scholarly journals Shear Strengthening of Reinforced Concrete Beams Using GFRP Wraps

10.14311/800 ◽  
2006 ◽  
Vol 46 (1) ◽  
Author(s):  
M. A. A. Saafan
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Structural Behavior ◽  
Shear Strengthening ◽  
Premature Failure ◽  
Web Reinforcement ◽  
Strengthening Technique

The objective of the experimental work described in this paper was to investigate the efficiency of GFRP composites in strengthening simply supported reinforced concrete beams designed with insufficient shear capacity. Using the hand lay-up technique, successive layers of a woven fiberglass fabric were bonded along the shear span to increase the shear capacity and to avoid catastrophic premature failure modes. The strengthened beams were fabricated with no web reinforcement to explore the efficiency of the proposed strengthening technique using the results of control beams with closed stirrups as a  web reinforcement. The test results of 18 beams are reported, addressing the influence of different shear strengthening schemes and variable longitudinal reinforcement ratios on the structural behavior. The results indicated that significant increases in the shear strength and improvements in the overall structural behavior of beams with insufficient shear capacity could be achieved by proper application of GFRP wraps.

Study on Damaged Reinforced Concrete Beams Strengthened with Basalt Fiber Polymer Sheets

2012 ◽  
Vol 446-449 ◽  
pp. 2941-2944 ◽  
Author(s):  
Hua Nan He ◽  
Wei Dong
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reference Beam ◽  
Basalt Fiber ◽  
Reinforced Concrete Beams ◽  
Steel Bar ◽  
Polymer Sheets ◽  
Fiber Sheet ◽  
Strengthening Technique

In practical concrete structures, once reinforced concrete beams serve in case of over cracking or are even damaged due to sudden overloading, it is necessary to repair or strengthened the damaged members for purpose of restoring the structural capacities and keeping the structures working well. At present FRP strengthening technique is one of the most accepted methods available in civil engineering. This paper particularly presents a new FRP material，basal fiber, which is applied to strengthen flexural behaviors of reinforced concrete beams suffering from different amplitudes of cracking damage. Herein, total 4 reinforced concrete beams were tested including one reference beam and three beams strengthened with basalt fiber polymer sheets. The three strengthened beams were preloaded to an expected load and then strengthen by basalt fibers under loading. The test parameters are involved in different pre-loads and layers of basalt fiber sheets. During test some flexural behaviors were obtained in terms of variation of strain in concrete, steel bar and basalt fiber sheet, flexural deflection, collapse loads and the failure modes as well as cracking properties of R.C beams strengthened with basalt fiber sheets. The results of test indicated that flexural behaviors of the beams strengthened under loading with basalt fiber polymer could be improved in different degree with varied initial flexural moment and numbers of basalt fiber.

Shear capacity of indirectly loaded reinforced concrete beams under and after fire exposure

2020 ◽  
Vol 23 (13) ◽  
pp. 2942-2951
Author(s):  
Yamin Song ◽  
Chuanguo Fu ◽  
Shuting Liang ◽  
Jichen Shi ◽  
Longji Dang
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reference Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Furnace Chamber ◽  
Transverse Reinforcement ◽  
Fire Exposure

To investigate the shear capacity of indirectly loaded reinforced concrete beams under and after fire exposure, load tests were conducted on eight full-scale specimens exposed to fire testing in a furnace chamber, and the effects of additional transverse reinforcement in the junction region between the primary and secondary beams on the shear capacity, fire resistance, failure modes and deflection were analysed. The results indicate that the slopes of the diagonal cracks in post-fire tested reinforced concrete beams without additional transverse reinforcement were shallower than those of a similar reference beam not exposed to fire, and that the ultimate capacities of reinforced concrete beams with additional transverse reinforcement decreased obviously after fire exposure. However, beams with additional transverse reinforcement exhibited increased fire resistance times and reduced strains in their reinforcement, indicating the benefit of conservatively providing such reinforcement. The findings of this study are expected to provide a reference for the improved fire-resistant design of indirectly loaded beams.

A Comparative Study of the Shear Strength Prediction for Reinforced Concrete Beams without Shear Reinforcement

2014 ◽  
Vol 584-586 ◽  
pp. 1135-1140
Author(s):  
Leandro Mouta Trautwein ◽  
Luiz Carlos de Almeida ◽  
Ricardo Gaspar
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Strength Prediction ◽  
Beam Depth ◽  
Web Reinforcement ◽  
Concrete Elements

This paper focuses on the assessment of the shear strength prediction established in the brazilian concrete code, NBR6118/2007[1], for reinforced concrete beams without web reinforcement. The values obtained by using the brazilian code equation are compared with a significant number of available experimental data and with those predicted by the expressions of other national and international codes, such as CEB-FIP MC90[2] and ACI-318/11[3]. The brazilian concrete code regarding shear capacity of reinforced concrete elements are explicitly assumed to be valid only for concrete strengths up to 50 MPa. It is shown that the code equation may be unconservative in a large number of cases. This discrepancy increases with increasing concrete strength, decreasing longitudinal reinforcement ratio and increasing beam depth.

Experimental Study on Shear Strengthening of Reinforced Concrete Beams Using Different Techniques of Concrete Jacketing

2021 ◽  
Vol 21 (2) ◽  
pp. 53-61
Author(s):  
Mohammed F. Ojaimi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Load Carrying

A large number of RC structures or at least some of their members need strengthening or rehabilitation. Among the typical failure modes, the shear failure is more dangerous and less predictable, because of usually brittle behavior and sudden collapse. Therefore, there are necessities for upgrading the shear capacity and the local ductility of reinforced concrete beams. In this study, four different techniques of concrete jacketing were used to improve the behaviors of the shear deficiencies beams. The four techniques used in this study to enhance the behavior of the beams were by using a Self-Compacted Fiber Reinforced Concrete jacket without stirrups (S.-J. + Steel Fiber), a concrete jacket of Self Compacted Concrete with stirrups (S.-J. + Stirrups), a concrete jacket of ferrocement jacket (S.-J. + Ferrocement), and a concrete jacket of ferrocement jacket with external steel reinforcing bars (S.-J. + Ferrocement + R). These techniques contributed to enhancing the load-carrying capacity and delaying the appearance of the first crack in tested beams compared with the control beam by a percentage of (35, 59, 30, 6) % and (18, 35, 81, 80) %, respectively. The specimen (S.-J. + Stirrups) showed the best performance in comparison with the other used strengthening techniques used in this study in terms of stiffness and the ultimate load-carrying capacity. The ferrocement jacket (S.-J. + Ferrocement) was found to be the most suitable jacketing system used to enhance the shear capacity in terms of cracking load.

scholarly journals Shear Capacity of Reinforced Concrete Beams under Monotonic and Cyclic Loads: Experiments and Computational Models

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4092
Author(s):  
Kamil Bacharz ◽  
Barbara Goszczyńska
Keyword(s):  
Reinforced Concrete ◽  
Laboratory Tests ◽  
Computational Models ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Image Correlation ◽  
Engineering Practice ◽  
Cyclic Loads ◽  
Loading Modes

The paper reports the results of a comparative analysis of the experimental shear capacity obtained from the tests of reinforced concrete beams with various static schemes, loading modes and programs, and the shear capacity calculated using selected models. Single-span and two-span reinforced concrete beams under monotonic and cyclic loads were considered in the analysis. The computational models were selected based on their application to engineering practice, i.e., the approaches implemented in the European and US provisions. Due to the changing strength characteristics of concrete, the analysis was also focused on concrete contribution in the shear capacity of reinforced concrete beams in the cracked phase and on the angle of inclination of diagonal struts. During the laboratory tests, a modern ARAMIS digital image correlation (DIC) system was used for tracking the formation and development of diagonal cracks.

scholarly journals Statistical and Reliability Study on Shear Strength of Recycled Coarse Aggregate Reinforced Concrete Beams

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3321
Author(s):  
Hyunjin Ju ◽  
Meirzhan Yerzhanov ◽  
Alina Serik ◽  
Deuckhang Lee ◽  
Jong R. Kim
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Construction Material ◽  
Safety Margin ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Rc Structures ◽  
Coarse Aggregates

The consumption of structural concrete in the construction industry is rapidly growing, and concrete will remain the main construction material for increasing urbanization all over the world in the near future. Meanwhile, construction and demolition waste from concrete structures is also leading to a significant environmental problem. Therefore, a proper sustainable solution is needed to address this environmental concern. One of the solutions can be using recycled coarse aggregates (RCA) in reinforced concrete (RC) structures. Extensive research has been conducted in this area in recent years. However, the usage of RCA concrete in the industry is still limited due to the absence of structural regulations appropriate to the RCA concrete. This study addresses a safety margin of RCA concrete beams in terms of shear capacity which is comparable to natural coarse aggregates (NCA) concrete beams. To this end, a database for reinforced concrete beams made of recycled coarse aggregates with and without shear reinforcement was established, collecting the shear specimens available from various works in the existing literature. The database was used to statistically identify the strength margin between RCA and NCA concrete beams and to calculate its safety margin based on reliability analysis. Moreover, a comparability study of RCA beams was conducted with its control specimens and with a database for conventional RC beams.

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