scholarly journals Shear Behavior of RC Deep Beam Strengthened by V-Shaped External Rods

2020 ◽  
Vol 10 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Pramod Rai ◽  
Kitjapat Phuvoravan
Keyword(s):  
Experimental Test ◽  
Shear Failure ◽  
Experimental Tests ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Deep Beam ◽  
Nominal Strength ◽  
Rod System ◽  
Strengthened Beam ◽  
Strengthening Technique

This research investigated the shear strengthening technique of Reinforced Concrete (RC) deep beams using a V-shaped external rod system. Shear behavior, the stress in an external rod, and the shear capacity at the diagonal shear failure of a strengthened beam were focused mainly. Experimental tests of control and two strengthened beams were carried out to observe the effect of the external rod on shear behavior of RC deep beam. A theoretical approach to compute the stress in the external rod and the nominal strength of the strengthened beam in the diagonal shear failure were examined based on the experimental test results and verified using Finite Element Method (FEM) in ABAQUS. The computed nominal shear strength of the strengthened beam was 10% higher than the experimental test. The strengthening technique shifted the brittle shear failure to ductile shear failure and improved the performance of RC deep beam.

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 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.

Review of the Punching Shear Behavior of Concrete Flat Slabs in Ambient and Elevated Temperature

2013 ◽  
Vol 4 (4) ◽  
pp. 259-280 ◽  
Author(s):  
Mehrafarid Ghoreishi ◽  
Ashutosh Bagchi ◽  
Mohamed Sultan
Keyword(s):  
Elevated Temperature ◽  
Shear Failure ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Punching Shear ◽  
Ambient Conditions ◽  
Flat Slab ◽  
Flat Slabs ◽  
Analytical Studies ◽  
In Fire

There are a number of benefits associated with two-way concrete flat slab construction for office buildings, parking garages and apartments - for example, reduced formwork, prompt erection, flexibility of partitions, and minimal increase in story heights. However, concrete flat slabs could be quite vulnerable to punching shear failure in the event of a fire. The objective of the present article is to provide a state of the art review of the existing research and the issues associated with concrete flat slabs in fire and elevated temperature. There are a number of experimental and analytical studies on the punching shear behavior of concrete flat slabs in ambient conditions, available in the literature. Based on these studies, it is found that punching shear capacity in ambient condition is affected by many factors, which may not remain constant during a fire exposure. Only a limited number of studies on concrete flat slabs for punching shear failure in fire are available. This paper reviews the available experimental and analytical studies, standards and codes to address the research gap in estimating of punching shear strength of concrete flat slab-column connections without shear reinforcement.

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.

Masonry Reinforcement with IMG Composites: Experimental Investigation

2014 ◽  
Vol 624 ◽  
pp. 275-282 ◽  
Author(s):  
A. Balsamo ◽  
Ivano Iovinella ◽  
M. di Ludovico ◽  
Andrea Prota
Keyword(s):  
Experimental Tests ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Stone Masonry ◽  
Theoretical Expression ◽  
Reinforced Polymer ◽  
Diagonal Compression ◽  
Historical Masonry ◽  
Strengthening Technique ◽  
Inorganic Matrix

The interest in strengthening of historical masonry structures is significantly grown especially to techniques which combine properties like as reversibility, compatibility, and sustainability of the intervention. Among these, a promising technique is the use of inorganic matrix grid (IMG) composites. Several experimental tests have been carried out to prove the effectiveness of this system as a strengthening solution for different masonry types. The present paper presents the original results of five tests on uncoursed stone masonry panels under diagonal compression and collect the data of previous tests carried out by the authors on other masonry typologies. The tests results on several masonry types and strengthening layouts as well as Fiber reinforced Polymer (FRP) grid and mortar types are reported and discussed. The experimental programs clearly confirmed the effectiveness of the investigated strengthening technique to increase the panels shear capacity and ductility; however, a suitable theoretical expression to quantify the benefits provided by this strengthening solution, based on the reinforcement layout and on the masonry type, is still missing. The comparative analysis of the experimental data is presented in the paper in order to clarify the benefits provided by each strengthening system.

scholarly journals Assessment of shear capacity. Part II: Experimental test

2018 ◽  
Vol 196 ◽  
pp. 02040
Author(s):  
Maria Włodarczyk
Keyword(s):  
Failure Mode ◽  
Experimental Test ◽  
Failure Modes ◽  
Shear Failure ◽  
Load Capacity ◽  
Shear Capacity ◽  
Transverse Reinforcement ◽  
Shear Reinforcement ◽  
Theoretical Results ◽  
Capacity Estimates

Results of experiments carried out on beams with varying shear reinforcement are presented. Depending on the amount of transverse reinforcement different failure modes with different ultimate loads were recorded. The results were compared to theoretical load capacity estimates. Three models for shear capacity were used: classical, EC and Zararis described in the accompanying paper [1]. When shear failure mode governs beam behaviour, theoretical results according to the EC and Zararis are in good compatibility with experiments.

scholarly journals Application of critical shear crack theory on punching of flat slabs

2021 ◽  
Vol 1209 (1) ◽  
pp. 012060
Author(s):  
S Sarvaicova ◽  
V Borzovic
Keyword(s):  
Experimental Test ◽  
Shear Crack ◽  
Experimental Tests ◽  
Shear Capacity ◽  
Nonlinear Program ◽  
Flat Slab ◽  
Crack Theory ◽  
Flat Slabs ◽  
Significant Difference ◽  
Non Linear

Abstract This article deals with the punching capacity of a flat slab fragment supported by an internal atypically elongated column. Based on the results of this analysis and the application of Critical Shear Crack Theory, the reliability of two design models was determined. The CSCT model is a mechanical model where the shear force transferred by concrete in shear crack can be determined by accounting for the roughness and opening of a critical shear crack. The crack width is proportional to the slab rotation, which was obtained from a nonlinear program Atena and from experimental test and shear capacity was obtained by integrating the shear strength along the control perimeter. The aim of this analysis was to compare the application of CSCT in non-linear analysis and experimental test to point out the significant difference between obtained results, which shows the importance of experimental tests realization. Non-linear analyses provided unsafe results. Contrary the currently used EC2 model provided safe results when reduction of the control perimeter was applied. The best results were obtained in a combination of the CSCT model with measured rotations of the slab specimen.

On axial compressive behavior of steel fiber reinforced concrete confined by FRP

2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Steel Fiber ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Frp Confinement

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.

scholarly journals Influence of Patching on the Shear Failure of Reinforced Concrete Beam without Stirrup

2021 ◽  
Vol 6 (7) ◽  
pp. 97
Author(s):  
Stefanus Adi Kristiawan ◽  
Halwan Alfisa Saifullah ◽  
Agus Supriyadi
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Numerical Study ◽  
Unsaturated Polyester ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Shear Capacity ◽  
Rc Beam ◽  
Shear Span ◽  
Shear Cracking

Deteriorated concrete cover, e.g., spalling or delamination, especially when it occurs at the web of a reinforced concrete (RC) beam within the shear span, can reduce the shear capacity of the beam. Patching of this deteriorated area may be the best option to recover the shear capacity of the beam affected. For this purpose, unsaturated polyester resin mortar (UPR mortar) has been formulated. This research aims to investigate the efficacy of UPR mortar in limiting the shear cracking and so restoring the shear capacity of the deteriorated RC beam. The investigation is carried out by an experimental and numerical study. Two types of beams with a size of 150 × 250 × 1000 mm were prepared. The first type of beams was assigned as a normal beam. The other was a beam with a cut off in the non-stirrup shear span, which was eventually patched with UPR mortar. Two reinforcement ratios were assigned for each type of beams. The results show that UPR mortar is effective to hamper the propagation of diagonal cracks leading to increase the shear failure load by 15–20% compared to the reference (normal) beam. The increase of shear strength with the use of UPR mortar is consistently confirmed at various reinforcement ratios.

scholarly journals A Computational Study of the Shear Behavior of Reinforced Concrete Beams Affected from Alkali–Silica Reactivity Damage

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3346
Author(s):  
Bora Gencturk ◽  
Hadi Aryan ◽  
Mohammad Hanifehzadeh ◽  
Clotilde Chambreuil ◽  
Jianqiang Wei
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Parametric Study ◽  
Computational Study ◽  
Element Model ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Alkali Silica Reactivity ◽  
Concrete Mechanical Properties

In this study, an investigation of the shear behavior of full-scale reinforced concrete (RC) beams affected from alkali–silica reactivity damage is presented. A detailed finite element model (FEM) was developed and validated with data obtained from the experiments using several metrics, including a force–deformation curve, rebar strains, and crack maps and width. The validated FEM was used in a parametric study to investigate the potential impact of alkali–silica reactivity (ASR) degradation on the shear capacity of the beam. Degradations of concrete mechanical properties were correlated with ASR expansion using material test data and implemented in the FEM for different expansions. The finite element (FE) analysis provided a better understanding of the failure mechanism of ASR-affected RC beam and degradation in the capacity as a function of the ASR expansion. The parametric study using the FEM showed 6%, 19%, and 25% reduction in the shear capacity of the beam, respectively, affected from 0.2%, 0.4%, and 0.6% of ASR-induced expansion.

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