朔黄铁路超低高度预应力混凝土梁重载改造技术研究

发布时间：2018-02-12 20:50

本文关键词： 重载运输铁路桥梁超低高度预应力混凝土简支T梁折减系数加固改造　出处：《中国铁道科学研究院》2014年硕士论文　论文类型：学位论文

【摘要】：铁路重载运输具有运能大、效率高、运输成本低等优势，是大宗货物最为经济有效的运输方式，发展30t及以上轴重货车重载运输是朔黄铁路货运发展的主要方向之一。本文以朔黄铁路跨度24m、32m超低高度预应力混凝土简支T梁为研究对象，对30t及以上轴重货车作用下梁体的承载能力和重载改造技术进行了深入研究。根据运营货车活载效应检算分析，受二期恒载增加和设计参数变化的影响，中-活载作用下，超低高度预应力混凝土简支梁的部分参数已不满足现行铁路规范的要求；1.2倍ZH（2010）活载作用下，，梁体的抗裂安全系数、强度安全系数和竖向刚度均不满足现行铁路规范的要求，因此，需对梁体进行重载加固改造；受梁体高度限制，常用的加固方法难以达到加固效果，超低高度梁的重载改造难度大。通过多种加固方案的综合比选，选取顶升预弯辅助钢梁的方案，对跨度24m、32m超低高度预应力混凝土梁进行重载加固改造。该方案的具体思路为：原混凝土梁与预弯辅助钢梁在跨中截面进行横向连结形成共同受力结构，二者在活载作用下跨中挠度协调一致，混凝土梁和钢梁按竖向刚度分配活载效应；同时考虑到混凝土实际弹性模量较设计值大、结果检算未考虑挡碴墙对截面特性的影响、作用于混凝土梁和钢梁的荷载图式不同等因素，引入辅助钢梁活载分配折减系数，模拟原混凝土梁的实际受力状态；通过顶升预弯辅助钢梁，使钢梁在分担原混凝土梁活载的同时承担原梁的部分恒载，达到梁体重载改造的目的。跨度24m、32m超低高度预应力混凝土简支T梁采用顶升预弯辅助钢梁的加固方案，在1.2倍ZH（2010）活载作用下，梁体的抗裂安全系数、强度安全系数和竖向刚度等指标满足现行铁路桥梁规范的要求，能够达到梁体重载改造的目的，对保证朔黄铁路重载运输顺利实施具有重要意义。
[Abstract]:Heavy haul railway transportation has the advantages of large capacity, high efficiency, low transportation cost and so on. It is the most economical and effective way to transport large quantities of goods. It is one of the main development directions of freight transportation of Shuohuang railway to develop the heavy load transportation of freight cars of 30 t and above. This paper takes the simply supported T-beam of prestressed concrete with a span of 24m and 32m in the span of Shuohuang Railway as the research object. The bearing capacity and heavy load modification technology of the beam body under the action of 30 t and above axle load freight cars are studied in depth. According to the analysis of the live load effect of the operating freight car, under the influence of the increase of the second stage dead load and the change of the design parameters, under the action of mid-live load, Some parameters of ultra-low height prestressed concrete simply supported beam can no longer meet the requirements of current railway code (1.2 times ZH / 2010). Under the action of live load, the safety factor of crack resistance, strength safety factor and vertical stiffness of beam body do not meet the requirements of current railway code. Therefore, it is necessary to carry on the heavy load reinforcement to the beam body; limited by the beam body height, the commonly used reinforcement method is difficult to achieve the reinforcement effect, and the super-low height beam heavy load reconstruction is difficult. Through the comprehensive comparison and selection of various reinforcement schemes, the scheme of jacking pre-bending auxiliary steel beam is selected. The super-low height prestressed concrete beam with a span of 24m ~ 32m is retrofitted under heavy load. The concrete idea of the scheme is that the original concrete beam and the pre-bending auxiliary steel beam are connected horizontally in the middle section of the span to form a common force structure. Under the action of live load, the deflection of the two beams is consistent, the concrete beam and steel beam distribute the live load effect according to the vertical stiffness, and considering that the actual elastic modulus of concrete is larger than the designed value, the effect of the ballasted retaining wall on the section characteristic is not taken into account in the calculation. The load pattern of concrete beam and steel beam is different from other factors, the load distribution reduction coefficient of auxiliary steel beam is introduced to simulate the actual force state of the original concrete beam, The steel beam can share the live load of the original concrete beam and bear part dead load of the original beam at the same time, so as to achieve the purpose of reconstructing the beam body under heavy load. The simply supported T-beam of prestressed concrete with a span of 24m ~ 32m is reinforced with a steel beam supported by jacking pre-bending. Under the action of 1.2 times ZH / 2010), the safety factor of crack resistance of the beam is obtained. The indexes such as strength safety factor and vertical stiffness can meet the requirements of the current railway bridge code and can achieve the purpose of reconstructing the beam body. It is of great significance to ensure the smooth implementation of heavy haul transportation of Shuohuang railway.
【学位授予单位】：中国铁道科学研究院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U239.4;U445.6

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