【摘要】 施工方法与施工过程的控制对混凝土梁桥在营运阶段的受力性能有很大影响。为分析混凝土的收缩徐变特性对混凝土梁桥的影响,统计分析了国内已建成的大跨径预应力混凝土连续梁桥的技术现状,确定了加载龄期是影响混凝土收缩徐变的主要因素,以某八跨混凝土连续梁桥为例,采用按龄期调整的有效模量代替混凝土弹性模量来考虑混凝土收缩徐变的影响,并与有限元法相结合逐步计算超静定连续梁桥中混凝土收缩徐变次内力。计算结果表明混凝土梁桥加载龄期对成桥后的线型具有一定影响,因此施工过程中不可以盲目的为了提高施工速度,缩短混凝土的加载龄期。通过计算分析,建议混凝土连续梁桥的加载龄期选择5～7 d为宜。更多还原

【Abstract】 Construction method and construction control have great influence on the mechanical properties of concrete girder bridge in its ser-vice phase.On the basis of the statistics data of the existing long span prestressed concrete continuous girder bridges,it was proved that loading age was a major effect factor of concrete creep and shrinkage.Further taking an eight-span continuous concrete girder bridge as an example,the age-adjusted effective modulus was used to substitute for concrete elastic modular to consider the concrete shrinkage and creep effects.Finite ele-ment step-by-step analysis method was used to study the concrete creep and shrinkage secondary internal force for continuous bridge structures.The results show that the loading age of concrete influences the bridge alignment,so it is not rational to increase construction speed blindly,and shorten the loading age of concrete.According to the calculation,the recommended concrete loading age is five to seven days.更多还原