scholarly journals Review on NSM CFRP Strengthened RC Concrete Beams in Shear

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Majid M. A. Kadhim ◽  
Mohammed J. Altaee ◽  
Ali Hadi Adheem ◽  
Ali Chabuk ◽  
Nadhir Al-Ansari
Keyword(s):  
Concrete Beams ◽  
Concrete Structures ◽  
Experimental Results ◽  
Combined Effects ◽  
Research Topics ◽  
Existing Structures ◽  
Previous Review ◽  
Attractive Option ◽  
Frp Reinforcement ◽  
Frp Bars

The use of NSM FRP strengthening of concrete structures has become an attractive option to retrofit the existing structures against shear and flexure. This paper reviews only the utilization of NSM for shear in previous review articles. A database of tests of NSM strengthened beams in shear is presented to evaluate the existing design formulations of calculating the NSM contribution in shear. These formulations were in agreement with the experimental results in the database. Further research topics are also identified such as the shape of NSM FRP bars, combined effects of existing steel stirrups, and NSM FRP reinforcement and analytical formulations.

scholarly journals Nonlinear Analysis of Compressed Concrete Elements Reinforced with FRP Bars

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4410
Author(s):  
Małgorzata Wydra ◽  
Maria Włodarczyk ◽  
Jadwiga Fangrat
Keyword(s):  
Reinforced Concrete ◽  
Fem Analysis ◽  
Negative Influence ◽  
Experimental Results ◽  
Nonlinear Fem ◽  
Steel Reinforced Concrete ◽  
Failure Loads ◽  
Frp Reinforcement ◽  
Concrete Elements ◽  
Frp Bars

Although fiber reinforced polymer (FRP) bars have proved their usefulness in the case of reinforced concrete flexural elements, there are still limited data on their performance in such structures under compression. Despite multiple benefits of using FRP bars as the reinforcement in concrete elements, their potential application as main reinforcement in compressed elements is still very controversial, mainly due to the limited amount of published research results. The presented work partly fulfills this knowledge gap. Two series of theoretical analyses—one based on the stress distribution in the cross-section and the second using the finite elements method (FEM)—with reference to the experimental results are presented. The analyses concern basalt FRP, glass FRP, and steel-reinforced concrete elements under axial compression. There are derived calculations of load–displacement relations and stress values in bars. Damage progression was analyzed as well. Main findings are as follows: (1) a good agreement between calculated failure loads and experimental results has been achieved; (2) potential negative influence of FRP reinforcement on the compressive capacity of the reinforced element should not be neglected; (3) nonlinear FEM analysis is useful in predicting the maximum value of load and damage zones; (4) stress values of only about 100 MPa (much lower than their compressive strength value) were obtained in non-metallic bars. The results might be useful for the further establishment of design rules.

Deflection and Crack-Width Prediction of Partially Boned CFRP Concrete Beams

2010 ◽  
Vol 168-170 ◽  
pp. 2182-2185
Author(s):  
Yu Deng ◽  
Jiong Feng Liang
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Experimental Results ◽  
Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Low Modulus ◽  
Monotonic Loads ◽  
Frp Bars ◽  
Unbonded Length ◽  
Good Agreement

Concrete beams reinforced with fiber reinforced polymer(FRP)bars exhibit large deflections and crack widths as compared to concrete beams reinforced with steel due to the low modulus of elasticity of FRP. Consequently,in many cases,serviceability requirements may govern the design of such members. This paper describes six partial bonded concrete beams prestressed with CFRP tendons are tested under monotonic loads. deformation and crack width of this kind of beams with varying unbonded length are systematically investigated. The predictions of the 《Code for Design of Concrete Structures》（GB50010－2002）equations are compared with the experimental results obtained by testing six partial bonded concrete beams prestressed with CFRP tendons. Good agreement was shown between the theoretical and the experimental results.

scholarly journals Reinforced Concrete Beams with Carbon-Fiber-Reinforced Polymer Bars—Experimental Study

Fibers ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 99 ◽  
Author(s):  
Chris G. Karayannis ◽  
Parthena-Maria K. Kosmidou ◽  
Constantin E. Chalioris
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cracking Behavior ◽  
Reinforced Polymer ◽  
Frp Bars

Innovative reinforcement as fiber-reinforced polymer (FRP) bars has been proposed as alternative for the substitution of the traditional steel bars in reinforced concrete (RC) structures. Although the advantages of this polymer reinforcement have long been recognised, the predominantly elastic response, the reduced bond capacity under repeated load and the low ductility of RC members with FRP bars restricted its wide application in construction so far. In this work, the behavior of seven slender concrete beams reinforced with carbon-FRP bars under increasing static loading is experimentally investigated. Load capacities, deflections, pre-cracking and after-cracking stiffness, sudden local drops of strength, failure modes, and cracking propagation have been presented and commented. Special attention has been given in the bond conditions of the anchorage lengths of the tensile carbon-FRP bars. The application of local confinement conditions along the anchorage lengths of the carbon-FRP bars in some specimens seems to influence their cracking behavior. Nevertheless, more research is required in this direction. Comparisons of experimental results for carbon-FRP beams with beams reinforced with glass-FRP bars extracted from recent literature are also presented and commented. Comparisons of the experimental results with the predictions according to ACI 440.1R-15 and to CSA S806-12 are also included herein.

Flexural behavior of partially fiber-reinforced high-strength concrete beams reinforced with FRP bars

2018 ◽  
Vol 161 ◽  
pp. 587-597 ◽  
Author(s):  
Haitang Zhu ◽  
Shengzhao Cheng ◽  
Danying Gao ◽  
Sheikh M. Neaz ◽  
Chuanchuan Li
Keyword(s):  
High Strength Concrete ◽  
Concrete Beams ◽  
High Strength ◽  
Flexural Behavior ◽  
Fiber Reinforced ◽  
Strength Concrete ◽  
Frp Bars

Flexural performance of reinforced concrete beams made by innovative post-filling coarse aggregate process

2021 ◽  
pp. 136943322110093
Author(s):  
Jinqing Jia ◽  
Qi Cao ◽  
Lihua Zhang ◽  
Jiayu Zhou
Keyword(s):  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Filling Ratio ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Aggregate Concrete ◽  
Flexural Performance ◽  
Peak Value

Concrete made by post-filling coarse aggregate process could reduce the cement content greatly compared with traditional concrete placement method. Thus, it not only lowers the production cost of concrete through lower usage of cement but also reduces the CO2 emissions to the environment. In this paper, the compressive and tensile strength of post-filling coarse aggregate concrete with different post-filling ratios (PFRs) (0%, 10%, 15%, 20%, 25%, 30%) and concrete strength grades (C30, C40, C50) were first studied. Then the flexural performance of nineteen concrete beams with different concrete strength, post-filling ratios, reinforcement ratios was investigated. The experimental results showed that the compressive strength and elastic modulus of the post-filling coarse aggregate concrete increased with the increase of the post-filling ratio of coarse aggregate, reaching the peak value at the filling ratio of 20%. It indicated that there was no obvious difference in the failure mode as well as middle-span deflections between post-filling coarse aggregate concrete (PFCC) beams and ordinary concrete (OC) beams. Ductile failure was observed for all nineteen specimens. Results demonstrated that the cracking load, yield load, and ultimate load of the post-filling coarse aggregate concrete beams all reached the peak value at the post-filling ratio of 20%. In addition, the theoretical predictions of cracking loads and ultimate load carrying capacities matched the experimental results in satisfactory agreement.

Development of FRP Reinforcement Guidelines for Prestressed Concrete Structures

1997 ◽  
Vol 1 (4) ◽  
pp. 131-139 ◽  
Author(s):  
Jeremy M. Gilstrap ◽  
Chad R. Burke ◽  
Daniel M. Dowden ◽  
Charles W. Dolan
Keyword(s):  
Prestressed Concrete ◽  
Concrete Structures ◽  
Frp Reinforcement

Anchorages of stirrups under transverse tension in concrete - development of a design model

2019 ◽  
Author(s):  
Mirhat Medziti ◽  
Daia Zwicky
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Tensile Force ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Reinforced Concrete Beams ◽  
Design Model ◽  
Hook Effect ◽  
Internal Forces ◽  
Negative Bending

<p>According to Swiss code SIA 262 "Concrete structures", stirrups of reinforced concrete beams must "surround the tensile longitudinal reinforcement" and must "be anchored to mobilize the static height of internal forces". For existing concrete structures, Swiss code SIA 269/2 provides stirrup detailing requirements while limiting these directives for stirrup anchorage to the compression zone. In zones of negative bending, these requirements are often not satisfied for execution reasons. This question is addressed in a largely experimental Ra&amp;D project. Anchorage tests were performed and analyzed, with a total of 144 tests on 9 concrete beams. These underwent a longitudinal tensile force up to 1’000 kN to simulate transverse cracking at stirrup anchorages in negative flexure zones. The study parameters are crack width (0, 0.4 and 0.9 mm), stirrup diameter (10 and 14 mm), bar ribbing (smooth and ribbed) and hook angle (90°, 135°, 180° and straight bars). A design model based on the "tension chord model" (TCM) developed at ETH Zurich is proposed. This simple and practical design model has proved ist effectiveness to consider bond effects. Reduction factors for bar diameter (k<sub>Ø</sub>), relative bar ribbing (k<sub>fR</sub>), hook effect (k<sub>θ</sub>) and crack width (k<sub>w</sub>) were taken into account for calibration. Results of analytical calculations are coherent with experimental tests.</p>

scholarly journals A study on the behavior of beam-column connections in precast concrete structures: experimental analysis

2012 ◽  
Vol 5 (6) ◽  
pp. 848-873 ◽  
Author(s):  
M. N. Kataoka ◽  
M. A. Ferreira ◽  
A. L. H. C. El Debs
Keyword(s):  
Experimental Analysis ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Experimental Results ◽  
Hollow Core ◽  
Multistory Buildings ◽  
Cracking Control ◽  
Hollow Core Slab ◽  
Reinforcement Distribution

Due to the large increase in the use of precast concrete structures in multistory buildings, this work covers a study on the behavior of beam-column connection with emphasis on the continuity provided by the slab reinforcement. Two prototypes were tested, each one with a different detail of the continuity reinforcement distribution. In both connections, the steel area used on the concrete cover of the hollow core slab was the same, varying the amount of bars that passed through the column and the ones that were placed adjacent to the column. The experimental results showed that the connection with bars adjacent to the column presented stiffness increase and a better cracking control. According to the classification the two tested connections can be considered semi-rigid.

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