FRP组合梁试件静力学性能试验研究
发布时间：2019-01-01 14:58
【摘要】：组合梁桥是建立在整体现浇式钢筋混凝土与装配式钢筋混凝土新型桥梁形式,充分结合了两种桥梁形式的特点。FRP组合梁桥采用FRP材料作为永久模板,在其模板上后浇混凝土,在减少劳动力,降低工程造价,加快施工进度方面有着积极的作用,但是两者交界面的粘结强度是共同受力的基础。第二章FRP材料与后浇混凝土叠合结构与普通混凝土进行一般抗弯试验破坏对比分析。得出FRP材料与后浇混凝土的叠合结构较普通混凝土受力性能有明显的改善,叠合结构中抗弯承载力和挠度明显高于普通混凝土试件,并且叠合结构中以两种材料剥离破坏后,混凝土被压坏然而FRP材料未破坏,从而未充分发挥FRP材料抗拉强度高的特点为主,其原因为层间粘结强度弱的结论。第三章抗剥离强度试验研究中在第二章结论的基础上对两者间交界面分别采用的不同的方式增加交界面粘结强度,采用粘粗砂法、环氧胶法、剪力键法以及综合法对FRP材料粘结表面进行处理,然后在模板内后浇混凝土进行交界面抗剥离试验研究,通过试验研究两种材料交界面粘结破坏形式和特征,得出组合试件破坏形式主要有中部裂缝延伸引起的剥离破坏、斜裂缝延伸剥离破坏、试件混凝土端部剥离破坏、试件底部混凝土剥离破坏四种形式。同时考虑在混凝土中加入PVA纤维、玄武岩纤维、钢丝网改善混凝土自身的受力性能来研究组合构件对抗折强度的影响和交界面主要剥离破坏形式。增加组合试件交界面的粘结强度和改善混凝土的强度对试件的抗剥离强度和抗折强度均有明显的提高。在FRP板采用综合法为最佳的处理方式。第四章对GFRP箱形梁与后浇混凝土的组合结构形式采用各种假定以简化计算,通过弹性破坏和极限破坏形式下进行计算分析,为组合梁的设计提供理论基础。第五章中采用GFRP箱形管与后浇混凝土模拟GFRP箱形梁与混凝土组合梁结构进行试验分析,分别制作箱形梁顶面采用综合法处理并在混凝土中植入钢丝网并在混凝土加入玄武岩纤维和未处理的组合结构试件,对试件进行抗折试验,根据两种试件的试验过程与破坏特征,可知纯GFRP箱形梁在荷载作用下会产生较大的变形,未能发挥混凝土抗压强度高和GFRP材料抗拉强度高的特点,主要由于GFRP材料抗剪强度和GFRP箱形梁刚度低的原因,同时提出增加GFRP箱形梁抗剪强度和抗弯刚度的建议。
[Abstract]:Composite beam bridge is a new type of bridge built on integral cast-in-place reinforced concrete and prefabricated reinforced concrete, which fully combines the characteristics of two kinds of bridge forms. FRP composite beam bridge uses FRP material as permanent formwork and post-pouring concrete on its formwork. It plays an active role in reducing labor force, reducing project cost and speeding up construction progress, but the bond strength of the interface between the two is the basis of common force. In the second chapter, the failure analysis of the composite structure of FRP and post-cast concrete is compared with that of ordinary concrete under general flexural test. The results show that the composite structure of FRP and post-cast-in-situ concrete has better mechanical performance than ordinary concrete, and the flexural capacity and deflection of the composite structure are obviously higher than that of the ordinary concrete specimen, and the composite structure is stripped and destroyed by two kinds of materials. Concrete is crushed but FRP material is not destroyed, so the high tensile strength of FRP material is not fully brought into play, which is due to the conclusion that interlaminar bond strength is weak. In the third chapter, on the basis of the conclusion of the second chapter, the bonding strength of the interface is increased in different ways, and the bonding strength of the interface is increased by the method of bonded coarse sand and epoxy adhesive. Shear bond method and comprehensive method were used to treat the bonded surface of FRP material, and then the interfacial debonding resistance of post-cast concrete in the formwork was studied. The failure forms and characteristics of interfacial bond between the two materials were studied through experiments. It is concluded that the failure forms of composite specimens mainly include peeling failure caused by crack extension in middle part, delamination failure by slant crack extension, peeling failure at the end of concrete specimen and peeling failure of concrete at the bottom of the specimen. At the same time, PVA fiber, basalt fiber and steel wire mesh were added to the concrete to improve the mechanical properties of the concrete to study the influence of the composite members on the flexural strength and the main peeling failure form of the interface. Increasing the bond strength at the interface of the composite specimens and improving the strength of concrete can obviously improve the peeling strength and the flexural strength of the specimens. Comprehensive method is the best way to deal with FRP board. In chapter 4, various assumptions are used to simplify the calculation of the composite structure of GFRP box beam and post-cast-in-place concrete. Through the calculation and analysis under the form of elastic failure and ultimate failure, the theoretical basis is provided for the design of composite beam. In the fifth chapter, the structure of GFRP box beam and concrete composite beam is simulated by GFRP box tube and post-pouring concrete. The top surface of box beam was treated by comprehensive method and steel wire mesh was implanted in concrete. The specimens with basalt fiber and untreated composite structure were added to the concrete, and the flexural tests were carried out on the specimens. According to the test process and failure characteristics of two kinds of specimens, it can be concluded that the pure GFRP box beam will produce large deformation under the action of load, which fails to give full play to the characteristics of high compressive strength of concrete and high tensile strength of GFRP material. It is mainly due to the low shear strength of GFRP material and the low stiffness of GFRP box beam, and the suggestion to increase the shear strength and flexural stiffness of GFRP box beam is put forward.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446
本文编号：2397720
[Abstract]:Composite beam bridge is a new type of bridge built on integral cast-in-place reinforced concrete and prefabricated reinforced concrete, which fully combines the characteristics of two kinds of bridge forms. FRP composite beam bridge uses FRP material as permanent formwork and post-pouring concrete on its formwork. It plays an active role in reducing labor force, reducing project cost and speeding up construction progress, but the bond strength of the interface between the two is the basis of common force. In the second chapter, the failure analysis of the composite structure of FRP and post-cast concrete is compared with that of ordinary concrete under general flexural test. The results show that the composite structure of FRP and post-cast-in-situ concrete has better mechanical performance than ordinary concrete, and the flexural capacity and deflection of the composite structure are obviously higher than that of the ordinary concrete specimen, and the composite structure is stripped and destroyed by two kinds of materials. Concrete is crushed but FRP material is not destroyed, so the high tensile strength of FRP material is not fully brought into play, which is due to the conclusion that interlaminar bond strength is weak. In the third chapter, on the basis of the conclusion of the second chapter, the bonding strength of the interface is increased in different ways, and the bonding strength of the interface is increased by the method of bonded coarse sand and epoxy adhesive. Shear bond method and comprehensive method were used to treat the bonded surface of FRP material, and then the interfacial debonding resistance of post-cast concrete in the formwork was studied. The failure forms and characteristics of interfacial bond between the two materials were studied through experiments. It is concluded that the failure forms of composite specimens mainly include peeling failure caused by crack extension in middle part, delamination failure by slant crack extension, peeling failure at the end of concrete specimen and peeling failure of concrete at the bottom of the specimen. At the same time, PVA fiber, basalt fiber and steel wire mesh were added to the concrete to improve the mechanical properties of the concrete to study the influence of the composite members on the flexural strength and the main peeling failure form of the interface. Increasing the bond strength at the interface of the composite specimens and improving the strength of concrete can obviously improve the peeling strength and the flexural strength of the specimens. Comprehensive method is the best way to deal with FRP board. In chapter 4, various assumptions are used to simplify the calculation of the composite structure of GFRP box beam and post-cast-in-place concrete. Through the calculation and analysis under the form of elastic failure and ultimate failure, the theoretical basis is provided for the design of composite beam. In the fifth chapter, the structure of GFRP box beam and concrete composite beam is simulated by GFRP box tube and post-pouring concrete. The top surface of box beam was treated by comprehensive method and steel wire mesh was implanted in concrete. The specimens with basalt fiber and untreated composite structure were added to the concrete, and the flexural tests were carried out on the specimens. According to the test process and failure characteristics of two kinds of specimens, it can be concluded that the pure GFRP box beam will produce large deformation under the action of load, which fails to give full play to the characteristics of high compressive strength of concrete and high tensile strength of GFRP material. It is mainly due to the low shear strength of GFRP material and the low stiffness of GFRP box beam, and the suggestion to increase the shear strength and flexural stiffness of GFRP box beam is put forward.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446
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