Validation of a Shear Model for RC and Hybrid Beams with Two Different Inclinations of Transversal Reinforcement

2016 ◽  
Vol 847 ◽  
pp. 505-512 ◽  
Author(s):  
Piero Colajanni ◽  
Lidia La Mendola ◽  
Alessia Monaco ◽  
Antonino Recupero
Keyword(s):  
Field Theory ◽  
Stress Field ◽  
Analytical Approach ◽  
Concrete Beams ◽  
Numerical Data ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Rc Beams ◽  
Eurocode 2 ◽  
Hybrid Beams

The validation of an analytical model recently proposed for evaluation of the shear capacity in Reinforced Concrete (RC) beams containing multiple inclination of transverse stirrups is presented. The model is a suitable extension of that currently proposed in Eurocode 2 for the evaluation of the shear resistance, and it is derived by means of the the variable-inclination stress-field theory based on Nielsen’s plastic approach. Experimental and numerical data available in the literature on Hybrid Steel-Trussed Concrete Beams (HSTCBs) are used for model validation and result discussion. Finally, also the comparison with a different analytical approach for the assessment of the shear resistance of HSTCBs is provided.

Influence of Stirrup Corrosion on Shear Strength of RC Beams

2012 ◽  
Vol 204-208 ◽  
pp. 3287-3293
Author(s):  
Xin Xue ◽  
Hiroshi Seki ◽  
Yu Song
Keyword(s):  
Shear Strength ◽  
Mass Loss ◽  
Local Maximum ◽  
Shear Resistance ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Maximum Mass ◽  
Rc Beams ◽  
Load Carrying ◽  
Maximum Mass Loss

There have been few reports on shear behavior of reinforced concrete (RC) beams with corroded stirrups, and the influence of stirrup corrosion has yet to be identified. Given this background, experience was carried out to investigate the shear behavior of RC beams containing corroded stirrups. Investigation results indicate that if the percentage local maximum mass loss is below 35%, there is little influence on the load-carrying mechanism. The concrete shear resistance seems to change little and the shear capacity can be calculated by just taking into consideration the reduction in stirrup shear resistance. It is also found that the anchorage conditions of the stirrups have a predominant influence on the shears of RC beams.

scholarly journals Interaction between Internal Shear Reinforcement and External FRP Systems of RC Beams: Experimental Study

2017 ◽  
Vol 11 (1) ◽  
pp. 143-152
Author(s):  
Wee Teo ◽  
Kilian Lau Meow Hing ◽  
Mohd Shahir Liew
Keyword(s):  
Concrete Beams ◽  
Research Effort ◽  
Shear Resistance ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Shear Strengthening ◽  
Modes Of Failure ◽  
Externally Bonded ◽  
Good Agreement ◽  
Do So

Extensive research effort has been conducted on the shear strengthening of reinforced concrete (RC) beams with externally bonded FRP systems. However, there are still few aspects on their behaviour that are yet to be fully understood. One of them is the effect of shear interaction between internal transverse shear reinforcement and the external FRP systems. This paper is intended to study experimentally the interaction between these two shear reinforcement components. To do so, a total of five concrete beams were assembled in this investigation. All beams were properly instrumented in order to obtain as much data as possible. Four beams were externally strengthened with FRP with different strengthening and wrapping schemes. Their influence and interaction with the internal transverse stirrups in shear resistance were discussed based on the modes of failure exhibited, deflection and strain (steel and FRP) responses. Overall the results obtained are in good agreement with many researches which indicated that addition of externally bonded FRP, as a matter of fact, preserves the integrity of internal transverse stirrups. With continuous FRP sheets and U-wrapped scheme, greater FRP contribution to the shear resistance can be expected.

scholarly journals Theoretical prediction of punching shear capacity of flat slabs without shear reinforcement strengthened by concrete topping

2021 ◽  
Vol 1203 (2) ◽  
pp. 022108
Author(s):  
Daniel Čereš ◽  
Katarína Gajdošová
Keyword(s):  
Shear Resistance ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Model Code ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract The main reasons for strengthening flat slabs are the change of the use of a building, increase in the value of loads, degradation of the concrete cover layer, or insufficient reinforcement. This paper is focused on the assessment of punching shear capacity of the strengthened flat slabs without shear reinforcement. One of the possibilities how to enhance punching shear capacity is the addition of reinforced concrete topping. The main goal of this paper is to compare the possibilities for calculation of the increase in the punching shear capacity by investigation of the influence of different thicknesses of concrete toppings and different reinforcement ratio. A reference specimen is represented by a fragment of a flat slab with the thickness of h = 200 mm supported by circular column with the diameter of 250 mm. Three different thicknesses (50 mm, 100 mm, 150 mm) of concrete toppings were considered together with three different reinforcement ratios for each thickness of concrete overlay. Theoretical predictions of the punching shear resistance of flat slabs were evaluated by design guidelines according to the relevant standards: Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of the second generation of Eurocode 2 (prEN 1992-1-1). The differences in the influence of reinforcement ratio are significant. In Model Code 2010 the reinforcement ratio in concrete topping was considered in equation of moment of resistance. This is unlike in both of the mentioned Eurocodes, where the reinforcement ratio was assumed as a geometric average value of the original reinforcement ratio in the slab before strengthening and of the reinforcement ratio of concrete topping. All the predicted theoretical calculations are based on the perfect connection and bond between the original and new layer of concrete. These predictions should be verified by experimental investigation, which is going to be prepared shortly. By the additional increase in the thickness of concrete topping or in the amount of added reinforcement the attention should be payed to the limitation of the punching shear resistance by the value of the maximum punching shear resistance in the compression concrete strut.

scholarly journals Punching shear resistance of reinforced concrete footings: evaluation of design codes

2018 ◽  
Vol 11 (2) ◽  
pp. 432-454
Author(s):  
D. F. A. SANTOS ◽  
A. F. LIMA NETO ◽  
M. P. FERREIRA
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Shear Resistance ◽  
Test System ◽  
Shear Capacity ◽  
Experimental Results ◽  
Punching Shear ◽  
Complex Method ◽  
Shear Design ◽  
Eurocode 2

Abstract Punching is a possible failure mode for slender footings and it may lead a structure to ruin through progressive collapse. Although footing present different geometric characteristics, their punching shear design is based on the empirical methods used for flat slabs. This paper uses experimental results from 216 tests to evaluate the performance of design code recommendations presented by ACI 318 (2014), ABNT NBR 6118 (2014) and Eurocode 2 (2010) to estimate the punching shear resistance of reinforced concrete footings. Great dispersion between theoretical and experimental results was observed, being evident that the test system affects the punching shear capacity of footings. The more complex method proposed by Eurocode 2 resulted in a better correlation with experimental results.

Dynamic Shear Resistance of RC Beams Based on Modified Compression Field Theory

2016 ◽  
Vol 711 ◽  
pp. 799-805
Author(s):  
Kazunori Fujikake ◽  
Amornthep Somraj
Keyword(s):  
Field Theory ◽  
Analytical Model ◽  
Shear Capacity ◽  
Experimental Results ◽  
Rc Beams ◽  
Dynamic Shear ◽  
Loading Tests ◽  
Blast Loadings ◽  
Modified Compression Field Theory ◽  
Compression Field

The aim of this study was to develop an analytical model to estimate the dynamic shear capacity of RC beams which may exhibit diagonal tension failure under impact and blast loadings. Thus, the modified compression field theory has been extended to dynamic loading in this study. The developed analytical model has been applied to the experimental results obtained from rapid loading tests of RC beams. As a result, the developed analytical model has been in good agreement with the experimental results.

scholarly journals Strengthening flat slabs without shear reinforcement against punching shear by concrete overlay

2021 ◽  
Vol 1209 (1) ◽  
pp. 012056
Author(s):  
D Čereš ◽  
K Gajdošová
Keyword(s):  
Parametric Study ◽  
Shear Crack ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Flat Slab ◽  
Model Code ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract Research in this paper presents a theoretical study of increasing in punching shear capacity of the strengthened flat slab by concrete overlay. The parametric study is based on comparison of three different relevant standards design models and presents results how Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of second generation of Eurocode 2 (prEN 1992-1-1) take into account strengthening by concrete overlay. A reference specimen is represented by a fragment of a flat slab supported by circular column. Influence of concrete toppings depends on thickness and also on reinforcement ratio. In Eurocode 2 and new generation of Eurocode 2 the increase of punching shear resistance of the slab with concrete topping can be taken into account only by reinforcement ratio and thickness of the slab considering the perfect connection and bond between the original slab and new layer of concrete overlay. Model Code 2010 is based on Critical shear crack theory and the reinforcement ratio in concrete topping was considered in equation of moment of resistance and punching shear resistance is calculated by considering the rotation and deformation of the slab. Estimation of results by parametric study are compared by non-linear model from Atena software.

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 Research on Shear Property of Steel Bar/Wire Mesh Mortar Strengthening Concrete Beams

2012 ◽  
Vol 204-208 ◽  
pp. 3206-3212
Author(s):  
Yan Hua Sun ◽  
Qiu Dong Chen ◽  
Jin Wei Liu ◽  
Guang Jing Xiong
Keyword(s):  
Experimental Research ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Wire Mesh ◽  
Rc Beams ◽  
Experiment Study ◽  
Working Mechanism ◽  
Shear Property ◽  
Steel Bar ◽  
Diagonal Crack

In order to enhance the shear capacity of reinforced concrete (RC) beams more efficiently, a thought to strengthen concrete beams by using steel bar/wire mesh mortar was proposed. A comparison experiment study on shear behavior of two kinds of strengthening RC beams(namely steel bar mat(S)mortar strengthening, and steel bar / wire mesh(SW) mortar strengthening) was carried out. The experimental results show that SW strengthening can keep the advantages of a better dispersion of reinforcement due to the addition of wire mesh, leading to a much higher initial diagonal crack load, and a better control to the crack propagation of the strengthened beams. The initial diagonal cracking load and the shear capacity of SW strengthened beams are 83% and more than 30% higher than those of S strengthened beams respectively, while the reinforcement ratio of the formers is only 22% higher than that of the laters. The working mechanism of SM mortar strengthening was discussed.

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