共查询到19条相似文献，搜索用时 203 毫秒
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FRP加固RC圆柱正截面受弯承载力计算（英文） 总被引：1，自引：0，他引：1
运用数值计算方法对FRP加固钢筋混凝土（RC）圆柱截面特性进行计算,发现截面破坏时受压区高度主要受轴压比、FRP约束强度比和纵筋配筋特征值3个主要参数影响.根据数值计算的结果进行回归,提出了受压区对应圆心角θ的计算方法.数值计算结果显示,横向约束导致的混凝土应力提高以及纵筋屈服后的强化效应使RC柱破坏时截面受弯承载力远大于规范规定值.根据理论分析和36个大比例试件实测结果提出截面破坏时受弯承载力计算方法,计算结果与试验结果吻合很好.最后,对一个典型柱变形能力进行参数分析,研究轴压比,纵筋配筋特征值和FRP约束强度比对正截面变弯承载力的影响.结果显示FRP加固圆柱破坏时受弯承载力可以比规范规定的未加固柱受弯承载力提高50%左右. 相似文献
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《实验室研究与探索》2013,(12):48-53
借助有限元软件ANSYS,对钢筋混凝土简支梁在单调竖向荷载作用下进行受力全过程非线性计算,对超筋梁和适筋梁,提出分别以混凝土的极限压应变达到εcu和受拉钢筋的极限拉应变达到0.01作为达到极限承载力的判别标准;分析钢筋混凝土梁完整的破坏过程、力学特征,研究受压钢筋、配筋率和材料强度对梁极限承载力的影响,数值分析得出应用高强、高性能钢筋能提高资源利用效率,即截面承载力显著提高的同时,钢筋混凝土构件的延性并未降低等结论。 相似文献
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探讨钢筋混凝土T形柱最不利荷载角及其影响因素.利用编制的钢筋混凝土异形柱截面全过程数值分析程序,通过对多种工况下钢筋混凝土异形柱正截面承载力的计算分析,结果表明异形柱最不利荷载角的影响因素主要是轴压比;截面尺寸对最不利荷载角有些影响;而混凝土强度、纵筋配筋面积对最不利荷载角的影响很弱.研究结果为钢筋混凝土异形柱的设计和异形柱的可靠性分析提供参考依据. 相似文献
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从材料、设计基本原则、正截面承栽力计算原理等方面,对中国规范和美国规范中钢筋混凝土受弯构件正截面配筋设计方法进行比较分析．中美规范中材料的强度等级、强度值有不同,设计基本原则中的实用设计表达式有差异;设计公式建立的假设、建立过程相似,设计公式具体形式有差异．实例计算表明：按美国规范进行钢筋混凝土正截面受弯设计,其内力、配筋均比中国的规范大,构造要求比中国的规范严格． 相似文献
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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
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用于钢筋混凝土受弯构件补强加固的碳纤维织物的力学性能 总被引：1，自引：0，他引：1
讨论了用以测定碳纤维织物的抗拉强度及弹性模量等有关力学性能指标的相关方法 .对 5根碳纤维织物补强加固简支梁进行了试验研究和计算机模拟分析 ,试验数据与分析数据符合较好 ,说明碳纤维织物的实测力学性能指标可靠合理 .同时 ,在对试验数据进行分析整理的基础上 ,得出了碳纤维织物补强加固钢筋混凝土受弯构件正截面承载力的简化设计公式 . 相似文献
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为了研究钢筋增强ECC梁受弯性能,进行了钢筋增强ECC梁和普通钢筋混凝土梁受弯的对比研究.结果表明,相比普通钢筋混凝土梁,钢筋增强ECC梁的受弯承载力和延性分别提高了24.8%和187.76%,并且在梁中用ECC代替混凝土可有效延缓裂缝的发展.此外,采用简化的ECC本构模型对钢筋增强ECC及混凝土梁的受弯性能进行了非线性有限元分析,模拟结果与试验结果吻合较好,在服役期间钢筋增强ECC梁的裂缝可以控制在0.4 mm以下.ECC材料的使用可明显提高梁的抗弯承载力、变形能力、延性等受弯性能. 相似文献
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1 各章的学习要求 受弯构件正截面、斜截面承载力计算,受压构件承载力计算,钢筋混凝土梁板结构为重点内容。受弯构件与受压构件部分要求理解受力各阶段的应力分布、破坏特征及计算的基本假定,熟练掌握承载力计算。 钢筋混凝土的力学性能、结构设计方法、受拉构件承载力计算为次重点内容。 钢筋混凝土构件变形和裂缝验算、预应力混凝土的基本知识为了解内容。 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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罗纪彬 《湖南广播电视大学学报》2009,(3):46-49
根据混凝土碳化及其引起的钢筋锈蚀的机理,建立了钢筋混凝土构件的劣化模型。利用Monte Carlo模拟方法分别研究了一般运营和密集运营两种荷载模型下钢筋混凝土桥梁的时变可靠性,讨论了保护层厚度、混凝土强度、钢筋锈蚀损失率对混凝土耐久性的影响。研究表明：在服役过程中,由于大气环境的作用,混凝土碳化、钢筋锈蚀、桥梁结构可靠指标不断降低,混凝土的耐久性能不断下降;混凝土保护层厚度和混凝土抗压强度对可靠度指标的影响明显,而钢筋腐蚀率的影响不是很明显。 相似文献
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The marine structures such as harbour,pier and inshore concrete terrace are exposed in adverse circumstances in a long period of time . Owing to the attack of external corrosive medium, their safety, durability and reliability decline. Especially the reinforced concrete(RC) structures in the wave splash area are more likely to be subjected to destruction and the loss is vast. Now the safety ,durability and reliability of structure have become increasingly an important subject to be studied. By way of the soaking and drying cycle test on the different mix proportions oblique section of 10 pieces of RC beams suffered artificial sea water(ASW) corrosion under 0,35,70,105,140 times of dry-wet cycles, the compared results of exerting pressure test of these beams under simply supporting were investigated. The law about the changes of the mechanical performance for RC beams with different mix proportions under different time periods for suffering corrosion of dry-wet cycles is as follows: the resistivity to ASW corrosion of the concrete specimens with various water cement ratio(various initial strength) is different ; the characters of oblique section failure for RC beams attacked by sea water are about the same as those for ordinary RC beam; along with the extension of the time for sea water attack, the bearing capacity for oblique section of RC beams varies wave upon wave. The specimens attacked by sea water for about 35 times of corrosion cycle achieve minimum bearing capacity. 相似文献
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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
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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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Seismic behavior of steel reinforced ultra high strength concrete column and reinforced concrete beam connection 总被引：1，自引：1，他引：0
To investigate the seismic behavior of connections composed of steel reinforced ultra high strength concrete （SRUHSC） column and reinforced concrete （RC） beam, six interior strong-column-weak-beam connection specimens were tested subjected to reversal cyclic load. Effects of applied axial load ratio and volumetric stirrup ratio on ductility, energy dissipation capacity, strength degradation and rigidity degradation were discussed. It was found that all connection specimens failed in bending in a ductile manner with a beam plastic hinge. The ductility and energy dissipation capacity increased with the decrease of applied axial load ratio or increase of volumetric stirrup ratio. The displacement ductility coefficient and equivalent damping coefficient lay between those of steel reinforced ordinary concrete connection and those of reinforced concrete connection. The applied axial load ratio and volumetric stirrup ratio had less influence on the strength degradation and more influence on the stiffness degradation. The stiffness degraded sharply with the decrease of volumetric stirrup ratio or increase of applied axial load ratio. The experimental results indicate that SRUHSC column and RC beam connection exhibited better seismic performance and can provide reference for engineering application. 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
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基于ANSYS程序的钢筋混凝土梁非线性数值模拟 总被引：2，自引：0，他引：2
采用商用程序ANSYS对不同配筋率的钢筋混凝土梁进行非线性数值分析，以考察不同配筋率对钢筋混凝土梁受弯性能的影响。结合数值模拟分析过程，详细介绍了基于ANSYS程序的钢筋混凝土构件非线性数值分析的关键技术，分析了对不同配筋率的钢筋混凝土粱的刚度变化、破坏特征、截面应力分布、裂缝发展和钢筋、混凝土应力及应变发展过程。 相似文献
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Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability analysis are carried out by JC method (improved first-order second-moment method) based on the relevant experimental data. Results show that the resistance partial factor of the joint increases with the increase of the reliability index. The resistance partial factors are suggested corresponding to the reliability index under different load combinations. Moreover, the suggested resistance partial factor is adopted in reliability design, and it is found that the reliability index of the joint is larger than the target reliability index. The optimal load combination is the one in which live load plays an important control role. Finally, based on the suggested resistance partial factors, the reliability analysis of cast ball-and-socket support joints of a project is conducted. 相似文献