Study on Impaired Reinforced Concrete Beams Strengthening with Externally Steel Frame

2013 ◽  
Vol 438-439 ◽  
pp. 477-481
Author(s):  
Feng Lan Li ◽  
Xiong Huai Yu ◽  
Cheng Chen ◽  
Song Chen
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beam ◽  
Steel Plate ◽  
Reinforced Concrete Beam ◽  
Steel Frame ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Externally Bonded ◽  
Strengthening Method

A large impaired reinforced concrete beam with cracks was strengthened under self-weight action by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The normal service loading behaviors of this beam were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, it can be concluded that: the deformation of flexural cross section of this beam fitted the assumption of plain cross section, the steel plate could effectively enhance the flexural stiffness and decrease the deflection of this beam, no new cracks appeared under the normal service loads, the cracks at bottom of this beam were more confined by the steel frame than those at web zone. Therefore, other measure should be taken to avoid the opening of web cracks.

Effective Method of Repairing RC Beam Using Externally Bonded Steel Plate

2014 ◽  
Vol 567 ◽  
pp. 399-404 ◽  
Author(s):  
Md Ashraful Alam ◽  
Ali Sami Abdul Jabbar ◽  
Mohd Zamin Jumaat ◽  
Kamal Nasharuddin Mustapha
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Steel Plate ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Rc Beam ◽  
External Reinforcement ◽  
Externally Bonded ◽  
Damaged Beams

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.

Experimental Study of Cyclic Loading Behaviors of Reinforced Concrete Beams Strengthening with Externally Bonded Steel Frame

2012 ◽  
Vol 201-202 ◽  
pp. 304-307
Author(s):  
Li Yun Pan ◽  
Cheng Chen ◽  
Shun Bo Zhao ◽  
Chang Yong Li
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Steel Plate ◽  
Concrete Beams ◽  
Steel Frame ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Service Load ◽  
Externally Bonded ◽  
Ultimate Resistance

Two large impaired reinforced concrete beams with pre-loading cracks were strengthened by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The cyclic loading behaviors of these beams were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, the steel plate worked well with bonded concrete under normal service load, the hoop steel belts were necessary to prevent the peeling of bottom steel plate. The strengthened beams were effectively enhanced in flexural stiffness and ultimate resistance, and no new cracks appeared under the normal service load.

Research on Reinforced Concrete Beam Enlarged Cross Section Method Experiment and Finite Element Simulation

2014 ◽  
Vol 638-640 ◽  
pp. 208-213 ◽  
Author(s):  
Yuan Yuan Li ◽  
Bin Guo ◽  
Jiang Liu
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Simulation ◽  
Cross Section ◽  
Concrete Beam ◽  
Performance Test ◽  
Bending Strength ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Element Simulation

Increasing the beam cross section is a kind of traditional and universal strengthening methods of civil structure. The mechanical performance test were studied on the mechanics performance and deformation of four reinforced concrete beams in this study. The results show that increase of the cross section and tensile area at the bottom of the steel could effectively improve the performance of mechanical. The beam crack load, yield load, ultimate load and bending strength are increasing with cross section and mechanical. By simulating the relationship bwteen load and deflection. It is concluded that The finite element simulation of reinforced concrete beam with the reasonable concrete unit and reinforced unit can meet the demand of practical engineering.

Estimation of Ultimate Tendon Stress in Reinforced Concrete Beams Prestressed with External FRP Tendons

2013 ◽  
Vol 798-799 ◽  
pp. 374-377
Author(s):  
Shuan Jiang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Plastic Hinge ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Stress Increment ◽  
Hinge Zone ◽  
Good Agreement

The ultimate tendon stress is the key to calculation of flexural capacity in reinforced concrete beam prestressed with external FRP tendons (RCBPEFT). Based on the theory of equivalent plastic hinge zone, the general formulas for calculating the ultimate tendon stress increment and ultimate tendon stress in RCBPEFT are therefore proposed. Comparisons indicate that the predictions are in good agreement with the test results.

scholarly journals Experimental Study of Flexural Behavior of Reinforced Concrete Beam Strengthened with Prestressed Textile-Reinforced Mortar

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1137 ◽  
Author(s):  
Jongho Park ◽  
Sun-Kyu Park ◽  
Sungnam Hong
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Flexural Stiffness ◽  
Test Results ◽  
The Difference ◽  
Textile Reinforced Mortar

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.

scholarly journals Damage Evaluation in Shear-Critical Reinforced Concrete Beam using Piezoelectric Transducers as Smart Aggregates

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Constantin E. Chalioris ◽  
Nikos A. Papadopoulos ◽  
Georgia M. Angeli ◽  
Chris G. Karayannis ◽  
Asterios A. Liolios ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Piezoelectric Transducers ◽  
Reinforced Concrete Beams ◽  
Structural Safety ◽  
Shear Span ◽  
Externally Bonded ◽  
Diagonal Crack

AbstractDamage detection at early cracking stages in shear-critical reinforced concrete beams, before further deterioration and their inevitable brittle shear failure is crucial for structural safety and integrity. The effectiveness of a structural health monitoring technique using the admittance measurements of piezoelectric transducers mounted on a reinforced concrete beam without shear reinforcement is experimentally investigated. Embedded “smart aggregate” transducers and externally bonded piezoelectric patches have been placed in arrays at both shear spans of the beam. Beam were tested till total shear failure and monitored at three different states; healthy, flexural cracking and diagonal cracking. Test results showed that transducers close to the critical diagonal crack provided sound and graduated discrepancies between the admittance responses at the healthy state and thedamage levels.Damage assessment using statistical indices calculated from the measurements of all transducers was also attempted. Rational changes of the index values were obtained with respect to the increase of the damage. Admittance responses and index values of the transducers located on the shear span where the critical diagonal crack formed provided cogent evidence of damage. On the contrary, negligible indication of damage was yielded by the responses of the transducers located on the other shear span, where no diagonal cracking occurred.

scholarly journals Experimental Studies on Reinforced Concrete and Ferrocement Beams

2016 ◽  
Vol 5 (3) ◽  
pp. 77
Author(s):  
N. Jayaramappa
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beam ◽  
Experimental Studies ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Wire Mesh ◽  
Hollow Beam ◽  
Straight Beam ◽  
Hollow Beams

<div><p><em>Arch structures have been utilized through the ages, beginning in the ancient civilizations of Greece, Egypt and Rome, to present day with their common use in bridges. Arches are well known for the ability to carry loads spanning large areas. Also now a day’s Ferrocement is being used extensively for various applications where use of normal concrete is hard to fulfil the present day requirements. In this paper experimental studies are carried out to understand the flexural behaviour of Reinforced concrete beams of grade M20 with HYSD reinforcement and Ferrocement hollow beams of cement to sand ratio of 1:3 and water cement ratio of 0.4. A total of four beams were  cast in which two are straight beams and another two are arched beams. In that two straight beam, one is reinforced concrete beam with minimum reinforcement and another one is Ferrocement hollow beam and in two arch beams, one is reinforced concrete beam and other is Ferrocement hollow beam. All beams are rectangular in cross-section of size 200 x 200 mm and the span length is 2500 mm. The arch beam is provided with a rise at centre of 0.8 m. The Ferrocement beam is made of mortar with hollow cross section using hexagonal wire mesh with thickness of 40 mm and all the specimens are cured for 28 days. Flexural tests are carried out on conventional RC beam and Ferrocement hollow beams for simply supported condition. The test results are presented in terms of load deflection behaviour, ultimate load, cracking load and crack pattern with respect to reinforced concrete beam and Ferrocement hollow beam.</em></p></div>

Experimental Study on Shear of Reinforced Concrete Beams with High Strength Rebars as Stirrups under Different Shear Span Ratios

2014 ◽  
Vol 578-579 ◽  
pp. 164-167 ◽  
Author(s):  
Peng Li ◽  
Xian Tang Zhang ◽  
Ming Ping Wang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Shear Span

To investigate the influence of shear span ratio for the shear behavior of reinforced concrete beam with HRBF500 high strength rebars as stirrups, an experiment was carried out, which included 8 simply supported beams with HRBF500 rebars as stirrups. Under concentrated loads, the crack, deflection, strain of rebars, bearing capacity and failure mode are observed under different shear span ratios. Some comparisons are made between test results and calculated outcome. It shows that the shear span ratio has very important influent on the shear behavior of reinforced concrete beam with HRBF500 high strength bars as stirrups. Formula in code for design of concrete structures can be used to calculate its shear capacity with enough safety.

scholarly journals Experimental and Theoretical Studies on Flexural Performance of Stainless Steel Reinforced Concrete Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Qingfu Li ◽  
Wei Guo ◽  
Chenhui Liu ◽  
Yihang Kuang ◽  
Huitao Geng
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Calculation Results

In this paper, the flexural characteristics of stainless steel (SS) reinforced concrete beams are studied and analyzed. We mainly focus on their crack mode, failure mode, load-deflection curve, and bearing capacity. Six beams with test parameters, including the diameter of reinforcement, the type of the reinforcement, and the stirrup spacing, were tested in 4-point bending. The test results indicate that the failure mode of SS reinforced concrete beam can be divided into three stages: elastic stage, cracking stage, and failure stage. The midspan section deformation of SS reinforced concrete beam conforms to the assumption of plane section. Under the same reinforcement condition, the normal section and the oblique section bearing capacities of the SS reinforced concrete beams are significantly higher than those of the ordinary reinforced concrete beams. In addition, the prediction of cracking moment and bearing capacity calculated by ACI 318-14 and GB 50010-2010 was also evaluated. The calculation results of the two codes were safe and conservative, and GB 50010-2010 provided more accurate prediction of cracking moments. Furthermore, to verify the reliability of the test results, finite element models were established and the analytical results corroborated well with the test results.

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 .

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