【作者】 陈军；

【导师】 王景全；

【作者基本信息】 东南大学 ， 土木工程， 2016， 硕士

【摘要】 FRP拉挤型材和UHPC较好的满足了桥梁工程对轻质、高强、耐久的需求,已在国内外桥梁工程中得到较为广泛应用。本文提出的"FRP-UHPC板桁组合梁桥”顺应了FRP拉挤型材、UHPC及其组合结构在桥梁工程中的发展趋势,规避了FRP型材腹板易受剪破坏、组合结构整体刚度偏低以及纯FRP桁架桥桥面系耐磨性能差等关键问题。本文通过模型试验、理论解析和数值模拟等方法,研究了不同影响因素下FRP-UHPC板桁组合梁桥两类节点连接的破坏模式、抗滑移刚度及极限承载力,同时对整桥的受力性能进行了试验研究及参数化分析,并与不同类型的桥梁进行了对比研究。本文的主要研究内容包括：1)FRP拉挤型材螺栓连接件试验研究与分析进行了20组FRP螺栓连接件静力试验,研究了剪切形式、螺栓直径、螺栓个数、板的几何参数、预紧力和结构胶等因素对FRP螺栓连接件破坏模式、抗滑移刚度和极限承载力的影响。胶栓混合连接综合了胶接和螺栓连接的优点,具有刚度大、延性好等特点。FRP螺栓连接件主要发生FRP板的剪切破坏,其裂缝起始于孔周45。方向,沿纤维拉挤方向扩展,并最终破坏。通过试验及理论分析总结,提出了螺栓连接、胶栓混接的抗滑移刚度模型,以及剪切破坏模式下FRP螺栓连接件的极限承载力计算公式。2) FRP-UHPC板桁组合粱桥界面剪力连接件试葛断究与分析进行了10组FRP-混凝土连接件推出试验,研究了螺栓个数、螺栓直径、螺栓高度、混凝土板配筋率、混凝土等级等参数对FRP推出试件破坏模式、抗滑移性能、极限承载力的影响。FRP-UHPC推出试件的极限承载力大于FRP-普通混凝土推出试件,其单个螺栓的承载力提高了80%、抗滑移刚度提高了130%。FRP-混凝土推出试件主要发生翼板剪切破坏和螺栓直剪破坏；基于不同的破坏模式,给出了相应的抗滑移刚度模型。通过试验验证,给出了螺栓直剪破坏模式下FRP推出试件的极限承载力计算公式。3) FRP-UHPC板桁组合桥足尺模型试验研究与分析进行了1组FRP-UHPC板桁组合桥足尺模型静力加载试验,研究分析了三类荷载工况下板桁组合实桥的受力性能。试验表明,本实桥能够很好的满足设计要求,正常使用极限状态内,单调荷载作用下表现出线弹性受力性能,循环荷载下变形可全部恢复。本文建立的有限元数值模型计算结果与实桥试验值基本吻合,可以很好的反应板桁组合实桥的受力性能。4) FRP-UHPC板桁组合梁桥受力性能分析及不同桥型的对比研究对FRP-UHPC板桁组合梁桥受力性能影响因素进行了参数化分析,FRP下弦杆、FRP腹杆截面尺寸及组合梁高的变化对FRP-UHPC板桁组合梁桥刚度的影响比较明显。用UHPC材料作桥面板有利于提高组合梁桥界面的抗滑移刚度,提高FRP-UHPC板桁组合结构的整体刚度。与国内外3座典型的FRP桁架桥相比,本桥重量较轻,FRP材料用量较少,整桥的相对刚度较大。相对于同等跨径的3类公路桥梁,本桥的重量轻,施工方便,在近海区域、海洋岛礁环境中具有较大的应用优势。更多还原

【Abstract】 Pultruded FRP shapes and UHPC can adequately satisfy the sustainable requirement regarding light, high-strength and durable in the future bridge engineering, and have been widely used in the bridge engineering at home and abroad. The FRP-truss-UHPC-deck hybrid bridge system, proposed by this paper, complies with the development trend of pultruded FRP shapes, UHPC and their hybrid structure in the bridge engineering, and overcomes the disadvantages, such as web shear failure of FRP profiles, low stiffness of FRP hybrid structure and low wear-resisting performance of the pure FRP truss bridge deck. Through model test, theoretical analysis and fine element methods, this paper presents studies on the failure modes, anti-slipping stiffness and ultimate bearing capacity of the two types of joint connections under varied influence factors, also presents experimental research and fine element analysis on the FRP-truss-UHPC-deck hybrid bridge system, and gives comparison between FRP-truss-UHPC-deck hybrid bridge system and other 6 types of bridges. The main research contents are as follows:(1) Experimental research and analysis on FRP bolted connectors20 FRP bolted connectors are conducted to investigate the effect of shear form, bolt diameter, bolt number, plate geometry parameter, pre-tightening force, and structural adhesive bond on failure mode, anti-slipping stiffness and ultimate bearing capacity. FRP bonded/bolted connectors take the advantages of bolt connectors and bonded connectors, and hold many characteristics, such as high rigidity, good ductility. Shear damage of FRP plate is the main failure mode in FRP bolted connectors, and its crack starts from the 45° direction of bolt hole, then extending along the direction of fiber and eventually destroyed. Through experimental and theoretical analysis, the anti-slipping stiffness mode of FRP bolted connectors and FRP bonded/bolted connectors is proposed by this paper, and the formula about the ultimate bearing capacity of FRP bolted connectors is also presented under shear failure mode.(2) Experimental research and analysis on FRP shear connectors10 FRP push-out specimens are tested to investigate the effect of bolt number, bolt diameter, bolt height, reinforcement ratio of UHPC plate, concrete grade on failure mode, anti-slipping stiffness and ultimate bearing capacity. The ultimate bearing capacity of FRP-UHPC push-out specimens is higher than the FRP-NC push-out specimens, and the average bearing capacity of single bolt increased by 80%, the average anti- slipping stiffness increased by 130%. Shear damage of FRP wing plate and direct shear destruction of bolt are the two main failure modes of FRP push-out specimens. Based on different failure modes, two anti-slipping modes are proposed by this paper. Verified by the experiment, the ultimate bearing capacity of the FRP push-out specimens, under the direct shear destruction of bolt, can be calculated by the formula proposed by this paper.(3) Experimental research and analysis on FRP-truss-UHPC-plate hybrid bridge systemThe FRP-truss-UHPC-plate hybrid bridge system is tested to study its mechanical property under three kinds of load actions. This hybrid bridge system can meet the design requirements very well, showing good linear mechanical performance under the monotonic load, and good resume performance under the cyclic load. The results calculated by finite element numerical model conform to the experimental value, so the finite element numerical model can be well applied to predict the mechanical performance of the FRP-truss-UHPC-plate hybrid bridge.(4) Mechanical property analysis and comparison of FRP-truss-UHPC-plate hybrid bridge systemFinite element parametric analysis is carried out to study the mechanical property of FRP-truss-UHPC-plate hybrid bridge system. The change of the FRP bottom chord’s section size, the FRP web member’s section size and the hybrid bridge’s height have a bigger influence on the stiffness of FRP-truss-UHPC-plate hybrid bridge system. Using the UHPC material as the hybrid bridge’s deck can improve the anti-slipping stiffness of FRP-UPHC interface, and the bending stiffness of the FRP-truss-UHPC-plate hybrid bridge system. Compared with the three typical FRP truss bridges at home and abroad, this hybrid bridge is lighter, using less FRP materials, and its relative stiffness is bigger. Compared with the other three highway bridges of the same span, this hybrid bridge is also lighter, convenient to construct, possessing great application advantage in coastal area and marine environment.更多还原