【作者】 何余良；

【导师】 项贻强；

【作者基本信息】 浙江大学 ， 桥梁与隧道工程， 2014， 博士

【摘要】 近年来,钢-混组合结构在桥梁工程领域中逐步被使用,但对有关多梁式钢-混组合小箱梁桥的研究甚少,现行钢-混组合结构设计规范也未就其作出具体规定。为此本文对多梁式钢-混组合小箱梁桥的受力特性及行为进行研究,以为其在今后设计和运营后的管养提供参考。首先通过对十四个推出试件及两片组合箱梁模型的静载试验、数值模拟及国内外规范的对比,研究钢-混杂纤维混凝土组合梁的力学特性,给出了混杂纤维混凝土焊钉剪力件的荷载-滑曲线表达式及极限承载力计算方法,探讨了钢-混杂纤维混凝土组合箱梁在弹性状态和破坏状态的力学行为,并对钢-混杂纤维混凝土组合箱梁极限承载力的设计方法提出了建议。同时,试验研究和理论分析结果表明钢-混杂纤维混凝土组合箱梁在韧性和抗裂性等方面力学性能更优越于普通混凝土组合箱梁。其次,基于Newmark组合梁滑移模型,通过引入不同次幂抛物线翘曲函数来描述组合箱梁顶底板应力横向非均匀分布,建立一个能够同时考虑界面滑移、剪切变形和翼板剪力滞三重效应的钢混组合箱梁模型,推导了简支组合箱梁在均布荷载和集中荷载作用下的解析解。参数分析表明,随着混凝土板厚和钢梁高度的增加,在跨中腹板和顶板中部处剪力滞系数下降；当组合箱梁宽跨比减少时,在腹板处剪力滞系数下降,而在顶板中部处剪力滞系数略增加；与均布荷载相比,各因素变化在集中荷载作用下,对组合箱梁跨中截面的剪力滞系数影响较明显；滑移刚度变化对剪力滞系数的影响可以忽略不计。在上述理论分析及设计加工的试验模型基础上,进一步对典型的两片组合箱梁模型进行了剪滞试验研究,结果表明,理论分析与试验测试结果吻合很好,验证了理论模型和解析解的正确性。从实用设计方法出发,考虑多梁式钢-混组合小箱梁桥界面滑移效应,分别用传统的多梁式桥的偏心压力法、刚接梁法,推导了考虑界面滑移效应影响的偏心压力法、刚接梁法修正计算公式。通过实际工程算例表明,采用本文所提出的修正理论算法结果与有限元方法的计算结果吻合较好,表明所提出的修正刚接梁法适用于计算多梁式钢-混组合小箱梁桥跨中横向分布系数,当满足窄桥条件时,也可采用考虑滑移的修正偏心压力法。参数研究表明,在进行多梁式钢-混组合小箱梁桥设计时,为减少桥梁的偏载效应,建议采用不完全剪力连接形式。最后,基于比拟板法,在竖向荷载作用下具有多道横隔梁的多梁式钢混组合小箱梁桥通过纵横向刚度离散,同时考虑混凝土与钢梁间焊钉的滑移影响,将其比拟成一个正交异性板,利用薄板理论建立了多梁式钢混组合小箱梁桥整体分析的微分方程组,简化后求出在均布荷载下的滑移方程和挠度方程。通过算例与有限元数值结果及已有研究进行比较,验证其正确性。结果表明,剪力连接件的刚度变化对组合梁挠度影响可以忽略,而对滑移量影响较为明显。更多还原

【Abstract】 In recent years, steel-concrete composite structure is applied in bridge engineering step by step. At present, the researches of multi-beam steel-concrete composite box-girder bridge are few in the references and specifications. In order to provide the causes of the design and management, this paper has studied the mechanical properties of multi-beam steel-concrete composite box-girder bridge.The mechanical properties of steel concrete composite girders in hybrid-fiber are studied through the tests, numerical simulation and specification comparison of14push-out tests and two steel concrete composite girders. The load-slip formula and the calculation method of bearing capacity of the stud connector in hybrid-fiber concrete and the mechanical properties of steel concrete composite girders in hybrid-fiber in elastic state and failure state are gotten. Then the advised design method of bearing capacity of steel concrete composite girders in hybrid-fiber concrete is obtained. Compared with steel concrete composite girders in normal concrete, the toughness and durability of the steel concrete composite girders in hybrid-fiber concrete are better.A theory model is proposed for steel-concrete composite girders with the slip between the steel beam and concrete slab, shear deformation in the steel beam and the shear lag effect in the concrete slab. Different parabolic warping shape function accounting for the non-uniform transverse distribution of longitudinal displacements in the concrete slab and steel floor and transverse shear deformation of the girder web are introduced into Newmark’s model. Then analytical solutions for the cases of simply supported composite girder under uniform distribution load and end concentrated load are derived. The analytical solutions agree with the test results. The shear lags coefficient decrease at the web and middle of concrete slab in the mid-section when increasing thickness of concrete slab and height of steel beam. While the ratio between the width and span of composite girder declines, the shear lag coefficient decreases at the web and increases at the middle of concrete slab in the mid-section. It is also indicated that the shear lag effect is more apparently varying with different factors under end concentrated load compared with uniform distribution load. The variation of the slip stiffness has a negligible effect to the shear lag coefficient.The eccentric-pressed method and rigid jointed girder method are modified considering the interface slippage’s effect of multi-beam composite small box-girder bridge. The results obtained from FEM validated by experiments are compared with the modified theoretical algorithm, and the result shows that slippage considered rigid jointed girder method is applicable for calculating mid-span load transverse distribution of multi-beam composite small box-girder bridge. For narrow bridges, it is better to use slippage considered eccentric-pressed method. Furthermore, when designing multi-beam composite small box-girder bridge, the author suggests using incomplete shear connection form to reduce the bridge of the partial load effect.In the end, the analysis model about multi-beam steel-concrete composite box girder bridge is built and the integral analysis of the differential equations are obtained under the uniform load by the simulation plate method. Then the slip equation and deflection equation are obtained under the uniform load by simplified method. The analytical solutions agree with the FEM and other research results through the example. Finally, the stiffness variation of the shear connector has a neglected effect on the defection and an obvious effect on the slip.更多还原