Study On Seismic Ductility Of Staggered Truss Frame Hybrid Structure

Staggered truss structure originated from the United States in the 1960 s.Its purpose is to provide a more economical new structure form for multi-storey and high-rise public facilities(hotels,schools,hospitals).There are two times of column space in staggered truss structure,which can provide more space for the building.However,due to the large difference of stiffness in the two main directions,there are great differences in dynamic characteristics.At the same time,due to the large stiffness of the structure in the truss direction and the low seismic ductility,it is not suitable to be used in areas with seismic fortification degree above 8.Under the support of related topics,a new staggered truss frame structure is proposed.Based on the improvement of seismic performance of the original structure,the structure maintains the superiority of the original structure and increases the flexibility of the building layout,such as: the elevator room is added locally in the structure;the comprehensive building group;the building system with double large column distance is needed locally.Two general finite element analysis software SAP2000 and MIDAS / Gen are used to analyze the non-linear elastic-plastic behavior of ordinary staggered truss structure and staggered truss frame hybrid structure.The static elastic-plastic interlayer response and the vertex displacement curve under dynamic time history condition are studied.The target displacement of the structure is calculated by the capacity spectrum method,and the interlayer response of the structure is analyzed.Two natural waves are usa01201,usa02622 and a man-made wave RZ.According to the structural ductility theory,the seismic energy dissipation capacity of the structure is evaluated.Finally,the failure law and ductility capacity of the structure are summarized.The results show that:(1)the traditional hybrid staggered truss has excellent seismic performance under small earthquake,but the energy dissipation capacity of large earthquake is weak,and its structural ductility is 3.33(hysteretic ductility capacity is 2.64);the seismic ductility of double Vierendeel staggered truss is not significantly improved(Pushover ductility coefficient is 4.99,hysteretic average ductility capacity is 3.16);the Vierendeel staggered truss has the best ductility,but the structural ductility is not improved significantly The results show that the interlaminar response of small earthquake is large;the staggered truss frame hybrid structure not only meets the seismic requirements of small earthquake,but also has better seismic ductility than the hybrid staggered truss in large earthquake.The truss direction is fully plastic under pushover condition,and the maximum ductility of the structure is 70-80% higher than that of the traditional hybrid staggered truss.(2)Under the premise of transforming the whole truss into a frame,the structure with constant number of interlayer trusses has smooth transition and parabolic response curve.The energy dissipation capacity of the structure is improved on the premise that the elastic-plastic interlayer response is consistent with the hybrid staggered truss,and the energy dissipation capacity of the structure with mix 1-3-mix 2-8 is the best.In this paper,through the calculation of nine cases,the reasonable scheme and suggestions of frame layout in staggered truss system are given,and the elastic and elastic-plastic analysis is carried out.Through the comparison of the interlayer response of the structure and the damage of components,the optimal structural layout scheme is proposed.