Abstract: In this article we calculate the reliablity target of calculation and restriction pattern given by 《Standard of Highway and Bridge》 for crevices' width of bridge by analysing relevant factors.Further more,from the result of calculation and analysis,we point out the pattern's reliablity and inadequacy which will be useful in practice.

Key words: reliablity, uncertainty, reliablity target

摘要： 如何较为精确地计算出桥梁在荷载作用下的裂缝宽度及如何控制裂缝宽度[δ_fmax],将直接影响到桥梁的安全性、耐久性和美观.然而,影响裂缝因素复杂,以至于我国现行《公桥规》裂缝宽度计算公式尚属经验公式且裂缝控制条件欠全.笔者在详实占有裂缝分析资料的基础上,通过影响裂缝开展因素的不定性分析,抗裂因素的不定性分析,计算出按《公桥规》计算和控制裂缝宽度时的可靠指标,并在此基础上客观、科学地评价了经验公式的可靠性和不足之处.文中的计算分析结果可望在实践中起到一定的指导意义.

关键词: 可靠度, 不定性, 可靠指标