上海世博会主题馆采用黏滞阻尼器支撑的结构分析

Structural analysis of the Shanghai World Expo 2010 Theme Hall with viscous damper bracings

2010年上海世博会主题馆有4个展厅,平面尺寸约180m×288m,高度约23.3m,是一个大空间钢结构,其最大跨度在房屋长、短向分别为180m和126m。建筑上的审美和使用耐久性要求结构布置上不设任何伸缩缝,导致该建筑的结构体系在平面和立向布置上均呈现不规则性。为了满足地震作用下的变形要求,需要增加柱间支撑,若采用全部的钢支撑体系将给部分构件增加较大的温度应力。为此在钢框架中设计三种支撑体系进行受力对比分析,即全部钢支撑(最初的方案,结构1)、部分黏滞阻尼器支撑加部分钢支撑(结构2)和全部黏滞阻尼器支撑(结构3)。通过地震时程动力响应及温度荷载作用效应分析表明:结构2和结构3与结构1受力情况相比,温度应力减小了,地震作用下的层间剪力和层间位移角也减小了。经过经济与效果均衡考虑,最后采用了结构2的方案。

The Theme Hall of Shanghai World Expo 2010 consists of four exhibition halls,and is designed as a large space steel frame structure. The space is large and asymmetrical,288m long,188m wide and 23.3m high,with the largest span being 180m in the longitudinal direction and 126m in the transverse direction. For earthquake resistance,steel bracings with large horizontal stiffness were inserted at first,which induced large temperature stress. Eventually,a viscous damper bracing system was introduced to dissipate the earthquake energy and reduce temperature-induced stress. Each of the viscous damper bracings consists of inverted a V-shaped steel brace,two viscous dampers and two rubber bearings,with the viscous damper and the rubber isolator supported on the inverted V-shaped steel brace at one end and connected with the frame joint at the other end. The dampers can dissipate earthquake energy,and the rubber isolators can keep the damper bracings vibrating in their own directions and thus absorbing certain earthquake energy. Time history analysis found that the seismic performances of the structure are greatly enhanced with the damper bracing. These advantages are verified by comparison of dynamic responses of the steel frame with three types of bracing systems： a） 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. The comparison 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 that 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 was chosen and the construction was completed at the end of 2008.