体外预应力加固PC箱梁的非线性分析
发布时间：2018-08-17 09:10
【摘要】：在桥梁运营过程中,大量桥梁或多或少存在不同程度的的病害,对桥梁的安全性和耐久性产生严重的影响,需对其进行加固改造。体外预应力加固方法就是布置在被加固结构体外的预应力筋通过锚固系统和转向系统与被加固结构连接并把一定的预加力施加其上,抵消部分由外荷载产生的内力,从而改善结构的受力状态,提高结构的承载力、抗裂性和减小变形的方法。本文主要进行了以下工作:(1)从设计、施工和运营管理方面分析总结了在役桥梁产生病害的原因,对常用加固技术的优势及局限性进行对比分析。(2)研究了体外预应力加固的基本原理,结构内力和应力增量的计算公式,并对其进行比较。从截面平衡,整体协调变形出发,推导了体外预应力筋应力增量的计算公式。(3)以体外预应力简支箱梁为研究对象,利用软件Midas FEA建立13个三维有限元模型,在建模时考虑材料非线性和开裂后加固的几何非线性,利用施工阶段真实模拟加固全过程进行非线性分析。从承载力、挠度、应力和裂缝扩展情况入手研究分析了高跨比、转向块布置、综合配筋率和张拉控制应力对加固后桥梁受力性能的影响。(4)以一座四跨连续箱梁桥为工程背景,进行了体外预应力加固箱梁的设计计算,从承载力、挠度和裂缝扩展等多方面对比分析非线性条件下加固前后桥梁的工作状态,证明采用体外预应力加固满足设计荷载要求,并为以后同类工程设计施工提供一定的经验和借鉴。
[Abstract]:In the process of bridge operation, a large number of bridges have more or less different degrees of disease, which has a serious impact on the safety and durability of the bridge, so it needs to be strengthened and reformed. The method of external prestressing reinforcement is that the prestressed tendons arranged outside the strengthened structure are connected to the strengthened structure through the anchor system and steering system and applied certain prestressing forces to counteract some internal forces generated by external loads. In order to improve the stress state of the structure, increase the bearing capacity of the structure, crack resistance and the method of reducing deformation. The main work of this paper is as follows: (1) from the aspects of design, construction and operation management, the causes of existing bridge diseases are analyzed and summarized. The advantages and limitations of common reinforcement techniques are compared and analyzed. (2) the basic principle of external prestressing reinforcement and the calculation formula of internal force and stress increment of structure are studied and compared. In this paper, the calculation formula of stress increment of external prestressed tendons is derived from section balance and overall coordinated deformation. (3) taking external prestressing simply supported box girder as research object, 13 3D finite element models are established by using software Midas FEA. Considering the material nonlinearity and the geometric nonlinearity of post-cracking reinforcement, the nonlinear analysis is carried out by using the real simulation of the whole process of reinforcement in the construction stage. Based on the analysis of bearing capacity, deflection, stress and crack propagation, the effects of high span ratio, steering block arrangement, comprehensive reinforcement ratio and tension control stress on the mechanical performance of strengthened bridge are analyzed. (4) A four-span continuous box girder bridge is used as the engineering background. The design and calculation of the box girder strengthened by external prestressing are carried out, and the working state of the bridge before and after strengthening under nonlinear conditions is compared and analyzed from the aspects of bearing capacity, deflection and crack expansion, and it is proved that the external prestressing reinforcement meets the design load requirements. And for the future similar engineering design and construction to provide certain experience and reference.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72
本文编号：2187149
[Abstract]:In the process of bridge operation, a large number of bridges have more or less different degrees of disease, which has a serious impact on the safety and durability of the bridge, so it needs to be strengthened and reformed. The method of external prestressing reinforcement is that the prestressed tendons arranged outside the strengthened structure are connected to the strengthened structure through the anchor system and steering system and applied certain prestressing forces to counteract some internal forces generated by external loads. In order to improve the stress state of the structure, increase the bearing capacity of the structure, crack resistance and the method of reducing deformation. The main work of this paper is as follows: (1) from the aspects of design, construction and operation management, the causes of existing bridge diseases are analyzed and summarized. The advantages and limitations of common reinforcement techniques are compared and analyzed. (2) the basic principle of external prestressing reinforcement and the calculation formula of internal force and stress increment of structure are studied and compared. In this paper, the calculation formula of stress increment of external prestressed tendons is derived from section balance and overall coordinated deformation. (3) taking external prestressing simply supported box girder as research object, 13 3D finite element models are established by using software Midas FEA. Considering the material nonlinearity and the geometric nonlinearity of post-cracking reinforcement, the nonlinear analysis is carried out by using the real simulation of the whole process of reinforcement in the construction stage. Based on the analysis of bearing capacity, deflection, stress and crack propagation, the effects of high span ratio, steering block arrangement, comprehensive reinforcement ratio and tension control stress on the mechanical performance of strengthened bridge are analyzed. (4) A four-span continuous box girder bridge is used as the engineering background. The design and calculation of the box girder strengthened by external prestressing are carried out, and the working state of the bridge before and after strengthening under nonlinear conditions is compared and analyzed from the aspects of bearing capacity, deflection and crack expansion, and it is proved that the external prestressing reinforcement meets the design load requirements. And for the future similar engineering design and construction to provide certain experience and reference.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72
【参考文献】
相关期刊论文 前1条
1 申同生,戴公连,方淑君;求解无粘结预应力混凝土梁力筋应力增量的能量法[J];国外公路;2000年05期
，本文编号：2187149
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