某博物馆大跨拱形入口结构设计

Design of Large-span Arch Entrance Structure of a Museum

某博物馆大跨入口形态呈拱形,矢跨比较小,为扁平拱,扁平拱兼具拱形结构与梁式结构的受力特征,构件承受轴力的同时也会承受弯矩,并会在拱脚处产生更大的水平推力。根据选型分析可知,混凝土结构自重产生的水平推力为钢结构的4~10倍,且跨中承受较大的弯矩,易使混凝土受拉开裂,不能充分发挥混凝土结构的受压性能。另外,混凝土构件的施工精度不高,容易造成初始缺陷偏大,不利于拱的稳定。综合比较,采用钢桁架拱结构较为合理,通过对该大跨钢桁架拱结构详尽的静力分析、强度验算、稳定性分析,可知钢桁架拱自重轻、刚度大、冗余度高、稳定性好,结构经济合理,且能很好地实现建筑形态和功能需求。

A large-span entrance of a museum is a flat arch.According to the analysis,the horizontal reaction force under self-weight of a concrete structure is 4~10 times of the corresponding steel structure.Under bending moment,the concrete is apt to crack and cannot fully utilize the compression performance of concrete structures.In addition,the construction accuracy of concrete members is not high,which can lead to large initial defect,and this is not beneficial for the stability of the arch.Through comprehensive comparison,it is found that a steel truss arch structure is more reasonable.Through static analysis,strength calculation and stability analysis,the steel truss arch has the advantages of light weight,high rigidity,high redundancy and good stability.This structure is both economical and reasonable,and can realize the architectural form and function requirements.