某室内主题乐园重载大跨屋盖结构设计

Structural design of heavy load and large-span roof of an indoor theme park

某室内主题乐园采用双向平面钢桁架与钢筋混凝土框架的混合结构形式,其中主桁架跨度103.4m×75.4m,桁架高度为8m,采用Q390高强钢材;屋面采用钢筋混凝土屋面,其上有4个用于支撑外部装饰构件的钢塔。采用MIDAS/Gen软件对整体结构进行了计算分析,计算结果显示各项设计指标均满足规范要求,选用的结构体系做法简洁、便于现场施工。重点针对混合结构协同分析时阻尼比的取值以及屋面桁架支座选用方面进行分析,得出统一阻尼比法与振型阻尼比法的计算结果较为接近,且前者设计内力偏于安全;一半固定铰+一半弹性支座的支座类型基底内力最小,且其动力特性最为合理。

An indoor theme park adopts mixed structural form of two-way plane steel truss and reinforced concrete frame.The span of main truss is 103.4m×75.4m,and the height of the truss is 8m,and high strength steel Q390 is used in main trusses.The roof is reinforced concrete roof,on which there are four steel towers used to support exterior decoration members.The software MIDAS/Gen was used to calculate and analyze the overall structure,the calculation results show that all design indexes meet the codes requirements,and the selected system is simple and convenient for on-site construction.Focusing on the analysis of the value of damping ratios used to cooperative analysis of mixed structures,and the selection of roof truss supports,it is concluded that the calculation results of the unified damping ratio method and the mode shape damping ratio method are relatively close,and the design internal force of the former is safer;the support type of"half fixed hinge support+half elastic support"has the smallest base internal force and the most reasonable dynamic characteristics.