【作者】 杨海旭；

【导师】 刘晚成；

【作者基本信息】 东北林业大学 ， 道路与铁道工程， 2002， 硕士

【摘要】 无粘结预应力结构作为一种方兴未艾的结构形式，在我国的应用日益广泛。对这种结构形式的理论研究早已经深入展开。工程实践又不断的为预应力混凝土学科的科技工作者提出了一系列问题，其中急需解决的一个问题就是怎样才能确定真实有效的预应力筋等效荷载。由于未能很好的把握预应力的本质，使预应力筋等效荷载的确定和计算没有完整、准确的方法，这会影响无粘结预应力结构的进一步推广和应用。本文的研究有望解决这一问题。 本文立足于有关的工程背景，深入分析了无粘结预应力结构的本质和特征，综合考虑了预应力混凝土的一些使用设计方法后，认为应该建立一个概念清晰、考虑全面、简捷实用、便于推广的等效荷载计算方法。本文从正确解决预应力筋等效荷载的角度出发，全面系统地阐述了加减约束法的基本概念，及应用价值。用加减约束法确定预应力筋的等效荷载，可以准确真实的反映出等效荷载的作用方向和数值大小，并使人们对等效荷载有了一个完整、清晰的概念，这一点是其它方法所不具备的。 本文在无粘结预应力混凝土折梁中先采用加减约束法确定的预应力筋等效荷载，然后又用一般计算手册所提供的现成公式对等效荷载进行了计算，将两种计算结果及其对预应力筋有效预加力的影响作了比较分析。 由于建筑造型日趋多样化和无粘结预应力技术的广泛应用，经常会遇到无粘结预应力折梁的设计与应用。由于预应力筋等效荷载确定方法上的不完善，限制了无粘结预应力混凝土折梁的应用，使建筑设计方案无法实施。为了解决这一问题，本文采用加减约束法对无粘结预应力折梁进行了定性的分析与计算，对于折梁在施工阶段和使用阶段的裂缝控制问题进行了全面系统的论述，消除了人们对折梁在转折点处开裂问题的担心，认为根据建筑造型和使用要求，完全可以在实际工程应用中采用无粘结预应力混凝土折梁。并且在发挥预应力筋的作用方面，折梁同直梁相比，有更大的应用优势。 最后，本文对加减约束法的进一步理论分析工作提出了建议。更多还原

【Abstract】 As a novel structure style, unbonded prestressed concrete structure have been widely applied in china, and prossess capacious prospect. Although the relative research has been carried out and obtained some achievements. Engineering practice provides a series of problems in prestressed concrete science to experimental engineering continually. One of the problems that should be solved above all is how to decide the real and effective pretressed steel equivalent load. Because the natcre aren’t be grasped and understood exactly, there aren’t a complete and exact method on computing and determining prestressed steel equivalent load.This situation will obstract further application of prestressed concrete structure. The work of this paper tries to develop the research on the subject.Based on relevant engineer backgrounds, deeply analyzing the nature and characteristis of unbonded prestressed concrete structure, conceiving comprehensively some practical designing methods of prestressed concrete, this paper considers that a computational method of equivalent load should be established which has exact concept and be thought comprehensively and be used conviently and practically and rapidly. From the point of view to solve prestressed steel equivalent load, this paper comprehensively and systematically discusses the basic concept of dding and substracting constraints method and practical value. Using adding and substracting constraints method to decide prestressed steel equivalent load, it can provides the real affecting orientation and magnitude, and set up a complete and exact concept of equivalent load in human beings’brain. Other methods havn’t the excellence.At first, this paper uses adding and substracting constraints method in unbonded prestressed concrete polygonal beam, then second uses nomal formulas existed in practical computational manual to compute equivalent load. Finally, the two computational results and its effect on prestressed steel effective prestressed stress be analyzed and compared.Because of the polytrope of architectural style and unbonded prestressed concrete structure used widely day after day, the designing and applicatiion of unbonded prestressed concrete polygonal beam often be centered.Because of unperfectio of computational method on prestressed steel equivalent load, the application of unbonded prestressed concrete polygonal beam is limited and architectural schemes cann’t be adopted. To solve this problem, this paper uses adding and substracting constraints method to analyze and compute unbonded prestressed concrete polygonal beam qualitatively. This paper also comprehensively and systematically discusses the problem of controlling crack in con-structure phase and using phase, which let people unworry about the polygonal beam cracking in luring point.Based on architectural style and requirement in use , unbonded prestressed concrete polygonal beam can be used completely in practically engineering.On performing the effect of prestressed steel, polygonal beam has more dominance in application than straight line beam.In the last part of paper, some suggests about later analyzing work of adding and substracting constraints method are refereed.更多还原