Story Shear Distribution In K-braced EBFs Under Severe Earthquakes

The story shear distribution of the present seismic code is deriveed from elasticanalysis. However, these story shear distributions do not represent the maximum storyshear distributions that may be induced during nonlinear response under majorearthquakes, which may lead to inaccurate predictions of deformation and force.The story shear distribution in K-brace eccentrically braced frame under differentfar and near field earthquake level are investigated through nonlinear time-historyanalyses. The regularities of story shear distribution in K-brace EBF under different farand near field earthquake level are investigated. The distribution patterns of story shearin K-brace EBF for performance-based seismic design are derived, and thegoodness-of-fit of the distribution patterns is given, the main contents of thisdissertation are the followings:(1)10-story and3-span,15-story and5-span,15-story and3-span,15-story and3-span(the span length change from7.8m to7.2m),20-story and3-span K-brace EBF aredesigned;(2) Several far and near field seismic waves are selected according to certainprinciples and amplitude modulation method. The nonlinear time-history analyses areused to calculate the horizontal seismic action of five K-brace EBFs in SAP2000, and themaximum story shear in five K-brace EBFs under different far and near field earthquakelevel are exported from SAP2000.(3) The story shear distribution in five K-brace EBFs under different far and nearfield earthquake level are made some comparisons. The regularities and influences ofstory shear distribution in K-brace EBF under different far and near field earthquakelevel are investigated.(4) The problems in the distribution patterns of story shear proposed by Lee andGoel, etc are investigated. The distribution patterns of story shear in K-brace EBF forperformance-based seismic design are derived, and the goodness-of-fit of the distributionpatterns is given.