【作者】 屈凯锋；

【导师】 王正霖；

【作者基本信息】 重庆大学 ， 结构工程， 2002， 硕士

【摘要】 预应力混凝土技术已经在我国土木工程领域中得到越来越广泛的应用。预应力结构因其特殊的性能能显著解决大跨结构中混凝土梁的刚度问题,很好地控制裂缝和挠度问题,并可获得较大的安全储备。预应力混凝土超静定结构,更是以其优越的结构性能备受设计人员的青睐。但是，对于预应力混凝土超静定结构的受力性能，国内外预应力界的认识还普遍不够。例如在对预应力混凝土连续梁和框架的裂缝控制、次弯矩以及结构的塑性内力重分布尤其是弯矩重分布这些问题上还存在着广泛的争论。这些问题没有得到很好的解决，与缺乏系统的试验，尤其是有效的、大型足尺构件试验有很大的关系。对预应力连续梁，近年来重庆建筑大学一做了大量的足尺构件的试验研究，并取得了令人满意的研究结果。而对于预应力框架，目前国内所做的试验研究还较少，已做过的试验也主要是尺寸较小的模型试验，并基本仅考虑了竖向荷载的作用。为了对预应力框架的受力性能有一个全面深刻的认识，重庆建筑大学又制作了四榀接近足尺的单层单跨预应力框架，并对其中两榀同时施加水平荷载和竖向荷载进行了试验研究。对这样的大尺寸构件，该试验还开创性的利用试验验装置进行框架柱底嵌固进行模拟，并测出了柱底反力。本文针对两榀同时施加有水平荷载和竖向荷载的预应力框架，对其加载过程中的裂缝发展、结构的塑性弯矩重分布进行了探讨和研究。文中在参考重庆建筑大学多年研究成果的基础上，通过研究四榀预应力框架梁的裂缝发展情况，推荐了一套了实际结构工程设计中方便的裂缝控制方法——以名义拉应力γftk控制短期荷载及长期荷载作用下预应力梁的裂缝要求。本文重点研究了有水平荷载和竖向荷载同时作用下的单层单跨预应力框架的弯矩重分布问题。分析了预应力框架中的次弯矩对弯矩重分布的影响以及水平荷载作用对弯矩重分布的影响。最后，在综合考虑各因素的影响的情况下提出了一套弯矩调幅公式，对预应力框架的工程结构设计有一定的参考价值。更多还原

【Abstract】 The technique of prestressed concrete is already to get in our civil engineering realm more and more extensive application. Because of its special function the prestressed concrete shows the greatly advantages to resolve the lacking of stiffness of concrete beam, to nicely control the development of the cracks and deflection of beam and acquire bigger safety store in long span construction. For the statically indeterminate structure of pestressed concrete, it is especially have the favor of the designers by its superiority. However now days the cognition about the behavior of such structure under loads is not enough for the realm of prestressed concrete all of the word.For example still the arguments exist about the cracking controlling, the behavior of secondary moment and the re-distribution of internal forces, especially for the moment, of the prestressed concrete continues beam or frame. To some degree those existing problems is due to the lacking of plenty of experiments with enough-size members that can reflect the practical structures effectively. To the prestressed concrete continues beam, considerable experiments have been finished and nice achievements have been acquired at Chongqing JianZhu University (renamed Chongqing University since the year 2000) in these years. But few of experiments have been finished about the prestressed concrete frame. And the finished experiments were mainly based on members with the shorten size and the vertical loads. For the comprehensive cognition to the prestressed concrete frame, four monolayer and monospan frames is built, two of which are loaded only vertically and the other two are loaded vertically and horizontally at the same time. In the experiments the fixed supports of the bottom of the columns are simulated creatively and the reaction of forces is tested. In this article the development of the cracks and the moment redistribution are discussed based on the two frames which are loaded vertically and horizontally at the same time. On the base of the research about the prestressed concrete structures at Chongqing JianZhu University, a convenient and practical way to control the cracks is introduced in the pages, which is called the method of nominal tension stress that control the width of cracks by the nominal tension stress γftk under the working loads and the limited loads. The discussion is focused on the moment redistribution of the frames, the effects of the secondary moment and horizontal loads under the loads vertical and horizontal at the same time. In conclusion, a formulae about the moment distribution is introduced on the consideration of several factors, which is suggestive for the designing of practical prestressed concrete structures.更多还原