Experimental Investigation On Stainless Steel Tubular Trusses

Concrete-filled steel tubular truss has become popular in engineering field,such as exhibition halls,pipeline structures,stadiums and bridges.Likewise,stainless steel tubular truss has shown to possess high strength,high stiffness,strong integrity,low maintenance cost and durability.However,few researches of the structural behavior and the design methods of stainless steel tubular truss have been conducted.For this reason,it is essential to study the structural behaviour of stainless steel tubular truss.This paper focusses on the behaviour of stainless steel tubular trusses subjected to static loading.To this end,the experimental tests and non-linear finite element analysis were conducted.Failure modes,initial stiffness,ultimate bearing capacity,load Vs.strain curves and design recommendations are reported as follows:(1)Sixteen stainless steel tubular trusses were fabricated and subjected to static loading through experimental tests.Results of these tests show that the common failure modes were the combination of surface plasticity,local buckling,weld fracture,cracking and chord bending.(2)Based on the load-displacement curves,the test data of ultimate bearing capacity,ductility and initial stiffness,mechanical properties of the truss elements were obtained.The outer width effect of brace members,the type of joint and the location of concrete-filled were the main parameters analyzed.(3)The efficiency of different types of stainless steel tubular truss was assessed by comparing their load carrying capacity per unit weight.Thus,truss with concrete-filled in the top chord was more efficient than that of other concrete-filled stainless steel tubular trusses according to the test results.The load carrying capacity per unit weight of the hollow stainless steel tubular truss is higher than the concrete-filled stainless steel tubular truss.Moreover,square stainless steel tubular truss with T-joint presented has the larger loading capacity per unit weigth than that of specimens with N-joint or K-joint.Finally,the load carrying capacity per unit weight of circular stainless steel tubular truss with N-joint is superior than that of specimens with T-joint or K-joint.(4)Finite element modelling results are compared with the experimental tests outcomes to prove the applicability of the proposed non-linear models.(5)Based on 48 models of different concrete-filled stainless steel tubular truss,sensitive parametric analysis was carried out.The results show the whole modelling and validation process,and the influence of geometric parameters on stainless steel tubular truss.As a result,design methodology for concrete-filled stainless steel tubular truss is developed.And then the design recommendations are given for applications.(6)Finally,a discussion is taken about the difficulties of further research.