（华南理工大学建筑设计研究院，广州 510640）

［摘要］2010年上海世博会中国馆B3区为中国馆裙楼的组成部分之一，该区坐落在地铁M8号线车站上方，故设置四根托换梁托住上部结构，使其与地铁站顶盖完全脱离。托换梁采用空腹预应力混凝土梁，最大跨度达45m。托换梁在施工和使用过程中受荷下沉，导致上部结构的柱脚支座产生不均匀沉降和转动，增大了上部结构的内力，故设计和施工时采用改变支承边界条件的方法：即施工阶段柱脚铰接，而使用阶段柱脚刚接，采用该方法减小了上部结构的弯矩值，在节省用钢量方面有一定效果。

［关键词］世博会；托换梁；支座边界条件

Structural design on China Pavilion B3 zone of Expo 2010 Shanghai

Wang Fan, Zhang Zhigang, Chen Fuxi（Architectural Design and Research Institute, South China University of Technology, Guangzhou 510640, China）

Abstract:China Pavilion B3 zone of Expo 2010 Shanghai, which is an integral part of China Pavilion, is located at the top of subway station of M8 Line In order to make it completely separated from the roof of subway, four underpinning beams were set up to support the upper structure The largest span of underpinning beams was as much as 45m Prestressed concrete was adopted in those beams, and the abdomen was cavity. Underpinning beams will sink under the action of the load in the process of construction and operational phase, which leads to produce nonuniform settlement and rotation to column foot of the upper part of the structure. The final result is to increase the internal forces of the upper structure. For the purpose of reducing this impact, an approach of changing