Seismic Analysis of the Structure with Viscous Damper Bracing of the Theme Hall of The World Expo 2010 Shangai China

Abstract

The Theme Hall of The World Expo 2010 Shanghai China consists of four exhibition halls, and is designed as a large spatial steel moment frame. For resisting the earthquake force, at first steel bracings with great horizontal stiffness are inserted into the structure. Then the temperature stress of the structure would be very large. At last a viscous damper bracing is introduced in the Theme Hall, which can dissipate the earthquake energy and reduce the temperature-induced stress. The viscous damper bracing consists of inverted V-shaped steel brace, two viscous dampers and two rubber isolators for each one. In the bracing, the viscous damper and rubber isolator are supported on inverted V-shaped steel brace in one end and connected with frame joint. The dampers can dissipate earthquake energy and the rubber isolators can keep the damper bracings vibrating in their direction, which also can dissipate a part of earthquake energy. Through time history analysis it can be found that the seismic performances of the structure are greatly enhanced with the help of the damper bracing. And these advantages are verified by comparison of dynamic responses of three kinds of bracing systems: a) steel moment frame with steel bracings(ST1), b) partially damper bracings(ST2) in which some steel bracings are replaced by damper bracings, and c) totally damper bracings(ST3) in which all steel bracings are replaced by damper bracings. From the comparison, it is found that the inter-storey shear forces, the inter-storey drifts and the torsion effects of ST3 and ST2 are much less than those of ST1. And also the axial forces in columns (induced by temperature differences) near the bracing system and the axial brace forces in ST2 and ST3 are much less than those in ST1. The ST2 system has been chosen in the last and the construction was completed in the end of 2008.