Static Stability Behavior Of Plane Beam String Structure

The static stability behavior of plane beam string structure (BSS) is studied in thispaper.The performance of arch is enhanced by the struts and strings, so is the stabilityof the whole structure. However, the BSS still belongs to a kind of large-span spacestructures which contain stability problem normally, compared with ordinarystructures. Presently more and more engineering projects adopt BSS as the roofstructure since the merits of BSS is gradually realized by engineers. Nevertheless, theresearch and exploring of the BSS is far from systematic and mature. Therefore,advanced works should be done on the behavior of BSS including the static stabilitycharacters and collapse patterns.The main work of this paper consists of two parts: the theoretical analysis andexperimental test of struts structure of BSS and the overall static stability performanceanalysis of plane BSS.First, linear buckling method is adopted to analyze the axial compression member,and then the conclusions are exerted to the struts structure of BSS. The strut can betreated as compression member constrained by lateral translation nonlinear spring.The stability performance of the strut can be obtained by conducting both nonlinearanalysis of the whole structures and checking calculation of the member which maycommit bend, torsion or bend-torsion action.A test fig is designed to experimentally explore the behavior of the strut structureunder vertical concentrated load. The results show all the test members buckles underself-bending case. The axial ultimate forces of the struts are all appropriately uniformand close to the ultimate forces of the compression member with two ends hinged.The results conform to the theoretical analysis in principle.Numerical calculation is conducted on the tested strut structure by employingsoftware ABAQUS on the base of nonlinear finite element method. All the resultsaccord with the test data well.A calculation model with solid web uppercord is designed and used to observe thestability behavior of plane BSS. Software ANSYS is employed to carry elastic-plasticanalysis. The results show the collapse of the structure is due to strength failure of theextrado of the uppercord of BSS. The post-buckling path only contains a smalldropping portion, and then the stiffness of the structure rise back quickly. Thestructure may contain secondary buckling according to the calculation results.Lastly, parameter study is carried out to explore the influences of the variousparameters including the rigidity of the supporting, prestress, number of struts, sag ofthe lowercord, rise of the uppercord, stiffness of uppercord, as well as the load pattern.The results show all the factors are of obvious influences to the stability performanceof BSS excluding the factor of the number of struts.