scholarly journals Experimental Study on the Flexural Behavior of over Reinforced Concrete Beams Bolted with Compression Steel Plate: Part I

2020 ◽  
Vol 10 (3) ◽  
pp. 822 ◽  
Author(s):  
Shatha Alasadi ◽  
Payam Shafigh ◽  
Zainah Ibrahim

The purpose of this paper is to investigate the flexural behavior of over-reinforced concrete beam enhancement by bolted-compression steel plate (BCSP) with normal reinforced concrete beams under laboratory experimental condition. Three beams developed with steel plates were tested until they failed in compression compared with one beam without a steel plate. The thicknesses of the steel plates used were 6 mm, 10 mm, and 15 mm. The beams were simply supported and loaded monotonically with two-point loads. Load-deflection behaviors of the beams were observed, analyzed, and evaluated in terms of spall-off concrete loading, peak loading, displacement at mid-span, flexural stiffness (service and post-peak), and energy dissipation. The outcome of the experiment shows that the use of a steel plate can improve the failure modes of the beams and also increases the peak load and flexural stiffness. The steel development beams dissipated much higher energies with an increase in plate thicknesses than the conventional beam.

2013 ◽  
Vol 6 (1) ◽  
pp. 36-49
Author(s):  
Ali Sabah AL-Amili

In this work aims at studying the influence of steel plate on the deflection of self- compacted reinforced concrete beams was investigated experimentally in this study to know the flexural behavior of these beams. Eight simply supported reinforced concrete beam were tested under the action of two point loads .The deflections of the beams with and without plate are measured. The steel plates of thickness (3 mm) with dimensions ( 170 × 350 mm) were used. These plates were sticked on the concrete beams using epoxy. The steel plate inside the beam was sticked with and without epoxy (epoxy type EP), while the beams were taken with and without opening (10 mm diameter). The results show that the plate increased the capacity of the beam by increased the value of failure load. Hence, the beam with internal plate with epoxy increased the failure load by 34.2% than beam without plate , and 24.6% than beam with internal plate without epoxy , and 19.7% than beam with external plate with epoxy .


2012 ◽  
Vol 166-169 ◽  
pp. 1736-1739
Author(s):  
Yu Tian Wang ◽  
Xiu Li Du ◽  
Fu Xiang Jiang ◽  
Wei Zhang

Experiments on flexural behavior of strengthened pre-damaged reinforced concrete beams with CFRP and those exposed to seawater for different time have been carried out. By comparison, the rule of seawater effecting on failure modes of beams, fissure condition, strain development and flexural capacity, and so on have been studied. The results show that reinforcement treatment on the mechanical damaged reinforced concrete beams with bonding CFRP can effectively improve their flexural capacity and stiffness, and constrain the development of cracks. With the extension of time under seawater environment, although performance of pre-damaged beam strengthened with CFRP is influenced significantly, the strengthening effect is still more reliable.


2012 ◽  
Vol 166-169 ◽  
pp. 1807-1810
Author(s):  
Xue Song Gao ◽  
Dong Hui Huo ◽  
Shao Hua Lv ◽  
Xu Zhao

This paper presents a three-dimensional nonlinear finite elemental analysis about the reinforcement concrete beams strengthened by bolting steel plate. The contact effects between the steel plate with reinforced concrete beam surface was simulated by developing the contact elements. The effect of strengthening is analyzed and the effects of the deformation and stress distribution of anchor bolt on the failure mode were investigated. It is declared that this strengthening method can obviously improve the capacity and stiffness of beam, and the flexural deformation of anchor bolt is key problem inducing the failure of strengthened beam. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.


Author(s):  
Nguyen Ngoc Tan ◽  
Nguyen Dang Nguyen

This study investigated experimental bearing capacity of corroded reinforced concrete beams. Six testing beams were made of concrete having compressive strength of 25 MPa, with the dimensions of 1200 x 80 x 120 mm. They were divided into two groups depending of tension reinforcement ratio. Of which, two beams were used as the controls, whereas the other fours ones having tension reinforcement were subjected to corrosion by the electrochemical accelerated corrosion method. After accelerated corrosion, the beams were tested under monotonic loading to investigate their performance. All the tested beams were failed in flexural failure mode corresponding to spalling of cover concrete. Test results showed that as corrosion rate in tension reinforcement increased, the lower cracking load and the displacement at the cracking load were observed. As the corrosion rate of tension reinforcement ranging from 7.5% to 8.3%, it had little effect on the peak load. As the corrosion rate increased further, approximately 10.8% and 14.1% in this study, the peak load decreased significantly. The higher the corrosion rate, the lower the displacement of corroded beams. Moreover, as corrosion rate of tension reinforcement increased the number of concrete cracks and their spacing reduced, and the width of cracks was generally larger. Keywords: reinforced concrete beam; electrochemical accelerated corrosion; corrosion rate; load-carrying capacity; displacement; concrete cracking. Received 08 January 2019, Revised 16 January 2019, Accepted 17 January 2019  


2019 ◽  
Vol 5 (12) ◽  
pp. 2569-2578 ◽  
Author(s):  
Ali Sabah Al Amli ◽  
Laith Shakir ◽  
Ali Abdulredha ◽  
Nadhir Al-Ansari

This study presents experimental work including an investigation conducted on five simply supported reinforced concrete beams under pure torsion. First beam without strengthening as a control beam. The other four beams were strengthened externally by bolted thin steel plates. For this test the load was applied gradually. The torque was increased gradually up to failure of the beam.  The variables were the thickness and height of the steel plate that was externally connected to both sides of the rectangular reinforced concrete beam. The test results for the beams discussed are based on torque-twist behavior. The experimental results show that the attachment of thin steel plates by mechanical means to beams provides a considerable improvement in the torsional behavior of the reinforced concrete beams. Comparable to the reference beam, the maximum increase in the cracking and the ultimate torque of the composite beam was recorded for the reinforced concrete beam that strengthen by steel plate of (150) mm height, (2mm) thickness and (50mm) spacing between shear connectors (B1). The results revealed that the cracking torque, ultimate torque, global stiffness of beam and beam ductility for all composite beams increase with the increase of the plate's thickness, plate's height.


2014 ◽  
Vol 567 ◽  
pp. 399-404 ◽  
Author(s):  
Md Ashraful Alam ◽  
Ali Sami Abdul Jabbar ◽  
Mohd Zamin Jumaat ◽  
Kamal Nasharuddin Mustapha

Repair of reinforced concrete beam with externally bonded steel plate or fibre reinforced polymer (FRP) laminate is becoming both environmentally and economically preferable rather than replacement of deficient beam. The well known advantages of external reinforcement over other methods include; low cost, ease of maintenance and the ability to strengthen part of the structure while it is still in use. The disadvantage of this method, however, is the premature debonding of the externally bonded strips which is brittle and undesired mode of failure. It is also known that debonding of the externally bonded steel plates prevents the reinforced concrete (RC) beam from reaching its full strengthening capacity. The aim of this study was to increase the scientific understanding on the behaviour of damaged reinforced concrete beams strengthened and/or retrofitted for shear using vertical steel plate fixed with adhesive and steel connectors to eliminate or delay debonding failure. Four reinforced concrete beam specimens were prepared to investigate the effects of connectors in preventing or delaying premature debonding of shear strips to restore the capacities of fully damaged beams. Three damaged beams have been repaired and strengthened with steel plates and loaded monotonically up to the maximum load capacities in order to define load–deflection relationship. It is concluded that the repairing of severely shear-damaged RC beams with steel plates by using steel and adhesive connectors can fully restore the original shear capacities of the beams.


2021 ◽  
Vol 318 ◽  
pp. 03016
Author(s):  
Khalid I. Qaddoory ◽  
Ahmed A. Mansor ◽  
Ahlam S. Mohammed ◽  
Bilal J. Noman

In the past few years, new techniques have emerged using steel plates instead of traditional reinforcement in the reinforced concrete beams. This study deals with using a new method for reinforced concrete beams using steel plates instead of traditional steel bars with different thicknesses of (4, 5, and 6 mm) placed vertically inside the lower part of the beam. Four reinforced concrete beams were cast and tested under a two-point load. All beams had the same cross-sectional area of reinforcement and dimensions of 2100 mm in length, 350 mm in height, and 250 in width. The results showed that as the thickness of the steel plate increases, the samples would have greater resistance until more deflection is produced. In addition, there is a reduction in the crack load, ultimate load, and yield load when replacing reinforcing bars with steel plates. In which, a reduction in crack load by about 11.1, 15.5, and 22.2% plate thicknesses of 4,5,6 mm respectively, compared to reference beam that had a deformed steel bar (Dia. 16 mm). In addition, a reduction in yielding load was observed about 42, 53, and 60% for steel plate thickness of 4, 5, and 6 mm respectively, compared to the reference model. Finally, the cracks for all the steel plate specimens compared to reference specimens were wider and smaller.


2021 ◽  
Vol 11 (5) ◽  
pp. 2348
Author(s):  
Min Sook Kim ◽  
Young Hak Lee

Many structural retrofitting methods tend to only focus on how to improve the strength and ductility of structural members. It is necessary for developing retrofitting strategy to consider not only upgrading the capacity but also achieving rapid and economical construction. In this paper, a new retrofitting details and technique is proposed to improve structural capacity and constructability for retrofitting reinforced concrete beams. The components of retrofitting are prefabricated, and the components are quickly assembled using bolts and chemical anchors on site. The details of modularized steel plates for retrofitting have been chosen based on the finite element analysis. To evaluate the structural performance of concrete beams retrofitted with the proposed details, five concrete beams with and without retrofitting were tested. The proposed retrofitting method significantly increased both the maximum load capacity and ductility of reinforced concrete beams. The test results showed that the flexural performance of the existing reinforced concrete beams increased by 3 times, the ductility by 2.5 times, and the energy dissipation capacity by 7 times.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1137 ◽  
Author(s):  
Jongho Park ◽  
Sun-Kyu Park ◽  
Sungnam Hong

In this study, nine specimens were experimentally tested to analyze the strengthening efficiency of textile-reinforced mortar (TRM) and the difference in flexural behavior between prestressed and non-prestressed TRM-strengthened reinforced concrete beam. The test results show that TRM strengthening improves the flexural strength of TRM-strengthened reinforced concrete beams with alkali-resistant-(AR-) glass textile as well as that with carbon textile. However, in the case of textile prestressing, the strengthening efficiency for flexural strength of the AR-glass textile was higher than that of the carbon textile. The flexural stiffness of AR-glass textiles increased when prestressing was introduced and the use of carbon textiles can be advantageous to reduce the decreasing ratio of flexural stiffness as the load increased. In the failure mode, textile prestressing prevents the damage of textiles effectively owing to the crack and induces the debonding of the TRM.


2020 ◽  
pp. 136943322097478
Author(s):  
Qi Cao ◽  
Jiadong Bao ◽  
Changjun Zhou ◽  
Xianrui Lv

This paper aims to study the flexural behavior of CFRP enclosed reinforced concrete beams with different shear reinforcement. Four-point bending tests were carried out on six concrete beams with different contents of steel fibers (0.5%, 1.0%, and 1.5%) as well as six beams with different stirrup spacing (100 mm, 150 mm, and 300 mm) without fiber. The effect of steel fiber (SF) content as well as stirrup spacing on flexural properties of concrete beams were investigated. Meanwhile, the effect of expansive agent on the properties of specimens was also studied. The data collected in this test include cracking load, ultimate load, mid-span deflection, strain of CFRP (Carbon fiber reinforced polymer), strain of longitudinal steel reinforcement as well as the failure modes. Test results show that both cracking loads and ultimate loads of the SF reinforced beam specimens are generally higher than those of the corresponding stirrup reinforced beam specimens. Experimental results also indicate that the addition of SF can improve the ductility and cracking resistance of specimens. This therefore demonstrates that it is feasible to replace stirrup reinforcement with SF as shear reinforcement. In addition, it exhibits a good agreement between experimental results and analytical predictions in cracking loads and ultimate loads.


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