Shear strengthening of reinforced concrete beams strengthened using embedded through section steel bars

Breveglieri, Matteo; Aprile, Alessandra; Barros, Joaquim A. O.

doi:10.1016/j.engstruct.2014.09.026

Cited by 44 publications

(33 citation statements)

References 29 publications

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“…All anchors were set in a vertical direction which is for overhead installation on site preferred to an inclined setting. In comparison, fully bonded postinstalled reinforcement is favorably set at an angle (see References ) mainly in order to increase the available anchorage length. With the designed new anchor system, the concentrated end anchorage based on the undercut principle allows for shorter embedments and does not necessarily require setting at an angle.…”

Section: Experimental Campaignmentioning

confidence: 99%

Developing optimized strengthening systems for shear‐deficient concrete members

Randl

Harsányi

2017

Structural Concrete

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Austrian Federal Railways ÖBB, Austrian motorway operator ASFINAG Strengthening methods for shear-deficient bridges were developed and tested in cooperation with the HILTI Corporation and SIKA Austria. In order to identify the strengthening effect in shear, a number of 12 T-shaped RC-beams with a length of 5.38 m were designed. In the experimental campaign two different types of strengthening systems were applied and subjected to shear loading until failure. The successful use of a modern digital image correlation system provided the basis for an in-depth analysis of failure mode and crack pattern as well as shear degradation at each load stage. Finally, the applicability of existing shear design models with consideration of the strengthening elements analogously to cast-in shear reinforcement was evaluated.anchorage, carbon fiber, FRP, postinstalled, shear, shear test, strengthening, undercut anchor 1 | INTRODUCTION Subsequent strengthening of existing structures has gained in importance over the last decades due to the decreasing number of new structures and the ever-growing number of existing ones. The ongoing increase in traffic loads, continuous updating of design codes, and also paradigm shifts lead to the fact that a number of existing bridge structures do not fulfill the required safety level concerning the shearbearing capacity as required by codes of practice such as Eurocode 2. 1 Meanwhile, there exist refined methods for the verification of the shear load-bearing capacity 2-7 , developed from more consistent mechanical models. MC2010 8 provides advanced design approaches allowing for a better utilization of the real structural resistance. Nevertheless, the need for sound technical solutions in the subsequent shear strengthening of existing reinforced concrete (RC) structures is constantly increasing.While the flexural strengthening of RC members has become a routine task, the retrofitting of shear-deficient members is still a challenging issue for the following reasons:• Local shear retrofitting requires the introduction of forces over very short distances. In comparison, flexural strengthening is oriented in the longitudinal direction of a structural member and usually applied over larger sections. Therefore, adequate stiffness and proper anchorage solutions are needed when strengthening in shear. • The strengthening system must be reliably activated without the necessity of large additional live loads or deformations of the structure. • Currently, there are no harmonized recommendations for RC shear design itself available; therefore, the rather complex design of shear strengthening is even more disputable.A few established methods to strengthen RC structures in shear already exist (see e.g., overview in Reference 9). Selected popular methods for shear strengthening are discussed and compared on the basis of experimental investigations in Reference 10. With respect to the affected sections of a structure and the impact on the overall structural behavior, such strengthening solutions can generally be...

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Section: Experimental Campaignmentioning

confidence: 99%

Developing optimized strengthening systems for shear‐deficient concrete members

Randl

Harsányi

2017

Structural Concrete

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“…Many studies have applied the NSM FRP strengthening method to improve the flexural and shear strength of RC beams [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], whilst others have used conventional steel bars instead of FRP materials for flexural and shear strengthening [21][22][23][24][25][26][27][28]. However, only few of these studies have focused on torsion strengthening [29][30][31]32] and no previous work has investigated the application of conventional steel bars for the torsion strengthening of RC beams.…”

Section: Introductionmentioning

confidence: 99%

Torsional Strengthening of RC Beams with Near‐Surface Mounted Steel Bars

Askandar

Mahmood

2020

Advances in Materials Science and Engineering

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e strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and nearsurface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening.erefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. e practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. e torsional performance of the RC beams was significantly improved by using NSM steel bars, whereas in various NSM configurations, the 90°NSM beams outperformed the 45°NSM beams.

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“…is strengthening technique has already been proven to be effective for the shear and flexural strengthening of RC beams [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]. Many studies have also used conventional steel bars instead of FRP materials for flexural and shear strengthening by employing the NSM method [59][60][61][62][63][64]. However, only few of these studies have focused on torsion strengthening [65,66], and no previous work has investigated the application of conventional steel bars for the torsion strengthening of RC beams.…”

Section: Introductionmentioning

confidence: 99%

Comparative Investigation on Torsional Behaviour of RC Beam Strengthened with CFRP Fabric Wrapping and Near‐Surface Mounted (NSM) Steel Bar

Askandar

Mahmood

2019

Advances in Civil Engineering

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Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials and near-surface mounted (NSM) to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, studies on torsional strengthening are limited. Although a few studies have focused on torsional strengthening, none of them simultaneously investigated torsion with shear and/or bending moment. This study aims at demonstrating the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and NSM steel bars with different spacing that was subjected to combined actions of torsion and bending moment and making a comparison between them. Seven beams with a dimension of 15 × 25 × 200 cm were casted. One of the beams was not strengthened; three of them were strengthened with carbon FRP, and the others were strengthened with NSM steel bar. The angle of twist at torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional and strengthened beams during the testing process are compared. Results show a significant improvement in the torsional performance of RC beams using carbon FRP and NSM steel bar. The test beams that were strengthened with CFRP wrapping showed better enhancement in the ultimate torsional moment as opposed to the beams that were strengthened with NSM steel bar.

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Shear strengthening of reinforced concrete beams strengthened using embedded through section steel bars

Cited by 44 publications

References 29 publications

Developing optimized strengthening systems for shear‐deficient concrete members

Developing optimized strengthening systems for shear‐deficient concrete members

Torsional Strengthening of RC Beams with Near‐Surface Mounted Steel Bars

Comparative Investigation on Torsional Behaviour of RC Beam Strengthened with CFRP Fabric Wrapping and Near‐Surface Mounted (NSM) Steel Bar

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