某混凝土连续梁桥中预应力钢束受力特性分析

发布时间：2018-05-24 13:05

本文选题：应力损失 + 有效应力　；参考：《河北工程大学》2015年硕士论文

【摘要】：预应力混凝土桥梁上部结构中的预应力钢束的有效应力计算是预应力设计中的关键步骤。预应力钢束的有效应力等于钢束预应力张拉值减去预应力损失。但是在实际的桥梁工程中,预应力钢束应力损失的影响因素很多,结构的施工过程和使用过程中造成计算误差的成因也很复杂,最终难以得到较为精确的有效预应力值。相关规范给出了预应力设计阶段中计算钢绞线应力损失的几种情况及对应的计算公式,按照规范计算出的钢束各项预应力损失与实测值基本一致,但仍存在一定误差。钢绞线的有效预应力实际值和计算值之间的误差可直接影响到结构的寿命和使用性能,二者差值过大甚至会导致桥梁出现安全事故。因此我们需要更加细致和全面地掌握预应力钢束在实际使用情况下的有效应力,以此为依据来指导预应力设计,以此为参考来了解桥梁的使用性能,并以此为前提条件来进行结构的评估和检测。本研究运用有限元理论对某预应力混凝土曲线桥梁工程实例进行了一系列计算分析。首先得出该曲线箱梁在自重作用下受力特点,后通过探索曲线箱梁受力状态随曲率半径的变化规律和钢束张拉次序对结构受力性能分析全面掌握了该箱梁及其预应力钢束的受力状态。最后分别采用传统有效应力计算理论和有限元分析计算两种方法对比该工程实例中的预应力钢束的有效应力,两种计算结果数值接近且规律相似,进一步得到箱梁不同部位预应力钢束的应力损失规律。计算结果肯定了本研究所使用的有限元建模理论的正确性,可对类似箱梁的相关研究提供一定参考价值。
[Abstract]:The calculation of the effective stress of prestressed steel bundle in the superstructure of prestressed concrete bridge is a key step in the design of prestressed concrete bridge. The effective stress of the prestressed steel bundle is equal to the prestressing tensioning value minus the prestress loss. However, in the actual bridge engineering, there are many factors affecting the stress loss of prestressed steel beam, and the causes of the calculation error in the construction process and the use process of the structure are also very complicated, so it is difficult to obtain the more accurate effective prestress value. Several cases and corresponding formulas for calculating the stress loss of steel strands in the stage of prestress design are given in the relevant codes. The calculated prestressing loss of steel strands according to the code is basically consistent with the measured values, but there are still some errors. The error between the actual value of effective prestress and the calculated value of steel strand can directly affect the service life and performance of the structure. The difference between the two values is too large and even leads to the safety accident of the bridge. Therefore, we need to grasp the effective stress of prestressed steel bundle in practical use more meticulously and comprehensively, so as to guide the design of prestressing force, and use it as a reference to understand the performance of the bridge. And take this as the premise condition to carry on the structure appraisal and the inspection. In this paper, the finite element theory is used to calculate and analyze a prestressed concrete curved bridge project. First of all, the stress characteristics of the curved box girder under the action of deadweight are obtained. After that, the stress state of the box girder and its prestressed steel beam are fully grasped by exploring the variation of the stress state of the curved box girder with the curvature radius and the tension sequence of the steel bundle. Finally, the traditional effective stress calculation theory and the finite element analysis method are used to compare the effective stress of the prestressed steel beam in the engineering example. The results of the two methods are close and the law is similar. Furthermore, the stress loss law of prestressed steel bundle in different parts of box girder is obtained. The calculation results confirm the correctness of the finite element modeling theory used in this paper, and can provide some reference value for similar box girder research.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441

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