Study On The Overall Stability Of High-strength Circular Hollow Section Members Under Axial Compression

All kinds of large-span spatial structures,employed in stadiums,entertainment center and museums,are constantly emerging.High-strength circular hollow section(HSCHS)members have been commonly utilized in large-span spatial structures owing to the non-directionality,excellent bending and torsional properties,as well as efficient and architecturally aesthetic building shapes offered by their tubular shape design.However,previous research jobs on the global buckling behavior of axial compression HSCHS were mainly focus on welded pipes,with geometric parameters more suitable for beam-column systems or transmission line towers.Few studies have addressed the overall stability of hot-rolled HSCHS members.Additionally,design method for HSCHS members is all the same as that for ordinary low-carbon steel members in "Steel Structure Design Standard" GB50017-2017.As far as slender HSCHS members in large-span spatial structures are concerned,sufficient tests and numerical analyses are urgently needed to validate current design code.Therefore,both experimental and numerical analyses were conducted systematically to obtain the global buckling performance and reasonable design method of axial compression hot-rolled HSCHS members in this paper,considering section sizes widely adopted in large-span space structures.Main works are as follows:(1)Twelve full-scale model tests on axially compressed hot-rolled Q460 HSCHS specimens were carried out to obtain the ultimate global bucking bearing capacity and failure mode.And the influence of slenderness ratio and diameter-thickness ratio were analyzed.(2)Based on experimental results of HSCHS specimens,detailed finite element analyses were performed using ABAQUS software.A comparison of the numerical simulation results and tested results exhibited good agreement and validated the effectiveness of the finite element models.(3)Through the verified numerical simulation method,a parametric analysis was also conducted on the global buckling behavior of axial compression hot-rolled HSCHS members made of Q460 and Q690 steels.The influence of two geometric parameters,slenderness ratio and diameter-to-thickness ratio,were discussed.(4)According to the experimental and parametric analysis results,new design recommendations for the global buckling bearing capacity of axial compression HSCHS members were proposed,based on the design equations in "Steel Structure Design Standard" GB50017-2017.