Experimental and numerical investigation on the flexural performance of spatial weathering steel composite girders with concrete-filled tubular flange

This study presents an experimental and numerical investigation on the flexural performance of spatial weathering steel composite girders with concrete -filled tubular flange (CGCTF). Two spatial weathering steel CGCTFs with varied top flanges were tested using the midspan single -point loading way. The influence of the upper flange plate on the failure modes of girders, flexural capacity, and deformation development were examined. The test results shown that the overall bending failure of the two spatial weathering steel CGCTFs is comparable, and the flexural bearing capacity of the spatial composite girder increases by 22.8% owing to the addition of upper flange plates. The finite element analysis model of spatial weathering steel CGCTF was then developed and verified against the measured results. The flexural mechanism of the spatial weathering steel CGCTF was investigated, namely the typical bending moment -deflection curves, stress distribution, and deformation development. The flexural performance of spatial and planar weathering steel CGCTF with different top flanges were also compared. A parametric study was conducted to investigate the effects of different parameters on the bending moment -deflection curves and ultimate flexural capacity of the two spatial weathering steel CGCTFs. Simplified design methods were finally proposed for calculating the flexural bearing capacity of the spatial composite girders with tube flange.