北京市古建筑大型石梁试验研究

发布时间：2018-10-14 16:01

【摘要】：近年来,我国对古建筑的加固修复越来越重视,在古建筑中独树一帜的石建筑也随之引起人们的关注。目前,已有的对石质构件的加固方法主要有碳纤维布加固、碳纤维筋加固、预应力加固和钢筋网砂浆加固等。研究发现,这些加固方法大多并不宜直接应用于文物建筑中,因为它们在不同程度上对原构件造成了一定的损伤,且很难实现古建筑可逆性的加固原则,在古建筑加固中有一定的局限性。此外,相关试验试件尺寸较小,而实际结构中多为大型构件,尺寸效应对试验误差的影响不容忽视。针对以上情况,本文在对石材材性试验的基础上,研发了体外预应力加固和角钢-PET带组合加固两种新型、实用的加固方法,并进行了23个大型石梁构件的受力性能试验,石材选用北京市古建筑中应用较多的青白石和汉白玉两种石材。分别研究了未加固石梁的受弯性能、3种不同加固方法加固石梁(CFRP加固、体外预应力加固、角钢-PET带组合加固)的受弯性能、未加固石梁的受剪性能、CFRP加固石梁的受剪性能。同时,对加固前后石梁的受力性能进行了对比分析。试验结果表明:(1)加固后,石梁的极限受弯承载力均有所提高,变形能力较未加固石梁典型的脆性破坏有所改善,且加固石梁断裂后仍有一定的承载力裕量;(2)石梁的抗剪能力较强,试验中均未出现石梁的剪切破坏,剪切破坏的工况在实际加固工程中仅需适当考虑;(3)开裂前,加固及未加固石梁跨中截面基本满足平截面假定,极限受弯承载力与石材材质、具体加固措施等有关。通过试验数据与理论分析的对比,提出了加固及未加固石梁受弯承载力及受剪承载力的简化计算公式,计算结果与试验结果吻合较好,对实际加固修复工程有一定的指导意义,实际加固工程中可根据具体的施工条件、经济条件等因素综合选取适宜的加固方法。
[Abstract]:In recent years, more and more attention has been paid to the reinforcement and restoration of ancient buildings. At present, the existing methods of strengthening stone members mainly include carbon fiber sheet reinforcement, carbon fiber reinforcement, prestress strengthening and reinforcement with mesh mortar, etc. It is found that most of these reinforcement methods are not suitable for direct application in cultural relic buildings, because they have caused certain damage to the original members in varying degrees, and it is difficult to realize the reinforcement principle of the reversibility of ancient buildings. There are some limitations in the reinforcement of ancient buildings. In addition, the size of the related test specimen is small, but the actual structure is mostly large, so the effect of size effect on the test error can not be ignored. In view of the above situation, on the basis of the tests on the properties of stone, two new and practical strengthening methods, external prestressed reinforcement and angle steel-PET combined reinforcement, are developed, and the mechanical performance tests of 23 large stone beam members are carried out. Stone used in ancient buildings in Beijing more use of green white stone and white jade two kinds of stone. The flexural behavior of unstrengthened stone beams, the flexural behavior of three different strengthening methods (CFRP reinforcement, external prestressing strengthening, angle steel-PET combined reinforcement), the shear behavior of unstrengthened stone beams and the shear behavior of CFRP strengthened stone beams are studied respectively. At the same time, the stress behavior of stone beam before and after reinforcement is compared and analyzed. The experimental results show that: (1) after strengthening, the ultimate flexural bearing capacity of the stone beam is improved, and the deformation capacity is improved compared with the typical brittle failure of the unstrengthened stone beam. And there is still a certain bearing capacity margin after the fracture of the strengthened stone beam. (2) the shear ability of the stone beam is relatively strong, there is no shear failure of the stone beam in the test, and the shear failure condition only needs to be properly considered in the actual strengthening project; (3) before the cracking, The cross section of the reinforced and unstrengthened stone beams basically meets the assumption of the horizontal section. The ultimate flexural capacity is related to the material of stone and the concrete reinforcement measures. By comparing the experimental data with the theoretical analysis, a simplified formula for calculating the flexural and shear bearing capacity of reinforced and unstrengthened stone beams is proposed. The calculated results are in good agreement with the experimental results, which is of certain guiding significance to the practical reinforcement and repair works. According to the concrete construction conditions, economic conditions and other factors, the appropriate reinforcement method can be comprehensively selected in the actual reinforcement project.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU363

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