There is a considerable uncertainty regarding the evaluation of the maximum allowable story drift as well as the maximum allowable lateral drift at the top of a building. Various seismic codes suggest values that range from h/50 to h/2000 where h is the height of a building. This paper reviews the maximum allowable drift presented in various seismic codes and uses structural dynamics along with the finite element method to suggest a formula that can be used to determine the maximum allowable drift at the top of a shear wall based on the maximum allowable strain values in that shear wall. This formula provides an elastic limit for the drift after which the designer knows that his reinforced concrete section is going into the plastic region. In comparing the results generated by the suggested formula with the drift values suggested by other codes, it can be observed that the results are very close to the values obtained by the use of the French code PS92 and far from the values suggested by UBC and IBC.
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