Study On The Mechanical Behavior Of Light-weight Portal Frame With Tapered Section Under The Cyclic Loading

Light-weight portal frame structure system with tapered section using the portal frame asthe main load-bearing structure. The frame component is use of the H-shaped weldedcross-section. Tapered section components by changing the web height to achieve variablecross-section in order to adapt the structure bending moment of the internal force distributionlaw.It is more economical than general steel structure under the same conditions. Moreresearch on the nodes of the light portal frame structure on currently. However，Few studies ofvariable cross-section light portal frame structure in which specimens of frame. Therefore,study on the mechanical behavior of light-weight portal frame with tapered section has animportant the meaning of theoretical study and value of engineering applications.In this paper, using finite element analytical software ANSYS10.0, considering thematerial nonlinearity, geometric nonlinearity and states of nonlinear was systematic studiedon the mechanical behavior of light-weight portal frame with tapered section under monotonicand cyclic loading. Depth study of its hysteretic behavior, stress development and failuremechanism. The series of specimens were conducted finite element simulation and analysiswith the different parameters of the friction coefficient, bolt grade and steel strength grade.Studies have shown that light-weight portal frame structure with tapered section have strongstiffness and ultimate load capacity. Consumed energy behavior is good under cyclic loading.The web stress of columns and beams is smaller, the flange stress is larger. The positions fromthe end plate of beam-column joint accounting for the length of half span of oblique beambetween40%and60%, upper and lower flange of oblique beam the Von Mises stress is small.Oblique beam splicing joints are prone to damage, between the end plate of the first andsecond rows of bolts and between the last row and the second to last row of bolts are prone tolarge deformation and opened. Different friction coefficients are not effect to the specimen bearing capacity and seismic performance. Friction coefficient decreases, reduced the seismicdeformation capacity, the less energy dissipation. Lower bolt level will reduce the bearingcapacity, ductility and deformation capacity of light-weight portal frame structure withtapered section. Improve the strength of steel grades can increase the bearing capacity oflight-weight portal frame with tapered section, but reduce the seismic performance. With thestrength of steel grades to improve structural capacity continuously improve, but the structureof the plastic deformation capacity decreases.This article establishes the finite element models consideration question is morecomprehensive, the precision is high, can real simulation the light-weight portal frame withtapered section under the cyclic load behavior.The study analyzing the light-weight portalframe with tapered section load-bearing performance in a rather comprehensive andsystematic way are very useful for revising design specifications and guiding design ofengineering. This paper will play a basic role in the further study on light-weight portal framewith tapered section and analyzing the seismic-resistant behavior of whole structure.