非常规合拢顺序对连续刚构桥影响分析

The Inflence Study of Unconventional Closure Method on Continuous Rigid Frame Bridge

连续刚构桥的常规合拢顺序为先边跨合拢,然后次边跨合拢,最后中跨合拢。本文研究针对某高速公路上的一座主桥为5跨连续刚构桥采用的先同时合拢边跨(第1、5跨)——再合拢一侧次边跨(第2跨)——最后同时合拢中跨(第3跨)和另一侧次边跨(第4跨)的比较特殊的合拢顺序,建立反映其非常规合拢顺序的有限元数值模型,并对其进行计算。非常规合拢顺序和常规合拢顺序有限元对比分析发现,成桥后和成桥10 a后2个工况下,桥梁的线型、顺桥向上下缘截面最大正应力和墩顶位移以及墩底截面竖直向最大正应力差别非常小;在有效的施工控制下,2种合拢顺序都能满足设计和使用要求。

The conventional closure method of continuous rigid frame bridge is to close the side span first,then the secondary side span and finally the mid-span. Through the study of the special closure method of a five-span prestressed continuous rigid frame bridge in which the two side spans（ the first and fifth spans） are closed,then the secondary side span（ the second span） and finally the mid-span and another secondary side span（ the third and fourth spans）,a finite element numerical model is built for calculation which can reflect its unconventional closure order. According to the comparison between the conventional and unconventional closure methods,it can be found that,under the work conditions of the construction and 10 years after the construction of the bridge,the linearity of the bridge,the maximal normal stress at the lower edge section along the bridge,the displacement of the top of the pier and the vertical maximal normal stress at the bottom section of the pier are of little difference. With effective construction control,both the conventional and unconventional closure methods can satisfy the requirements of design and usage.