钢—超薄UHPC层轻型组合桥面性能研究

发布时间：2018-06-18 04:37

本文选题：桥梁工程 + 超薄UHPC层　；参考：《湖南大学》2015年硕士论文

【摘要】：为了将更薄的超高性能混凝土UHPC(Ultra-High Performance Concrete)层与正交异性钢桥面组合形成正交异性钢桥面-超薄UHPC层轻型组合桥面(以下简称为钢-超薄UHPC组合桥面),使之适用于设计铺装层较薄(50mm~55mm)的桥面结构,而尽量不改变原桥梁结构的受力状态,本文对钢-超薄UHPC组合桥面结构的基本性能进行了研究。钢-超薄UHPC组合桥面就是将薄至35mm的UHPC层与正交异性钢桥面板结合形成组合结构,并将UHPC层内的钢筋网直接焊接于正交异性钢桥面顶板上,用以承担两者之间的剪力。除了35mm的UHPC层外,组合桥面整体还包括铺设在UHPC层上15~20mm厚的磨耗层。这种组合桥面结构需要在保证其安全性、耐久性等基本使用性能的前提下,通过降低自身的厚度,扩大适用范围,从而同时达到增加桥面刚度,降低了正交异性钢桥面的疲劳开裂风险,避免采用传统沥青铺装时出现的铺装层病害问题。本文是以润扬长江公路大桥南汊悬索桥作为研究对象,拟对其正交异性钢桥面进行钢-超薄UHPC组合桥面板方案的研究,本论文主要完成了以下工作:(1)论述了传统正交异性钢桥面板及其铺装的病害问题,提出了钢-超薄UHPC组合桥面方案,阐述其构造特点和在组合桥面设计中的必要性。(2)利用有限元软件Midas对润扬长江大桥的钢-超薄UHPC组合桥面方案进行整体计算。计算结果表明,采用组合桥面对大桥整体受力影响很小,对结构整体安全性基本没有影响。(3)利用ANSYS有限元软件对钢-超薄UHPC组合桥面进行了基于热点应力法的局部轮载分析,使用国内规范规定的汽车荷载对组合桥面进行分析,由分析的结果得知,35mm厚UHPC层对正交异性钢桥面板受力性能改善明显,钢桥面顶板应力幅下降达到68.72%,U肋和横隔板应力幅下降接近11.98%到32.38%,因此可大大降低钢桥面板疲劳开裂风险。同时计算得出的UHPC层表面最大拉应为7.48MPa,横桥向最大拉应力为7.36MPa。(4)对35mm厚UHPC层组合板进行横桥向抗弯试验研究,试验结果表明:UHPC层的开裂强度和极限强度与其截面配筋率密切相关。随着配筋率的增大,抗弯强度逐渐提高,开裂应力也逐渐增大。B5试件UHPC表层最小开裂应力已经达到了26.3MPa,是理论计算中横桥向拉应力7.36MPa的将近3.6倍,可以认为,在规定的汽车荷载作用下,UHPC表层产生的最大拉应力小于试验得出的UHPC层能够承担的拉应力,因此是能够保证结构安全可靠的,证明了此新型组合桥面结构的可行性。(5)阐述了钢桥疲劳评估的基本理论,简述了钢桥疲劳设计的三种方法,对美国、欧洲和中国钢桥疲劳设计规范进行了简要的对比。对润扬长江大桥钢-超薄UHPC组合板方案的疲劳寿命进行评估,引入热点应力法,根据欧洲规范(Eurocode)确定疲劳荷载模型,计算其热点应力并确定最不利构造细节的应力频值谱,最后通过热点应力S-N曲线和Miner线性累积损伤理论确定其疲劳寿命。
[Abstract]:In order to combine the thin UHPC-UHPC Ultra-High performance concrete deck with orthotropic steel deck to form the light composite deck of orthotropic steel deck and ultra-thin UHPC layer (hereinafter referred to as the steel-ultra-thin UHPC composite deck), it is suitable for the design of UHPC composite deck. A bridge deck structure with a thin overlay of 50 mm to 55 mm, The basic performance of steel-ultrathin UHPC composite deck structure is studied in this paper. The composite deck of steel and ultra-thin UHPC is composed of 35mm layer and orthotropic steel bridge panel, and the steel mesh in the layer is welded directly to the roof of orthotropic steel deck, which is used to bear the shear force between them. In addition to the UHPC layer of 35mm, the whole composite deck also includes a 15~20mm thick wear layer laid on the UHPC layer. This kind of composite deck structure needs to reduce its thickness and expand its application range under the premise of guaranteeing its safety and durability, so as to increase the stiffness of bridge deck at the same time. The risk of fatigue cracking of orthotropic steel deck was reduced, and the problem of pavement damage occurred in traditional asphalt pavement was avoided. In this paper, the suspension bridge of Runyang Changjiang River Highway Bridge is taken as the object of study, and the scheme of steel and ultra-thin UHPC composite deck slab is studied on the orthotropic steel deck of the bridge deck. The main work of this paper is as follows: (1) this paper discusses the problem of the defects of the traditional orthotropic steel bridge panel and its pavement, and puts forward the scheme of the steel-ultra-thin UHPC composite deck. The structural characteristics and the necessity in the design of composite deck are described. The finite element software Midas is used to calculate the steel-ultrathin UHPC composite deck scheme of Runyang Yangtze River Bridge. The calculation results show that the composite bridge has little effect on the overall stress of the bridge, and has no effect on the overall safety of the structure. The finite element software ANSYS is used to analyze the local wheel load of the steel-ultra-thin UHPC composite deck based on the hot spot stress method. The combined deck is analyzed by using the vehicle load specified in the domestic code. The results show that the stress performance of the deck of orthotropic steel bridge is improved obviously by the UHPC layer of 35mm thick. The stress amplitude of steel bridge deck roof decreases to 68.72U rib and transverse diaphragm by 11.98% to 32.38%, so the risk of fatigue cracking of steel bridge slab can be greatly reduced. At the same time, the maximum tensile strength of 35mm layer surface should be 7.48 MPA and the maximum tensile stress of transverse bridge is 7.36 MPA / L). The experimental results show that the cracking strength and ultimate strength of the 35mm layer are closely related to the reinforcement ratio of the cross section. With the increase of reinforcement ratio, the flexural strength and crack stress of UHPC are gradually increased. The minimum cracking stress of UHPC surface layer has reached 26.3MPa, which is 3.6 times of the tensile stress of 7.36MPa calculated in theory. The maximum tensile stress produced by UHPC surface layer under specified vehicle load is smaller than that of UHPC layer, so it can ensure the safety and reliability of the structure. The feasibility of this new composite deck structure is proved. The basic theory of fatigue assessment of steel bridge is expounded, three methods of fatigue design of steel bridge are briefly described, and the fatigue design codes of steel bridge in America, Europe and China are compared briefly. The fatigue life of Runyang Yangtze River Bridge steel-ultra-thin UHPC composite plate scheme is evaluated. The hot spot stress method is introduced, and the fatigue load model is determined according to Eurocode. the hot spot stress is calculated and the stress frequency spectrum of the most unfavorable structural details is determined. Finally, the fatigue life is determined by the hot spot stress S-N curve and Miner linear cumulative damage theory.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.31

【参考文献】