NEHRP Clearinghouse

Title
Effects of Spatial Variation of Ground Motions on Large Multiply-Supported Structures.
File
PB91229161.pdf
Author(s)
Hao, H.
Source
National Science Foundation, Washington, DC., July 1989, 171 p.
Identifying Number(s)
UCB/EERC-89/06
Abstract
The fourth report in a research series based on measurements made of seismic strong ground motion by the large-scale digital array of accelerometers in Taiwan, called SMART-1, advances the study of the effects of the spatial variation of ground motions on large multiply-supported structures. Random processes are applied to develop particular simulation techniques that generate multiple-support inputs which allow more realistic assessment of structural response than the usual present practice. The main conclusions bear on two aspects of the problem. The first is the simulation of realistic ground motion for spatially-correlated, quasi-stationary multiple ground motions; and the second is the development of an appropriate computer program which would simulate structural response itself, including soil-structure interaction effects. A model for coherency with four parameters is suggested and the nonlinear interaction between the parameters explored. The models have been tested using earthquakes recorded by SMART-1. Ways are developed to interpolate multiple-motion time histories to preserve the properties of the prescribed ground motion and response spectra. A newly-written computer program demonstrates that often there is a general reduction in structural response when multiple inputs are used and that response modes such as rocking and rotation are significant when different phasing is allowed at each input.
Keywords
; Seismic waves; Earthquake engineering; Earthquakes; Structural vibration; Soil-structure interactions; Earth movements; Degrees of freedom; Displacement; Computerized simulation; Mathematical models; Accelerometers; Taiwan; Dynamic structural analysis