【作者】 黄彩萍；

【导师】 张仲先；

【作者基本信息】 华中科技大学 ， 结构工程， 2012， 博士

【摘要】 国内外已建成和正在建设的大跨度混合梁斜拉桥数量很多,但每个斜拉桥的主梁钢混结合段的设计和构造细节都各不相同,国内外规范对大跨度混合梁斜拉桥主梁钢混结合段的设计均未给出详尽的说明,设计依据不明确。在钢-混凝土组合结构中,剪力连接件对钢和混凝土这两种性能差别较大的材料的协同工作具有重要作用。目前国内外对剪力钉的承载能力和抗剪刚度做了大量的研究,但研究工作主要是针对设置单枚或多枚剪力钉的试件的推出试验进行的,对剪力钉在主梁钢混结合段中的受力性能的研究较少。因此,分析主梁钢混结合段中剪力钉、钢板、混凝土三者之间的相互工作方式,研究混合梁斜拉桥主梁钢混结合段的计算方法具有重要意义。本文在国内外进行的大跨度混合梁斜拉桥主梁钢混结合段试验和剪力钉承载能力及抗剪刚度试验的研究成果的基础上,进行了两种构造形式的主梁钢混结合段缩尺模型试验和理论研究。将有限元分析结果和模型测试结果进行了对比,分析表明有限元计算结果和模型试验结果吻合得较好,合理的有限元分析可以准确的反映试验模型的受力状态,根据模型试验结果和有限元计算结果评判了实桥钢混结合段设计的合理性。研究内容和取得的成果如下：1.对组合结构常用的剪力钉设计和制作了单枚剪力钉型钢混凝土试件,并进行了推出试验。通过推出试验,研究分析了推出试件中单枚剪力钉的受力特性、荷载-滑移规律和破坏机理,计算分析了单枚剪力钉的抗剪承载力及剪切刚度。在对组合结构中钢-混凝土界面的模拟方法进行了研究后,建立了有限元分析模型,研究了剪力钉、钢板、混凝土三者的相互作用机理。根据推出试验结果和有限元计算结果的对比分析,表明合理的有限元计算可以准确的计算出单枚剪力钉的极限承载力和荷载-滑移曲线,弥补了以往剪力钉承载能力和剪切刚度只能通过推出试验得出的不足。2.对南昌英雄大桥和武汉二七长江大桥主梁钢混结合段分别进行了大比例的缩尺模型设计和制作,并进行了试验。在模型试验中,对两座桥的钢混结合段试验模型分别进行了正常使用荷载、设计极限荷载和超载三种工况的试验,研究了在不同工况荷载作用下两座桥梁钢混结合段的应力分布情况和结合段的承载能力,分析了具有不同构造形式的两座桥梁主梁钢混结合段的受力与变形性能。3.在对钢混结合段钢-混凝土界面的有限元模拟方法进行了研究后,对上述具有不同构造形式的两座桥梁主梁钢混结合段试验模型进行了有限元分析,并将模型实验值和有限元计算值进行了对比,分析表明有限元计算结果和模型试验结果吻合得较好,合理的有限元分析可以准确的反映试验试件的受力状态。4.根据上述剪力钉推出试验和主梁钢混结合段的模型试验及有限元分析得出的结论,在不影响不同构造形式的钢混结合段的受力特性的基础上,在本文的有限元分析中,分别对两座桥梁的钢混结合段进行了简化,对简化后的分析模型进行了非线性仿真计算,研究了钢板和混凝土不同结合程度对钢混结合段中剪力钉群的受力特性的影响,分析了钢混结合段简化模型受力机理。5.结合剪力钉推出试验和主梁钢混结合段的模型试验及有限元分析得出的结论,研究了钢-混凝土界面的滑移量对钢混结合段抗弯、抗压性能的影响,提出了在钢-混凝土界面存在滑移量的情况下,钢混结合段分别受轴力和弯矩作用时钢板和混凝土应变计算公式。更多还原

【Abstract】 There are many large span hybrid cable-stayed bridges have been built or under construction at home and abroad, but the design and structure of each hybrid-stayed bridge steel-concrete joint section in the main beam are different from each other. Because there is no detailed design statement of the cable-stayed bridge steel-concrete joint section in the bridge design codes at home and abroad, so the design consideration is not clear and definite. In steel-concrete composite structure, the shear connector can make implement cooperation work between steel and concrete which are great differents in the material property, so it is very important. In present, there are many works study the shear capacity and shearing stiffness of shear studs, but they are more centering on push-out test of single or several shear studs, and less centering on the mechanical behavior of the shear studs in the steel-concrete joint section of the main beam, so it is very important to analyse the mutual action mechanism among shear stud, steel and concrete, and research the calculation method of the steel-concrete joint section in the main beam of the hybrid-stayed bridge.Based on the model test of the steel-concrete joint section in the main of the large span hybrid cable-stayed bridges and carrying capacity and shearing stiffness test of shear studs at home and abroad, two different structure styles main beam steel-concrete joint section model test and research are carried out. The comparison research on the experiment measured result and the numerical calculation results shows that the numerical calculation tallies with the experiment result, and the reasonable finite element analysis can accurately reflect the forced state of the test model. According to the experiment measured result and numerical calculation results, the rationality of the design of the main beam steel-concrete joint section in real bridge is verified. The following main contents are studied and some impotant results and conclusions have been achieved as follows:1. Taking the shear stud commonly used in steel-concrete composite structure as research objects, the specimen of single shear stud steel reinforced concrete is designed and constructed, and the push-out test is done. Through push-out test, the force characteristics, load-slippage rule, failure mechanism of single shear stud in joint section are studied, the shear capacity and shearing stiffness of single shear stud are calculated. After the the method to simulate the interface between steel and concrete in steel-concrete composite structure is investigated in finite element software, the finite element calculation model is established to study the mutual action mechanism among shear stud, steel and concrete. The comparison analysis between the experiment measured result and numerical calculation results shows that the reasonable finite element calculation can accurately calculate the ultimate bearing capacity and load-slippage curve of single shear stud, this finite element calculation method makes up the deficiency that the ultimate bearing capacity of single shear stud can only be achieved by push-out test.2. The huge rate models of Nanchang Yingxiong Bridge and Wuhan ErQI Changjiang River Bridge main beam steel-concrete joint section is designed and constructed, and the static experiments are done. The static experiments of the models of the two bridges main beam steel-concrete joint section under three load conditions that they are respectively scenarios of service limit state load, design ultimate limit state load and 1.4 times design ultimate limit load state are carried out, the stress distribution, load bearing capacity, force bearing and deformation behavior of the two bridges main beam steel-concrete joint section which have two different structure styles are reseached under the three load conditions.3. After the the method to simulate the interface between steel and concrete of main beam steel-concrete joint section is investigated in finite element software, the finite element analysis is done for the two different structure styles of main beam steel-concrete joint section ahout the two bridges above mentioned. The comparison analysis between the experiment measured result and numerical calculation results shows that the finite element calculation result tallies with the experiment result, and the reasonable finite element calculation can accurately reflect the forced state of the tset model.4. According to the shear stud push-out test result, main beam steel-concrete joint section model test result and related finite element analysis result above mentioned, taking that there are no influences on force characteristics of the different styles main beam steel-concrete joint section of the two bridge above mentioned as prerequisite, the main beam steel-concrete joint section is simplified in the finite element analysis. Nonlinear simulative calculation of the simplified model is done, the effect of the different degree of binding between steel and concrete on the force characteristics of crowded shear in the simplified model is studied, the force mechanism of the steel-concrete joint section simplified model is researched.5. Combining with the shear stud push-out test result, main beam steel-concrete joint section model test result and related finite element analysis result, the effect caused by the interface slip between steel and concrete on the compressive strength and bending strength is researched, and this paper puts forward the formula to calculate the strain of the steel and concrete in steel-concrete joint section under axial force or moment loading in the condition that the interface slip occurred between steel and concrete.更多还原