Civil Engineers have to do more than one task for the successful completion of the project and this video deals with many important aspects.
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Civil Engineers have to do more than one task for the successful completion of the project and this video deals with many important aspects.
Watch it now and please comment on it!
The ACI Code gives approximate formulas for finding shear and bending moments in continuous beams and one way slabs. A summary list of these formulas follows. They are equally applicable to USCS and SI units. Refer to the ACI Code for specific applications of these formulas.
For Positive Moment
1 ) End spans
If discontinues end is unrestrained = wl2n /11
If discontinues end is integral with the support= wl2n /14
American Society for Testing and Materials (ASTM) specifications cover renforcing steel. The most important proper- ties of reinforcing steel are
1. Modulus of elasticity E s , lb/in 2 (MPa)
2. Tensile strength, lb/in 2 (MPa)
The tensile strength of concrete is used in combined-stress design. In normal-weight, normal-density concrete the tensile strength can be found from
The modulus of elasticity of concrete E c adopted in modified form by the ACI Code can be calculated by the formula given below:
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 V a of the four components—cements, gravel, sand, and water.
Find the V a for each component from
V a = W L / ( SG ) W u
where V a = absolute volume, ft 3 (m 3 )
The water / cementitious (w/c) ratio is used in both tensile and compressive strength analyses of Portland concrete cement. This ratio is found from
w / c = w m / w c
where w m = weight of mixing water in batch, lb (kg); and w c = weight of cementitious materials in batch, lb (kg).
Those flat roof which face a problem of water accumulation require stability analysis under ponding conditions. For checking the stability we need to see the following equations, if both of these are fulfilled
Cp+0.9Cs<= 0.25
Id>=25S4/106
Where
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We take the smaller value out of these two conditions to calculate the total horizontal shear which is to be to be resisted by the shear connectors in building construction
Vh= 0.85f‘cAc/2
Vh=As Fy/2
where
Vh = 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)
Ac = Actual area of effective concrete flange in inch2(mm2)
As = Area of steel beam in inch2(mm2)