考虑脱空缺陷的钢管混凝土拱承载力计算方法研究OA

Current specifications for concrete-filled steel tubular(CFST)arch bridges have already considered the impact of gap defects in the core concrete on the bearing capacity of arch ribs.However,in practical engineering projects,the degree of gap defects in arch ribs may exceed the limits specified in the specification,making it difficult to accurately assess the bearing capacity of CFST arch ribs with gap defects.Therefore,this paper conducted parametric analysis of large-diameter circular CFST(CCFST)columns with gap defects using the general finite element software ABAQUS and proposed calculation formulas for the gap defect reduction factor.Meanwhile,a spatial frame finite element model of an actual CFST arch bridge was established using MIDAS software,and the calculation formulas for the gap defect reduction factor were applied to the bearing capacity analysis of the arch ribs.The results indicate that when bi-axial and uni-axial compressive constitutive models are adopted for the core concrete with spherical-cap gaps and crescent-shaped gaps,respectively,the fundamental mechanical behavior of the members can be accurately simulated.As the gap ratio or gap angle ratio increases,both spherical-cap gap defect reduction factor and crescent-shaped gap defect reduction factor show a decreasing trend.When the gap ratio or gap angle ratio remains constant,spherical-cap gap defect reduction factor and crescent-shaped gap defect reduction factor increase with the increase in concrete strength grade and slenderness ratio of the member,while they decrease with the increase in steel strength grade and wall thickness of the steel tube.The influence of eccentricity is relatively small.The formula for calculating the gap defect reduction factor based on parameter analysis results can be used to assess the bearing capacity of CFST arch ribs that exceed the limit of gap defects degree specified in current specifications,and the calculation results are conservatively safe.