scholarly journals Textile-Reinforced Mortar (TRM) Strengthened One-Way Reinforced Concrete Slabs

2021 ◽  
Vol 28 (2) ◽  
pp. 107-123
Author(s):  
Amenah Dheyab ◽  
Saad Raoof
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Loading Capacity ◽  
Flexural Capacity ◽  
Reinforced Concrete Slabs ◽  
Partial Cover ◽  
Ultimate Moment ◽  
Rc Slabs ◽  
Textile Reinforced Mortar ◽  
Good Agreement

The issue of upgrading and strengthening the reinforced concrete (RC) infrastructure has become of great importance. Recently, textile-reinforced mortar (TRM) was used in the field of structural strengthening. In the current study, using of TRM for flexural retrofitting of one-way reinforced concrete (RC) slabs was experimentally and theoretically investigated. The parameters examined included; the number of TRM layers (1, 3, 5 layers) and the strengthening configuration fully and partially). For this purpose, eight specimens were prepared and tested under three points- loading up to failure. The result showed that the TRM increases substantially the flexural capacity of RC slabs. The highest flexural capacity increase recorded was 103 %. It was also noted that increasing the number of retrofitting layers resulted in different increases in the flexural capacity. It was also shown that the strengthening configuration plays an important role in the effectiveness of the technique. The fully covered approach showed higher loading capacity than the partial cover technique provided that the same TRM layer is applied. Finally, the ultimate moment of the strengthened specimens was calculated theoretically and compared with that obtained experimentally. The results of calculations showed a good agreement between the theoretical and experimental results.

Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Crack ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Crack Theory ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

scholarly journals Analysis of Orthotropic RC Rectangular Slabs Supported on Two Adjacent Edges - A Simplistic Approach

2020 ◽  
Vol 6 (10) ◽  
pp. 1992-2001
Author(s):  
Sushant Gupta ◽  
Sanjeev Naval
Keyword(s):  
Mirror Image ◽  
Concrete Slabs ◽  
Collapse Mechanism ◽  
Uniform Load ◽  
Analysis And Design ◽  
Yield Line ◽  
Reinforced Concrete Slabs ◽  
Ultimate Moment ◽  
Rectangular Slab ◽  
Rc Slabs

The design of reinforced concrete slabs supported on two adjacent edges involves complex formulations. In this paper, a simplistic approach is presented for designing orthotropic slabs supported on two adjacent edges. Slab supported on two adjacent edges (existing slab) is transformed into a slab supported on three edges (equivalent slab) by taking a mirror image of the yield line pattern of two adjacent edges supported RC slabs about its unsupported edges to get the exact collapse mechanism for the slabs supported on three edges. The equivalent aspect ratio can be used in the equations already developed for the slabs supported on three sides. Ultimate moment carrying capacity of the slab carrying uniform load can be evaluated by using the available analytical formulations of the slab supported on three edges. So, the present approach gives a simplified method to analyse and design the orthotropic RC rectangular slab supported on two adjacent edges using the equations available for slab supported on three adjacent edges. Hence, the simplistic approach will be very helpful for structural designers dealing with analysis and design of slabs supported on two adjacent edges. Doi: 10.28991/cej-2020-03091598 Full Text: PDF

Computational Analysis of Punching Shear Models of Steel Fiber Reinforced Concrete Slabs

2020 ◽  
Vol 38 (2A) ◽  
pp. 126-142
Author(s):  
Mereen H. Fahmi Rasheed ◽  
Ayad Z. Saber Agha
Keyword(s):  
Reinforced Concrete ◽  
Computational Analysis ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Concrete Slabs ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Properties ◽  
Reinforced Concrete Slabs ◽  
Good Agreement

A computational analysis is presented to predict the ultimate and cracking shear strength of steel fiber reinforced concrete slabs. Different models are suggested considering the effect of concrete compressive and tensile strength, amount of flexural reinforcements, yield strength of the reinforcement bars and steel fiber properties (volume percent, aspect ratio, and type of steel fibers). The predicted results are compared with the experimental data found in literature and found good agreement.

scholarly journals Experimental study of solid RC slabs strengthened on the upper surface

2018 ◽  
Vol 11 (2) ◽  
pp. 255-278
Author(s):  
C. O. CAMPOS ◽  
L. M. TRAUTWEIN ◽  
R. B. GOMES ◽  
G. MELO
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Failure Load ◽  
Concrete Strength ◽  
Reinforcement Rate ◽  
Concrete Slabs ◽  
Minimum Reinforcement ◽  
Reinforced Concrete Slabs ◽  
Load Limit ◽  
Rc Slabs

Abstract The current study presents the results of tests conducted in 5 reinforced concrete slabs (415 cm x 415 cm x 7 cm) in order to experimentally check the possibility of reinforcing their upper surface, as well as to assess the adhesion between the old and the reinforcing concrete layers in the slab. The main variables were the concrete and reinforcement strength deficiencies. Reference slab “L1” was tested until reaching the failure load, whereas the others were tested until reaching certain load limit, reinforced and retested until reaching the failure load. All slabs failed under bending. The strengthening increased the failure load by 30% in slabs reinforced at minimum reinforcement rate when they were compared to similar non-reinforced slabs, regardless of the original concrete strength. None of the tests conducted in the reinforced slabs showed detachments or evidence of adhesion loss between the old and reinforcing concretes.

Behavior of Two-way RC Slabs Combination Strengthened with CFRP Strips and Steel Sheets

2014 ◽  
Vol 501-504 ◽  
pp. 1048-1052 ◽  
Author(s):  
Xiao Jin Li ◽  
Yi Yan Lu ◽  
Na Li
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Test Results ◽  
Reinforced Concrete Slab ◽  
Steel Sheets ◽  
Reinforced Concrete Slabs ◽  
Rc Slab ◽  
Rc Slabs ◽  
Strengthening Technique

A total of four two-way reinforced concrete slabs strengthened with three methods were tested. The four test specimens were one unstrengthened reinforced concrete slab (control), one slab strengthened with CFRP strips, one slab strengthened with steel sheets, and one slab strengthened with an innovative method of applying CFRP strips and steel sheets combination bonding to the tension face of the slab. The test results show the CFRP-Steel combination strengthened technique is a rapid and effective strengthening technique for two-way RC slab. The increase in ultimate capacities of CFRP-Steel combination strengthened slab is 221.1% over the control slab, 84.4% over the CFRP-strengthened slab, and 45.2% over the steel-strengthened slab. In addition, the CFRP-Steel combination strengthened slab exhibited superior ductility than the CFRP-strengthened slab.

scholarly journals Reinforced Concrete Slabs Strengthened with Carbon Textile Grid and Cementitious Grout

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5046
Author(s):  
Hyeong-Yeol Kim ◽  
Young-Jun You ◽  
Gum-Sung Ryu
Keyword(s):  
Plastic Deformation ◽  
Reinforced Concrete ◽  
Test Data ◽  
Concrete Slabs ◽  
Test Results ◽  
Structural Elements ◽  
Textile Reinforced Concrete ◽  
Rc Structures ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

A textile reinforced concrete (TRC) system has been widely used for repair and strengthening of deteriorated reinforced concrete (RC) structures. This paper proposes an accelerated on-site installation method of a TRC system by grouting to strengthen deteriorated RC structures. Four RC slabs were strengthened with one ply of carbon textile grid and 20 mm-thick cementitious grout. The TRC strengthened slab specimens were tested under flexure and the test results were compared with those of an unstrengthened specimen and theoretical solutions. Furthermore, the TRC strengthened specimens experienced longer plastic deformation after steel yield than the unstrengthened specimen. The TRC strengthened specimens exhibited many fine cracks and finally failed by rupture of the textile. Therefore, TRC system with the proposed installation method can effectively be used for strengthening of deteriorated RC structural elements. The theoretically computed steel yield and ultimate loads overestimate the test data by 11% and 5%, respectively.

Data Base for Punching Shear Strength of Reinforced Concrete Slabs and Evaluation for CCES Equation

2011 ◽  
Vol 90-93 ◽  
pp. 933-939 ◽  
Author(s):  
Qiu Ning Yang ◽  
Ming Jie Mao ◽  
Sumio Hamada
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Factors Affecting ◽  
Reinforced Concrete Slabs ◽  
Numerous Test ◽  
Rc Slabs

Several equations for punching shear strength of the reinforced concrete slab have been proposed in the world. These equations have their own factors affecting the strength. There are numerous test data for punching shear strength of RC slabs, which have been obtained by numerous researchers. A database with approximately 300 specimens has been structured through the present study. In the present study seven equations for punching shear strength are evaluated based on the database. CCES equation is also evaluated from the present database.

scholarly journals Reinforced Concrete Slabs Strengthened with Lap-Spliced Carbon TRC System

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3340
Author(s):  
Hyeong-Yeol Kim ◽  
Young-Jun You ◽  
Gum-Sung Ryu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Textile Reinforced Concrete ◽  
Lap Splice ◽  
Flexural Failure ◽  
Reinforced Concrete Slabs ◽  
Tensile Performance ◽  
Matrix Properties ◽  
Rc Slab ◽  
Rc Slabs

Construction with precast or prefabricated elements requires the connecting of structural joints. This study presents an accelerated construction method to strengthen reinforced concrete (RC) slab-type elements in flexure using precast lap-spliced textile-reinforced concrete (TRC) panels. The objectives of this study are to identify the tensile behavior of a TRC system with lap-spliced textile, and to experimentally validate the performance of the proposed connecting method by flexural failure test for the concrete slabs strengthened by TRC panels with lap-spliced textile. Twenty-one coupon specimens were tested in tension with two different matrix systems and three different lap splice lengths. The influence of the lap splice length and matrix properties on the tensile performance of the TRC system was significant. Five full-scale RC slabs were strengthened by the precast TRC panels with and without the lap splice, and was tested in flexure. The results of the failure test for the strengthened specimens showed that the ultimate load of the strengthened specimen with the TRC panel increased by a maximum of 24%, compared to that of the unstrengthened specimen. Moreover, the failure-tested specimens were re-strengthened by a new TRC panel system and tested again in flexure. The objective of the re-strengthening of the damaged RC slabs by the TRC panel is to investigate whether the yielded steel reinforcement can be replaced by the TRC panel. The initial cracking load and the stiffness of the re-strengthened specimens were significantly increased by re-strengthening.

scholarly journals Experimental and numerical studies on punching shear strength of concrete slabs containing sintered fly ash aggregates

2021 ◽  
Vol 20 (1) ◽  
pp. 15-25
Author(s):  
Ranjith Babu B. ◽  
◽  
Thenmozhi R ◽  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Constitutive Modelling ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs ◽  
Plate Connection ◽  
Ash Aggregates

This paper presents experimental and numerical investigations on M30 Grade of concrete containing 40% of sintered fly ash aggregates (SFAs) on the punching behaviour of reinforced concrete (RC) slabs. Two 1000 x 1000 x 100 mm reinforced concrete slabs were cast and subjected to punching tests. The experimental results were compared with creating a nonlinear finite element programme using ABAQUS. This 3D Finite element analyses were performed with the appropriate modelling of element size and the constitutive modelling of concrete. The material parameters of the damaged plasticity model in ABAQUS were calibrated based on the test results of slab – plate connection. The comparison between experimental and numerical results indicates that the calibrated model correctly predicts the punching shear response of the slabs. A modification of 0.4 is introduced in MC2010 code.

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