【作者】 胡志旺；

【导师】 宋一凡；

【作者基本信息】 长安大学 ， 结构工程， 2009， 硕士

【摘要】 由于体外预应力结构体系与有粘结和无粘结预应力结构体系相比较而言,具有很多优点,近年来这种结构形式在世界范围内得到了广泛的运用和不断的创新。然而,从现有资料看,我国对这一新技术的研究和应用多限于既有结构的加固,对新建体外预应力结构的力学性能的研究还不够深入。本文在分析研究国内外大量试验研究资料、设计规范以及相关文献的基础上,通过对五根简支梁和四根两跨连续梁的试验,较系统地研究分析了应力增量和挠度变形计算的原理与方法,具体研究工作如下:简述了体外预应力混凝土结构的发展和研究现状,综合分析了体外预应力结构在极限承载力下的各种计算理论,并讨论了各自的优缺点。在荷载作用下体外力筋的位移和梁截面无关,体外力筋的应力变化可以通过整根梁的变形协调条件得到。通过对应力增量与挠度变化内在规律的分析,推导出了不同布筋形式、不同加载方式下的基于挠度变化的应力增量计算公式,该公式适用于简支梁、超静定梁。精心设计制作了九根体外预应力混凝土梁,包括5根简支梁、4根两跨连续梁,并对它们进行了静载试验。试验中量测了梁的位移、混凝土的应变以及体外筋的应力增量等关键数据,并对试验结果进行了分析。试验结果分析发现,体外力筋的应力增量与梁跨中挠度成直线或近似直线关系。对比体外预应力筋应力增量计算值和试验值后发现,基于挠度变化的应力增量计算公式与试验结果相比,精度大体接近。更多还原

【Abstract】 Compared with traditional prestressing, external prestressing system has its own merits. That is why this kind of structure has been widely used and constantly innovated all over the world in recent years. But, As far As existing information is concerned, the study and application of this new technique are almost limited in existing structural’s strengthening, mechanical behavior studies of new concrete structural with external prestressing still lack very much. Based on the analysis of a large number of pilot studies at home and abroad research data, specifications, as well as the basis of ralated literature, through the five simply supported beam and four two-span continuous beam test, more systematic analysis of stress increment and deflection deformation of the principle and method of caculation, specific research work are as follows:On the in vitro development of prestressed concrete structures and research, comprehensive analysis of externally prestressed structures at the ultimate bearing capacity under a wide variety of computing theory, and discussed their respective advantages and disadvantages.At loads lower body external tendons of beam displacement and nothing to do with the stress in vitro tendon force can change the entire root beam deformation conditions are. Through the incremental stress and deflection analysis of the inherent law changes, derived from a different cloth reinforcement forms, under different loading mode changes based on the deflection formula for calculating the stress increment, the formula applies to simply supportes beams and statically indeterminate beams.Specimens of 9 external prestressing concrete beams, including 5 simply-supported beams and 4 two-span continuous beams , and the static load tests were finished. Several critical dates as deformations,strains of the beams and the stress increments of external tendons were measured, and the test results were analyzed. Analysis of test results found that in vitro ten don force and the stress increment in the deflection of beam cross-linear or approximate linear relationship.After comparing calculated values with experimental values of stress incremeng of exermally prestressed tendons. based on the deflection formula for calculating the stress increment by this formula is almost as accurate as the result of the test.更多还原