气膜钢筋混凝土扁壳结构设计分析

Analysis and design on reinforced concrete shallow shell structure using inflated forms

以充气膜为模板的钢筋混凝土扁壳结构在国内极少运用,设计和施工没有专用规范可循.对某气膜钢筋混凝土扁壳结构的设计进行了详细的介绍和分析,结合气膜钢筋混凝土结构施工工艺,讨论了结构在荷载作用下的变形和内力、温度作用的影响、支座约束对结构的影响、基础环梁对扁壳结构的作用、形态偏差对结构受力性能的影响、扁壳结构的配筋及基础设计.分析表明:壳体结构中间区域以薄膜内力为主,在基础边缘位置轴力和弯矩都较大;支座节点刚度的增大能有效减小结构的变形和内力;温度作用对结构内力和变形影响很大,升降温引起结构挠度变化幅度达到-37.5%~43.75%;环梁对壳体边缘的约束作用能减小结构的变形,对边缘壳体产生较大的附加内力;结构位移和内力随形态偏差的增大而增大;扁壳结构的配筋采用双层双向钢筋,采用混凝土矩形截面偏心拉压公式在同一高度分层计算;气膜混凝土扁壳结构的基础设计需考虑施工荷载和工艺的特殊性.

Reinforced concrete shell structures using inflated forms are rarely used in China.The design and analysis of a reinforced concrete shell structure using inflated forms are discussed in this paper.This study focuses on the internal forces and deformation under loads,the influence of boundary conditions,the behavior of the shell structure under the temperature loads,the effect of ring beam,the influence of different shape error,reinforcement computation and the foundation design.The result shows that,membrane force dominates the shell central area,and axial force and bending moment on the edge of foundation are large.The increases of boundary stiffness can reduce the deformation and internal forces of the shell structure effectively.Thermal action increases the structural inner force,and changes the displacement from -37.5% to 43.75%.The constraint effect of the ring beam reduces the displacement of the structure,however increases the internal forces of shell near the foundation. The maximum deformation and the hoop axil force increase with the increase of shape error.The design of the doublelayer two-way reinforced shell is based on the eccentrically-loaded rectangular section.The construction loads and construction technology should be considered in the foundation design of such structure.