Study On Ultimate Bearing Capacity Of Light-weight Steel Portal Frame Structures Under Wind Loading And Snow Loading

By the rise of the steel sheet metal pressure of portal frame light steel plant is widely used in engineering,but this kind of structure due to its own defects easily happened in wind and snow weather damage.When we research bearing gantry frame ultimate bearing capacity lacking of consideration outside surface 3d component function response of the steel,steel plant modeling space,research space rigid frame structure of door type when it reaches the critical stable state of the wind and snow resistance and failure modes.In a domestic light steel plant as an example,under the premise of considering the initial defects,according to the current load code for the selection of the most unfavorable wind and snow load combination,with the help of a large general finite element analysis software ANASYS on the nonlinear stability analysis.Getting the space gantry frame when it achieve the ultimate bearing capacity of breaking the form as well as the ability to resist wind and snow.And to our country most small slope portal rigid frame under uneven distribution of snow load safety skills,and failure modes were analyzed.The results showed that under wind load,the space frame to achieve stable limit bearing capacity safety redundancy ability is stronger,but should pay attention to the control action of wind load effects on space rigid frame.Uneven distribution under snow load carrying capacity of strong,but should pay attention to basic snow pressure is too big lead to the destruction of the space rigid frame structure of door type.Two kinds of working conditions,the destruction of the space structure embodied in a single common frame of the local elastic buckling failure,local buckling failure location: close to the column flange plate and web plate connection of the beam-column joints and snow on one side of the column flange plate.Beam-column joints and the column foot also have higher stress.When spatial structure damage occurs,the space structure of two kinds of load conditions find the most frame is not reached the critical instability state,steel are not good use,and adjacent two common frame are created serious out-of-plane deformation.For two kinds of working conditions of analysising single cross frame stability ultimate bearing capacity,found when the single common door frame plastic buckling failure,it reach the material yield strength.Therefore,the steel space overall analysis should be adopted when analysising the ultimate bearing capacity,to achieve the desired effect.Based on points for partial discharge evil thoughts to a higher degree of improving the ultimate bearing capacity of the type of door rigid frame structure in wind and snow,the method is simple and good economic benefit.After unloading the gantry reach ultimate bearing capacity of frame structure,the most rigid frame close to the yield stress of material,outside surface deformation is small,it can avoid the snow make frame oblique beam bend torsion and cause premature local buckling.In addition,the buckling of the web and flange plate Angle steel reinforcement,and brace on nodes and strengthen the out-of-plane adjacent frame end of support,can promote the overall stability of portal frame building,improve the service life of the structure and security.