Study on Flexural Performance of RC Beams Strengthened with Bonded Prestressed CFL

2014 ◽  
Vol 578-579 ◽  
pp. 1338-1342
Author(s):  
Jin Lin Huang ◽  
Pei Yan Huang ◽  
Jin Hui Xie

Based on experimental research and calculation theory of flexural bearing capacity, a method for calculating the ultimate load bearing of normal section member strengthened with prestressed CFL is proposed. Static load experimental results of two beams show that when prestress level is 20%, the cracking load and yield load of RC beams strengthened with prestressed CFL are 37.5% and 39.3% respectively. It is larger than that of RC beam strengthened with nonprestressed CFL.

2009 ◽  
Vol 405-406 ◽  
pp. 343-349 ◽  
Author(s):  
Zong Cai Deng ◽  
Jian Hui Li ◽  
He Fei Lin

In order to investigate the strengthening effects of aramid fiber reinforced polymer (AFRP) sheets on the flexural performance of the corroded beams, the flexural behaviors of corroded RC beams strengthened with AFRP sheets under different degrees of corrosion (minor: reinforcement mass loss is 2.0%, medium: reinforcement mass loss is 6.0%) are researched experimentally in this paper, and compared with that of the control beams (un-corroded) and un-strengthened corroded beams. The results show that,compared with un-strengthened corroded beams under same degrees of corrosion, the cracking load, yield load and ultimate load of minor corroded RC beam strengthened with AFRP sheets is respectively increased by 20%, 27% and 60%, and increased by 15%, 36% and 83% for medium corroded RC beam strengthened with AFRP sheets respectively; The ultimate deflection of the medium corroded beam strengthened with AFRP sheets is 166% larger than that of corroded un-strengthened beam. AFRP sheets can improve significantly the bearing capacity and deformation for corroded RC beams.


The focus of this analysis is the review of steel plate strengthened RC beams using Single row and Stagger row bolt arrangements and to compare the bonding behaviour of different bolts arrangement under flexure. Also, to investigate the behaviour, load bearing capacity and the deflection for control and steel plate bonded beams. This research is constrained by FEM analysis utilizing ANSYS to the actions of standard RC Beam and RC beam steel plate associated.


2011 ◽  
Vol 250-253 ◽  
pp. 3361-3366
Author(s):  
Hua Chen ◽  
Kan Kang ◽  
Lang Ni Deng ◽  
Peng Zhang

For RC beams strengthened with prestressed carbon fiber reinforced polymer (CFRP) plates, calculate methods for the cracking load, the yield load and the ultimate load are derived base on the analysis of normal section stress. The test of reinforced concrete beams strengthened with prestressed CFRP plates were carried out, and analytical results are compared with experimental results. Comparisons show that the calculated values agree well with the experimental results.


2012 ◽  
Vol 6 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Guibing Li ◽  
Yugang Guo ◽  
Xiaoyan Sun

It is an effective way to improve the flexural behavior of reinforced concrete (RC) members by externally bonded carbon fiber reinforcement polymer (CFRP) laminates on the soffit of the members. However, there is little investigation on flexural performance of RC beam flexurally strengthened by side-bonded FRP laminates. To investigate the flexural behavior of RC beams side-bonded CFRP laminates and the difference of RC beams strengthened by soffit-bonded and side-bonded CFRP laminates, a total of 8 CFRP-strengthened beams and 1 control beam were tested. The experimental results show that: 1) the first crack loads of RC beams strengthened by side-bonded CFRP laminates are much higher than that of RC beams strengthened by soffit-bonded CFRP laminates. The first crack loads of side-bonded CFRP laminates beams improved significantly; 2) Side-bonded and soffit-bonded CFRP laminates have almost the same effect on the flexural stiffness of RC beams strengthened with same quantity of CFRP laminates before tension rebar yielding. However, side-bonded CFRP laminates can affect crack width and crack pattern of the strengthened beams, and the pre-crack stage of RC beam by sidebonded CFRP laminates extended remarkably. 3) different to soffit-bonded CFRP laminates RC beams, side-bonded CFRP laminates cannot improve the first yielding and the ultimate load bearing capacity of RC beams.


2016 ◽  
Vol 10 (1) ◽  
pp. 598-614 ◽  
Author(s):  
Su Linwang ◽  
Cai Jian ◽  
Chen Qingjun ◽  
Li Guobao ◽  
Zhao Juan

The paper presents an investigation on the flexural behavior of corroded reinforced concrete (RC) beam strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets. Different levels of corrosion are considered as a new method for classifying the corrosion levels of the corroded RC members. Twenty RC beams with five corrosion levels were fabricated by accelerated corrosion equipment, and then the CFRP were used to strengthen these members, considering the effect of different CFRP layers and different strengthened schemes, finally the static flexural load test was carried out. The test results show that the bearing capacity of the CFRP strengthening corroded RC beams is effectively enhanced, the crack width is restrained, and the flexural stiffness is improved. The ultimate flexural capacity of the specimens strengthened by one layer of CFRP sheet raises by 30% to 50% than that of the unstrengthened ones, with the increase of the corrosion level, the enhancement decreased. With the increase of the number of CFRP layers, the bearing capacity increases, while the increasing ratio reduces with the increase in the number of layers. For specimens with obvious cracks, the effectiveness of the strengthening method by bonding CFRP after cutting or chiseling off concrete method (RM1 or RM2) is higher than the method of bonding CFRP directly (DM). It is suggested that the corroded RC members with Level A, B or C1 can be strengthened by DM, while the other level members should be strengthened by RM1 or RM2. The formulae in current design code are used to predict the flexural bearing capacity of the RC beam strengthened with CFRP and their results are compared with experimental ones. A revised formula that can give a better prediction for multi-layer CFRP strengthening members is also proposed.


2021 ◽  
Vol 60 (1) ◽  
pp. 503-518
Author(s):  
Juan Han ◽  
Lu Zhu ◽  
Hai Fang ◽  
Jian Wang ◽  
Peng Wu

Abstract This article proposed an innovative composite sandwich structure reinforced with trapezoidal latticed webs with angles of 45°, 60° and 75°. Four specimens were conducted according to quasi-static compression methods to investigate the compressive behavior of the novel composite structures. The experimental results indicated that the specimen with 45° trapezoidal latticed webs showed the most excellent energy absorption ability, which was about 2.5 times of the structures with vertical latticed webs. Compared to the traditional composite sandwich structure, the elastic displacement and ultimate load-bearing capacity of the specimen with 45° trapezoidal latticed webs were increased by 624.1 and 439.8%, respectively. Numerical analysis of the composite sandwich structures was carried out by using a nonlinear explicit finite element (FE) software ANSYS/LS-DYNA. The influence of the thickness of face sheets, lattice webs and foam density on the elastic ultimate load-bearing capacity, the elastic displacement and initial stiffness was analyzed. This innovative composite bumper device for bridge pier protection against ship collision was simulated to verify its performance. The results showed that the peak impact force of the composite anti-collision device with 45° trapezoidal latticed webs would be reduced by 17.3%, and the time duration will be prolonged by about 31.1%.


2012 ◽  
Vol 204-208 ◽  
pp. 1066-1069
Author(s):  
Yan Jun Li ◽  
Ping Liu

Four specially shaped columns with HRB500 reinforcement were tested under low cyclic loading. The hysteretic curve, yield load, ultimate load, displacement ductility and rigidity degradation were compared in order to research the effect of axial compression ratio on ductility and bearing capacity of specially shaped column with HRB500 reinforcement. It is shown that the axial compression ratio has greater influence on ductility and bearing capacity. With the increase of axial compression ratio, the bearing capacity of HRB500 reinforcement concrete specially shaped column can be enhanced while the deformation capacity becomes worse. The hysteretic characteristic of specially shaped columns with HRB500 reinforcement is improved and the stiffness degeneration becomes slow with the decrease of axial compression ratio.


2011 ◽  
Vol 311-313 ◽  
pp. 1941-1944
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun

intermediate crack-induced debondingis one of the most dominant failure modes in FRP-strengthened RC beams. Different code models and provisions have been proposed to mitigateintermediate crack-induced debondingfailure.However, these models and provisions can not mitigate this failure mode effectively. Recnetly, new models have been proposed to solve this problem. Out of all the existing models, four typical ones are investigated in the current study. A comprehensivecomparison among these models is carried out in order to evaluate their performance and accuracy. Test results offlexural specimens with intermediate crack-induced debonding failurecollected from the existing literature are used in the current comparison. The effectivenessand accuracy of each model have been evaluated based on these experimental results. It is shown that the current modals are all conservative and inadequite to effectively mitigate intermediate crack-induced debonding in flexurally strengthened members.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1187-1190
Author(s):  
Hong Yu Zheng ◽  
Huai Yan Jiang ◽  
Yan Qing Wu ◽  
Zhi Qiang Zhao ◽  
Yong Chun Zeng ◽  
...  

Four pairs of prefabricated reinforced concrete slabs were designed, cast, cured, assembled and test to investigate the flexural performance of prefabricated underground thin-wall box RC structure. One traditional integrated slab specimen with same size, material and reinforcement was also cast and test for comparison purpose. Four rebar constructional forms were conceived to compare the ability of transferring tension force between two slabs. Symmetric two-points monotonic static load test were performed to attain their flexural performance. The test results indicates: the prefabricated RC slab can provide better deformability and ductility, but the flexural bearing capacity is lower, comparing with cast-in-situ integrated RC slab; steel rebar form at seam have some effect on the flexural bearing capacity of prefabricated RC slab.


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