scholarly journals Structural Performance of Externally Strengthened Rectangular Reinforced Concrete Beams by Glued Steel Plate

2019 ◽  
Vol 4 (9) ◽  
pp. 101-106 ◽  
Author(s):  
A. T. John ◽  
E. Nwankwo ◽  
Solomon Teminusi Orumu ◽  
S. O. Osuji
Keyword(s):  
Reinforced Concrete ◽  
Structural Steel ◽  
Steel Plate ◽  
Failure Load ◽  
Concrete Strength ◽  
Epoxy Adhesive ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Shear Behaviour ◽  
Type C

This paper examines both flexural and shear behaviour of eight full-scale (2700×160×100-mm) reinforced concrete rectangular beams subjected to one-third point load. Two types of beams were investigated; Type-E and Type-C. Type-E are reinforced concrete rectangular beams strengthened externally by 1.5mm thick structural steel plate glued to the tensile face with epoxy as adhesive while type-C are reinforced concrete rectangular beams without structural steel plate glued to the tensile face. An average concrete strength of 30N/mm2 at 28 days was used. Required internal reinforcement according to BS 8110-1:1997 was provided for the concrete rectangular beams. Before the beams were externally strengthened, the beam surface to be plated was gritted to take off the cement membrane and to open up the aggregates. Epoxy adhesive was applied as a paste to both the plate and concrete surfaces: the two surfaces were then put together and held in place under pressure of 3.84kN/m2 until the glue was cured.  The beams were subjected to flexural testing after 28 days, using loading frame. Each of the rectangular beams support at both ends were subjected to one-third point load, deflection readings were recorded using a dial gauge at every 1.82kN increment. At ultimate load, the beams failed by a crack initiated at the bottom fiber of the beams. From the test results, an average flexural and shear strengths of Type-C beams are; 21.91N/mm2 and 1.05N/mm2 respectively, while type-E beams are; 28.91N/mm2 and 1.39N/mm2 respectively. The results of the investigation showed that flexural and shear strengths of reinforced concrete rectangular beam increased when strengthened externally by bonded steel plate. A straightforward analytical procedure was developed to validate the experiment results of type-E and type-C beams, using rectangular stress block for concrete. Experimental average failure load for beams Type-C and Type-E are 22.44kN and 29.60kN respectively while theoretical failure load for Type-C and Type-E beams are 20.86kNand 31.2kN respectively. Generally, there were acceptably fair correlations between analytical and experimental failure loads of Type-C and Type-E beams.

scholarly journals Effect of Using Different Aspect Ratio of Longitudinal Steel Plates in Reinforced Concrete Beams

2021 ◽  
Vol 318 ◽  
pp. 03016
Author(s):  
Khalid I. Qaddoory ◽  
Ahmed A. Mansor ◽  
Ahlam S. Mohammed ◽  
Bilal J. Noman
Keyword(s):  
Reinforced Concrete ◽  
Steel Plate ◽  
Concrete Beams ◽  
Reference Model ◽  
Plate Thickness ◽  
Reference Beam ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Cross Sectional

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.

scholarly journals The Effect of Steel Plate on the Deflection of Self Reinforced Concrete Beam with and Without Opening

2013 ◽  
Vol 6 (1) ◽  
pp. 36-49
Author(s):  
Ali Sabah AL-Amili
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Steel Plate ◽  
Failure Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Flexural Behavior ◽  
External Plate

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 .

Application of acoustic emission monitoring for assessment of bond performance of corroded reinforced concrete beams

2016 ◽  
Vol 16 (6) ◽  
pp. 732-744 ◽  
Author(s):  
Ahmed A Abouhussien ◽  
Assem AA Hassan
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Signal Strength ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Bond Failure ◽  
Acoustic Emission Monitoring ◽  
Bond Performance ◽  
Emission Monitoring

This article presents the results of an experimental investigation on the application of acoustic emission monitoring for the evaluation of bond behaviour of deteriorated reinforced concrete beams. Five reinforced concrete beam–anchorage specimens designed to undergo bond failure were exposed to corrosion at one of the anchorage zones by accelerated corrosion. Two additional beams without exposure to corrosion were included as reference specimens. The corroded beams were subjected to four variable periods of corrosion, leading to four levels of steel mass loss (5%, 10%, 20% and 30%). After these corrosion periods, all seven beams were tested to assess their bond performance using a four-point load setup. The beams were continuously monitored by attached acoustic emission sensors throughout the four-point load test until bond failure. The analysis of acquired acoustic emission signals from bond testing was performed to detect early stages of bond damage. Further analysis was executed on signal strength of acoustic emission signals, which used cumulative signal strength, historic index ( H( t)) and severity ( Sr) to characterize the bond degradation in all beams. This analysis allowed early identification of three stages of damage, namely, first crack, initial slip and anchorage cracking, before their visual observation, irrespective of corrosion level or sensor location. Higher corrosion levels yielded significant reduction in both bond strength and corresponding acoustic emission parameters. The results of acoustic emission parameters ( H( t) and Sr) enabled the development of a damage classification chart to identify different stages of bond deterioration.

Laboratory Fast Corrosion Test of Plain Steel Bars in Concrete Beams

2012 ◽  
Vol 535-537 ◽  
pp. 1803-1806
Author(s):  
Shun Bo Zhao ◽  
Peng Bing Hou ◽  
Fu Lai Qu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Numerical Models ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Uniform Corrosion ◽  
Pure Bending ◽  
Accelerated Corrosion ◽  
Steel Bars ◽  
Bending Length

An experimental study was carried out to examine the non-uniform corrosion of plain steel bars in reinforced concrete beams partially placed in 5% sodium chloride solution under conditions of accelerated corrosion. 4 reinforced concrete beams with different concrete strength were made. The crack distributions of the beams due to pre-loads and expansion of corrosion product, and the sectional corrosion characteristics of plain steel bars are described in detail. The sectional area loss relating to mass loss and change along pure bending length of the beams are discussed. These can be used as the basis of test for further studies to build the numerical models of serviceability of corroded reinforced concrete beams.

scholarly journals Effect of Plastering Layer on Corrosion Resistances of Reinforced Concrete Beams

2019 ◽  
Vol 9 (1) ◽  
pp. 1390-1393
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Structural Elements ◽  
Accelerated Corrosion ◽  
Total Mass Loss ◽  
Load Arrangement

Reinforced concrete structures are subjected to deterioration due to many factors such as corrosion of reinforcing steel. Ultimate strengths of structural elements can be greatly affected by these deteriorating factors. There are numerous methods and techniques used to protect these structural elements. The mortar layer (Plastering) is considered the first defense line against all the deteriorating factors. The main goal of this research is to investigate to what extent the plastering layer can protect reinforced concrete beams against corrosion. The aim of the experimental program is to study the effect of plastering layer on corrosion resistance of reinforced concrete beams. Four reinforced concrete beams (1002001100 mms) and four Lollypop specimens (cylinders 100200 mms) were tested and described as follows: • A beam and a lollypop specimen without any plastering layer (control). • A beam and a lollypop specimen with traditional plastering layer (cement + sand + water). • A beam and a lollypop specimen with modified plastering (traditional plastering + waterproof admixtures). • A beam and a lollypop specimen with painted and modified plastering layer (traditional plastering + waterproof admixtures + external waterproof paint). These eight specimens were subjected to corrosion using accelerated corrosion technique, after that the four beams were tested in flexure under three point load arrangement while the four lollypops were used to calculate the total mass loss due to accelerated corrosion. The test results were used to figure out the effect of plastering layer on corrosion resistance of RC beams.

scholarly journals Seismic Behaviors of Concrete Beams Reinforced with Steel-FRP Composite Bars under Quasi-Static Loading

2018 ◽  
Vol 8 (10) ◽  
pp. 1913 ◽  
Author(s):  
Tong-Liang Xiao ◽  
Hong-Xing Qiu ◽  
Jia-Le Li
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Ultimate Capacity ◽  
Shear Span ◽  
Frp Composite ◽  
Drift Ratio ◽  
Seismic Behaviors

Steel-fiber reinforced polymer (FRP) composite bar (SFCB) is a new composite material with good corrosion resistance and designable post-yield stiffness. Substitution of steel bar with SFCB can greatly increase the durability and ultimate capacity associated with seismic performance. First, the method and main results of the experiment are briefly introduced, then a simplified constitutive model of composite bar material was applied to simulate the seismic behaviors of the concrete beams reinforced with SFCBs by fiber element modeling. The simulation results were found to be in good agreement with test results, indicating that the finite element model is reasonable and accurate in simulating the seismic behaviors of beams reinforced with SFCB. Based on the numerical simulation method, a parametric study was then conducted. The main variable parameters were the FRP type in composite bars (i.e., basalt, carbon FRP and E-glass FRP), the concrete strength, basalt FRP (BFRP) content in SFCBs and shear span ratio. Seismic behaviors such as load-displacement pushover curves, seismic ultimate capacity and its corresponding drift ratio of the SFCBs reinforced concrete beams were also evaluated. The results showed that (1) the fiber type of the composite bar had a great impact on the mechanical properties of the beam, among which the beam reinforced with BFRP composite bar has higher seismic ultimate capacity and better ductility. With the increase of the fiber bundle in the composite bar, the post-yield stiffness and ultimate capacity of the component increase and the ductility is better; (2) at the pre-yield stage, concrete strength has little influence on the seismic performance of concrete beams while after yielding, the seismic ultimate capacity and post-yielding stiffness of specimens increased slowly with the increase in concrete strength, however, the ductility was reduced accordingly; (3) as the shear span ratio of beams increased from 3.5 to 5.5, the seismic ultimate capacity decreased gradually while the ultimate drift ratio increased by more than 50%. Through judicious setting of the fiber content and shear span ratio of the composite bar reinforced concrete beam, concrete beams reinforced with composite bars can have good ductility while maintaining high seismic ultimate capacity.

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
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Steel Plate ◽  
Concrete Beams ◽  
Peak Load ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Flexural Behavior ◽  
Flexural Stiffness

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.

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