剪力作用下配筋混凝土砌体墙的可靠度分析

Structural reliability for reinforced concrete block masonry walls in shear force

针对水平剪力作用下配筋混凝土砌块墙体的抗剪承载力可靠度水平,提出其可靠度计算模型与方法,该方法考虑了模型误差的分布形式、灌孔混凝土砌块砌体的抗压强度、活荷载类型、荷载效应比、墙体内水平钢筋的配筋率、墙体截面高度、墙体的竖向荷载以及剪跨比等影响因素.通过受剪墙体的试验数据统计与分析,确定Lognormal为最佳的可靠度模型误差概率分布形式;可靠度计算结果表明:模型误差的概率分布形式对配筋砌块墙体抗剪承载力的可靠度指标影响最大,其中Lognormal、Gamma和Gumbel分布下的可靠度指标皆大于或接近目标可靠度3.7,而Normal和Weibull分布下的可靠度结果小于3.7.

The present paper developed a probabilistic model to calculate the structural reliability of typical reinforced grouted concrete block masonry walls designed to Chinese standards,loaded with horizontal shear force.The statistical parameters of materials and loads used for the structural reliability analysis were obtained on the basis of test database and statistical results from China.The effect of probability distribution of model error,the compressive strength for grouted concrete block masonry,live load type,load effect ratio,reinforcement ratio of horizontal rebar,wall sectional height,vertical compressive load,and ratio of shear span to depth were considered when calculating the structural reliability of reinforced masonry walls in shear force.The structural reliability for reinforced concrete block masonry walls in shear is sensitive to the probability distribution of model error.Lognormal is the optimal error probability distribution of the reliability model determined by statistics and analysis of the test data.The reliability calculation result shows that the probability distribution form of the model error is the most influential factor for the anti-shearing reliability index of the reinforced block walls.It was found that the existing（design） reliability levels are all larger or close to the target reliability of 3.7 under the Lognormal,Gamma,and Gumbel distribution for typical structures,whereas the safety levels were less than 3.7 using Normal and Weibull distributions.