体外预应力加固变截面梁的应用研究

发布时间：2018-02-16 00:13

本文关键词： 体外预应力加固设计仿真模拟加固评价　出处：《沈阳建筑大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着时代的发展,对桥梁事业的发展提出了更高的要求。然而我国现存的很多旧桥已经无法满足现有的交通需求,桥梁病害日益突出,严重影响交通运输。对旧桥进行加固维修成为了目前解决此类问题的主要方法之一。体外预应力加固法在众多加固方法中以其简单,方便,加固时不影响交通,有效的提高结构刚度等优点,近年来被广泛的应用到桥梁加固之中。本文依托实践工程,以变截面连续梁桥的体外预应力加固技术为研究对象。通过病害成因分析、有限元软件模拟、施工监测数据对比,对体外预应力加固技术进行分析与评价。本文采用数值模拟以及理论分析的方法,对体外预应力加固变截面连续梁桥的加固机理、加固设计、加固效果评价等方面进行了细致的分析和研究。这不仅具有重要的理论意义,还能为以后的体外预应力加固设计提供参考。本文研究主要内容如下：1)通过介绍国内外桥梁现状,论述加固的重要意义以及紧迫性。同时简单介绍了体外预应力加固法在国内外的研究现状及其优缺点。2)对比分析各种适合桥梁加固方法的特点以及适用范围,着重介绍了采用体外预应力的加固方法的优缺点及其加固机理。针对体外预应力的加固技术,分别从体外预应力的加固方法、体系的基本组成、体内外预应力的理论计算异同等方面进行理论阐述。3)为避免引起共振的影响,通过计算确定合理的体外预应力索的自由长度范围,根据体外预应力结构的布置原则对体外索的线形布置进行优化计算,从这两方面来对体外索的布置形式进行优化设计。4)利用有限元软件Midas/civil对国内某大桥体外预应力加固进行仿真模拟分析,分别从加固前后的应力状态,位移变化等方面进行比较分析。结果表明：利用体外预应力加固变截面连续后,桥梁线形得到有利的恢复,主梁压应力储备明显,裂缝缩小甚至消失。说明体外预应力加固变截面连续梁应用的可行性。5)通过模拟分析,对此大桥进行体外预应力加固设计,对比分析加固前后的监测数据。通过各工况下主梁变形监测点处的挠度理论值与实测值的对比分析,可以得到以下结论：体外预应力在张拉完毕的各个工况下挠度的增量正常。各张拉阶段主梁应力变化以及挠度变形的实测值与Midas计算分析得出的结果相近,偏差很小,变化趋势一致。说明施工效果达到了设计的预期效果。同时也验证了采用Midas/civil对体外预应力加固施工的模拟的合理性。
[Abstract]:With the development of the times, higher requirements have been put forward for the development of bridges. However, many existing old bridges in our country have been unable to meet the existing traffic demand, and the bridge diseases are becoming increasingly prominent. The reinforcement and maintenance of old bridges has become one of the main methods to solve this kind of problems. In many reinforcement methods, the external prestressing reinforcement method is simple, convenient and does not affect the traffic. In recent years, it has been widely used in bridge reinforcement. Based on practical engineering, the external prestressing reinforcement technology of variable section continuous beam bridge is taken as the research object. Finite element software simulation, comparison of construction monitoring data, analysis and evaluation of external prestressing reinforcement technology are carried out. In this paper, the reinforcement mechanism of externally prestressed continuous beam bridge with variable cross-section is analyzed by numerical simulation and theoretical analysis. The design of reinforcement and the evaluation of reinforcement effect are analyzed and studied in detail, which is not only of great theoretical significance, but also of great theoretical significance. The main contents of this paper are as follows: (1) by introducing the current situation of bridges at home and abroad, This paper discusses the importance and urgency of reinforcement. At the same time, it simply introduces the research status and advantages and disadvantages of external prestressing reinforcement method at home and abroad. This paper mainly introduces the advantages and disadvantages of the external prestressing strengthening method and its strengthening mechanism. In view of the external prestressing strengthening technology, the basic composition of the external prestressing reinforcement method and the system are introduced respectively. In order to avoid the influence of resonance, the reasonable free length range of external prestressing cable is determined by calculation. According to the layout principle of external prestressing structure, the linear arrangement of external cable is optimized and calculated. From these two aspects to optimize the external cable layout design. 4) using the finite element software Midas/civil to simulate and analyze the external prestressing reinforcement of a bridge in China, respectively from the stress state before and after reinforcement. The results show that the linear shape of the bridge can be recovered and the compressive stress reserve of the main beam is obvious after the continuous reinforcement of the variable section by external prestressing. The feasibility of using external prestressing to reinforce continuous beams with variable cross-section is illustrated. 5) through simulation analysis, the external prestressing reinforcement design of this bridge is carried out. The monitoring data before and after reinforcement are compared and analyzed. The deflection of the main beam deformation monitoring point is compared with the measured value under various working conditions. The following conclusions can be drawn: the deflection increment of external prestressing is normal under every working condition after tensioning. The measured values of stress change and deflection deformation of the main beam in each tensile stage are close to those obtained by Midas calculation and analysis, and the deviation is very small. The trend of change is consistent, which indicates that the construction effect has reached the expected effect of design. At the same time, it also verifies the reasonableness of using Midas/civil to simulate the external prestressing reinforcement construction.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.72

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