【摘要】 恒载性超载主要是由桥面铺装大修、路线改造引起。为衡量在役桥梁恒载性超载的程度,引入恒载超载系数的概念。以斜截面受剪构件(T形截面)为例,借鉴"校准法"的基本原理,分析恒载性超载对基于原规范(JTJ 023-85)和现行规范(JTG D60-2004)设计建造的桥梁可靠性指标的影响规律。得出结论:若设计采用的活、恒载标准值效应比值ρ一定,可靠指标随着恒载超载系数ζd的增加近似呈线性减小趋势。ρ值越大,可靠指标的降低幅度越小,表明设计采用的恒载效应所占比重越大,桥梁的抗恒载性超载能力越弱,反之越强。桥梁结构或构件隐含的可靠度越高,桥梁的承载潜力越大,相应结构或构件的抗恒载性超载能力越强。更多还原

【Abstract】 The overload of dead load nature is a kind of the load mainly caused by the rehabilitation of deck pavement and improvement of carriageways on a bridge.To judge the degree of such overload on the in-service bridges,the concept of the overload coefficient of dead load nature is introduced.By way of example of the shear member with inclined section(T-section) and with reference to the fundamental principle of the "calibration method",the laws of influence of the overload on the reliability index of the bridge design and construction based on the original code(JTJ 023-85) and the present code(JTG D60-2004) are analyzed.The conclusions generalized are that if the ratio ρ of the live load and dead load standard value effect adopted in the design is given,the reliability index approximately tends to linearly decrease with the increase of the overload coefficient ζd.The greater the ρ value is,the less the decreasing amplitude of the reliability index will be,showing that the greater the portion of the dead load effect in the design is,the weaker the resistance capacity of a bridge to the overload will be,otherwise the stronger resistance capacity will be.The higher the implicit reliability of the bridge structure or members is,the greater the carrying capacity of the bridge will be and accordingly the stronger the resistance of the structure and members to the overload will also be.更多还原