锚固区锈胀开裂钢筋混凝土梁锚固可靠度分析

Reliability analysis for anchorage of reinforced concrete beam with corrosion-induced longitudinal crack in anchorage zone

为研究锚固区混凝土锈胀开裂后构件的锚固可靠度的变化,采用一次二阶矩方法分析锈胀裂缝的长度及宽度、保护层厚度、钢筋锚固长度以及配箍率等参数对锚固可靠度的影响.结果表明,当保护层刚开裂时,锈胀裂缝长度对锚固可靠指标β0的影响很小,此后,随着裂缝宽度的增加,β0有明显的降低;保护层厚度和锚固长度的变化对β0有相当大的影响;改变箍筋的直径或间距对锚固抗力的影响很小,β0变化的幅度也很小.

A reliability analysis approach for concrete elements affected by corrosion of reinforcement in the anchorage zone is developed. Effects of various parameters, such as length and width of corrosion-induced crack, cover depth, initial anchorage length, and stirrup ratio, on the anchorage reliability were analyzed by the first-order second-moment method. Results show that the effect of corrosion-induced crack length on the reliability index β0 of anchorage is negligible when the crack on the concrete surface is just appearing, but with the crack widening, thefβ0 value is reduced significantly; the variation of cover depth and anchorage length results in the considerable changes ofβ0 ; the variation of diameter or space of stirrups has little influence on the anchorage resistance, thus the variation ofβ0 is quite slight.