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.

Implication of Unbondedness in Reinforced Concrete Beams

2012 ◽  
Vol 587 ◽  
pp. 36-41 ◽  
Author(s):  
S.F.A. Rafeeqi ◽  
S.U. Khan ◽  
N.S. Zafar ◽  
T. Ayub
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Failure Mode ◽  
Shear Failure ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Flexural Reinforcement

In this paper, behaviour of nine (09) RC beams (including two control beams) after unbonding and exposing flexural reinforcement has been studied which were intentionally designed and detailed to observe flexural and shear failure. Beams have been divided into three groups based on failure mode and unbounded and exposed reinforcement. Beams have been tested under two-point loading up to failure. Experimental results are compared in terms of beam behaviour with respect to flexural capacity and failure mode which revealed that the exposed reinforcement does not altered flexural capacity significantly and unbondedness positively influences shear strength; however, serviceability performance of beams with unbonded and exposed reinforcement is less.

Prediction Method of the Load Resisting Mechanisms in the Corroded RC Beams

2014 ◽  
Vol 919-921 ◽  
pp. 203-209
Author(s):  
Wei Dong ◽  
Hideki Oshita ◽  
Tomoaki Tsutsumi
Keyword(s):  
Failure Mode ◽  
Prediction Method ◽  
Rc Beam ◽  
Rc Beams ◽  
Decision Point ◽  
Bond Performance ◽  
Flexural Failure ◽  
Bottom Portion

The failure mode of the corroded RC beam may shift from designed failure mode to others failure mode, as the load resisting mechanism changes due to the corrosion ratio of rebars. In this study, the load resisting mechanism and the failure mode of the corroded RC beam were investigated based on the bond performance. If the corroded RC beam is non-uniformly corroded, the beam suffers beam action and fails in flexural failure. Otherwise, the load resisting mechanism and the failure mode depend on the corrosion ratio of bottom portion stirrups. Moreover, the decision point is proposed to predict the load resisting mechanisms in the corroded RC beam.

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.

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.

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 Fatigue Stress-Life Model of RC Beams Based on an Accelerated Fatigue Method

2019 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Eljufout ◽  
Toutanji ◽  
Al-Qaralleh
Keyword(s):  
Cyclic Loading ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Rc Beam ◽  
Rc Beams ◽  
Testing Methods ◽  
Load Range ◽  
Fatigue Stress ◽  
Life Model ◽  
Prediction Band

Several standard fatigue testing methods are used to determine the fatigue stress-life prediction model (S-N curve) and the endurance limit of Reinforced Concrete (RC) beams, including the application of constant cyclic tension-tension loads at different stress or strain ranges. The standard fatigue testing methods are time-consuming and expensive to perform, as a large number of specimens is needed to obtain valid results. The purpose of this paper is to examine a fatigue stress-life predication model of RC beams that are developed with an accelerated fatigue approach. This approach is based on the hypothesis of linear accumulative damage of the Palmgren–Miner rule, whereby the applied cyclic load range is linearly increased with respect to the number of cycles until the specimen fails. A three-dimensional RC beam was modeled and validated using ANSYS software. Numerical simulations were performed for the RC beam under linearly increased cyclic loading with different initial loading conditions. A fatigue stress-life model was developed that was based on the analyzed data of three specimens. The accelerated fatigue approach has a higher rate of damage accumulations than the standard testing approach. All of the analyzed specimens failed due to an unstable cracking of concrete. The developed fatigue stress-life model fits the upper 95% prediction band of RC beams that were tested under constant amplitude cyclic loading.

Flexural Fatigue Performance of RC Beams Strengthened with Hybrid Fiber Sheets

2012 ◽  
Vol 166-169 ◽  
pp. 1657-1662
Author(s):  
Xu Jun Chen ◽  
Xiao E Zhu ◽  
Zhong Yang ◽  
Mu Xiang Dai
Keyword(s):  
Fatigue Life ◽  
Basalt Fiber ◽  
Reinforced Concrete Beams ◽  
Fatigue Performance ◽  
Rc Beam ◽  
Rc Beams ◽  
Hybrid Fiber ◽  
Cycle Number ◽  
Flexural Fatigue ◽  
Variation Characteristics

Based on the fatigue test for flexural performance of five reinforced concrete beams, the variation characteristics of the crack development, concrete strain, steel strain, fiber strain with the cycle number of the fatigue load were analyzed, and the effect of hybrid fiber sheets and basalt fiber reinforced polymer(BFRP)sheets on flexural fatigue performance of the strengthened beam was studied. The results show that the accumulated damage of RC beams strengthened with hybrid fiber sheets was slowed down significantly, the anti-crack property was much improved, and the fatigue life was greatly prolonged. Compared with the ordinary RC beam and the RC beam strengthened with double BFRP sheets, the fatigue life of RC beams strengthened with hybrid CFRP/BFRP(C/BFRP) sheets and hybrid CFRP/GFRP(C/GFRP) sheets was increased by 291.26%, 298.63% and 10.73%, 13.53%.

scholarly journals Elasto-Plastic Impact Analysis on RC Beams with Statically Bending Failure Mode.

1999 ◽  
pp. 215-233 ◽  
Author(s):  
Norimitsu KISHI ◽  
Hiroshi MIKAMI ◽  
Ken-ichi G. MATSUOKA ◽  
Tomohiro ANDO
Keyword(s):  
Failure Mode ◽  
Impact Analysis ◽  
Rc Beams ◽  
Bending Failure

Comparison of flexural capacity of different hollow slab beams with/without pavement layer reinforced by steel plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Long Liu ◽  
Lifeng Wang ◽  
Ziwang Xiao
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Plate Thickness ◽  
Experimental Results ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Content Type

PurposeReinforcement of reinforced concrete (RC) beams in-service have always been an important research field, anchoring steel plate in the bottom of the beams is a kind of common reinforcement methods. In actual engineering, the contribution of pavement layer to the bearing capacity of RC beams is often ignored, which underestimates the bearing capacity and stiffness of RC beams to a certain extent. The purpose of this paper is to study the effect of pavement layer on the RC beams before and after reinforcement.Design/methodology/approachFirst, static load experiments are carried out on three in-service RC hollow slab beams, meanwhile, nonlinear finite element models are built to study the bearing capacity of them. The nonlinear material and shear slip effect of studs are considered in the models. Second, the finite element models are verified, and the numerical simulation results are in good agreement with the experimental results. Last, the finite element models are adopted to carry out the research on the influence of different steel plate thicknesses on the flexural bearing capacity and ductility.FindingsThe experimental results showed that pavement layers increase the flexural capacity of hollow slab beams by 16.7%, and contribute to increasing stiffness. Ductility ratio of SPRCB3 and PRCB2 was 30% and 24% lower than that of RCB1, respectively. The results showed that when the steel plate thickness was 1 mm–6 mm, the bearing capacity of the hollow slab beam increased gradually from 2158.0 kN.m to 2656.6 kN.m. As the steel plate thickness continuously increased to 8 mm, the ultimate bearing capacity increased to 2681.0 kN.m. The increased thickness did not cause difference to the bearing capacity, because of concrete crushing at the upper edge.Originality/valueIn this paper, based on the experimental study, the bearing capacity of hollow beam strengthened by steel plate with different thickness is extrapolated by finite element simulation, and its influence on ductility is discussed. This method not only guarantees the accuracy of the bearing capacity evaluation, but also does not require a large number of samples, and has certain economy. The research results provide a basis for the reinforcement design of similar bridges.

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