钢筋混凝土及预应力混凝土板桥加固方法研究

发布时间：2018-06-23 18:02

本文选题：板桥 + 病害成因　；参考：《重庆交通大学》2015年硕士论文

【摘要】：板桥是中小跨径桥梁中常用的桥型之一,其施工工艺简单、建筑高度较小,曾一度被大量建造。而近年来的工程实践和检测结果表明,板桥已经呈现出越来越多的病害,对于出现的病害一方而需要从设计理念和施工角度查找原因,一方面需要及时采取加固措施予以补救。本文系统地总结了桥梁加固技术的研究现状,钢筋混凝土及预应力混凝土板桥病害成因、各种加固技术和相应的计算理论,在计算理论方面重点阐述了桥梁加固分阶段受力与带载加固的特点。本文提出了分清加固性质、明确加固目的、注意多种加固技术综合利用的桥梁改造加固设计原则,对预应力加固体系做了较为详细的介绍,最后以一座钢筋混凝土空心板桥和两座预应力混凝土空心板桥为例,对有粘结预应力加固方法和粘贴钢板加固方法的流程和常见问题做出了一定的分析。通过总结分析,对于空心板桥的加固方案选择给出以下建议：(1)对于原桥空心板底面出现严重横向裂缝,抗弯承载力不足,且混凝土碳化较严重的情况,宜优先采用有黏结预应力加固方案。采用锚固于被加固梁体上的小直径预应力筋,对梁体施加预应力,然后喷注高性能复合砂浆的有粘结预应力加固方案,对空心板桥进行正截面加固,可以较大幅度提高板的正截面抗弯承载力。后喷注的复合砂浆层可以保护钢筋免于锈蚀,提高结构的耐久性,达到承载力加固和耐久性加固的双重目的。此外,由于后喷注的复合砂浆层加大了原梁截面尺寸,增加了截面刚度,对解决变形过大问题也有所帮助。(2)对原桥面破损严重的情况,应结合桥面铺装改造维修,首先考虑采用加大截面法对空心板的受压区进行加固(加厚桥面板)。结合桥面铺装改造维修,适当加大桥面铺装层厚度,考虑新加厚的桥面铺装参与空心板共同工作,使梁的有效高度增加,可以提高梁的抗弯承载力。(3)空心板梁结构的梁高较小,原梁的配筋率相对较大,由于受原梁变形的限制,极限状态下后加补强材料更难以发挥作用,后加补强材料应变(应力)滞后所带来的各种不利影响将更加突出。因此,直接粘贴钢板或高强纤维复合材料对空心板梁进行加固是不适宜的。
[Abstract]:Plate bridge is one of the commonly used bridge types in medium and small span bridges. Its construction technology is simple and the building height is small. The engineering practice and test results in recent years show that more and more defects have appeared in the plate bridge. The cause of the disease should be found from the point of view of design concept and construction. On the one hand, it is necessary to take timely reinforcement measures to remedy it. This paper systematically summarizes the research status of bridge reinforcement technology, the causes of disease of reinforced concrete and prestressed concrete slab bridge, various reinforcement techniques and corresponding calculation theory. In the aspect of calculation theory, the paper expounds the characteristics of bridge reinforcement by stages and with loads. In this paper, the design principles of bridge reconstruction and reinforcement, which distinguish the nature of reinforcement, clear the purpose of reinforcement, pay attention to the comprehensive utilization of various reinforcement technologies, are put forward, and the prestressed reinforcement system is introduced in detail. Finally, taking a reinforced concrete hollow slab bridge and two prestressed concrete hollow slab bridges as examples, the flow and common problems of bonded prestressed reinforcement method and bonded steel plate reinforcement method are analyzed. Through summing up and analyzing, the following suggestions are given for the selection of reinforcement scheme of hollow slab bridge: (1) for the serious transverse cracks on the bottom surface of hollow slab of the original bridge, the flexural bearing capacity is insufficient, and the concrete carbonization is serious. Priority should be given to the use of bonded prestressed reinforcement scheme. The small diameter prestressed tendons which are anchored on the strengthened beams are used to apply prestress to the beam body, and then the bonded prestressed reinforcement scheme of high performance composite mortar is sprayed to reinforce the hollow slab bridge with normal section. The flexural bearing capacity of the normal section of the plate can be greatly improved. The composite mortar layer can protect the steel bar from corrosion, improve the durability of the structure, and achieve the dual purpose of bearing capacity strengthening and durability strengthening. In addition, the composite mortar layer after injection increases the cross-section size of the original beam, increases the stiffness of the section, and helps to solve the problem of excessive deformation. (2) for the serious damage of the original bridge deck, it should be combined with the bridge deck pavement reconstruction and maintenance. Firstly, the method of increasing section is used to strengthen the compressed area of hollow slabs (thickened deck slab). Combined with bridge deck pavement modification and maintenance, the thickness of deck pavement is increased appropriately, and the new thickened deck pavement is considered to participate in the joint work of hollow slab, so that the effective height of beam can be increased, and the flexural bearing capacity of beam can be improved. (3) the beam height of hollow slab beam structure is smaller, The reinforcement ratio of the original beam is relatively large. Due to the limitation of the deformation of the original beam, it is more difficult to exert the function of the post-reinforcement material under the limit state, and all kinds of adverse effects caused by the strain (stress) lag of the post-reinforcement material will be more prominent. Therefore, it is not appropriate to reinforce hollow slab beam with steel plate or high-strength fiber composite directly.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72

【共引文献】