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Civil Engineering/Slab load distribution to beams

Question
QUESTION: A reinforced concrete slab is supported by four beams, the shorther span being 3.5 m and the longer span being 5m. The slab carries a  uniform load. What would be the uniform load (wl) distribution carried by each beam? if the the deflection is inversely proportional to the fourth power of the span of each beam, can i use this ratio-and-proportion to determine the load distribution?

Assuming that the slab is designed and reinforced as 2-way spanning, you will have a trapezoidal shape of loading on the longer beams and triangular loading on the shorter span- just draw lines at 45 degrees on plan from each corner and where they meet this is the triangular loading on the shorter spans.

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QUESTION: Can i design this as one way spanning,wherein the tributary area for the shorter span would be the area of the slab. How do i determine the loading in
the longer span?

Hi Roy,

Assuming that this is an internal span (or slab is simply supported at the beams), then just take 50% load onto each of the longer spans. If it is an edge span and the slab is part of a continuous multi-span slab then the edge beam would carry around 40% of the span loading and the first internal beam will carry about 60% of the span loading.

For the shorter span you can consider them carry a trip of slab loading around 0.6m wide

All these factors are give in text books or in codes such as BS8110
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Civil Engineering

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