scholarly journals Experimental Study on the Shear Performance of Reinforced Concrete Beams Strengthened with Bolted Side-Plating

2019 ◽  
Vol 11 (9) ◽  
pp. 2465
Author(s):  
Xin Liu ◽  
Yu Chen ◽  
Ling-Zhi Li ◽  
Mei-Ni Su ◽  
Zhou-Dao Lu ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Rc Beams ◽  
Shear Performance ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Oxychloride Cement

To investigate the residual shear capacity of post-fire bolted side-plated (BSP) reinforced concrete (RC) beams with different depths of steel plate and types of anchor adhesive, i.e., magnesium oxychloride cement (MOC) and HIT-RE500, a control beam and five BSP beams were fabricated, of which two were exposed to fire in accordance with ISO834 temperature curve. Four-point bending shear tests were conducted to investigate the influence of elevated temperature on the failure mode, cracking load, shear capacity, stiffness, ductility and strain development, etc. The shear capacities of RC beams were found to be improved significantly by using the BSP technique. However, the stiffness of BSP beams was seriously degraded after exposed to fire, but the reduction in shear capacity was negligible, whereas the ductility and the strain of longitudinal reinforcement were obviously increased. Thus, the failure-mode was changed from shear failure to flexural failure. Regarding the adhesive mortar used for bolt anchorage, magnesium oxychloride cement (MOC) achieved higher shear capacity and better ductility but lower stiffness for BSP beams compared with HIT-RE500. Additionally, increasing the depth of bolted steel plates effectively improved the shear performance of BSP beams. In the tests, uneven relative slips were observed on the plate-RC interface due to the shear deformation of bolt shafts and the plates’ tensile principal stress perpendicular to the main diagonal crack, which proved the deformation lag of the bolted steel plates with respect to the RC beam. The outcomes of this study provide a better understanding on the shear performance of BSP beams at room temperatures and at fire conditions.

Predicting the effect of stirrups on shear strength of reinforced normal-strength concrete (NSC) and high-strength concrete (HSC) slender beams using artificial intelligence

2006 ◽  
Vol 33 (8) ◽  
pp. 933-944 ◽  
Author(s):  
H El Chabib ◽  
M Nehdi ◽  
A Saïd
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Strength Concrete ◽  
Shear Design

The exact effect that each of the basic shear design parameters exerts on the shear capacity of reinforced concrete (RC) beams without shear reinforcement (Vc) is still unclear. Previous research on this subject often yielded contradictory results, especially for reinforced high-strength concrete (HSC) beams. Furthermore, by simply adding Vc and the contribution of stirrups Vs to calculate the ultimate shear capacity Vu, current shear design practice assumes that the addition of stirrups does not alter the effect of shear design parameters on Vc. This paper investigates the validity of such a practice. Data on 656 reinforced concrete beams were used to train an artificial neural network model to predict the shear capacity of reinforced concrete beams and evaluate the performance of several existing shear strength calculation procedures. A parametric study revealed that the effect of shear reinforcement on the shear strength of RC beams decreases at a higher reinforcement ratio. It was also observed that the concrete contribution to shear resistance, Vc, in RC beams with shear reinforcement is noticeably larger than that in beams without shear reinforcement, and therefore most current shear design procedures provide conservative predictions for the shear strength of RC beams with shear reinforcement.Key words: analysis, artificial intelligence, beam depth, compressive strength, modeling, shear span, shear strength.

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.

scholarly journals Behaviour of Reinforced Concrete Beams with Wire Mesh As Shear Reinforcement

2019 ◽  
Vol 8 (12) ◽  
pp. 781-784
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Wire Mesh ◽  
Shear Behaviour ◽  
Experimental Program ◽  
Shear Reinforcement ◽  
Loading System ◽  
Shear Performance

This paper presents a study of shear behaviour of reinforced concrete beams. The major parameters used were type of shear reinforcement, namely stirrups alone, wire mesh alone and combination of both wire mesh and stirrups as shear reinforcement. The replacement of wire mesh was done on the basis of weight with stirrups. The experimental program includes four beams. All the beams were tested using two point loading system. It is evident from the result that the use of wire mesh enhanced improved shear performance and bearing capacity in the examined beams. Beams with wire mesh as shear reinforcement and combination of both wire mesh and stirrups exhibited some amount of increase in shear capacity with respect to the beams with stirrups alone as shear reinforcement. Furthermore beams with wire mesh and combination of wire mesh and stirrups as reinforcement exhibited less number of crack patterns compared beams with stirrups.

scholarly journals The effects of corrosion on the performance of reinforced concrete beams

2021 ◽  
Author(s):  
Roger W Smith
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Structural Behaviour ◽  
Load Carrying ◽  
Impressed Current ◽  
Dramatic Shift ◽  
The Relationship ◽  
Non Destructive

This report presents the results of a laboratory investigation into the effects of corrosion on the structural behaviour of reinforced concrete (RC beams. Twelve RC beams (156 x 176 x 1150 nun) were constructed, ten of which were corroded to various levels by impressed current while the remaining two were set aside as the control beams. Each beam was tested using non-destructive methods and then by four-point loading and the corresponding loads and deflections were recorded Following the mechanical testing, the tensile steel -was retrieved and cleaned in order to assess the mass loss. The results of this experiment clearly indicated a dramatic shift in the nature of the failure of corroded RC beams. Specifically, it was observed in the present study that as corrosion increased the failure mode of the beams shifted from predictable ductile flexure failures at mid-span, to more brittle failures near the support. Based on the data collected, several new corrosion-dependant empirical relationships were established to model the altered responses of RC beams (ie. stiffness, deflection ratio, ductility, and toughness). In addition to beam tests, a pullout study -was conducted in an effort to identify the relationship between the reduction of load-carrying capacity and the residual bond strength of the tensile steel Other behavioural changes examined are initial cracking load, flexural crack development and the evolution of the failure mode. It was found that the overall behaviour of the beam specimens tested conforms to that reported in the literature, with reductions in the ultimate capacity, deflection capacity and stiffness upon increasing corrosion. Also, the results of this experiment clearly indicated a dramatic shift in the nature of the failure of corroded RC beams. Specifically, it was observed that as corrosion increased, the failure mode of the beams shifted from predictable ductile flexure failures at mid-span, to more brittle failures near the support.

Numerical Analysis for Reinforced Concrete Beams with Circular Openings in Flexural and Shear Zones Strengthened by Steel Plates

2018 ◽  
Vol 23 (2) ◽  
pp. 31-48
Author(s):  
Ahmed Ali AL-Dhabyani ◽  
Abdulwahab AL-Ansi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Shear Zones ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Study Results ◽  
Load Carrying

In the modern building construction, openings in beams are necessary to accommodate several service pipes and ducts. Due to these openings, high stress concentration occurs at its edges. Local cracks also appear around the openings as a result of the reduction in the beam stiffness, the load carrying capacity and the shear capacity. There are many studies which were conducted to develop and test different strengthening methods for the beams opining to increase the ultimate load capacity of the beams. However, from a practical point of view, it is better to have one strengthening method having the same specifications to be used in both; shear and flexural zones for circular opining beams in buildings. In spite of the prior studies, no study has addressed this issue; therefore, there is a need to study such a case. In this paper, an analytical study was conducted to investigate the behavior of the reinforced concrete (RC) beams with circular openings in flexural and shear zones strengthened by steel plates. A 3D FE modeling (ABAQUS 6.12) software was used to simulate five different specimens of RC beams. The study results showed that when the openings were strengthened by steel plates, the ultimate load carrying capacity increased, but the deflection was decreased when compared to the openings without strengthening. In addition, the model reliability was verified via good agreements between the experimental and numerical results.

scholarly journals Experimental investigation of reinforced concrete beams with and without CFRP wrapping

2012 ◽  
Vol 20 (3) ◽  
pp. 15-26
Author(s):  
K.V. Venkatesha ◽  
S.V. Dinesh ◽  
K. Balaji Rao ◽  
B.H. Bharatkumar ◽  
S.R. Balasubramanian ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Shear Failure ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Experimental Investigations ◽  
Flexural Failure ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Cfrp Wrapping

AbstractThis paper presents the results of experimental investigations on six reinforced concretebeams, with three different shear span-to-depth ratios, which were tested under two-pointloading. The aim of the work was to study the efficacy of Carbon Fibre Reinforced Polymer(CFRP) strips in enhancing shear capacity and/or changing the failure mode from brittleshear failure to ductile flexural failure. The results of the study indicate that while thereis a marginal increase in first crack and ultimate loads, it is possible to achieve a changein the failure mode, and the monitored strain gauge data can be used to explain the failurepattern observed.

Investigation on Intermediate Crack Induced Debonding Failure of FRP Laminates in Flexurally FRP-Strengthened RC Beams

2011 ◽  
Vol 243-249 ◽  
pp. 641-644
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Concrete Beams ◽  
Interfacial Shear Stress ◽  
Reinforced Concrete Beams ◽  
Tension Stress ◽  
Rc Beams ◽  
Fundamental Reason ◽  
Three Stages ◽  
Opening Up

Debonding failure is commonly observed in FRP-strengthened RC beams. It can be classified into two types: plate end debonding and intermediate crack induced debonding. Intermediate crack induced debonding is the main failure mode in FRP-strengthened RC beams.There is no specialized experiment study on this failure mode. To investigate intermediate crack induced debonding failure of FRP-strengthened reinforced concrete beams, 9 CFRP-strengthened reinforced concrete beams were tested. Based on the investigation of the strain in the FRP laminates, the width of the main crack and tributary crack, as well as the phenomena of the test beams, the whole debonding process can be separated into three stages: initial debonding stage, stable debonding stage, and the final debonding failure. The fundamental reason of intermediate crack indued debonding are the opening-up of intermediate crack and the flexural deformation induced high interfacial shear stress and peeling stress. When the principal tension stress acting on the concrete substrate exceeded the tension stress of concrete, the CFRP laminate would debond from the concrete substrate.

Calculation of Shear Capacity of Steel Reinforced Concrete Beams Strengthened with Near-Surface Mounted CFRP Rods

2012 ◽  
Vol 193-194 ◽  
pp. 852-854
Author(s):  
Wei Hua Chen ◽  
Mei Qin Wu
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Near Surface ◽  
Steel Reinforced Concrete ◽  
Carbon Fiber Reinforce Polymer ◽  
Near Surface Mounted ◽  
Fiber Reinforce

Some calculated methods of shear capacity of RC beams strengthened with NSM(near-surface mounted) CFRP(Carbon fiber reinforce polymer) rods are reviewed based on the experimental data on shear capacity of RC beams strengthened with NSM CFRP rods. Therefore, according to the destruction forms of steel reinforced concrete beam strengthened with NSM CFRP rods, the formula for calculating the shear capacity of the beam is given. The formula is expressed clearly, simple and easy to use.

scholarly journals REPAIR OF FLEXURAL DAMAGED REINFORCED CONCRETE BEAMS USING EMBEDDED BAMBOO REINFORCED EPOXY COMPOSITE

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Samson Olalekan Odeyemi ◽  
Rasheed Abdulwahab ◽  
Sefiu Adekunle Bello ◽  
Ahmed Olatunbosun Omoniyi ◽  
Adewale George Adeniyi
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Concrete Beams ◽  
Epoxy Composite ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Rc Beams ◽  
Existing Structures ◽  
Load Carrying ◽  
Alternative Material

In recent years, repair and retrofit of existing structures such as buildings and bridges have been among the most important challenges in Civil Engineering. Strengthening reinforced concrete (RC) members with steel plates is a conventional method that has been adopted for decades. The corrosive nature of steel plates, its weight and the need for many anchor bolts for attachment makes it inefficient for retrofitting damaged structures. Thus, there is a need to source for an alternative material which does not corrode and still be used in the strengthening of reinforced concrete. Bamboo Reinforced Epoxy Composite (BREC) was used to repair five (5) damaged reinforced concrete beams in this research. Two of the beams were preloaded to 40 % and 60 % of the ultimate load before strengthening with BREC and all the beams were loaded to failure. The RC beams implanted with BREC rods experienced a rise in their load carrying capacity when tested. Beams preloaded up to 40 % and 60 % had an increase in flexural strength of 33.7 % and 39.3 % respectively when compared with beams reinforced with steel reinforcements. BREC rods in concrete is an effective method in increasing the flexural strength of RC beams.

Shear Strength of Reinforced Concrete Beams after Fire

2012 ◽  
Vol 256-259 ◽  
pp. 742-748 ◽  
Author(s):  
Kai Xiang ◽  
Guo Hui Wang ◽  
Hua Xin Liu
Keyword(s):  
Reinforced Concrete ◽  
Calculation Method ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Test Analysis ◽  
Concentrated Load ◽  
Transfer Mechanisms ◽  
Reduction Factors

In order to research the calculation method of shear capacity for fire-damaged reinforced concrete (RC) beams, the reason of drop of shear capacity was analyzed from material properties and transfer mechanisms of RC beams after fire. Formulas of shear capacity were suggested for fire-damaged RC beams. Based on test analysis, the values of reduction factors of shear capacity were proposed under concentrated load. The results show that suggested calculation method is capable of predicting shear capacity of fire-damaged RC beams exactly. The values of reduction factors of shear capacity need further experiments research.

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