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Continous Beams And One Way Slabs

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

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Reinforcing Steel

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)

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Tensile Strength Of Concrete

The tensile strength of concrete is used in combined-stress design. In normal-weight, normal-density concrete the tensile strength can be found from

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Modulus Of Elasticity Of Concrete

The modulus of elasticity of concrete E c adopted in modified form by the ACI Code can be calculated by the formula given below:

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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 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 )

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