Experimental Study on the Fatigue Properties of RC Beam Strengthened by Prestressed CFL

2008 ◽  
Vol 33-37 ◽  
pp. 169-173 ◽  
Author(s):  
Yi Yang ◽  
Pei Yan Huang ◽  
Jun Deng
Keyword(s):  
Experimental Study ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Rc Beam ◽  
Rc Beams ◽  
Rc Structures ◽  
Reinforcing Effect

Bonding prestressed CFL to strengthen reinforced RC structures can improve the bending capability of structures and the working efficient of CFL. Base on the fatigue experiments of 4 RC beams strengthened by prestressed CFL, the present paper analyzes the fatigue properties of prestressed CFL reinforced RC beams. Comparing with the experimental results of strengthened RC beams without prestress, it can be concluded that the prestressed technology can improve the reinforcing effect and fatigue lives.

scholarly journals EXPERIMENTAL STUDY ON FLEXURAL AND SHEAR REINFORCING EFFECT OF RC BEAM THICKENED BY UHPFRC WITH CFRP ROD EMBEDDED

2021 ◽  
Vol 74 (1) ◽  
pp. 287-293
Author(s):  
Masahiro MINODA ◽  
Haotian LI ◽  
Ayumi SATOH ◽  
Kiyoshi MURAKAMI
Keyword(s):  
Experimental Study ◽  
Rc Beam ◽  
Reinforcing Effect

Bending Resistance of Short-Chopped Basalt Fiber Hydraulic Concrete and RC Element

2011 ◽  
Vol 261-263 ◽  
pp. 407-410 ◽  
Author(s):  
Jun Zhi Zhang ◽  
Hua Ting Liu ◽  
Yan Dong Zhu ◽  
Zhao Qi Fu ◽  
Jing Zhao
Keyword(s):  
Elastic Modulus ◽  
Bending Strength ◽  
Basalt Fiber ◽  
Experimental Results ◽  
Rc Beams ◽  
Reinforcing Effect ◽  
Hydraulic Concrete ◽  
Bending Resistance ◽  
Fiber Concrete ◽  
Chopped Basalt Fiber

According to a series experiment for bending resistance of hydraulic concrete and RC element of mixing short-chopped basalt fiber, the reinforcing effect of bending strength and flexural elastic modulus of short-chopped basalt fiber concrete are analyzed, and increased cracking-resistance loads of short-chopped basalt fiber RC beams is also researched. Experimental results show that bending resistances of short-chopped basalt fiber concrete are increased, short-chopped basalt fiber in concrete is useful to reinforce the bending strength of concrete and cracking loads of RC beams.

scholarly journals Impact Resistance Behavior of Reinforced Concrete Beams Deteriorated due to Repeated Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yusuke Kurihashi ◽  
Yoshinori Nonomura ◽  
Hisashi Konno
Keyword(s):  
Propagation Velocity ◽  
Impact Resistance ◽  
Frost Damage ◽  
Rc Beam ◽  
Rc Beams ◽  
Residual Deflection ◽  
Rc Structures ◽  
Freeze Thaw ◽  
Ultrasonic Propagation ◽  
The Impact

Many existing reinforced concrete (RC) structures constructed more than 50 years ago now require maintenance. This is especially true in cold, snowy regions where significant frost damage deterioration of RC structures becomes a severe problem. In this study, falling-weight impact tests were performed to investigate the impact resistance behavior of RC beams degraded by frost damage. An RC beam was subjected to approximately 900 freeze-thaw cycles to emulate the frost damage before the execution of the impact test. The surface of the beam was remarkably scaled, and its coarse aggregate was exposed. The degree of deterioration was evaluated by the distribution of ultrasonic propagation velocity. The following conclusions were drawn. (1) The ultrasonic propagation velocity of RC beams was significantly reduced following 872 freeze-thaw cycles. At the upper edge of the RC beam, the ultrasonic wave propagation velocity decreased from 4,000 m/s to 1,500 m/s in some parts. This corresponds to a relative dynamic elastic modulus of approximately 14%. (2) The residual deflection of RC beams with frost damage increased at most by 20% compared with beams without frost damage. The increase in residual deflection was primarily related to the peeling of concrete at the collision site and the opening of multiple bending cracks. (3) According to the existing residual deflection calculation formula, an increase of 20% in the residual deflection corresponds to a decrease of about 17% in the bending capacity of the RC beam. When the relationship between the degree of frost damage deterioration and the impact resistance of RC structures is defined, existing structures subjected to accidental impact force from rockfalls are safer and can be maintained more efficiently.

Experimental Study on Shear Capacity of RC Beams Strengthened with Carbon Fiber Reinforced Polymer Mandated by ACli 440

2016 ◽  
Vol 845 ◽  
pp. 154-157
Author(s):  
Sri Tudjono ◽  
Himawan Indarto ◽  
Monica Devi
Keyword(s):  
Experimental Study ◽  
Carbon Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beam ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

Shear reinforcement for retrofitting an RC beam using unidirectional Carbon Fiber Reinforced Polymer (CFRP) woven can only be applied on the beam’s body below the concrete floor slab. Thus, it cannot fully curb like the way stirrups do, in which it will affect the shear capacity. The CFRP can only be ‘n’or ‘u’ shaped, taking into consideration the direction of shear force. Herein, the experimental study of the shear capacity ofshear capacity the beam strengthened by FRP is carried out.shear capacity The beams are RC beams of width 150 mm, height 300 mm, span of 1000 mm, f'c = 26 MPa having 2 bar of 19 mm diameter (fy = 403.65 MPa) and stirrups 6 mm diameter of 250 mm spacing (fy=375 MPa). The shear capacity measured is then compared with the shear capacity calculated using ACI 440. The result shows that the shear capacity measured from experiment is greater than the shear capacity calculated by ACI 440. Also, theshear capacity of RC beam with CFRP reinforcement n shape is greater than u shape.

Experimental Study on Flexural Performance of Corroded RC Beams Strengthened with AFRP Sheets

2009 ◽  
Vol 405-406 ◽  
pp. 343-349 ◽  
Author(s):  
Zong Cai Deng ◽  
Jian Hui Li ◽  
He Fei Lin
Keyword(s):  
Experimental Study ◽  
Mass Loss ◽  
Ultimate Load ◽  
Fiber Reinforced Polymer ◽  
Rc Beam ◽  
Rc Beams ◽  
Yield Load ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Strengthened Beam

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.

A Study on Flexural Performance of RC Beam Strengthened with UHTCC for Improved Durability

2008 ◽  
Vol 400-402 ◽  
pp. 43-54
Author(s):  
Shi Lang Xu ◽  
Xiu Fang Zhang ◽  
Christopher K.Y. Leung
Keyword(s):  
Composite Beam ◽  
Crack Width ◽  
Tensile Strain ◽  
Experimental Results ◽  
Rc Beam ◽  
Rc Beams ◽  
Strain Capacity ◽  
Flexural Performance ◽  
High Toughness ◽  
Tensile Strain Capacity

Ultra-high toughness cementitious composite (UHTCC) exhibits the pseudo-hardening feature when subjected to tensile load and has high tensile strain capacity of normally up to 3%. Also, UHTCC has a unique cracking behavior. From cracking up to ultimate tensile strain capacity, the crack width in UHTCC could be still kept below 100m. This paper presents the utilization of UHTCC to replace a layer of concrete surrounding the main flexural reinforcement in ordinary RC beam to improve flexural performance especially beam durability as UHTCC displays high toughness and shows multiple fine cracks. Analytical closed-form formulae for flexural capacity, curvature and deformation of UHTCC/RC composite beam derived based on the elastic beam theory is presented first. Subsequently, experimental results of two groups of different reinforcement ratios of UHTCC/RC beams and control RC beams tested under flexural loading to verify the feasibility of analytical formulae as well as to examine the performance improvement of UHTCC/RC composite beam over the control beam is presented. Moment-curvature curves and load-mid span displacement curves for the tested beams are compared with the theoretical analysis. A good agreement between experimental and analytical results is found. The experimental results show that the use of a layer of UHTCC in RC beams can enhance both flexural capacity and ductility. The improvement is not significant with the increase in reinforcement ratio; however, the maximum crack width under service load even in the case of lightly reinforced beams can be limited within 0.1mm.

scholarly journals Experimental and Analytical Study on Reinforced Concrete Beams in Bending Strengthened with FRP

2014 ◽  
Vol 8 (1) ◽  
pp. 153-163 ◽  
Author(s):  
C. C. Spyrakos ◽  
I. G. Raftoyiannis ◽  
L. Credali ◽  
J. Ussia
Keyword(s):  
Reinforced Concrete ◽  
Analytical Investigation ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Laboratory Research ◽  
Rc Beams ◽  
Rc Structures ◽  
Factors Affecting ◽  
Frp Composites ◽  
Anchoring System

The performance of the interface between fiber reinforced polymer (FRP) composites and concrete is one of the key factors affecting the behavior of strengthened reinforced concrete (RC) structures. Existing laboratory research has shown that RC beams strengthened with FRP sheets usually fail because of either debonding of the impregnated fabric from the concrete substrate or fracture of the FRP. This work presents an experimental and analytical investigation of the effectiveness of FRP strengthening sheets on RC beams aiming at increasing their flexural strength and stiffness. Experimental results obtained from beam specimens tested under four-point bending are examined with main parameters being the resin type and the anchoring system. In addition, the procedure suggested by the EC8 - Greek Assessment & Retrofitting Code (EC8-GARC) provisions is applied and compared with the experimental results.

scholarly journals Experimental and analytical investigations of reinforced concrete beams strengthened by different CFRP sheet schemes.

2021 ◽  
Vol 15 (56) ◽  
pp. 123-136
Author(s):  
Mahmoud Madqour ◽  
khaled fawzy ◽  
Hilal Hassan
Keyword(s):  
Numerical Study ◽  
High Strength ◽  
Epoxy Adhesive ◽  
Ease Of Use ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Finite Element Program ◽  
Rc Structures ◽  
Bending Load

The use of bonded externally polymer reinforced fiber (FRP) Laminates has been introduced as an effective approach in rehabilitating (RC) structures due to their high strength, corrosion resistance, reduced weight, and ease of use. This paper discusses the experimental results of the flexural reinforcement of RC beams by CFRP sheets bonded by epoxy adhesive to the tensile surface of the beams. Using a four-point bending load system over an effective clear length of 1800 mm, a total of ten beams with an overall dimension of 150 * 200 * 2000 with different degrees of strengthening schemes were constructed and tested. A numerical study using ANSYS finite element program was conducted by modeling RC beams. The number of layers, strengthening scheme (side and U-shape bonding) and reinforcement ratio are the major parameters of the experimental study. the research indicate that the flexural strength of the beams was substantially improved as the layers of laminate increased between 31.80 and 71.50 % and using U shape in ends delaying or preventing debonding failure. The result obtained using ANSYS model showed acceptable agreement with the experimental results, with deviations varying no more than 10 % for all specimens. 

Influence of Type of Contact of RC Beam and Strengthening Slab on Limit States of Strengthened Element

2015 ◽  
Vol 769 ◽  
pp. 294-301 ◽  
Author(s):  
Martin Krizma ◽  
Jaromir Petrzala ◽  
Marián Kišac
Keyword(s):  
Numerical Simulations ◽  
Failure Mode ◽  
Mutual Coupling ◽  
Experimental Results ◽  
Rc Beam ◽  
Rc Beams ◽  
Limit States ◽  
Commercial Software ◽  
Contact Type ◽  
Experimental Programme

The paper deals with an issue of strengthening of damaged RC beams by a coupling slab. Within the experimental programme, the non-strengthened beams had been first loaded up to the level 0.7, consequently were strengthened by an overconcreted slab and loaded up to the failure. The mutual coupling was performed by different techniques. We complete obtained results of tests of an influence of a contact type of a repaired beam and a slab on a resistance, serviceability characteristics and a failure mode of a resultant strengthened element. The experimental results are compared, and thus serve as their verification, with designed values of resistance determined according to the corresponding standard and also with results of numerical simulations performed using the commercial software ATENA.

Experiment on Flexural Capacity of Damaged RC Beams Strengthened with Composite CFRP

2014 ◽  
Vol 501-504 ◽  
pp. 932-935
Author(s):  
Tao Luo
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Experimental Results ◽  
Rc Beam ◽  
Rc Beams ◽  
Reinforcement Effect ◽  
Flexural Capacity ◽  
Loading Test ◽  
Research Results ◽  
Cfrp Sheets

In order to study the flexural capacity of the seismic damaged RC beams after reinforcement, the bearing capacity and ductility are comprehensively evaluated, which is based on the results of three points of division loading test on 8 models which are divided into 4 groups. Experimental results show that compared with the direct pasting CFRP, the ultimate bearing capacity of RC beam strengthened by composite CFRP sheets is much higher, the average is 20.7%. Cracking load and ductility are also improved higher. The reinforcement effect of CFRP sheets is used very well. The research results provide advice and reference for the next seismic damaged RC beams in the reinforcement engineering.

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