Bounding of earthquake response via critical double impulse for efficient optimal design of viscous dampers for elastic-plastic moment frames

An input velocity adjustment method of the critical double impulse (DI) is presented for efficient design of viscous dampers for elastic-plastic moment frames. The input velocity is adjusted so that the input energy to the lowest eigenmode under the critical DI is equal to those under the selected recorded ground motions. This adjustment makes the critical DI work as the active earthquake. The response bounding property of the critical DI is supported by, (1) the multimodal property of the critical DI, (2) the usual excitation of the lowest mode response under recorded ground motions, (3) the large proportion of the instantaneous input energy to the total input energy in the critical DI. The proposed method can treat not only pulse-like near-fault ground motions but also ground motions of random nature. To validate the proposed method, the input energies and the maximum interstory drifts under the recorded ground motions and the critical DI with the adjusted input velocity are investigated for elastic singledegree-of-freedom (SDOF) models, elastic proportionally damped MDOF models, and elastic-plastic proportionally damped MDOF models. The optimization method presented in the previous paper is extended so that the critical DI can be treated for the design of viscous dampers for elastic-plastic moment frames.

Automated summary

This paper presents an input velocity adjustment method for the critical double impulse (DI) in order to efficiently design viscous dampers for elastic-plastic moment frames. The adjustment ensures that the input energy to the lowest eigenmode under the critical DI matches that under the recorded ground motions, allowing the critical DI to function as the active earthquake. The proposed method is capable of handling both pulse-like near-fault ground motions and random ground motions.