CFRP筋無粘結(jié)部分預(yù)應(yīng)力混凝土梁受力性能的試驗(yàn)研究

1、CFRP筋無粘結(jié)部分預(yù)應(yīng)力混凝土梁受力性能的試驗(yàn)研究        【中文摘要】為解決鋼筋的銹蝕題目,纖維增強(qiáng)塑料筋Fiber Reinforced Polymer(FRP)作為一種新型復(fù)合材料,以其輕質(zhì)、高強(qiáng)、耐腐蝕的優(yōu)良特性被引進(jìn)到土木工程中。當(dāng)FRP筋用于普通混凝土結(jié)構(gòu)時(shí),由于其彈性模量較小,結(jié)構(gòu)的變形和裂縫難以控制,材料性能得不到充分發(fā)揮,為此,本文考慮將FRP筋應(yīng)用到預(yù)應(yīng)力混凝土結(jié)構(gòu)中。Carbon Fiber Reinforced Polymer(CFRP)筋以其優(yōu)異的綜合性能,在土木工程中應(yīng)用最為廣泛

2、,但由于錨具的題目使其在預(yù)應(yīng)力結(jié)構(gòu)中的應(yīng)用受到限制。本文從制約其進(jìn)一步推廣應(yīng)用的預(yù)應(yīng)力專用錨具進(jìn)手,對(duì)研制的膨脹水泥鋼套筒粘結(jié)式錨具和擠壓式錨具分別進(jìn)行了試驗(yàn)研究并設(shè)計(jì)了與之配套的張拉裝置。初步研究表明,兩種錨具均能滿足使用要求,擠壓式錨具具有更好的錨固性能,受力均勻,值得進(jìn)一步研究;膨脹水泥鋼套筒粘結(jié)式錨具在承受荷載時(shí)將有80%的荷載通過膨脹水泥傳遞給鋼套筒承擔(dān),鋼套筒受力很大,對(duì)粘結(jié)長(zhǎng)度及壁厚的要求較高。另外,應(yīng)用錨固性能較好的擠壓式錨具,制作四根CFRP筋無粘結(jié)部分預(yù)應(yīng)力混凝土梁進(jìn)行了深進(jìn)的試驗(yàn)研究;最后運(yùn)用有限元分析軟件ANSYS對(duì)四根試驗(yàn)梁進(jìn)行了非線性有限元全過程分析,驗(yàn)證了模型建立

3、的正確性,為以后的深進(jìn)研究提供了依據(jù)。本文的研究成果將為CFRP筋無粘結(jié)部分預(yù)應(yīng)力混凝土結(jié)構(gòu)在實(shí)際工程的應(yīng)用提供科學(xué)依據(jù),對(duì)CFRP筋預(yù)應(yīng)力混凝土結(jié)構(gòu)的進(jìn)一步研究具有一定的參考價(jià)值。');【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-weig

4、ht 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 couldnt give full play,so we consider FRP tendons applied to prestressed concrete structures.CFRP tendons

5、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 constra

6、int to FRP further application.In this *,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 c

7、an 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 *, the use of reinf

8、orced 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 no

9、n-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 se

10、cond 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

11、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 cra

12、cking, 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 stag

13、e.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

14、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 und

15、er 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 CF

16、RP tendens is accomplished.It is modeling method,selecting element,defining constitutive relationship of materials and solution method that are elaborated on in this *. 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 r