S280冷轧薄板冷弯超薄壁型钢构件设计可靠度分析

Design reliability analysis of cold-formed thin-walled steel members with S280 hard-rolled steel sheets

摘要:

基于国内厚度不大于2mm的S280冷轧薄钢板材性数据、S280冷弯薄壁型钢构件的几何尺寸数据以及已完成的轴压、偏压、受弯构件承载力试验数据，对厚度不大于2mm的S280冷弯超薄壁型钢构件的强度不定性、几何特性不定性、计算模式不定性进行分析。采用改进的一次二阶矩法，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。结果表明：对于厚度不大于2mm的S280冷弯超薄壁型钢构件，当宽厚比符合规范要求时，按现有规范的抗力分项系数计算得到的可靠指标均能满足目标可靠度的要求。最后给出了厚度不大于2mm的S280冷轧薄板冷弯超薄壁型钢构件材料的强度设计指标建议值。

Abstract:

Based on the data including the yield strength, the dimensions of sections and the load-carrying capacity of existing experiments on axially-compressed members, eccentrically-compressed members and bending members，the uncertainty of material strength, geometric characteristics and calculation mode of S280 cold-formed thin-walled steel with thickness no more than 2mm was analyzed. Then, the improved second-order moment probability method was used to check the required reliability index of S280 cold-formed thin-walled steel sections with thickness no more than 2mm using the resistance partial factor in current codes under deferent load combinations. The results show that, using the recommended resistance partial factor in current codes, the reliability indexes of the axially-compressed members, the eccentrically-compressed members and the bending members with width-thickness ratio within the limitation of current codes can well meet the target reliability index. Finally, the recommended design strength value of S280 cold-formed thin-walled steel sheets with thickness no more than 2mm was proposed for structural design.