【作者】 代帅；

【导师】 王庆华；

【作者基本信息】 吉林大学 ， 结构工程， 2009， 硕士

【摘要】 为解决钢筋的锈蚀问题,纤维增强塑料筋Fiber Reinforced Polymer(FRP)作为一种新型复合材料,以其轻质、高强、耐腐蚀的优良特性被引入到土木工程中。当FRP筋用于普通混凝土结构时,由于其弹性模量较小,结构的变形和裂缝难以控制,材料性能得不到充分发挥,为此,本文考虑将FRP筋应用到预应力混凝土结构中。Carbon Fiber Reinforced Polymer(CFRP)筋以其优异的综合性能,在土木工程中应用最为广泛,但由于锚具的问题使其在预应力结构中的应用受到限制。本文从制约其进一步推广应用的预应力专用锚具入手,对研制的膨胀水泥钢套筒粘结式锚具和挤压式锚具分别进行了试验研究并设计了与之配套的张拉装置。初步研究表明,两种锚具均能满足使用要求,挤压式锚具具有更好的锚固性能,受力均匀,值得进一步研究;膨胀水泥钢套筒粘结式锚具在承受荷载时将有80%的荷载通过膨胀水泥传递给钢套筒承担,钢套筒受力很大,对粘结长度及壁厚的要求较高。另外,应用锚固性能较好的挤压式锚具,制作四根CFRP筋无粘结部分预应力混凝土梁进行了深入的试验研究;最后运用有限元分析软件ANSYS对四根试验梁进行了非线性有限元全过程分析,验证了模型建立的正确性,为以后的深入研究提供了依据。本文的研究成果将为CFRP筋无粘结部分预应力混凝土结构在实际工程的应用提供科学依据,对CFRP筋预应力混凝土结构的进一步研究具有一定的参考价值。更多还原

【Abstract】 In order to solve the problem of corrosion of steel,Fiber Reinforced Plastic(FRP) was introduced to the Civil Engineering as a new type of composite material,with its properties of light-weight and non- corrosive.When the FRP tendons was used in general concrete structures,due to the smaller elastic modulus,the deformation and the crack were difficult to control,material properties couldn’t give full play,so we consider FRP tendons applied to prestressed concrete structures.CFRP tendons were high tensile strength,anti-corrosive and so on,but were weak shear strength and anti-squeezing,if using the traditional anchor directly,shear failure occurs in the tensile process,its high-tensile strength cannot be exploited.So the problem of prestressed FRP tendons anchor has become a constraint to FRP further application.In this paper,based on a large number of domestic and foreign research results,reseach the expansive cement steel sleeve bond-type anchor and extrusion-type anchor,and designed the matching tensioning device.Primary studies shown that the use of two kinds of anchors both can meet the requirements,the.extrusion-type anchor has better anchoring efficiency,it is worthy of further study,80% of the load was transferred to steel sleeve by expansive cement.The steel sleeve assumed a large load,so called for a higher bond length and wall thickness.In this paper, the use of reinforced unbonded tendons, the flexural properties of four post-tensioned concrete beams were studied, on the basis of analysis of the experimental data,the main research and achievements are as follows:1. CFRP tendons of unbonded prestressed concrete beams in accordance with the process by force of non-prestressed reinforcement are two different situations:(1)Non-prestressed reinforcement yield point for the ordinary steel, the load-deflection relaship is divided into three stages. From the beginning of the first stage of loading to the specimen cross-section cracking; From the section of the second stage of cracking in tension zone to the non-prestressed reinforcement yield, the deflection of the sample changed little; From the third phase of non-prestressed reinforcement to yield concrete compression zone of the sample was crushed, to speed up changes in specimen deflection, deformation larger, the specimen deformation is still larger after Concrete crushing.(2) Non-prestressed reinforcement is no obvious yield point of the fiber reinforcement, the load-deflection relaship is divided into two stages. From the beginning of the first stage of loading to the specimen cross-section cracking, From the section of the second stage of cracking to the concrete compression zone of the sample was crushed, reduced to speed up the specimen stiffness, the ultimate deformation of the sample is relatively large. Both cases, the specimen after the crack did not exist in significant yield stage.2.the mechanical properties,such as load-deflection curve,load-strain curve of prestressing tendon, load-strain curve of non-prestressed rebars, load-strain curve of concrete compression zone, strongly depend on the non-prestressed rebars of the mechanical properties of its own;3. Non-prestressed rebars can play the role of dispersed cracks,which was the impact of CFRP unbonded partially prestressed concrete beam cracks in the number, width and spacing of the important factors;4. Test results show that the use of FRP prestressed beams as a non-prestressed rebars play a better performance under the normal load, but also to meet the special requirements of the environment, it is worth further study.In addition, based on the analysis of experiment,we used commercial finit element software-ANSYS,nonlinear finite element simulation of prestressed concrete beams with unbonded prestressing CFRP tendens is accomplished.It is modeling method,selecting element,defining constitutive relationship of materials and solution method that are elaborated on in this paper. The analytical results of the prestressed beam specimens,such as ultimate load-carrying capacity, defleetion as well as stresses of prestressing tendons and steel rebars are in good agreement with the experimental results, which is to verify the correctness of the model,providing analysis tools for further research. Test results and studies obtained in this paper can provide scientific principles for CFRP unbonded partially prestressed reinforced concrete structure in the actual application,and in the further study of CFRP tendons have certain reference value.更多还原