SEISMIC UPGRADE OF STEEL FRAMES USING DISSIPATIVE KNEE BRACING ELEMENTS

摘要

This study investigates the effectiveness of dissipative knee bracing as seismic performance improvement strategy for steel frames. A simplified model of a knee element is used for global analyses of frames in order to accurately simulate the bending and shear behaviour observed in laboratory tests reported in literature. The seismic response of a five-storey steel frame incorporating dissipative knee elements is investigated. Nonlinear static analyses are performed to estimate the deformation capacity of the frame and to assess the sequence of yielding in the members. Nonlinear dynamic analyses with different intensity levels are carried out to compare the seismic performance of the steel frame in the unprotected and protected configurations. The influence of different lengths of the knee elements on the seismic response of the protected frame is investigated. The results of the numerical investigations show that the use of knee elements has the potential to improve the seismic performance of steel frames.