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基于国内厚度不大于2mm的S350冷轧薄钢板材性数据、冷弯薄壁型钢构件几何尺寸数据及已完成的轴压、偏压、受弯构件承载力试验数据,对厚度不大于2mm的S350超薄壁冷弯型钢构件的材料强度不定性、几何特性不定性、计算模式不定性进行了分析。采用JC法,按现有规范的抗力分项系数计算了各类基本构件在不同可能荷载组合下的可靠指标,并根据可靠度分析结果,提出了对现有规范承载力计算值的建议修正方法。结果表明:对于厚度不大于2mm的S350超薄壁冷弯型钢构件,当翼缘宽厚比满足规范要求时,按现有规范的抗力分项系数计算得到的轴压构件可以满足目标可靠度的要求,偏压构件的可靠指标低于目标可靠指标,受弯构件的可靠指标略低于目标可靠度。按建议方法计算偏压构件的承载力时,偏压构件的可靠指标大于目标可靠指标。最后给出了厚度不大于2mm的S350超薄壁冷弯型钢构件的强度设计指标建议值。
Based on the S350 cold-rolled steel plate thickness data of not more than 2mm in thickness, the geometric data of cold-formed thin-wall steel members and the tested data of bearing capacity, bias and flexural strength, the thickness of S350 The material strength of the thin-walled cold-formed steel members, the uncertainty of the geometric properties and the uncertainty of the calculation mode were analyzed. The JC method is used to calculate the reliable index of various basic components under different possible load combinations according to the resistance normalization coefficient of the existing codes. According to the reliability analysis results, the proposed correction method for the calculated values of the existing normalized bearing capacity is proposed . The results show that for S350 thin-walled cold-formed steel members with thickness less than 2 mm, the axial compression members calculated according to the existing resistance coefficient can meet the requirements of target reliability when the flange width-thickness ratio meets the specification , The reliable index of the biasing member is lower than the target reliable index, and the reliable index of the flexural member is slightly lower than the target reliability. When calculating the bearing capacity of the biasing member according to the proposed method, the reliable indicator of the biasing member is larger than the target reliable indicator. Finally, the recommended value of the strength design of the S350 thin-walled cold-formed steel member with the thickness less than 2mm is given.