Study On Elastic-plastic Dynamic Analysis Of90m-span Steel-pipe Arch Truss Under The Earthquake Effect

Span structures play an important role of victims in shelters in the earthquake. Moreover, the steel arch truss is widely used in the exhibition hall,stadium and other large public buildings because of its many advantages. How to keep that they have sufficient seismic capacity and a reasonable degree of security in the design and construction, is a vitral problem in the engineering sector and the academic community.Based on the numerical analysis, and SAP2000, a kind of software of the finite element analysis, this thesis makes an elasto-plastic dynamic analysis of the rectangular section arch truss with a s pan of90m under the action of earthquake. Dual nonlinear effects of materials and geometry have been taken into consideration in the analysis. In this thesis different factors such as the selection and the input direction of shock waves as well as rise-span ratios are compared, and following work have been carried out.1) Dynamic response analysis of structure under the action of earthquake Set up a finite element model of the rectangular section arch truss with a span of90m and input earthquake waves in the direction of X, Z and XZ. Then gradually increase the peak acceleration, and make a seismic time history analysis of each acceleration peak and record the different response characteristics in order to get some change rules of the arch truss according to the varieties of the peak acceleration.2) Arch truss were studied from two aspects in this article. One is when the span ratio is0.25, enter the three different seismic wave structure of the study to compare; The other is compare the seven different span ratio structures under Ninghe wave.The results show that:(1) with the input of seismic wave in the direction of X, the critical load value of structure will gradually decrease with the increase of rise-span ratio; with the input of seismic wave in the direction of Z, the critical load value of structure will gradually increase with the increase of rise-span ratio; with the input of seismic wave in the direction of XZ, the critical load value of structure will gradually decrease with the increase of rise-span ratio.(2) When the seismic waves were input from different directions,the critial load of the LWD wave is the most, the critial load of the Shanghai wave is the minumum.(3) When the structure of seismic wave was input from different directions. Regardless of is the different seismic waves, or a different vector cross than that. When the structure is destroyed, the destructive position of the arch truss occurs mostly in the arch springing, extrados,1/4of the span or3/4of the span.(4) When structure is under the action of the same seismic waves the appearance of peak acceleration of plastic hinges has much to do with the destruction critical peak acceleration, which shows that structure still enjoys a larger energy dissipation capacity in the elastic stage.