Study on the Seismic Optimization Scheme of Steel Bundled-Tube Structure with Vertical Setback

Abstract

In order to improve the seismic performance of vertical setback steel bundled-tube structure and meet the dynamic multi-objective requirements of seismic performance-based design, the optimization effects under rare earthquakes on the zone of fortification intensity 7 and 8 in China are researched by improving members stiffness and adding dampers in the weak parts of structure, based on dynamic elastic-plastic analysis. The results show that: 1) Under rare earthquakes on the zone of fortification intensity 7, increasing the stiffness of weak skirt beam can improve the seismic performance of spiral and symmetrical setback structure; 2) For the spiral setback structure, under rare earthquakes on the zone of fortification intensity 7, the damper can only be arranged at the junction of the first layer of the setback frame unit and the frame unit without setback. However, under rare earthquakes on the zone of fortification intensity 8, it is not advisable to install dampers at the weak areas; 3) After incorporating dampers at the weak areas of symmetrical setback structure, the optimized members experienced a reduction in stress levels, significantly decreased the inter-layer displacement angles with a maximum reduction of 43%, and the optimization effect is significant.