scholarly journals Shear Strengthening of Deep T-Section RC Beams with CFRP Bars

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6103
Author(s):  
Zheng-Nan Jing ◽  
Rong-Gui Liu ◽  
Gui-Hua Xie ◽  
Dan Liu
Keyword(s):  
Design Theory ◽  
Experimental Tests ◽  
Economic Benefits ◽  
Shear Capacity ◽  
Shear Strengthening ◽  
Engineering Structures ◽  
Near Surface ◽  
Strut And Tie ◽  
Beam Design ◽  
Strut And Tie Model

Deep T-section beams have been widely used in engineering structures due to their high bearing capacity, high construction efficiency and economic benefits, while the current beam design theory can hardly interpret reasonably the mechanical behaviors of deep beams. The performance features of the deep T-beam were investigated, involving in strain distribution and principal stress trace using experimental tests. Different near surface mounted (NSM) reinforcement schemes were proposed for deep T-beams aiming at improving the shear capacity. The results show that the behaviors of deep T-beams dissatisfy the assumption of plane cross-section, and the ‘strut-and-tie’ model is applicable in such structures. The reinforcement systems can significantly relieve the strain concentration, mid-span deflection and crack width in deep T-beams, consequently improving the shear capacity range from 45 to 65%. The scheme is preferential for the reinforcement of deep T-beams when the applied angles, positions and lengths of CFRP bars are optimized based on the ‘strut-and-tie’ model.

Test Study on the Resisting Shear Strengthening Effect with External Pre-Stressed Wire Rope

2011 ◽  
Vol 243-249 ◽  
pp. 5571-5575 ◽  
Author(s):  
Tian Lai Yu ◽  
Qiang Ma ◽  
Lei Lei Tian
Keyword(s):  
Reinforced Concrete ◽  
Strengthening Mechanism ◽  
Wire Rope ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Strengthening Effect ◽  
Shear Strengthening ◽  
Research Results ◽  
Beam Design

The resisting shear strengthening technology of existing reinforced concrete bridges as an important research topic in the field of old bridges, play an important significance to improve the mechanical properties of old bridges and reduce security incidents. Based on comparative test analysis on two basic beams and twelve reinforced concrete beams strengthened with external pre-stressed wire rope, the influence of the shear strengthening effect was studied systematically caused by the original beam design parameters and the spacing of wire rope, in the meantime the strengthening mechanism was analyzed. Research results showed that the shear capacity of the strengthened beams was improved, because the development of cracks was not only effectively limited, but also stirrup strain was reduced, and yield load was put off. Along with the increasing of the ratio of original beams longitudinal reinforcement and the ratio of stirrup ,and the concrete grade, as well as the decreasing of spacing of external wire rope, the stirrups strain were decreasing and the shear capacity of strengthened beams increased. With the spacing of external wire rope decreasing, the diagonal crack resistance of the strengthened beams increased. The research results can provide reference for the design and research on shear strengthening of bridges.

Strength and Ductility of Embedded Steel Composite Coupling Beams

2003 ◽  
Vol 6 (1) ◽  
pp. 23-35 ◽  
Author(s):  
W. Y. Lam ◽  
R. K. L. Su ◽  
H. J. Pam
Keyword(s):  
Energy Absorption ◽  
Experimental Tests ◽  
Preliminary Test ◽  
Shear Capacity ◽  
Coupling Beam ◽  
Coupling Beams ◽  
Diagonal Reinforcement ◽  
Beam Design ◽  
Steel Composite ◽  
Strength And Stiffness

The stringent requirements on dimensions, ductility, energy absorption, strength and stiffness of coupling beams have resulted in much research on various alternative coupling beam designs, which include the use of diagonal reinforcement, rhombic arrangement of main bars and steel composites. Experimental results showed that each of these designs offered better performance than the conventional type but had its own limitations. A new embedded steel composite coupling beam design is therefore proposed. This paper presents the findings from the experimental tests of a coupling beam fabricated with this proposed design and a conventionally reinforced coupling beam, which serves as the reference. The preliminary test results showed that the embedded steel coupling beam with relatively large span-to-depth ratio ( l/h = 2.5) had excellent shear capacity (∼10MPa) and very good energy absorption.

scholarly journals Experimental and Numerical Investigation of Self Compacting Reinforced Concrete Dapped End Beams Strengthened with CFRP Sheets

2018 ◽  
Vol 26 (7) ◽  
pp. 16-35
Author(s):  
Qasim Mohammed Shakir ◽  
Baneen Basim Abd ◽  
Ali Talib Jasim
Keyword(s):  
Reinforced Concrete ◽  
Failure Load ◽  
Load Capacity ◽  
Experimental Tests ◽  
Experimental Program ◽  
Cfrp Sheets ◽  
Strut And Tie ◽  
Strut And Tie Model ◽  
Cracked Specimens ◽  
Good Agreement

This study aims to investigate experimentally the behavior of self-compacting reinforced concrete dapped end beams strengthened with CFRP sheets and, then theoretically by ANSYS 15.0 software. The experimental program consists of testing 14-specimens each of dimensions (200x400x1500 mm) with two values of Shear span to depth effective (a/d), namely (1.5 and 1.0). Two of the beams are a control beams (with full reinforcement), and four beams with reduced reinforcement in hanger and nib regions. The other beams have been strengthened with several configurations by CFRP sheets for the same values of (a/d), the comparison between results included load-deflection curves and cracked specimens. It was found that the strut and tie model (STM) is very conservative somehow, reduction the nib reinforcements by about (60%), in reduction in failure load by about (35% and 15%) for the two values of (a/d). With respect to the strengthened specimens, it observed that the strengthening with inclined CFRP strips (450) yielded better results in comparison with other configurations. The improvement in load capacity was about (23%) for (a/d=1.5 and 1.0). Also, it is found that the nonlinear model adopted in the present work compered the experimental tests yielded a good agreement with difference of about (12%).

scholarly journals Reinforced Concrete Corbel’s Behavior using Strut and Tie Model

2018 ◽  
Vol 4 (2) ◽  
pp. 97 ◽  
Author(s):  
Mutmainnah Rahman Putri ◽  
Djoko Sulistyo ◽  
Andreas Triwiyono
Keyword(s):  
Reinforced Concrete ◽  
Conventional Method ◽  
Shear Capacity ◽  
Public Works ◽  
Axial Loads ◽  
Strut And Tie ◽  
Compressive Strength Of Concrete ◽  
Monotonic Loads ◽  
Group 2 ◽  
Strut And Tie Model

Reinforced concrete (RC) corbel is one of a disturbed region of elements of the structure. SNI 2847: 2013 as a guideline from Ministry of Public Works provides the design of RC corbels by the conventional method and with Strut and Tie Model (STM). The aim of this study is to determine and compare the behaviors of corbels experimentally that designed with both methods. The testing was conducted on two series of specimens and each series consisted of two specimens. Group 1 was designed using conventional method while group 2 designed using Strut and Tie Model. The axial column was tested under 50 kN fixed axial loads and corbels was tested under monotonic loads gradually increased up to failure. The results showed that with the provided steel and compressive strength of concrete, the shear capacity using the conventional method by analysis and experimental respectively were 363.164 kN and 345.7 kN, while the shear capacity using Strut and Tie Model by analysis and experimental respectively were 306.953 kN and 299.35 kN. The shear capacity of specimens using conventional method was 13.40 % greater than by using Strut and Tie Model and the shear capacity for each conventional and STM method were 1.9232 and 1.6653 greater than designated load.

Shear-bearing capacity analysis under static force for shear key of the reinforced concrete open-web sandwich slab applied to long-span structure

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yu hui Fan ◽  
Pan pan Liu ◽  
Bo Shen ◽  
Kejian Ma ◽  
Bang Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Shear Capacity ◽  
Content Type ◽  
Benchmark Model ◽  
Shear Key ◽  
Strut And Tie ◽  
Long Span ◽  
Shear Bearing Capacity ◽  
Strut And Tie Model

PurposeThe reinforced concrete open-web sandwich slab is composed of upper rib, lower rib, surface plate and shear key and was applied to long-span structure crossing at 18–30 m. The shear-bearing capacity of shear key, having vital effects on the slab’s bearing capacity, is analysed to present its calculation formula used for the engineering application of the slab.Design/methodology/approachThe shear-bearing capacity of shear key is analysed by the strut-and-tie model and the benchmark model established by the finite element method. Furthermore, the design formula of its shear capacity is given by the parametric analysis of FEM to adjust the result of the strut-and-tie model, using multivariate linear regression analysis of these parameters.FindingsThe calculation result of the benchmark model is compared with those of the strut-and-tie model and the standard formula, which indicates that the result of the strut-and-tie model is closer to that of the benchmark model than that of the standard formula. Moreover, the parametric analysis of the finite element model indicates that the volume–stirrup ratio of the shear key and the compression strength of the concrete have lesser effect on the shear capacity compared with the longitudinal reinforcement ratio and the shear-to-span ratio of the shear key and the relative section height of the rib.Originality/valueThe shear capacity of the shear key is provided in the paper by combining the finite element method and the strut-and-tie model, which is different from the calculation of the shear key in local codes and Chinese code, based on the theory of short corbel and the experiment of member. Furthermore, the formula of the shear capacity could be employed in the design and construction of the RC open-web sandwich slab, mainly used in the public and industrial multi-story building with long span to save the dwindling land resource currently.

scholarly journals An Anchorage Technique for Shear Strengthening of RC T-Beams Using NSM-BFRP Bars and BFRP Sheet

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Hesham M. Diab ◽  
Ahmed M. Sayed
Keyword(s):  
Reinforced Concrete ◽  
Basalt Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Shear Strengthening ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Anchorage System ◽  
Near Surface Mounted

Abstract This study presents a detailed experimental program for reinforced concrete T-beams strengthened in shear with near-surface mounted (NSM) basalt fiber-reinforced polymer (BFRP) bars. This paper aims to introduce and evaluate a nonmechanical anchorage technique for shear strengthening using NSM-BFRP bars. T-beams were strengthened using manually manufactured closed or U-shaped hybrid BFRP stirrups (BFRP bars and BFRP sheets). The experimental program was developed to study the effects of these anchorage techniques. The results showed that the shear capacity increased by 8%–46% for beams strengthened with NSM-BFRP bars without anchorage. However, the presence of the proposed anchorage system increased the shear capacity of the strengthened beams by 39.6%–81.6%. Moreover, the maximum strains induced in the BFRP bars ranged from 27 to 59% of their ultimate strains according to the spacing between the NSM and the presence of the anchorage. The proposed anchorage technique prevented the premature debonding of the NSM-BFRP bars.

scholarly journals Design of deep pile caps by strut-and-tie models

2019 ◽  
Vol 12 (4) ◽  
pp. 832-857
Author(s):  
D. M. SANTOS ◽  
M. L. CARVALHO ◽  
F. R. STUCCHI
Keyword(s):  
Bearing Capacity ◽  
Classical Method ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Strut And Tie ◽  
Pile Cap ◽  
Pile Caps ◽  
Strut And Tie Model

Abstract There are many methods for designing pile caps, but there is still no consensus on which one provides the best approach for the practical engineers. In Brazil, many structural designers use the classical Blévot method; however, the applicability of the method has been questioned after the revision of the NBR 6118 standard for design of concrete structures in 2014. To support structural designers, a strut-and-tie model has recently been developed that relates the classical method to the most current concepts of strut-and-tie models. The theoretical bearing capacity of four-pile cap obtained through several strut-and-tie models are compared with experimental tests. The results show that this recently developed model is suitable for the design of deep pile cap.

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