Seismic Behavior And Optimization On Irregular Structure Of Theatre Building

Grand theatres are public-good buildings, their main functions are filming, performing and meeting. The functions determine their irregular structures, which could be seriously damaged by earthquake. Therefore it is necessary to study the seismic behavior on the irregular structures of the theatre buidings.The study of this paper is based on Gansu Grand Theater. Features of the theater is summarized as follows.(1) The height and the rigidity of the stage, the auditorium and the hall differ significantly from each other, which causes misalign of the centroid and the center of rigidity, so the torsional effect is prominent under seismic action.(2) The total height and the story height of the stage, the auditorium and the hall are largely deviated from each other. There are problems such as staggered floors and columns of different heights at different functional areas, which are unfavorable factors for structural seismic resistance.(3) There are also many challenges like long cantilever beams and column transfer girder.(4) The types of roofs are usually not consistent in one theater, which means the concreate beam and slab structure and steel structural grid frame are employed simultaneously. The interaction between lower concrete structure and grid frame structure needs to be studied.The structure of Gansu Grand Theater belongs to complicated irragular structure. In this paper, the structure is calculated by finite element software and its seismic behavior is analysed.The total height, story height and the number of stories of the stage, the auditorium and the hall are different, and the definition of the’floor’is ambiguous. The applicability of the seismic design criteria such as inter-story displacement angle, displacement ratio, shear-weight ratio, floor stiffness ratio should be further investigated and the resolution should be proposed. The calculation results show that Gansu Grand Theater has multi-line defendence of earthquake, according to the requests of seismic design. It can reach the three level design principle. All these insure that Gansu Theater won’t fall under severe earthquake. This paper further studys on the interaction between lower concrete structure and grid frame structure and optimization of seismic behavior.The influence of grid structure on the concrete structure is small. The grid frame structure only impacts on the lower supporting beams, so simplified calculation by equivalent stiffness and weight is adopted to analyze the substructure. But local displacement of concrete structure exerts a big influence on grid frame, for it requires larger internal forces to resist the displacement. Therefore, in the grid frame design, the impact of the displacement of concrete structure should be fully considered.Wall limb of irregular structures of theatres should be reasonable arranged, which can optimize the seismic performance, and can reduce torsion, and reduce substantially internal force of local corner column.