基于GFRP体内不配筋混凝土桥面结构工作性能研究

发布时间：2018-06-02 01:30

本文选题：GFRP + 桥面板　；参考：《华南理工大学》2014年硕士论文

【摘要】：钢筋混凝土梁板式桥梁结构因其良好的受力性能、造价便宜等优点而广泛用于高速公路桥梁建设中。通常情况下碱性混凝土包裹着钢筋，使得钢筋具有一定的耐腐蚀性。近年来环境污染问题日益严重以及除冰盐的大量使用，现实中的钢筋混凝土桥梁通常是带裂缝工作，钢筋暴露在外环境下导致钢筋的锈蚀、外保护层的脱落，这将影响结构的承载能力，增加桥梁的维修成本。纤维增强聚合物筋材（FRP bar）在外层酸性树脂保护层的包裹下具有一定抗化学腐蚀能力，同时具有自重轻、强度高、膨胀系数同混凝土相近等优点，为土木工程师解决桥梁的抗腐蚀、提高使用年限带来了希望。现行FRP筋混凝土结构设计规范配筋率要高于钢筋混凝土板配筋率，加之FRP筋材的价格又高于钢筋价格，因此阻碍了FRP筋材的推广应用。研究表明：传统梁板式混凝土桥梁中存在压缩薄膜效应。在桥梁面板设计时考虑这种效应，能够降低配筋率，降低建造成本。为了能够更为显著地降低维护成本，本课题设计一种新型的桥梁面板结构，采用GFRP锚杆作为横向约束构件、桥面板内不配筋材，结合压缩薄膜效应对模型进行结构设计和计算。该新型结构体系外置GFRP筋材与混凝土的没有直接接触，避免了碱性的混凝土对GFRP酸性外保护层的损害。本文主要进行了一下几个方面的工作： 1.在前期改变支撑梁宽度的基础上增加了两组试验，改变外置GFRP横向约束构件间距、和加载位置，对1:3比例缩小的桥面板进行静力加载试验，测量模型在加载过程中的承载力、应变、变形等数据，考察该新型结构面板的基本力学性能，对承载力计算方法进行探讨。因为本次试验为全GFRP配筋桥面结构，，通常FRP受弯梁的延性较差，因此在研究了GFRP混凝土梁的抗弯延性进行了初步研究，并将研究的成果用在了新型整桥试验中。 2.研究和分析桥面板在轮胎荷载作用下，支撑梁的侧向位移、桥面板的裂缝扩展形态和破坏形式，揭示压缩薄膜效应的变化及对结构性能的影响。 3.利用通用有限元软件Abaqus对模型静力加载过程进行模拟。模拟结果能够较好的与实验数据吻合程度较好，充分证明有限元模型的合理性，在此基础上进行新型整体面板模型参数分析。通过试验和有限元分析发现：支撑梁宽度、外置GFRP横向约束构件、桥面板截面形式对整体面板的承载力有较大的影响。该新型桥面结构能够在保证桥梁结构在承载力和建造费用不受影响的情况下，有效的提高结构的耐久性，降低维护费用，解决了桥梁面板频繁置换钢筋对交通运输的干扰与环境的破坏。
[Abstract]:Reinforced concrete beam-slab bridge structure is widely used in highway bridge construction because of its good mechanical performance and low cost. Usually, alkaline concrete is wrapped in steel bar, which makes the steel bar corrosion resistant to a certain extent. In recent years, the problem of environmental pollution is becoming more and more serious and the extensive use of deicing salt. In reality, reinforced concrete bridges usually work with cracks. The exposure of steel bars to the outside environment leads to the corrosion of steel bars and the fall off of the outer protective layer. This will affect the bearing capacity of the structure and increase the maintenance cost of the bridge. Fiber reinforced polymer bar (FbarRP) has some advantages such as light weight, high strength, close coefficient of expansion and so on, under the cover of outer layer of acid resin, it has the ability to resist chemical corrosion, and has the advantages of light weight, high strength and close to that of concrete, etc. It brings hope for civil engineers to solve the corrosion resistance of bridges and improve their service life. The reinforcement ratio of current FRP reinforced concrete structural design code is higher than that of reinforced concrete slabs, and the price of FRP reinforcement is higher than that of steel bar, which hinders the popularization and application of FRP reinforcement. The results show that the compression film effect exists in the traditional beam-slab concrete bridge. Considering this effect in the design of bridge panel, the reinforcement ratio can be reduced and the construction cost can be reduced. In order to reduce the maintenance cost more significantly, a new type of bridge panel structure is designed in this paper, in which GFRP anchor is used as the transverse constraint member, the bridge deck is not reinforced, and the model is designed and calculated with the compression membrane effect. The new structure system has no direct contact with concrete, which can avoid the damage of alkaline concrete to the acidic outer protective layer of GFRP. This article mainly carries on the following several aspects of work: 1. On the basis of changing the width of supporting beam in the early stage, two groups of tests were added to change the spacing and loading position of the lateral restrained members of the external GFRP. The static loading test was carried out on the bridge deck plate which was scaled down at 1:3, and the bearing capacity of the model was measured during the loading process. The basic mechanical properties of the new structural panel are investigated and the calculation method of bearing capacity is discussed. Because the ductility of FRP flexural beam is usually poor for the whole GFRP reinforced bridge deck structure, the flexural ductility of GFRP concrete beam is studied preliminarily, and the results are applied to the new type of bridge test. 2. The lateral displacement of the supporting beam and the crack propagation and failure form of the bridge deck are studied and analyzed under the tire load. The change of the compression film effect and the influence on the structure performance are revealed. 3. The static loading process of the model is simulated by the universal finite element software Abaqus. The simulation results are in good agreement with the experimental data, which fully proves the rationality of the finite element model. On this basis, the parameter analysis of the new integral panel model is carried out. Through the test and the finite element analysis, it is found that the width of the bracing beam, the lateral restrained member of the external GFRP and the section form of the deck slab have great influence on the bearing capacity of the whole slab. The new bridge deck structure can effectively improve the durability of the bridge structure and reduce the maintenance cost without affecting the bearing capacity and construction cost of the bridge structure. It solves the interference and environment damage caused by the frequent replacement of steel bar on bridge face.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.31

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