【作者】 汪小鹏；

【导师】 郝宪武；

【作者基本信息】 长安大学 ， 建筑与土木工程， 2011， 硕士

【摘要】 随着我国国民经济的发展,公路交通量急剧增加,一些主要高速公路已经不满足通行要求,需要进行拓宽改造。一些高速公路拓宽改造一两年后,装配式空心板底出现纵向裂缝,其中钢筋混凝土空心板桥出现纵向裂缝的桥梁占18%,预应力混凝土空心板桥出现纵向裂缝的桥梁占64%；桥台盖梁出现竖向裂缝,占检查桥梁的59%；薄壁台身出现纵向裂缝,占检查桥梁65.8%。研究桥梁拓宽后病害产生的原因,对维修、加固拓宽桥梁病害,指导将要拓宽桥梁的设计、施工有着重要意义。论文对现有桥梁拓宽方式进行了介绍,综述了装配式桥梁加宽效果评价方法,总结了装配式桥梁加宽长期效应分析。运用铰接板梁法对装配式空心板的横向内力进行研究,分析了横向内力与汽车荷载的关系、与桥梁跨径的关系、与桥梁宽度的关系；研究了台后拓宽的路基自重荷载在桥台桩基础处产生的附加应力,提出了路基拓宽后桩基础不均匀沉降的计算方法。然后通过有限元分析,研究了20米预应力混凝土板底纵向裂缝产生的原因,分析了正常支撑条件和一个支座脱空条件下,空心板自重、预应力荷载及汽车轮载作用下,空心板应力变化；研究了薄壁桥台竖向裂缝的产生原因,分析了薄壁桥台在上部结构自重及桥面车道荷载、基础变位荷载和台后土压力作用下,台身应力的变化。最后根据研究结果提出了空心板纵向裂缝的加固维修方法；桥台盖梁的加固维修方法和薄壁台台身竖向裂缝的加固维修方法,并在桥梁维修加固中使用,取得良好的效果,值得推广利用。更多还原

【Abstract】 With the development of our national economy and sharply increase of highway traffic, some main freeway can not meet the traffic requirements, and need be broadened. Of the prefabricated slabs of the bridge with longitudinal cracks in one or two years, reinforced concrete slabs take up 18%, prestressed concrete slabs 64%, among which capping beam of the abutments with vertical cracks account for 59%, and the abutments with vertical cracks 65.8%. Studying on the causes of the broaden bridge diseases is important to maintain and reinforce the prefabricated bridge, which can be guidance to the design and construction of broaden bridge.This paper makes an introduction of the bridge broaden ways, gives an evaluation method about the broaden effectiveness, and summarizes long-term effect analysis for built-up bridge. And this paper reseaches the lateral force in the prefabricated slabs with the hinged panels beam method, analyzes the relationship between the lateral force and automobile load, and bridge spans, and the width of the bridge; studied the additional stress in the abutment foundation with the subgrade self-weight load, puts forward a calculation method to uneven settlement of pile foundation in the widen bridge.Then through the finite element analysis, this paper researches the causes of longitudinal cracksin the prestressed concrete slabs with 20 meters long, analyzes the stress changes in the slabs on the condition of the normal supports or one pedestal out of work, and the condition of the load with slab self-weight, prestressed load, or automobile wheel load; studies the abutment vertical cracks, analyzes the stress changes in the abutment with the load of the upper structure weight, driveway load on the deck, foundation displacement load and soil pressure behind the abutment.At last, the maintenance and reinforcement mothods for the longitudinal cracks of hollow slab bridges, coping of bridge abutments and vertical cracks of thin-walled abutments are put forward, which have been applied in the projects. The well effects have been obtained which indicated that the methods worth to be popularized.更多还原