Experimental investigations of failure modes of reinforced concrete beams without web reinforcement

2019 ◽  
Vol 185 ◽  
pp. 47-57 ◽  
Author(s):  
Taozhi Xu ◽  
Jie Li
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Experimental Investigations ◽  
Web Reinforcement

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.

scholarly journals Shear resistance of welded inclined bars in rectangular reinforced concrete beams

2018 ◽  
Vol 250 ◽  
pp. 03003
Author(s):  
Noor Suhaida Galip ◽  
Roslli Noor Mohamed ◽  
Ramli Abdullah
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Shear Forces ◽  
Distance Ratio ◽  
Effective System ◽  
Horizontal Portion

The bent-up bars have not been used as shear reinforcement in beams since the past 40 years or so. In all cases of design and construction nowadays, shear forces are resisted by vertical links only. Some complications in installing the multiple set of bent-up bars, the less opportunity to have sufficient number of bent-up bars due to small number of flexural reinforcement provided at the mid-span of the beams and also the large anchorage required for the horizontal portion of the bars beyond the upper end of the bend could be the reasons behind this. This paper presents the results of tests on five rectangular reinforced concrete beams in which the effectiveness of welded inclined bars (WIB) as shear reinforcement was studied. Two of the beams were controlled specimens, with no shear reinforcement in one, and full design vertical links in another. The other three beams were provided with three different quantities of WIB, measured in terms of area to distance ratio, Asw / S as shear reinforcement in the shear spans. All beams were tested to failure under two point loads with a shear span to effective depth ratio of 2.34, which would ensure that the failure was due to shear unless their shear capacities were larger than the flexural capacity. The performances of the beams were measured in terms of deflection, crack formation, strains in WIB and on the concrete surfaces in the shear region, ultimate loads and failure modes. The results show that WIB alone is capable of carrying the whole shear forces in the beam, and larger shear capacities are achieved with a larger quantity of WIB, and a higher grade of the bars used. The beam with WIB requires 22% less in the quantity of Asw / S compared to that with vertical links to achieve the same shear resistance. These suggest that WIB can be used as an effective system of shear reinforcement in beams.

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.

Studies on Fire Resistance of FRP Shear Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 94-96 ◽  
pp. 1318-1321
Author(s):  
He Fan ◽  
Ze Fan
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Temperature Fields ◽  
Insulation Material ◽  
Rc Beams ◽  
Fire Resistance Rating ◽  
Resistance Rating

Fire-resistance performance experiments with static loading-fire are investigated about two carbon fiber sheet (CFS) shear strengthened reinforced concrete (RC) beams exposed to the ISO834 standard fire. Shear strengthened RC beams are wrapped with fire insulation material- thick painted fire retardant coatings. Relationship between measure points’ temperature and time are achieved. The results suggest that: the ratio of shear-span is the main factor to fire-resistance rating and failure modes of CFS shear strengthened RC beams in fire; shear-failure fire-resistance rating are increased by thickening fire insulation to shear strengthened RC beams. A computer program is developed to calculate the temperature fields of fire insulated concrete beams shear strengthened with CFS coated thick fireproof material. This program is validated comparing with experimental results. Researches can give a supplement to produce overall fire-resistance factors of CFS shear strengthened reinforced concrete beams at high temperatures.

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