共查询到18条相似文献，搜索用时 187 毫秒
1.
玻璃纤维布加固的钢筋混凝土梁试验研究与抗弯承载力计算 总被引：1，自引：0，他引：1
对9根玻璃纤维布加固的钢筋混凝土梁和3根对比梁进行了抗弯性能试验研究. 试验中考虑了配筋率、加固量、剪跨比与混凝土强度等级4个参数. 试验结果表明, 经玻璃纤维布加固的钢筋混凝土梁抗弯承载力有显著提高; 混凝土强度、配筋率、加固量对极限荷载有显著影响; 剪跨比对加固梁的破坏形态有影响. 根据不同的破坏模式, 提出了抗弯承载力计算方法. 相似文献
2.
孟浩 《淮南职业技术学院学报》2003,3(3):72-74,79
通过对六根钢筋混凝土梁的斜截面抗剪试验,研究了采用梁侧粘贴钢板网对梁进行抗剪加固的效果,并与未加固的钢筋混凝土梁作对比,对试验结果进行分析,得出这种加固方法的设计计算公式。 相似文献
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为研究碳纤维布(CFRP)对加固后钢筋混凝土梁的抗弯疲劳性能的影响,进行了3根CFRP加固梁及1根对比梁的抗弯疲劳试验.研究了碳纤维布加固方式、构件使用荷载等参数对碳纤维布加固损伤钢筋混凝土吊车梁的抗弯疲劳性能影响.试验研究表明:采用碳纤维布加固后,构件裂缝的宽度减小50.2%~66%,发展速度也得到控制,钢筋应力减小24.1%~28.2%,构件的刚度提高14.9%~16.1%.依据试验结果,从现有规范中关于构件刚度计算方法出发,进行了CFRP加固钢筋混凝土吊车梁的疲劳刚度计算分析,该计算方法可用于吊车梁加固工程设计.最后给出了CFRP加固梁的疲劳设计的合理化建议. 相似文献
4.
程怡 《福建工程学院学报》2013,11(1):24-28
通过4片部分预应力混凝土(PPC)梁试件采用CFRP板抗剪加固的试验,研究不同预应力水平对CFRP板加固PPC梁抗剪性能的影响.结果表明:采用CFRP板对PPC梁进行抗剪加固,能有效抑制斜裂缝的发展,提高加固梁的斜截面抗剪承载力,并在试验研究的基础上进行了非线性有限元分析,与试验结果吻合良好. 相似文献
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对15根玻璃纤维布加固的钢筋混凝土梁进行了试验研究。试验结果表明,玻璃纤维布加固的钢筋混凝土梁抗弯承载力显著提高,加固效果明显,但要有足够的粘贴长度以避免发生剥离破坏。 相似文献
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为了解玻璃纤维(GFRP)布与钢筋混凝土梁界面之间的粘结性能,进行了7根GFRP布加固的钢筋混凝土梁与2根对比梁的试验研究.试验的变化参数为GFRP布层数、粘结长度及配筋率.试验结果表明,GFRP布加固的钢筋混凝土梁极限荷载显著提高,但是发生剥离破坏的试验梁极限荷载有所降低,粘结长度是影响加固梁剥离破坏的主要因素.根据试验结果提出了GFRP布与钢筋混凝土梁界面粘结剪应力的试验分析方法并分析了界面间粘结剪应力的分布.同时,提出了GFRP布加固的钢筋混凝土梁剥离正应力与粘结剪应力的理论分析方法.最后,给出了GFRP布加固钢筋混凝土梁剥离荷载的计算方法.为验证理论分析方法的正确性,计算了试验梁界面间的粘结剪应力、剥离正应力及剥离荷载.计算结果表明,所提出的理论分析方法与试验值吻合较好. 相似文献
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通过对锈蚀钢筋混凝土构件的低周反复荷载试验，讨论了钢筋锈蚀对混凝土构件的滞回曲线、骨架曲线、刚度、延性、耗能能力、承栽力等不利影响，提出了锈蚀钢筋混凝土构件抗剪承栽力与抗弯承载力计算表达式。 相似文献
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实际工程中经常遇到混凝土构件斜截面粘钢加固的问题，通过结构试验，本得出了斜粘钢板的最佳锚固方式以及构件开裂后卸荷斜粘钢板抗剪承载力计算方法，可供工程加固计算时参考。 相似文献
10.
二次受力下碳纤维布加固梁抗弯性能试验研究 总被引：1，自引：0，他引：1
进行了4根不同二次受力条件下碳纤维布加固的钢筋混凝土梁和1根对比混凝土梁的抗弯性能试验研究。试验及分析结果表明,用粘贴碳纤维布的方法来提高梁的承载力十分有效,且预加载的存在使加固梁的极限荷载降低;碳纤维布能有效约束裂缝的开展,但裂缝的数量增加和分布区域变大,且预加载的大小会影响加固梁裂缝的开展和分布;碳纤维布加固可以增强梁的刚度,但延性有所降低。 相似文献
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Feras ALZOUB ZHANG Qi LI Zheng-liang 《重庆大学学报(英文版)》2007,6(4):305-310
This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side- bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results. 相似文献
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INTRODUCTION There is increased need in recent years for strengthening or rehabilitation of existing reinforced concrete structures adversely affected by overloading, construction material deterioration, seismic loads, structural deformation, etc. An effective method for increasing the shear capacity of reinforced concrete columns is the use of externally bonded carbon fiber reinforced plastic (CFRP) systems (ACI, 2002). FRP systems were first applied to reinforced concrete col-umns i… 相似文献
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This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer(CFRP) layer under long-term load action that lasted for 330 d.We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest.The conducted experiments showed that the additional anchorage influences the slip of the external layer with respect to the strengthened element.Thus,concrete and carbon fibre composite interface stiffness decreases with a long-term load action.Therefore,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load. 相似文献
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INTRODUCTION Externally bonded fiber reinforced polymer (FRP) composites can be used to improve the flexural strength of structural members. To evaluate the flex-ural performance of the strengthened members, it is necessary to study the flexural stiffness of FRP- strengthened RC members at different stages, such as pre-cracking, post-cracking and post-yielding. Up to now, only very few studies were focused on the structural members strengthened under pre-loading or pre-cracking (Arduin… 相似文献
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Carbon fiber reinforced polymer(CFRP)bars were prestressed for the structural strengthening of 8 T-shaped rein-forced concrete (RC)beams of a 21-year-old bridge in China.The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory.The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit.The field construction processes of strengthening with CFRP bars-including grouting cracks,cutting groove,grouting epoxy and embedding CFRP bars,surface treating,banding with the U-type CFRP sheets,releasing external prestressed steel tendons-were introduced in detail.In order to evaluate the effectiveness of this strengthening method,field tests using vehicles as live load were applied before and after the retrofit.The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge,including the bending strength and stiffness,is enhanced.The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges.Therefore,the proposed strengthening technology is feasible and effective. 相似文献
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The earthquake-resistant property of reinforced concrete members depends on the interaction between reinforcing bars and surrounding concrete through bond to a large degree,In this paper a general system aimed at dealing with the failure analysis of reinforced concrete columns strengthened with carbon-fiber-reinforced plastic(CFRP) sheets including bond-slip of the anchored reinforcing bars at the foot of the columns is presented.It is based on the yield design theory with a mixed modeling of the structue,according to which the concrete material is treated as a classical two-dimensional continuum ,whereas the longitudinal reinfocing bars are regarded as one-dimensional rods including bond-slip at the foot of the columns,In shear reinforced zones both the shear CFRP sheets and transvers reinforcing bars are incorporated in the analysis throuth a homogenization procedure and they are only in tesion ,The approach is then implemented numerically by means of the finite-element formulation,The numerical procedure produces accurate estimates for the loading-carrying capactiy of the shear members taken as an illustrative application by correlation with the experimental results,so the proposed approach is valid. 相似文献
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Extensive research has shown that externally bonded carbon fiber reinforced polymer (CFRP) laminates are particularly suitable for improving the fatigue behavior of reinforced concrete (RC) beams. This paper presents the research on flexural rigidity evolvement laws by testing 14 simple-supported RC beams strengthened with carbon fiber laminates (CFL) under cyclic load, and 2 under monotone load as a reference. The cyclic load tests revealed the peak load applied onto the surface of a supported RC beam strengthened with CFL is linear to the logarithm of its fatigue life, and the flexural rigidity evolvement undergoes three distinct phases: a rapid decrease from the start to about 5% of the fatigue life; an even development from 5% to about 99% of the fatigue life; and a succedent rapid decrease to failure. When the ratio of fatigue cycles to the fatigue life is within 0.05 to 0.99, the flexural rigidity varies linearly with the ratio. The peak load does not affect the flexural rigidity evolvement if it is not high enough to make the main reinforcements yield. The dependences of the flexural rigidity of specimens formed in the same group upon their fatigue cycles normalized by fatigue life are almost coincident. This implies the flexural rigidity may be a material parameter independent of the stress level. These relationships of flexural rigidity to fatigue cycles, and fatigue life may be able to provide some hints for fatigue design and fatigue life evaluation of RC member strengthened with CFL; nevertheless the findings still need verifying by more experiments. 相似文献
18.
Carbon fiber reinforced polymer （CFRP） bars were prestressed for the structural strengthening of 8 T-shaped reinforced concrete （RC） beams of a 21-year-old bridge in China. The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory. The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit. The field construction processes of strengthening with CFRP bars including grouting cracks, cutting groove, grouting epoxy and embedding CFRP bars, surface treating, banding with the U-type CFRP sheets, releasing external prestressed steel tendons-were introduced in detail. In order to evaluate the effectiveness of this strengthening method, field tests using vehicles as live load were applied before and after the retrofit. The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge, including the bending strength and stiffness, is enhanced. The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges. Therefore, the proposed strengthening technology is feasible and effective. 相似文献