Shear Behavior of CFRP Prestressed Concrete Beams without Stirrups

2011 ◽  
Vol 266 ◽  
pp. 126-129 ◽  
Author(s):  
Zuo Hu Wang ◽  
Xiu Li Du ◽  
Jing Bo Liu
Keyword(s):  
Prestressed Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Shear Span ◽  
Compression Failure ◽  
Concrete Members ◽  
Prestressed Beams

Five beams were tested up to failure to study the shear behavior of concrete beams prestressed with fiber reinforced polymer (FRP). Different factors were taken into consideration: the type of prestressing tendons and the shear span ratio. The shear failure modes and the influence of different factors on shear behavior were investigated in details. The test results showed that FRP prestressed beams without stirrups had two shear failure modes: diagonal compression failure and shear compression failure; the shear span ratio was the most important factor to determine the failure mode and shear capacity of the prestressed beams. The shear capacity of concrete members prestressed with FRP tendons was lower than that of concrete beams prestressed with steel cables.

Parametric Analysis of Shear Behavior of Concrete Beams Reinforced with Continuous FRP Rectangular Spirals

2012 ◽  
Vol 217-219 ◽  
pp. 2435-2439
Author(s):  
Ying Tao Li ◽  
Shi Yong Jiang ◽  
Bing Hong Li ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Parametric Analysis ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Experimental Program ◽  
Longitudinal Reinforcement ◽  
Shear Span ◽  
Depth Ratio

An experimental program was carried out by the author to investigate the shear behavior of concrete beams reinforced with continuous FRP rectangular spirals, the main variables considered in the test were the shear reinforcement ratio and the shear span to depth ratio and the longitudinal reinforcement ratio. However, the experimental program is inadequate to gain insight into the shear behavior of the members. First, the quantities of test specimens were too small, only six beams were made and tested, the experimental database was so limited that the resultant analytical results and conclusions may not be sound enough. Second, not all the main factors that have influences on the shear behavior of the members have been treated as variables in the experimental program, such as the effective transverse compression stress and the concrete compression strength, the influences of these two factor on the shear behavior of the members were not clear yet through the experimental study. Considering the insufficient information provided by the experimental investigation, the parametric analysis of the shear behavior of the members was carried out, and a revised rotating-angle softened truss model for the shear analysis of the members was proposed as the analytical tool. Based on the proposed model, the influences of various factors on the shear capacity and shear failure modes of the members were discussed, related nonlinear analysis was carried out using the arithmetic of iteration and step approximation, and several FORTRAN codes were written accordingly. Through the experimental study and the parametric analysis, it is indicated that the shear capacity and the shear failure modes of the members are greatly influenced by three major factors, including the shear reinforcement ratio and the shear span to depth ratio and the effective transverse compression stress. The influences of the concrete compression strength and the longitudinal reinforcement ratio on the shear capacity are not noticeable comparatively. The shear capacity is little affected by the shear span to depth ratio in the case of the shear-tension failure, there is no noticeable correlation between longitudinal reinforcement ratio and the shear failure modes.

Shear Capacity of Concrete Beams Reinforced with Continuous FRP Rectangular Spirals

2012 ◽  
Vol 204-208 ◽  
pp. 3009-3015
Author(s):  
Bing Hong Li ◽  
Shi Yong Jiang ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Point Load ◽  
Shear Capacity ◽  
Experimental Program ◽  
Arch Model ◽  
Longitudinal Reinforcement ◽  
Shear Reinforcement ◽  
Shear Span

The failure modes and the shear capacity of concrete beams reinforced with FRP reinforcement were discussed through an experimental investigation, in which continuous FRP rectangular spirals were used for shear reinforcement, while ordinary deformed steel bars are used for longitudinal reinforcement. Six concrete beams reinforced with FRP spirals were tested, the main variables considered were the shear reinforcement ratios, the shear span to depth ratios and the longitudinal reinforcement ratios. Two concrete beams of equal shear capacity which reinforced with continuous steel rectangular spirals were also tested to compare the behavior of concrete beams reinforced with different materials of spirals. All beams were tested as simply supported members subjected to a three-point load, the span of the beams varied in terms of different shear span to depth ratios. The test results show that the shear capacity and shear failure modes are greatly influenced by the shear reinforcement ratios and the shear span to depth ratios, the shear resistance provided by steel spirals is higher than that provided by FRP spirals in the case of equal shear capacity of beams, which is attributed to the differences in material properties and may result in different shear failure types. Based on the experimental program, four mechanical models are derived to give more accurate predictions of the shear capacity of test beams, the calculation results of these models are compared with that of the existing shear formulas or equations for concrete beams reinforced with FRP stirrups or spirals. The rotating-angle softened truss model, the strut-and-tie model, the shear formulas derived from the truss-arch model and Zsutty equations are suggested through comparison.

Shear Failure Analysis of Concrete Beams Reinforced with Newly Developed GFRP Stirrups

2006 ◽  
Vol 324-325 ◽  
pp. 995-998
Author(s):  
Cheol Woo Park ◽  
Jong Sung Sim
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Shear Stresses ◽  
Fiber Reinforced ◽  
Shear Span ◽  
Reinforced Polymer ◽  
A New Technique

Even though the application of fiber reinforced polymer (FRP) as a concrete reinforcement becomes more common with various advantages, one of the inherent shortcomings may include its brittleness and on-site fabrication and handling. Therefore, the shape of FRP products has been limited only to a straight bar or sheet type. This study suggests a new technique to use glass fiber reinforced polymer (GFRP) bars for the shear reinforcement in concrete beams, and investigates its applicability. The developed GFRP stirrup was used in the concrete instead of ordinary steel stirrups. The experimental program herein evaluates the effectiveness of the GFRP stirrups with respect to different shear reinforcing ratios under three different shear span-to-depth testing schemes. At the same shear reinforcing ratio, the ultimate loads of the beams were similar regardless the shear reinforcing materials. Once a major crack occurs in concrete, however, the failure modes seemed to be relatively brittle with GFRP stirrups. From the measured strains on the surface of concrete, the shear stresses sustained by the stirrups were calculated and the efficiency of the GFRP stirrups was shown to be 91% to 106% depending on the shear span-to-depth ratio.

Analysis of seismic performance and research of load capacity of steel reinforced high strength concrete columns with rectangular helical hoops

2020 ◽  
pp. 136943322098165
Author(s):  
Jianyang Xue ◽  
Xin Zhang ◽  
Xiaojun Ke
Keyword(s):  
Failure Mode ◽  
Seismic Performance ◽  
Calculation Method ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Shear Capacity ◽  
Strength Concrete ◽  
Shear Span

This paper mainly focused on the seismic performance and shear calculation method of steel reinforced high-strength concrete (SRHC) columns with rectangular helical hoops. An experimental investigation was performed in this paper. Eleven SRHC columns with rectangular helical hoops and one with ordinary hoops were constructed at the laboratory of Guangxi university. The failure modes, hysteresis loops, envelope curves, characteristic loads and displacements and cumulative damage analysis are presented and investigated. It can be seen from the test results that the failure modes of SRHC columns can be divided into three types with the shear span ratio increased, namely, shear baroclinic failure mode, flexure-shear failure mode and flexure failure mode. In addition, the specimens with rectangular helical hoops have plumper hysteretic loops. Shear span ratio is the main influencing factor of characteristic load; the axial compression ratio and concrete strength have less influence on characteristic load, while stirrup ratio has little effect on the characteristic load. Finally, a calculation method for shear capacity of SRHC columns under shear baroclinic failure and flexure-shear failure mode is proposed.

Study on Shear Behaviour of Concrete Beams Prestressed with External CFRP Tendons

2013 ◽  
Vol 275-277 ◽  
pp. 1167-1171
Author(s):  
Xin Ding Wang ◽  
Hang Dai ◽  
Yong Chao Zhang
Keyword(s):  
Shear Failure ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Behaviour ◽  
Similar Process ◽  
Shear Span ◽  
External Tendons ◽  
Straight Line ◽  
Steel Bars

Based on independent research and development of a CFRP tendons wedge-type anchorage, the shear tests of six CFRP external prestressing concrete beams were done. Among them, CFRP external tendons of three pieces were installed in straight line while other pieces were installed in curved line. The results of experimental research show that shear behaviour of concrete beams prestressed with CFRP external tendons are the similar process to the traditional prestressed reinforced concrete beams. They go through the elastic stage, the stage of crack extension, the yield stage of internal hoop reinforcements at the intersection of inclined cracks and the failure stage. When external CFRP tendons are arranged in the same situation, the cracking load and the shear capacity of concrete beams prestressed with CFRP external tendons reduce gradually along with the increase of shear-span ratio,.When shear-span ratio is equal, the cracking load and the shear capacity of concrete beams prestressed with curved arrangement of CFRP external tendons are larger than those of concrete beams prestressed with straight arrangement of CFRP external tendons. Compared with traditional concrete beams prestressed with external steel bars, due to elasticity modulus and shear modulus of CFRP tendons are both smaller than those of steel bars, the mid-span deflection of concrete beams prestressed with CFRP external tendons at the time of shear failure is bigger than that of traditional concrete beams prestressed with external steel bars under the same circumstance.

scholarly journals Analysis of the Shear Capacity of Ultrahigh Performance Concrete Beams Based on the Modified Compression Field Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wei Feng ◽  
Hongming Feng ◽  
Zhijun Zhou ◽  
Xiongwei Shi
Keyword(s):  
Field Theory ◽  
Failure Modes ◽  
Shear Capacity ◽  
Analysis Model ◽  
Shear Span ◽  
Compression Failure ◽  
Shear Bearing Capacity ◽  
Modified Compression Field Theory ◽  
Compression Field ◽  
Simplified Formula

An analysis model of the shear capacity of prestressed ultrahigh performance concrete (UHPC) beams under the combined action of bending and shearing was established in this paper based on the modified compression field theory and by considering the unique material constitutive relation of UHPC. Shear tests were performed using three prestressed UHPC-T beams with different shear-span ratios to verify the correctness of the model. The results showed that the shear-span ratio greatly influenced the shear capacity and failure modes of UHPC-T beams. Upon increasing the shear-span ratio, the failure modes of the three beams were inclined compression failure, shear compression failure, and diagonal tension failure, successively. When the shear-span ratio changed from 1.04 to 2.12, the shear bearing capacity decreased greatly; however, when the shear-span ratio changed from 2.12 to 3.19, the decrease of the shear bearing capacity was very small. In addition, the MCFT analysis model was used to analyze the experimental data, and the predicted results were in good agreement, which proved the applicability of the model. Finally, according to the existing shear test results of UHPC beams and based on the main influencing factors, a simplified formula for predicting the shear capacity of UHPC beams was obtained by fitting. Comparing the MCFT model with the results of other pieces of literature, this formula accurately predicted the shear capacity of UHPC beams. The MCFT model and the simplified formula presented in this paper provide a powerful tool for predicting the shear performance of UHPC-T beams, which will contribute to the design and analysis of UHPC-T beams.

scholarly journals Experimental Investigation of the Shear Behavior of a Concrete Beam without Web Reinforcements Using External Vertical Prestressing Rebars

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Xingwei Xue ◽  
Xuan Wang ◽  
Xudong Hua ◽  
Meizhong Wu ◽  
Longqing Wu ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Crack ◽  
Shear Resistance ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Shear Cracks ◽  
Web Reinforcement ◽  
Shear Performance

The shear performance of concrete beams is known to be an important mechanical feature; hence, enhanced shear resistance is critical for determining a beam’s performance in terms of security and service life. This paper presents a study on the shear behavior of concrete beams without web reinforcement strengthened by external vertical prestressing rebars (EVPRs). Experimental data were obtained from seven test beams with varying influencing factors (stirrup ratio ρsEP, arrangement spacing s, prestressing force Fp, and compressive stress degree γp of the EVPRs) to determine their effects on the shear behavior. The results reveal that the EVPRs can significantly improve the shear capacity and ductility of concrete beams without web reinforcement. Furthermore, the failure mode is changed from brittle diagonal tension to relatively ductile shear compression, and the flexural cracks and shear cracks are more fully developed. The shear capacity becomes enhanced as the ρsEP and γp are increased; vertical compressive stress provided by the EVPRs can reduce the principal tensile stress of the concrete structure to prevent the shear cracking and enhance the shear resistance of the concrete. Meanwhile, in the stage from the formation of the critical shear crack (CSC) to the shear failure, the EVPRs can be used as stirrups to share the shear load. It can be concluded that EVPRs can effectively improve the shear performance of concrete beams.

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 Shear Behavior of Reinforced Post-Filling Coarse Aggregate Concrete Beams Produced by Creative Construction Process

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 576
Author(s):  
Jinqing Jia ◽  
Qi Cao ◽  
Lihua Zhang ◽  
Yulong Hu ◽  
Zihan Meng
Keyword(s):  
Coarse Aggregate ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Engineering Practice ◽  
Aggregate Concrete ◽  
Strength Grade ◽  
Shear Span ◽  
Ultimate Shear Capacity

Different from the traditional concrete mixing procedure, the innovative post-filling coarse aggregate concrete (PFCC) reduces the cost of pumping concrete by increasing the coarse aggregate content and reducing the usage of cement. Previous studies have shown that PFCC enhances the compressive strength, elastic modulus, and flexural strength of concrete. In this paper, the shear behavior of 13 post-filling coarse aggregate concrete beams and 3 control beams was tested to determine the relationships between the shear performance of the beam and the post-filling coarse aggregate ratio, concrete strength grade, shear span ratio and stirrup reinforcement ratio. The results showed that the ultimate shear capacity of beam specimen increases first and then decreases with the increase in post-filling coarse aggregate ratio, reaching the maximum at 15% post-filling ratio. The results also indicated that the ultimate shear capacity of the beam increases with the increase in concrete strength grade and stirrup ratio. However, experimental results exhibited that the ultimate shear capacity decreases as the shear span ratio increases. This study provides a reference for the application of post-filling coarse aggregate concrete in engineering practice.

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.

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