length of the boom.
Tower Crane
The tower crane is a modern form of a balance crane. When fixed to the ground, tower cranes will often give the best combination of height and lifting capacity and are also used when constructing tall buildings.
Truck Mounted Crane
Cranes mounted on a rubber tire truck will provide great mobility. Outriggers that extend vertically or horizontally are used to level and stabilize the crane during hoisting.
Rough Terrain Crane
A crane that is mounted on an undercarriage with four rubber tires, designed for operations off road. The outriggers extend vertically and horizontally to level and stabilize the crane when hoisting. These types of cranes are single engine machines where the same engine is used for powering the undercarriage as it is for powering the crane. In these types of cranes, the engine is normally mounted in the undercarriage rather than
in the upper portion.
Loader Crane
A loader crane is a hydraulically powered articulated arm fitted to a trailer, used to load equipment onto a trailer. The numerous sections can be folded into a small space when the crane isn’t in use.
Overhead Crane
Also refered to as a suspended crane, this type is normally used in a factory, with some of them being able to lift very heavy loads. The hoist is set on a trolley which will move in one direction along one or two beams, which move at angles to that direction along elevated or ground level tracks, often mounted along the side of an assembly area.
In the excavation world, cranes are used to move equipment or machinery. Cranes can quickly and easily move machinery into trenches or down steep hills, or even pipe. There are many types of cranes available, serving everything from excavation to road work.
Cranes are also beneficial to building bridges or construction. For many years, cranes have proven to be an asset to the industry of construction and excavating. Crane operators make really good money, no matter what type of crane they are operating.
COMPACT EXCAVATOR:
The compact hydraulic excavator can be a tracked or wheeled vehicle with an approximate operating weight of 13,300 pounds.Normally, it includes a standard backfill blade and features an independent boom swing. The compact hydraulic excavator is also known as a mini excavator.
A compact hydraulic excavator is different from other types of heavy machinery in the sense that all movement and functions of the machine are accomplished through the transfer of hydraulic fluid.The work group and blade are activated by hydraulic fluid acting upon hydraulic cylinders.The rotation and travel functions are also activated by hydraulic fluid powering hydraulic motors.
Most types of compact hydraulic excavators have three assemblies - house, undercarriage, and the work group
House
The house structure contains the compartment for the operator, engine compartment, hydraulic pump and also the distribution components. The house structure is attached to the top of the undercarriage via swing bearing. Along with the work group, them house is able to rotate upon the undercarriage without limit due to a hydraulic distribution valve that supplies oil to the undercarriage components.
Undercarriage
The undercarriage of compact excavators consists of rubber or steel tracks, drive sprockets, rollers,idlers, and associated components and structures.The undercarriage is also home to the house structure and the work group.
Work group
The work group consists of the boom, dipper or arm, and attachment. It is connected to the front of the house structure via a swinging frame that allows the work group to be hydraulically pivoted left or right in order to achieve offset digging for trenching parallel with the tracks.
Independent boom swing
The purpose of the boom swing is for offset digging around obstacles or along foundations,
walls, and forms. Another use is for cycling in areas that are too narrow for cab rotation. Another major advantage of the compact excavator is the independent boom swing.
Backfill blade
The backfill blade on compact excavators are used for grading, leveling, backfilling, trenching, and general dozer work. The blade can also be used to increase the dumping height and digging depth depending on it’s position in relation to the workgroup.
The most common place you’ll find compact excavators is in residential dwellings. When digging phone lines or other things, these pieces of equipment are very common for getting between houses. Due to their small size, they can fit almost anywhere.Over the years, the capabilities for compact excavators have expanded far beyond the tasks of excavation. With hydraulic powered attachments such as breakers, clamps, compactors and augers, the compact excavator is used with many other applications and serves as an effective attachment tool as well. Serving many purposes, the compact excavator is a great addition to any job that requires the use of machinery.
BULLDOZER:
The bulldozer is a very powerful crawler that is equipped with a blade. The term bulldozer is often used to mean any type of heavy machinery, although the term actually refers to a tractor that is fitted with a dozer blade. Often times, bulldozers are large and extremely powerful tracked vehicles. The tracks give them amazing ground mobility and hold through very rough terrain. Wide tracks on the other hand, help to distribute the weight of the dozer over large areas, therefore preventing it from sinking into sandy or muddy ground.
Bulldozers have great ground hold and a torque divider that’s designed to convert the power of the engine into dragging ability, which allows it to use its own weight to push heavy objects and even remove things from the ground. Take the Caterpillar D9 for example, it can easily tow tanks that weight more than 70 tons. Due to these attributes,bulldozers are used to clear obstacles, shrubbery and remains of structures and buildings.
The blade on a bulldozer is the heavy piece of metal plate that is installed on the front. The
blade pushes things around. Normally, the blade comes in 3 varieties:
1. A straight blade that is short and has no lateral curve, no side wings, and can be used
only for fine grading.
2. A universal blade, or U blade, which is tall and very curved, and features large side wings to carry more material around.
3. A combination blade that is shorter,offers less curvature, and smaller side wings.
Modifications
Over time, bulldozers have been modified to evolve into new machines that are capable of things the original bulldozers weren’t. A good example is that loader tractors were created by removing the blade and substituting a large volume bucket and hydraulic arms which will raise and lower the bucket, therefore making it useful for scooping up the earth and loading it into trucks.Other modifications to the original bulldozer include making it smaller to where it can operate in small working areas where movement is very limited, such as mining caves and tunnels. Very small bulldozers are known as calfdozers.
History
The first types of bulldozers were adapted from farm tractors that were used to plough fields. In order to dig canals, raise earth dams, and partake in earthmoving jobs, the tractors were equipped with a thick metal plate in the front. Later on, this thick metal plate earned the name blade.
The blade of the bulldozer peels layers of soil and pushes it forward as the tractor advances.The blade is the heart and soul of the bulldozer, as it was the first accessory to make full use for excavation type jobs. As the years went by, when engineers needed equipment to complete larger jobs, companies such as CAT, Komatsu, John Deere, Case, and JCB started to manufacture large tracked earthmoving equipment.They were very loud, very large, and very powerful and therefore earned the nickname “bulldozer”.Over the years, the bulldozers got bigger, more powerful, and even more sophisticated. The important improvements include better engines,more reliable drive trains, better tracks, and even hydraulic arms that will enable more precise manipulation of the blade and automated controls.As an added option, bulldozers can come equipped with a rear ripping claw to break up pavement or loosen rocky soil.The best known manufacturer of bulldozer is CAT,which has earned a vast reputation for making
tough and durable, yet reliable machines.Even though the bulldozer started off a modified farmtractor, it rapidly became one of the most useful pieces of equipment with excavating and construction.
BACKHOE LOADER
Also referred to as a loader backhoe, the backhoe loader is an engineering and excavation vehicle that consists of a tractor, front shovel and bucket and a small backhoe in the rear end. Due to the small size and versatility, backhoe loaders are common with small construction projects and excavation type work.Originally invented in Burlington Iowa back in 1857, the backhoe loader is the most common variation of the classic farm tractor.As the name implies, it has a loader assembly on the front and a backhoe attachment on the back.
Anytime the loader and backhoe are attached it is never referred to as a tractor, as it is not normally used for towing and doesn’t normally have a PTO.When the backhoe is permanently attached, the machine will normally have a seat that can swivel to the rear to face the backhoe controls.Any type of removable backhoe attachments will normally have a seperate seat on the attachment itself.Backhoe loaders are common and can be used for many tasks, which include construction, light transportation of materials, powering building equipment, digging holes and excavating, breaking asphalt, and even paving roads.You can often replace the backhoe bucket with other tools such as a breaker for breaking and smashing concrete and rock. There are some loader buckets that offer a retractable bottom, which enable it to empty the load more quickly and efficiently.
The retractable bottom loader buckets are often times used for grading and scratching off sand.The front assembly on a backhoe may be either removable or permanently attached. Often times,the bucket can be replaced with other tools or devices. In order to mount different attachments to the loader, it must be equipped with a tool coupler. The coupler consists of two hydraulic cylinders on the end of the arm assembly, which can expand and retract to allow different tools to be attached to the unit. There are several types of backhoe loader brands,including New Holland, John Deere, and Case. Some will offer you cabs, while others won’t. The newer types of backhoe loaders even offer you air conditioning, radios, and other accessories that make you feel like you are working with luxury.Common with excavating jobs, the backhoe can serve many purposes. It can haul equipment and supplies in the loader bucket.Another great use is to cover up dirt when filling in trench lines or covering up pipe that was just put in the ground.The backhoe attachment at the rear is ideal for digging water pipes and sewer pipes.The best thing about the backhoe loader is the fact that they are easy to operate. You don’t need to be a rocket scientist to fully operate this nifty piece of equipment.
Monday, June 22, 2009
CIRCULAR CURVES
Circular curves are the most common type of horizontal curve used to connect intersecting tangent (or straight) sections of highways or railroads. In most countries, two methods of defining circular curves are in use: the first, in general use in railroad work, defines the degree of curve as the central angle subtended by a chord of 100 ft (30.48 m) in length; the second, used in highway work, defines the degree of curve as the central angle subtended by an arc of 100 ft (30.48 m) in length.
The terms and symbols generally used in reference to circular curves are listed next and shown in Figs. 11.1 and 11.2.
PC = point of curvature, beginning of curve
PI = point of intersection of tangents
PT = point of tangency, end of curve
R = radius of curve, ft (m)
D = degree of curve (see previous text)
I = deflection angle between tangents at PI, also
central angle of curve
T = tangent distance, distance from PI to PC or PT,
ft (m)
L = length of curve from PC to PT measured on 100-ft
(30.48-m) chord for chord definition, on arc for
arc definition, ft (m)
C = length of long chord from PC to PT, ft (m)
E = external distance, distance from PI to midpoint
of curve, ft (m)
The longest Rivers of the World
River Nile:
The River Nile is in Africa. It originates in Burundi, south of the equator, and flows northward through northeastern Africa, eventually flowing through Egypt and finally draining into the Mediterranean Sea.
Continent Africa
Countries it flows through Egypt, Ethiopia, Sudan, Burundi
Length 6,695 kilometres (4,160 miles)
Number of tributaries 2
Source Burundi, central Africa
Mouth Egypt into the Mediterranean Sea
Where is the source of the Nile?
The Ruvyironza River of Burundi is regarded as the true and ultimate source of the Nile. The Ruvyironza is one of the upper branches of the Kagera River, which follows the Rwanda-Tanzania and Uganda-Tanzania borders into Lake Victoria.
The source of the Nile is sometimes considered to be Lake Victoria, but the lake itself has feeder rivers of considerable size like the Kagera River.
Interesting Facts about the Nile river:
• The Nile River is the longest river in the world.
• The Nile flows into the Mediterranean Sea.
• The largest source of the Nile is Lake Victoria.
• The Nile has a length of about 4,160 miles (6,695 kilometres).
• Its average discharge is 3.1 million litres (680,000 gallons) per second.
• The Nile basin is huge and includes parts of Tanzania, Burundi, Rwanda, Congo (Kinshasa), Kenya.
• The Nile receives its name from the Greek Neilos, which means a valley or river valley.
The River Amazon:
The Amazon river runs 4,000 miles from the Andes to the sea, and is longer than any river but the Nile. The Amazon River is therefor the second longest river in the world. It is also the largest in terms of the size of its watershed, the number of tributaries, and the volume of water discharged into the sea. The vast Amazon basin covers more than two and a half million square miles, more than any other rainforests. No bridge crosses the river along its entire length.
Continent South America
Countries it flows through Peru, Brazil, Venezuela, Ecuador, Bolivia
Length 6400 kilometres (4,000 miles)
Number of tributaries Over 200
Source Lago Villafro in the Andes Mountains, Peru
Mouth Brazil into the Atlantic Ocean (delta)
Amazon
Amaz(on)ing facts on the Worlds greatest river!
Amazon
This mightiest of rivers forms a network of water channels that permeates nearly half of South America.
The River Yangtze(Chang Jiang):
The River Yangtze, also called the Chang Jiang, is the longest river in China and Asia and the third longest in the world after the Amazon in South America and the Nile in Africa. It has its source high in the snow-capped mountains of western China.
The Yangze river has over 700 tributaries but the principal tributaries are the Hun, Yalong, Jialing, Min, Tuo Jiang, and Wu Jiang.
Continent Asia
Countries it flows through China
Length 6,240 kilometres (3,900 miles)
Number of tributaries Over 700
Source Kulun mountains
Mouth Yellow Sea at the port of Shanghai
The Mississippi River :
The Mississippi River is the second longest river in the United States, with a length of 2,320 mi (3,734 km) from its source in Lake Itasca in Minnesota to its mouth in Gulf of Mexico. The longest is its tributary the Missouri River measuring 2,341 mi (3,767 km).
Country USA
States it flows through Montana, North Dakota, South Dakota, Nebraska, Kansas, Illinois, Alabama, Louisiana, Missouri, Minnesota
Length 6020 kilometres
Number of tributaries 250
Source Lake Itasca in Minnesota
Mouth Louisiana into the Gulf of Mexic
The River Nile is in Africa. It originates in Burundi, south of the equator, and flows northward through northeastern Africa, eventually flowing through Egypt and finally draining into the Mediterranean Sea.
Continent Africa
Countries it flows through Egypt, Ethiopia, Sudan, Burundi
Length 6,695 kilometres (4,160 miles)
Number of tributaries 2
Source Burundi, central Africa
Mouth Egypt into the Mediterranean Sea
Where is the source of the Nile?
The Ruvyironza River of Burundi is regarded as the true and ultimate source of the Nile. The Ruvyironza is one of the upper branches of the Kagera River, which follows the Rwanda-Tanzania and Uganda-Tanzania borders into Lake Victoria.
The source of the Nile is sometimes considered to be Lake Victoria, but the lake itself has feeder rivers of considerable size like the Kagera River.
Interesting Facts about the Nile river:
• The Nile River is the longest river in the world.
• The Nile flows into the Mediterranean Sea.
• The largest source of the Nile is Lake Victoria.
• The Nile has a length of about 4,160 miles (6,695 kilometres).
• Its average discharge is 3.1 million litres (680,000 gallons) per second.
• The Nile basin is huge and includes parts of Tanzania, Burundi, Rwanda, Congo (Kinshasa), Kenya.
• The Nile receives its name from the Greek Neilos, which means a valley or river valley.
The River Amazon:
The Amazon river runs 4,000 miles from the Andes to the sea, and is longer than any river but the Nile. The Amazon River is therefor the second longest river in the world. It is also the largest in terms of the size of its watershed, the number of tributaries, and the volume of water discharged into the sea. The vast Amazon basin covers more than two and a half million square miles, more than any other rainforests. No bridge crosses the river along its entire length.
Continent South America
Countries it flows through Peru, Brazil, Venezuela, Ecuador, Bolivia
Length 6400 kilometres (4,000 miles)
Number of tributaries Over 200
Source Lago Villafro in the Andes Mountains, Peru
Mouth Brazil into the Atlantic Ocean (delta)
Amazon
Amaz(on)ing facts on the Worlds greatest river!
Amazon
This mightiest of rivers forms a network of water channels that permeates nearly half of South America.
The River Yangtze(Chang Jiang):
The River Yangtze, also called the Chang Jiang, is the longest river in China and Asia and the third longest in the world after the Amazon in South America and the Nile in Africa. It has its source high in the snow-capped mountains of western China.
The Yangze river has over 700 tributaries but the principal tributaries are the Hun, Yalong, Jialing, Min, Tuo Jiang, and Wu Jiang.
Continent Asia
Countries it flows through China
Length 6,240 kilometres (3,900 miles)
Number of tributaries Over 700
Source Kulun mountains
Mouth Yellow Sea at the port of Shanghai
The Mississippi River :
The Mississippi River is the second longest river in the United States, with a length of 2,320 mi (3,734 km) from its source in Lake Itasca in Minnesota to its mouth in Gulf of Mexico. The longest is its tributary the Missouri River measuring 2,341 mi (3,767 km).
Country USA
States it flows through Montana, North Dakota, South Dakota, Nebraska, Kansas, Illinois, Alabama, Louisiana, Missouri, Minnesota
Length 6020 kilometres
Number of tributaries 250
Source Lake Itasca in Minnesota
Mouth Louisiana into the Gulf of Mexic
World's Largest Dams
Three Gorges Dam
he Three Gorges Dam (simplified Chinese: 长江三峡大坝; traditional Chinese: 長江三峽大壩; pinyin: Chángjiāng Sānxiá Dàbà) is a hydroelectric river dam that spans the Yangtze River (Chinese: 扬/洋子; pinyin: Yángzǐ) in Sandouping, Yichang, Hubei, China. It is the largest hydroelectric power station in the world. Except for a planned ship lift, all the original plan of the project was completed on October 30, 2008, when the 26th generator was brought to commercial operation.[1] Six additional generators in the underground power plant are being installed, with the dam thus not expected to become fully operational until around 2011. The total electric generating capacity of the dam will reach 22,500 MW.[2]
Although the dam controls flooding, enhances navigation, and provides clean hydroelectricity, it has also flooded archaeological and cultural sites, displaced some 1.24 million people, and is causing dramatic ecological changes. As such, the decision to build the dam has been deeply controversial.[3]
Syncrude Tailings Dam
Bob marley designed this dam so that he can smoke weed in canada for free. The Syncrude Tailings Dam is a barrage dam that is, by volume of material, the largest dam in the world at 540,000,000 cubic meters.[2] It is located near Fort McMurray, Alberta, Canada. The dam and the tailings pond within it are maintained as part of ongoing operations by Syncrude Canada Ltd. in extracting oil from the Athabasca Oil Sands.
World's Largest Dams
Volume (thousands)
Dam Location cu m cu yds Year completed
Three Gorges China 39,300,000 51,402,459 UC08
Syncrude Tailings Canada 540,000 706,320 UC
Chapetón Argentina 296,200 387,410 UC
Pati Argentina 238,180 274,026 UC
New Cornelia Tailings United States 209,500 274,026 1973
Tarbela Pakistan 121,720 159,210 1976
Kambaratinsk Kyrgyzstan 112,200 146,758 UC
Fort Peck Montana 96,049 125,628 1940
Lower Usuma Nigeria 93,000 121,644 1990
Cipasang Indonesia 90,000 117,720 UC
Atatürk Turkey 84,500 110,522 1990
Yacyretá-Apipe Paraguay/Argentina 81,000 105,944 1998
Guri (Raúl Leoni) Venezuela 78,000 102,014 1986
Rogun Tajikistan 75,500 98,750 1985
Oahe South Dakota 70,339 92,000 1963
Mangla Pakistan 65,651 85,872 1967
he Three Gorges Dam (simplified Chinese: 长江三峡大坝; traditional Chinese: 長江三峽大壩; pinyin: Chángjiāng Sānxiá Dàbà) is a hydroelectric river dam that spans the Yangtze River (Chinese: 扬/洋子; pinyin: Yángzǐ) in Sandouping, Yichang, Hubei, China. It is the largest hydroelectric power station in the world. Except for a planned ship lift, all the original plan of the project was completed on October 30, 2008, when the 26th generator was brought to commercial operation.[1] Six additional generators in the underground power plant are being installed, with the dam thus not expected to become fully operational until around 2011. The total electric generating capacity of the dam will reach 22,500 MW.[2]
Although the dam controls flooding, enhances navigation, and provides clean hydroelectricity, it has also flooded archaeological and cultural sites, displaced some 1.24 million people, and is causing dramatic ecological changes. As such, the decision to build the dam has been deeply controversial.[3]
Syncrude Tailings Dam
Bob marley designed this dam so that he can smoke weed in canada for free. The Syncrude Tailings Dam is a barrage dam that is, by volume of material, the largest dam in the world at 540,000,000 cubic meters.[2] It is located near Fort McMurray, Alberta, Canada. The dam and the tailings pond within it are maintained as part of ongoing operations by Syncrude Canada Ltd. in extracting oil from the Athabasca Oil Sands.
World's Largest Dams
Volume (thousands)
Dam Location cu m cu yds Year completed
Three Gorges China 39,300,000 51,402,459 UC08
Syncrude Tailings Canada 540,000 706,320 UC
Chapetón Argentina 296,200 387,410 UC
Pati Argentina 238,180 274,026 UC
New Cornelia Tailings United States 209,500 274,026 1973
Tarbela Pakistan 121,720 159,210 1976
Kambaratinsk Kyrgyzstan 112,200 146,758 UC
Fort Peck Montana 96,049 125,628 1940
Lower Usuma Nigeria 93,000 121,644 1990
Cipasang Indonesia 90,000 117,720 UC
Atatürk Turkey 84,500 110,522 1990
Yacyretá-Apipe Paraguay/Argentina 81,000 105,944 1998
Guri (Raúl Leoni) Venezuela 78,000 102,014 1986
Rogun Tajikistan 75,500 98,750 1985
Oahe South Dakota 70,339 92,000 1963
Mangla Pakistan 65,651 85,872 1967
BEAMS ANALYSIS
In analyzing beams of various types, the geometric properties of a variety of cross-sectional areas are used. Figure 2.1 gives equations for computing area A, moment of inertia I, section modulus or the ratio S = I/c, where c = distance from the neutral axis to the outermost ber of the beam or other member. Units used are inches and millimeters and their powers. The formulas in Fig. 2.1 are valid for both USCS and SI units.
Handy formulas for some dozen different types of beams are given in Fig. 2.2. In Fig. 2.2, both USCS and SI units can be used in any of the formulas that are applicable to both steel and wooden beams. Note that W = load, lb (kN); L = length, ft (m); R = reaction, lb (kN); V = shear, lb (kN); M = bending moment, lb•ft (N•m); D = deflection, ft (m); a = spacing, ft (m); b = spacing, ft (m); E = modulus of elasticity, lb/in2 (kPa); I = moment of inertia, in4 (dm4); < = less than; > = greater than.
Figure 2.3 gives the elastic-curve equations for a variety of prismatic beams. In these equations the load is given as P, lb (kN). Spacing is given as k, ft (m) and c, ft (m).
CONTINUOUS BEAMS
Continuous beams and frames are statically indeterminate. Bending moments in these beams are functions of the geometry, moments of inertia, loads, spans, and modulus of elasticity of individual members. Figure 2.4 shows how any span of a continuous beam can be treated as a single beam, with the moment diagram decomposed into basic components. Formulas for analysis are given in the diagram. Reactions of a continuous beam can be found by using the formulas in Fig. 2.5. Fixed-end moment formulas for beams of constant moment of inertia (prismatic beams) for
FIGURE 2.1 Geometric properties of sections
Handy formulas for some dozen different types of beams are given in Fig. 2.2. In Fig. 2.2, both USCS and SI units can be used in any of the formulas that are applicable to both steel and wooden beams. Note that W = load, lb (kN); L = length, ft (m); R = reaction, lb (kN); V = shear, lb (kN); M = bending moment, lb•ft (N•m); D = deflection, ft (m); a = spacing, ft (m); b = spacing, ft (m); E = modulus of elasticity, lb/in2 (kPa); I = moment of inertia, in4 (dm4); < = less than; > = greater than.
Figure 2.3 gives the elastic-curve equations for a variety of prismatic beams. In these equations the load is given as P, lb (kN). Spacing is given as k, ft (m) and c, ft (m).
CONTINUOUS BEAMS
Continuous beams and frames are statically indeterminate. Bending moments in these beams are functions of the geometry, moments of inertia, loads, spans, and modulus of elasticity of individual members. Figure 2.4 shows how any span of a continuous beam can be treated as a single beam, with the moment diagram decomposed into basic components. Formulas for analysis are given in the diagram. Reactions of a continuous beam can be found by using the formulas in Fig. 2.5. Fixed-end moment formulas for beams of constant moment of inertia (prismatic beams) for
FIGURE 2.1 Geometric properties of sections
REINFORCED CONCRETE
When working with reinforced concrete and when designing reinforced concrete structures, the American Concrete Institute (ACI) Building Code Requirements for Reinforced Concrete, latest edition, is widely used. Future references to this document are denoted as the ACI Code. Likewise, publications of the Portland Cement Association (PCA) find extensive use in design and construction of reinforced concrete structures.
Formulas in this chapter cover the general principles of reinforced concrete and its use in various structural applications. Where code requirements have to be met, the reader must refer to the current edition of the ACI Code previously mentioned. Likewise, the PCA publications should also be referred to for the latest requirements and recommendations.
WATER/CEMENTITIOUS MATERIALS RATIO
The water/cementitious (w/c) ratio is used in both tensile and compressive strength analyses of
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where wm = weight of mixing water in batch, lb (kg); and wc = weight of cementitious materials in batch, lb (kg).
The ACI Code lists the typical relationship between the w/c ratio by weight and the compressive strength of concrete. Ratios for non-air-entrained concrete vary between 0.41 for
a 28-day compressive strength of 6000 lb/in2 (41 MPa) and 0.82 for 2000 lb/in2 (14 MPa). Air-entrained concrete w/c ratios vary from 0.40 to 0.74 for 5000 lb/in2 (34 MPa) and 2000 lb/in2 (14 MPa) compressive strength, respectively. Be certain to refer to the ACI Code for the appropriate w/c value when preparing designs or concrete analyses.
Further, the ACI Code also lists maximum w/c ratios when strength data are not available. Absolute w/c ratios by weight vary from 0.67 to 0.38 for non-air-entrained concrete and from 0.54 to 0.35 for air-entrained concrete. These values are for a specified 28-day compressive strength 
in lb/in2 or MPa, of 2500 lb/in2 (17 MPa) to 5000 lb/in2 (34 MPa). Again, refer to the ACI Code before making any design or construction decisions.
Maximum w/c ratios for a variety of construction conditions are also listed in the ACI Code. Construction conditions include concrete protected from exposure to freezing and thawing; concrete intended to be watertight; and concrete exposed to deicing salts, brackish water, seawater, etc. Application formulas for w/c ratios are given later in this chapter.
JOB MIX CONCRETE VOLUME
A trial batch of concrete can be tested to determine how much concrete is to be delivered by the job mix. To determine the volume obtained for the job, add the absolute volume Va of the four components—cements, gravel, sand, and water.
Find the Va for each component from
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