【作者】 郭健；

【导师】 何益斌； 邹仲康；

【作者基本信息】 湖南大学 ， 建筑与土木工程， 2005， 硕士

【摘要】 随着经济的发展，建筑工程的重点从大规模新建阶段、新建与维修并举阶段。逐步向旧建筑维修改造阶段转移，统计资料显示，改建比新建工程可节约投资约40％，工期缩短约50％，收回投资速度比新建快3-4倍，同时大量的自然灾害使许多建筑物受到不同程度的损伤，影响了建筑物的正常使用，而由于时代发展带来的建筑物使用功能的改变以及建筑物自身不可抗拒的老化问题使得加固改造的问题日渐严峻。如何采取有效的加固措施对受损建筑物进行处理以恢复其使用功能是工程技术人员面临的重要课题，也是本文研究的初衷。本文根据加固工程的特点，阐明了加固工作的重要意义，对于混凝土结构的梁、板、柱等构件的加固条件及加固方式进行了全面的分析，通过比较，总结了常用加固方法如“加大截面法”，“外包钢法”“预应力加固法”“增设支点加固法”“粘钢加固法”的特点及适用范围，并介绍了各种加固方案的正截面和斜截面承载力计算方法，为建筑物的加固改造提供了计算依据。另外，加固结构属于二次受力构件，其工作特点决定了加固构件的混凝土应变滞后而钢筋应力超前，而这种性质所带来的结果是在受压区边缘的混凝土被压碎时，构件的挠度，裂缝都较整浇梁大得多，而受拉钢筋的应力比整浇梁在较低的弯矩作用下就可能达到流限。因此为保证新老部分混凝土整体工作，结合面必须进行承载力受剪验算，这是加固结构成败的关键。针对粘钢加固法粘结应力分布和传递长度的特点，作者还对局部粘结片材加固梁中界面应力进行了有限元分析，讨论了粘结胶的厚度和钢板厚度对局部粘贴钢板加固梁中界面应力的影响。结果认为钢板的厚度取4-6mm为宜，且在设计中应按最大剪应力对钢板厚度进行验算，为减小粘结胶对局部粘结钢板加固梁的界面应力的影响，建议胶的厚度取2-3mm。最后作者结合自己主持的加固工程实例，介绍了加固工程的工作程序，提出了不同加固方法的设计要点和施工要点，对钢筋混凝土结构的加固改造有一定的借鉴作用。更多还原

【Abstract】 With the development of economy, the focus of buildings is shifting from many new buildings to building and repairing and now to repairing and reforming of existing buildings. According to statistics, reforming saves investment by 40%, cuts construction time by 50%, recoups capital outlay two or three times faster, than building new ones. Moreover, many new buildings are damaged to different extents by numerous natural disasters, and cannot be put into normal use. Besides, modern developments have left many buildings outdated and unfit in function and use. Lastly, the aging of buildings is an irresistible problem. All these have made building strengthening and reforming an increasingly important and urgent. How to take effective strengthening measures to recover the functions of damaged buildings is an urgent project facing all structural engineers, which also serves the starting point for the present research.The paper summarized the characteristics of strengthening, demonstrated the practical significance of strengthening, offered a comprehensive analysis of concrete beams, plates and columns. The paper, through comparison, also pointed the characteristics and application scope of common methods, such as section expansion, surface shape steel wrapping, plate stressing, support point changes, and surface plate bounding The paper also introduced some computing methods of bending shearing of various strengthening plans.Strengthened elements are second-bending members, whose working mechanism caused concrete stress lapping and priority of steel stress, which results in enlargement of deformation and widening cracks of normal beams when the concrete at the top of beams are cracked, and earlier yielding of the steel stress at the bottom of beams than normal beams. The shear stress checking at the superposition is the key to ensuring that the existing and the new structure work concurrently.The paper also made an analysis of finite element methods of surface stress of beams after partly debounding and discussed the effects of surface stress. Our results show the proper thickness of steel is 4~6mm, checking of the steel thickness in design should be done according to the maxim shear stress, and the suggested thickness of adhesives is 2-3mm so that the effects on surface stress can be reducedLastly, the author, based on his own experience of strengthening projects, introduced the procedures, suggested the key points in design and construction. The author hopes that all these will be of some reference value.更多还原