Double Integration Method for Dynamic Analysis of Structures under Earthquake Load

The computational time in direct integration method depends on the integration time interval directly. The integration time interval is often restricted by the rapidity of variation in excitation, or by yielding and unloading in the structural members. Especially in case of structural analysis under earthquake load or non-linear problems, quite a small time interval must be used to assure high precision. In the proposed method, original equation of motion is transformed into equivalent equation of motion through double integration and an efficient numerical integration method for solution is employed. The proposed method permits larger time intervals to be used than usual techniques, and eliminates the difficulties for solution at yielding and unloading in structural dynamic analysis. The proposed method expects the reduction of computational time with high accuracy.