Though the effective depth of a T-beam is the distance between the top compression edge to the centre of the tensile reinforcement, for heavy loads, it is taken as

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For heavy loads in T-beams, the effective depth is often taken as the distance between the top compression edge to the centroid of the tensile reinforcement plus half the total depth of the T-beam. This adjustment is made to provide additional concrete above the centroid of the tensile reinforcement, ensuring that there is enough concrete to resist the high compressive forces resulting from heavy loads. In essence, increasing the effective depth in this manner helps to enhance the compression capacity of the T-beam and ensures that it can adequately withstand the applied loads without overstressing the concrete. This adjustment is typically made in heavy-duty T-beam designs to improve the overall load-carrying capacity and structural performance of the beam.