超高性能混凝土在肋拱桥中的应用

发布时间：2018-01-09 21:51

本文关键词：超高性能混凝土在肋拱桥中的应用　出处：《长沙理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：超高性能混凝土是一种新型的复合材料,也叫活性粉末混凝土(Reactive Powder Concrete,RPC),对比普通混凝土来说,它具有超高强度、高韧性、高抗渗性和耐久性好等优点。实际工程中使用超高性能混凝土材料,可达到减小构件截面尺寸,减轻结构自重,节省材料用量,增长材料使用寿命的效果。超高性能混凝土最显著的优点是抗压强度极高,而拱体系结构属于压弯构件,充分利用了超高性能混凝土抗压强度高的特点,对于RPC肋拱桥优异的受力性能非常值得研究探讨。在国内外对超高性能混凝土展开的研究和应用背景下,本文对超高性能混凝土在肋拱桥中的应用进行了尝试性的探讨和研究,证明了超高性能混凝土应用到肋拱桥中的可行性和优越性。其主要内容和相应的研究成果如下：(1)用ANSYS软件对RPC矩形截面拱肋进行优化设计分析。优化设计以混凝土材料和拱肋截面尺寸为设计变量,在一定的挠度和应力范围内,使得拱肋体积取得最小值,得出矩形截面拱肋的最优截面尺寸,其高度和宽度约为普通混凝土的0.80h倍和0.833b;(2)对RPC肋拱桥和普通混凝土肋拱桥进行Midas建模,研究了两者的静力性能,对比RPC肋拱桥和普通混凝土肋拱桥的应力、弯矩、轴力、剪力的大小,得出RPC肋拱桥由于截面尺寸的减小,其拱肋应力要比普通混凝土的要高出20%～34%,而各荷载工况下RPC肋拱桥的弯矩、轴力、剪力要比普通混凝土肋拱桥的要小,减小大约14%～5%；(3)对RPC肋拱桥和普通混凝土肋拱桥进行动力特性分析,对比研究两者的自振频率和振型,得出截面尺寸减小后RPC肋拱桥前十阶自振频率比普通混凝土肋拱桥的要小,减小1%～15%；(4)通过比较两者拱肋竖向位移,研究了它们的刚度,得出RPC肋拱桥拱肋各控制截面的竖向位移要比普通混凝土的要大,前者是后者的1.01～1.12倍,证明RPC肋拱桥的刚度比普通混凝土肋拱桥的要小,并在理论上简要分析了RPC肋拱桥的抗裂性,得出其抗裂性得到增强；(5)对RPC肋拱桥和普通混凝土肋拱桥进行了稳定性分析,对比了它们稳定系数的大小,得出RPC肋拱桥由于结构尺寸的减小使得其稳定系数减小,减小23%～33%。
[Abstract]:Ultra-high performance concrete (UHPC) is a new type of composite material, also called reactive Powder concrete (RPC), compared with ordinary concrete. It has the advantages of ultra-high strength, high toughness, high impermeability and good durability. The use of ultra-high performance concrete material in practical engineering can reduce the section size of members, reduce the weight of the structure, and save the amount of materials. The most significant advantage of UHPC is that the compressive strength is very high, while the arch system structure belongs to the compression and bending member, which makes full use of the high compressive strength of UHPC. The excellent mechanical performance of RPC rib arch bridge is worth studying and discussing. In the research and application background of UHPC at home and abroad. In this paper, the application of ultra-high performance concrete in rib arch bridge is discussed and studied. The feasibility and superiority of UHPC applied to rib arch bridge are proved. The main contents and corresponding research results are as follows: 1). The optimum design of RPC rectangular section arch rib is analyzed by ANSYS software. The concrete material and arch rib section size are taken as the design variables in the optimization design. In a certain range of deflection and stress, the volume of arch rib is minimized, and the optimum section size of rectangular section arch rib is obtained. The height and width of arch rib are about 0.80h and 0.833bcompared with ordinary concrete. The static behavior of RPC rib arch bridge and ordinary concrete rib arch bridge is studied. The stress, bending moment and axial force of RPC rib arch bridge and ordinary concrete rib arch bridge are compared. Because of the decrease of section size, the stress of RPC rib arch bridge is 20% higher than that of ordinary concrete, and the bending moment and axial force of RPC rib arch bridge under different load conditions. The shear force is smaller than that of the ordinary concrete rib arch bridge. The dynamic characteristics of RPC rib arch bridge and ordinary concrete rib arch bridge are analyzed, and the natural vibration frequency and vibration mode of the two bridges are compared and studied. It is concluded that the natural vibration frequency of the first ten steps of the RPC rib arch bridge is smaller than that of the ordinary concrete rib arch bridge after the section size is reduced, and the frequency of the first ten steps of the RPC rib arch bridge is reduced by 15%. 4) by comparing the vertical displacement of the two arch ribs and studying their stiffness, it is concluded that the vertical displacement of each control section of the arch rib of RPC rib bridge is larger than that of ordinary concrete. The former is 1.01 ~ 1.12 times of the latter, which proves that the stiffness of RPC rib arch bridge is smaller than that of ordinary concrete rib arch bridge, and briefly analyzes the crack resistance of RPC rib arch bridge in theory. It is concluded that the crack resistance is enhanced. The stability of RPC rib arch bridge and ordinary concrete rib arch bridge is analyzed, and the stability coefficient of RPC rib arch bridge is obtained by comparing their stability coefficients. Reduce the number 23 to 33.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U444

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