超低温下轴拉钢混构件裂缝控制可靠度分析

Reliability Analysis of the Maximum Crack of Reinforced Concrete Members under Axial Tension under Ultra-low Temperature

基于蒙特卡洛法,由规范给出的正常使用极限状态下的功能函数,通过改变钢筋混凝土构件的温度、保护层厚度、荷载效应比、钢筋尺寸、混凝土等级,对超低温下钢筋混凝土轴拉构件最大裂缝可靠度进行分析得出:钢筋混凝土轴拉构件由常温20℃降至-160℃情况下,构件轴拉可靠指标β呈先降低后升高最后趋于平稳的趋势;对超低温条件下构件可靠指标影响由大到小依次为钢筋尺寸、混凝土等级、荷载效应比、保护层厚度;随着温度的降低,通过提高钢筋混凝土构件材料的性能,对钢筋混凝土构件裂缝控制的效果更加明显。

Based on the Monte Carlo method and the function under the normal use limit state given by the specification,the reliability of the maximum cracks at the ultra-low temperature reinforced concrete axial tensile member is analyzed by changing the temperature of the reinforced concrete member,the thickness of the protective layer,the load effect ratio,and the size of the steel bar,the concrete grade.The analysis of the reliability of the maximum cracks shows that:when the reinforced concrete axial tension member is lowered from normal temperature 20℃ to -160℃,the axial reliability index β of the component decreases first,then increases,and tends to be stable;for ultra-low temperature components,the influence of the reliability index from large to small is the size of the steel bar,the concrete grade,the load effect ratio,and the thickness of the protective layer.As the temperature decreases,by improving the performance of the reinforced concrete member material,the effect of controlling the cracks of the member is more obvious.