scholarly journals Experimental Study of the Behavior of Reinforced Concrete Beams with Composite Dapped End under Effect of Static and Repeated Loads

2019 ◽  
Vol 2 (1) ◽  
pp. p43 ◽  
Author(s):  
Hussain Naser Hussain ◽  
Qasim M. Shakir
Keyword(s):  
Ultimate Load ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Different Types ◽  
Composite Section ◽  
Steel Sections ◽  
And Performance ◽  
Repeated Loads

In this study, the structural behavior and performance of the dapped end beams with composite section under effect of static and repeated loads was investigated by experimentally tested and included ten simply supported beams with dapped in one of ends. The parameters that have been taken into consideration represented by studying the effect of reparation longitudinal tensile reinforcement by steel sections, effect of repeated loads, different types of composite steel sections, and influence of increased the shear span to depth ratio (a/d) more than one on the composite dapped end region. The study focused on determining the first cracking load, ultimate strength (Pu), deflection at service and ultimate load, failure mode, load-deflection behavior, ductility ratios, and crack pattern at failure load. The results presented that using the composite I-section instead of normal section in dapped end beams developed the shear capacity for dapped end region and enhanced the first crack appearances about 33.33, and 39.42 % for shear span to depth ratio 1.0, and 1.5 respectively.

scholarly journals Analysis of fracture processes in reinforced concrete beams without stirrups

2021 ◽  
Vol 15 (57) ◽  
pp. 321-330
Author(s):  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Failure Process ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Slender Beams ◽  
Fracture Processes

The analysis of fracture processes which led to shear failure in reinforced concrete beams without transverse reinforcement was performed on the basis of test results from the author’s own experimental investigation and numerical simulations. The variable parameters during the experiment were a beam’s length and a shear span. It was observed that the character of failure in the beams depended on the beam’s length and the span-to-depth ratio. In slender beams characterized by the shear span-to-depth ratio 3.4 and 4.1, the formation of the critical diagonal crack caused a brittle, sudden failure and the shear capacity was low. In short beams, when the shear span-to-depth ratio was 1.8 and 2.3, the failure process had a more stable character with a slow developing of inclined cracks and the significantly higher load capacity was reached. The activation of various shear transfer mechanisms was examined with regard to the slenderness of the member and the transition between a beam action which took place in slender beams to an arch action which predominated in short beams was described.

scholarly journals Shear behavior degradation and failure pattern of reinforced concrete beam with chloride-induced stirrup corrosion

2019 ◽  
Vol 22 (14) ◽  
pp. 2998-3010 ◽  
Author(s):  
Zhao-Hui Lu ◽  
Hai Li ◽  
Wengui Li ◽  
Yan-Gang Zhao ◽  
Zhuo Tang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Shear Behavior ◽  
Reinforced Concrete Beams ◽  
Failure Pattern ◽  
Reinforcement Corrosion ◽  
Shear Span ◽  
Depth Ratio

Reinforcement corrosion exhibits an adverse effect on the shear strength of reinforced concrete structures. In order to investigate the effects of chloride-induced corrosion of reinforcing steel on the shear behavior and failure pattern of reinforced concrete beams, a total of 24 reinforced concrete beams with different concrete strength grades and arrangements of stirrups were fabricated, among which 22 beams were subjected to accelerated corrosion to achieve different degrees of reinforcement corrosion. The failure pattern, crack propagation, load–displacement response, and ultimate strength of these beams were investigated under a standard four-point loading test in this study. Extensive comparative analysis was conducted to investigate the effects of the concrete strength, shear span-to-depth ratio, and stirrup type on the shear behavior of the corroded reinforced concrete beams. The results show that increasing the stirrup yielding strength is more effective in improving the shear strength of corroded reinforced concrete beams than that of concrete compressive strength. In terms of three types of stirrups, the shear strength of the beams with deformed HRB-335 is least sensitive to stirrup corrosion, followed by the beams with smooth HPB-235 and the beams with deformed HRB-400. The effect of the different stirrups on the shear strength depends on the corrosion degree of stirrup and shear span-to-depth ratio of the beam. The predicted results of shear strength of corroded reinforced concrete beams by a proposed analytical model are well consistent with the experimental results.

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 The improved design method of shear strength of reinforced concrete beams without transverse reinforcement

2017 ◽  
Vol 12 (2) ◽  
pp. 39-45 ◽  
Author(s):  
Pavlo Vegera ◽  
Rostyslav Vashkevych ◽  
Roman Khmil ◽  
Zinoviy Blikharskyy
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Method ◽  
Variable Parameter ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Effective Depth ◽  
Improved Design

Abstract In this article, results of experimental testing of reinforced concrete beams without transverse shear reinforcement are given. Three prototypes for improved testing methods were tested. The testing variable parameter was the shear span to the effective depth ratio. In the result of the tests we noticed that bearing capacity of RC beams is increased with the decreasing shear span to the effective depth ratio. The design method according to current codes was applied to test samples and it showed a significant discrepancy results. Than we proposed the improved design method using the adjusted value of shear strength of concrete CRd,c. The results obtained by the improved design method showed satisfactory reproducibility.

scholarly journals Shear Performance of Reinforced Concrete Beams Affected by Satisfactory Composite-Recycled Aggregates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1711
Author(s):  
Changyong Li ◽  
Na Liang ◽  
Minglei Zhao ◽  
Kunqi Yao ◽  
Jie Li ◽  
...  
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Crack ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregates ◽  
Shear Span ◽  
Model Code ◽  
Model Code 2010

This paper is the outcome of experiments on the shear performance of reinforced concrete beams with approved composite-recycled aggregates. The strength grade of composite-recycled aggregate concrete (CRAC) was between 30 MPa and 60 MPa. The shear span-to-depth ratio varied from 1 to 3. The adaptability of HRB400 rebar, with critical yield strength of 400 MPa, used as stirrups was also verified. As the composite technology overcame the shortcomings of recycled coarse aggregate, CRAC had similar mechanical properties with those of conventional concrete. Details on the shear behaviors of test beams under a four-point loading test are presented. The results indicated that the changes of CRAC strain, stirrup strain, and shear-crack width depended on the failure patterns, which are controlled by the shear-span to depth ratio. The stirrups yield at the failure of reinforced CRAC beams. The shear cracking resistance and the shear capacity of reinforced CRAC beams can be predicted by the statistical equations. Based on the design codes GB50010, ACI318-19, Model Code 2010 and DIN-1045-1-2008 for conventional reinforced concrete beams, the shear strengths provided by CRAC and stirrups are statistical analyzed. The rationality of the design equations is examined by the utilization level of shear strength provided by CRAC. The maximum shear-crack widths are extracted from the test data of reinforced CRAC beams at normal service state. Comparatively, by specifying the lower limit of shear strength provided by the CRAC with various shear-span to depth ratios, China code GB50010 gives a rational method for utilizing CRAC. Under the premise that the design of shear capacity would give considerations to meet the normal serviceability, the factored strength of HRB400 rebar should be 360 MPa for the calculation of shear strength provided by stirrups. The design methods in codes of GB50010, ACI318-19 and Model Code 2010 are conservative for the shear capacity of reinforced CRAC beams.

scholarly journals Experimental Study on Shear Capacity of High Strength Reinforcement Concrete Deep Beams with Small Shear Span–Depth Ratio

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1218 ◽  
Author(s):  
Jun-Hong Zhang ◽  
Shu-Shan Li ◽  
Wei Xie ◽  
Yang-Dong Guo
Keyword(s):  
High Strength ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Longitudinal Reinforcement ◽  
Deep Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Diagonal Compression ◽  
Web Reinforcement ◽  
Small Shear

This study aimed to investigate the shear capacity performance for eight deep beams with HTRB600 reinforced high strength concrete under concentrated load to enable a better understanding of the effects of shear span–depth ratio, longitudinal reinforcement ratio, vertical stirrup ratio and in order to improve design procedures. The dimension of eight test specimens is 1600 mm × 200 mm × 600 mm. The effective span to height ratio l0/h is 2.0, the shear span–depth ratio λ is 0.3, 0.6 and 0.9, respectively. In addition, the longitudinal reinforcement ratio ρs is set to 0.67%, 1.05%, 1.27%, and the vertical stirrup ratio is taken to be 0%, 0.25%, 0.33%, 0.5%. Through measuring the strain of steel bar, the strain of concrete and the deflection of mid-span, the characteristics of the full process of shear capacity, the failure mode and the load deflection deformation curve were examined. The test results showed that the failure mode of deep beams with small shear span–depth ratio is diagonal compression failure, which is influenced by the layout and quantity of web reinforcement. The diagonal compression failure could be classified into two forms: crushing-strut and diagonal splitting. With decreasing of shear span–depth ratio and increasing longitudinal reinforcement ratio, the shear capacity of deep beams increases obviously, while the influence of vertical web reinforcement ratio on shear capacity is negligible. Finally, the shear capacity of eight deep beams based on GB 50010-2010 is calculated and compared with the calculation results of ACI 318-14, EN 1992-1-1:2004 and CSA A23.3-04, which are based on strut-and-tie model. The obtained results in this paper show a very good agreement with GB50010-2010 and ACI 318-14, while the results of EN 1992-1-1:2004 and CSA A23.3-04 are approved to be conservative.

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