共查询到19条相似文献,搜索用时 156 毫秒
1.
2.
3.
《工业建筑》2015,(9)
基于碳纤维加固材料(CFRP)布加固疲劳损伤后的钢筋混凝土梁和预应力混凝土梁进行的竖向荷载作用下试验,研究了CFRP布加固疲劳损伤后的混凝土梁受弯性能和抗弯承载力。试验结果表明:预应力钢筋明显减小加固梁的跨中挠度及CFRP布应变值;混凝土梁的疲劳损伤降低了CFRP布加固钢筋混凝土梁的极限抗弯承载力,且混凝土梁加固前损伤程度越大,加固后极限抗弯承载力降低的幅度亦越大;采用GB50367—2013《混凝土结构加固设计规范》和GB 50608—2010《纤维增强复合材料建设工程应用技术规范》中提出的抗弯承载力计算式(均未考虑梁加固前损伤程度),所得计算值均高于试验结果,表明加固前梁产生的疲劳损伤对加固后抗弯承载力的影响不可忽略。 相似文献
4.
5.
二次受力下预应力碳纤维布加固混凝土梁承载力计算 总被引:1,自引:0,他引:1
外贴预应力碳纤维布加固混凝土构件是一种简单且有效的加固方式.对预应力碳纤维布加固混凝土梁的全过程做了理论分析,根据应力—应变关系及变形协调原理,分析了预应力碳纤维布加固混凝土梁各个阶段的承载力计算,并计算了在二次受力时的抗弯承载力,各阶段理论分析计算值与试验值基本吻合,可为实际工程的加固设计提供理论参考. 相似文献
6.
碳纤维布具有轻质、高强、耐久性好等特性,预应力碳纤维布加固技术已成为一种新型建筑加固技术。在试验基础上,对预应力碳纤维加固钢筋混凝土梁的受力性能进行了分析,提出了预应力碳纤维布加固钢筋混凝土梁的抗弯正截面承载力的计算公式,计算公式与试验结果较为接近,试验值略高于理论值,说明理论计算有一定的安全储备,较为保守安全。 相似文献
7.
为研究碳纤维对锈蚀钢筋混凝土梁加固后抗弯承载力的变化情况,采用碳纤维对一根锈蚀率为9%的梁正截面进行加固,计算加固后的抗弯承载力。分析结果表明:钢筋锈蚀到一定程度后,无法满足承载力要求;采用碳纤维布进行加固后,梁抗弯承载力显著提升,满足承载力要求;在适用条件下,抗弯承载力随着碳纤维布用量的增加而增加。 相似文献
8.
9.
本文对预应力碳纤维布材加固混凝土梁构件的性能做了初步的研究,并提出了应用预应力碳纤维布材加固梁构件的施工工艺。在此基础上,作者进行了9根试件的试验。通过试验结果对比了预应力碳纤维布加固的受弯构件与非预应力碳纤维布加固的受弯构件的开裂荷载、极限荷载、抗弯刚度等工作性能,分析了预应力对构件弯曲性能的影响,讨论了预应力水平变化引起的构件使用荷载以及变形能力的变化。试验发现预应力碳纤维布材加固的试件的开裂荷载较对比试件提高了43%至214%,在对比试件屈服荷载下的变形为对比试件的29.8%至56.3%。试验结果与分析表明预应力碳纤维布材极大地提高了梁构件的工作性能。另外,本文提出了预应力碳纤维布材加固的受弯构件的界限补强率、极限承载力、抗弯刚度以及挠曲变形的计算公式。 相似文献
10.
碳纤维布加固高强钢筋混凝土梁抗弯性能试验研究 总被引:1,自引:0,他引:1
在12根梁的试验基础上,对碳纤维布加固高强钢筋混凝土梁后的受弯破坏特征及对梁的极限承载力、刚度等的影响进行了研究与分析.试验中考虑了纵筋配筋率、加固量与加固方式、锚固情况、粘结长度四个变化参数.试验结果表明,使用碳纤维布加固的高强混凝土梁抗弯承载力提高较多,加固效果明显. 相似文献
11.
Mohammad R. IRSHIDAT Rami S. AL-HUSBAN 《Frontiers of Structural and Civil Engineering》2022,16(1):131-143
This paper studied the effect of incorporation of carbon nanotubes (CNTs) in carbon fiber reinforced polymer (CFRP) on strengthening of reinforced concrete (RC) beams. The RC beams were prepared, strengthened in flexure by externally bonded CFRP or CNTs-modified CFRP sheets, and tested under four-point loading. The experimental results showed the ability of the CNTs to delay the initiation of the cracks and to enhance the flexural capacity of the beams strengthened with CFRP. A nonlinear finite element (FE) model was built, validated, and used to study the effect of various parameters on the strengthening efficiency of CNTs-modified CFRP. The studied parameters included concrete strength, flexural reinforcement ratio, and CFRP sheet configuration. The numerical results showed that utilization of CNTs in CFRP production improved the flexural capacity of the strengthened beams for U-shape and underside-strip configurations. The enhancement was more pronounced in the case of U-shape than in the case of use of sheet strip covers on the underside of the beam. In case of using underside-strip, the longer or the wider the sheet, the higher was the flexural capacity of the beams. The flexural enhancement of RC beams by strengthening with CNTs-modified CFRP decreased with increasing the rebar diameter and was not affected by concrete strength. 相似文献
12.
进行了碳纤维布加固钢筋混凝土梁的受弯性能试验研究,试验中考虑的变量有混凝土强度、纵筋配筋率及碳纤维加固量等。试验中采用了多种附加锚固措施,分析了各种锚固措施的影响。最后,参考本文试验结果及文献资料,统计出了碳纤维受弯计算折减系数取值,并与规范取值进行了对比。 相似文献
13.
14.
应用理论计算公式,对影响抗弯承载力的CFRP片材厚度、弹性模量以及混凝土强度等参数进行了分析,结果表明,使用弹性模量高、厚度大的CFRP片材加固的组合梁,承载力提高更大;采用高混凝土强度的梁,其极限抗弯承载力提高效果更明显。 相似文献
15.
《Construction and Building Materials》2007,21(6):1182-1190
Cracks in reinforced concrete (RC) should be repaired if they present the potential for durability related problems such as corrosion of reinforcing steel. One way to repair extensive cracks is the use of epoxy injection. Another repair technique to enhance shear or flexural strength in deficient RC members is the utilization of externally bonded carbon fiber reinforced polymer (CFRP) fabrics. The effect of environmental conditioning on crack injection with or without CFRP strengthening is of interest in this investigation. Test results showed that the crack injection provided an increase in initial stiffness for un-strengthened RC beams. An increase in initial stiffness and ultimate strength was achieved in CFRP strengthened RC beams. Surface roughness combined with crack injection significantly increased the flexural capacity of the specimens. Environmental conditioning significantly affected the bond performance of the epoxy injection. The presence of sustained load during environmental conditioning resulted in reduced section capacity and ductility. 相似文献
16.
灰色系统具有“少数据建模”的特点,着重研究概率统计、模糊数学所不能解决的“小样本、贫信息”的不确定问题.基于已有玻璃纤维(GFRP)筋—混凝土粘结性能试验研究的资料,运用灰色系统理论的关联度分析方法研究GFRP筋—混凝土粘结性能影响参数关联计算的技术.考虑的影响参数包括GFRP筋直径、肋高度、肋间距.灰色关联分析结果表明,对GFRP筋—混凝土粘结强度的影响程度从大到小排序依次为GFRP筋肋高度、直径、肋间距;对滑移的影响程度从大到小排序依次为GFRP筋直径、肋高度、肋间距.在关联分析基础上,构建了考虑各影响参数组合权系数的滑移计算模型,并回归出系数向量,公式计算值与试验值吻合良好. 相似文献
17.
为研究碳纤维增强复合(CFRP)网格和聚合物水泥砂浆(PCM)复合加固钢筋混凝土(RC)梁的抗弯性能,对5个RC梁试件进行抗弯性能试验,分析CFRP网格-PCM复合加固RC梁的抗弯破坏机理,研究网格不同层数和不同单位加固量对RC梁抗弯性能的影响。基于抗弯承载力的既有计算模型,引入剥离应变建立改良计算模型,并采用其他学者的9根FRP网格加固RC梁的受弯试验数据,验证改良计算模型的准确性。研究结果表明:CFRP网格-PCM对RC梁的抗弯加固效果明显,单位加固量较高的试件具有更高的承载能力,但其更易发生剥离破坏;在单位加固量相当的条件下,单层网格与双层网格呈现出相同的抗弯性能,双层网格重叠布置的加固方式是有效的;抗弯承载力的既有计算模型对试验结果拟合效果较差,所建立的改良计算模型拟合程度较好,能更好地反映CFRP网格-PCM复合加固层的实际受力状态。 相似文献
18.
19.
《Construction and Building Materials》2008,22(12):2355-2368
Various methods are developed for strengthening reinforced concrete beams against shear. Nowadays, external bonding of different composite members to RC beams was very popular and successful technique internationally. This study presents test results on strengthening of shear deficient RC beams by external bonding of carbon fiber reinforced polymer (CFRP) straps. Six RC beams with a T-section were tested under cyclic loading in the experimental program. Width of the CFRP straps, arrangements of straps along the shear span, and anchorage techniques that were applied at the ends of straps were the main parameters that were investigated during experimental study. Shear deficient beams with low strength concrete were strengthened by using CFRP straps for obtaining ductile flexural behavior. The test results confirmed that all CFRP arrangements improved the strength, stiffness and energy dissipation capacity of the specimens significantly. The failure mode and ductility of specimens were proved to differ according to the CFRP strap width and arrangement along the beam. Experimental results were compared with the analytical approaches that were suggested by ACI-440 Committee Report. 相似文献