The Mechanical Behavior Research For Portal Frame Under Cyclic Loading

Portal frame has been widely used in projects, and its mechanical behavior and designmethods have been deeply studied by domestic and foreign scholars. But studies werenormally focused on its node, while studies on mechanical behavior of the whole structurewere few, therefore studies on mechanical behavior of the whole structure have importanttheory and engineering significance. This paper studied the mechanical behavior of portalframe under horizontal monotonic load and cyclic loading, and proposed engineering designimprovement measures.This paper studied the mechanical behavior, stress distribution and failure mechanism ofportal frame under horizontal monotonic load and cyclic loading, using the finite elementsoftware ANSYS. In the study the material nonlinearity and geometric nonlinearity wereconsidered. By changing the thickness of the column flange, the flange thickness of beam, thebeam height and the strength grade of steel, this paper established12finite element models toanalysis effects for the mechanical behavior of portal frame under factors mentioned above.By finite results analysis, this paper obtained that: portal frame has good deformability,ductility and energy dissipation; the stresses in the range of frame joints were larger duringloading process, and then engineers should strengthen joints regional tectonic to comply withseismic design require,"strong nodes "; vertical stiffness of beams is obvious during the lateloading, therefore engineers should pay attention to vertical stiffness checking and control indesign; when the frame column flange thickness is increased, the limit bearing capacity ofportal frame improved more obvious, but the ductility had on change; the mechanicalbehavior of portal frame was rarely affected by the beam flange thickness; when the framecolumn flange thickness is increased, the limit bearing capacity of portal frame improvedobviously, but the ductility had no change; when frame beam height improved, the stiffness and bearing capacity of the portal frame increased significantly, but vertical stiffness of beamreduced obviously; when the strength grad of steel was improved, stiffness and bearingcapacity of portal frame were significantly improved, but the ductility got worse.This paper studied the mechanical behavior of portal frame under horizontal monotonicload and cyclic loading, not only the research work but the conclusion were valuable forproject reference, and laid a good foundation for further study of the portal frame.