Abstract
A simplified procedure to estimate drift based on the area of load-resisting elements is presented and its results are compared with those of the equivalent-period method and the target-displacement method as defined in FEMA-273 (1997). All three methods are used to estimate the upper-bound drift based on simple parameters that represent the lateral stiffness and mass of a structure. The accuracy of the methods was evaluated using experimental results from 152 earthquake simulator tests found in the literature. Coefficients of variation for the measured-to-calculated drift ratios ranged between 0.6 and 0.75, indicating that the accuracy of the drift estimates afforded by the three methods was similar for the set of test results evaluated. Additional comparisons are presented for the proposed method based on 720 nonlinear analyses of notional frames and the measured response of an instrumented building.
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