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本文以某一大跨径预应力混凝土刚构-连续组合梁桥的加固改造为背景,针对该桥在采用体外预应力加固运营若干年后仍出现梁体开裂和跨中下挠现象,从增加支承、提高预应力作用效率等概念出发,提出了不同于常规加固方法的4种加固方法,即:新增斜拉体系、增设波纹钢腹板、新增缆索体系及外穿体外束。从应力、线形、内力改善情况及施工工艺方面对4种加固方法进行分析研究,结果表明:对于在役大跨径预应力混凝土连续梁桥、连续刚构桥,4种加固方法均可使其满足加固设计和规范要求。综合考虑加固效果、施工风险、工期、费用和社会影响等,推荐新增斜拉体系作为这类桥梁出现梁体开裂、跨中下挠的处治方法。
In this paper, a long span prestressed concrete rigid frame - continuous composite girder bridge reinforcement transformation as the background, for the bridge in the use of external prestressing reinforcement operation for some years still appear beam cracking and mid-span deflection phenomenon, from increasing Support and improve the efficiency of prestressing, we put forward four kinds of reinforcement methods which are different from the conventional reinforcement methods: new cable-stayed system, corrugated steel webs, new cable system and external beam. Four kinds of reinforcement methods are analyzed from the aspects of stress, linearity, internal force improvement and construction technology. The results show that for the existing long-span prestressed concrete continuous girder bridge and continuous rigid frame bridge, four kinds of reinforcement methods can make them Meet reinforcement design and specification requirements. Considering reinforcement effect, construction risk, construction period, cost and social influence, it is recommended to add a new cable-stayed system as a method of treatment for cracking, mid-span deflection of such bridges.