Response of Damaged Reinforced Concrete Beams Strengthened with NSM CFRP Strips

2020 ◽  
Vol 857 ◽  
pp. 3-9
Author(s):  
Marwa R. Gaber ◽  
Hayder A. Al-Baghdadi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Scale Model ◽  
Beam Specimen ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Near Surface ◽  
Cross Sectional Dimension ◽  
Load Carrying

This paper presents a study (experimentally) for strengthening reinforced concrete (RC) beams with Near-Surface-Mounted (NSM) technique. The use of this technique with CFRP strips or rebars is an efficient technology for increasing the strength for flexure and shear or for repairing damaged reinforced concrete (RC) members. The objective of this research is to study, experimentally, RC beams either repaired or strengthened with NSM CFRP strips and follow their flexural behavior and failure modes. NSM-CFRP strips were used to strengthen three RC beam specimens, one of them was initially strengthened and tested up to failure. Four beam specimens have been initially subjected to preloading to 50% and 80% of ultimate load. Two of the specimens were either repaired or strengthened with NSM-CFRP strips. All the repaired/strengthened pre-damaged beams have been tested up to failure by using compression-testing machine. An appropriate-scale model was adopted. All the specimens have a cross-sectional dimension of 150 mm with an effective span of 110 mm. Depends on the experimental results, a better performance of the strengthened concrete specimens was obtained in both strength and serviceability. As a comparison with the control beam specimen, all the repaired specimens show a very good increase of about 40% in the load-carrying capacity and a high improvement in resistance to cracking of about 120% in NSM. On the other hand, the test results of NSM CFRP-strengthened concrete specimens with a preloading of 50% and 80% of the ultimate load show an increase of about 9% to 20% in the load-carrying capacity, for 50% and 80% pre-loading, respectively an improvement in deflection of about 2% to 27% in NSM, for 80% and 50% pre-loading, respectively.

Numerical Analysis for Reinforced Concrete Beams with Circular Openings in Flexural and Shear Zones Strengthened by Steel Plates

2018 ◽  
Vol 23 (2) ◽  
pp. 31-48
Author(s):  
Ahmed Ali AL-Dhabyani ◽  
Abdulwahab AL-Ansi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Shear Zones ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Study Results ◽  
Load Carrying

In the modern building construction, openings in beams are necessary to accommodate several service pipes and ducts. Due to these openings, high stress concentration occurs at its edges. Local cracks also appear around the openings as a result of the reduction in the beam stiffness, the load carrying capacity and the shear capacity. There are many studies which were conducted to develop and test different strengthening methods for the beams opining to increase the ultimate load capacity of the beams. However, from a practical point of view, it is better to have one strengthening method having the same specifications to be used in both; shear and flexural zones for circular opining beams in buildings. In spite of the prior studies, no study has addressed this issue; therefore, there is a need to study such a case. In this paper, an analytical study was conducted to investigate the behavior of the reinforced concrete (RC) beams with circular openings in flexural and shear zones strengthened by steel plates. A 3D FE modeling (ABAQUS 6.12) software was used to simulate five different specimens of RC beams. The study results showed that when the openings were strengthened by steel plates, the ultimate load carrying capacity increased, but the deflection was decreased when compared to the openings without strengthening. In addition, the model reliability was verified via good agreements between the experimental and numerical results.

scholarly journals Experimental and Numerical Assessment of Reinforced Concrete Beams with Disturbed Depth

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
A. Hamoda ◽  
A. Basha ◽  
S. Fayed ◽  
K. Sennah
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Geometric Properties ◽  
Beam Shape ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

AbstractThis paper investigates numerically and experimentally the performance of reinforced concrete (RC) beam with unequal depths subjected to combined bending and shear. Such beams can geometrically be considered for unleveled reinforced concrete (RC) floor slab-beam system. However, it may generate critical disturbances in stress flow at the re-entrant corner (i.e. location of drop in beam depth). This research investigates the use of shear reinforcement and geometric properties to enhance cracking characteristics, yielding, ultimate load-carrying capacity, and exhibiting ductile failure mode. Ten reinforced concrete (RC) beams were constructed and tested experimentally considering the following key parameters: recess length, depth of smaller beam nib, and amount and layout of shear reinforcement at re-entrant corner. Finite element analysis (FEA) with material non-linearity was conducted in two RC beams that were tested experimentally to validate the computer modelling. The FEA models were then extended to conduct a parametric study to investigate the influence of geometric parameters (beam shape and width) and amount and arrangement of shear reinforcement on the structural response. Results confirmed that geometric properties and ratio of shear reinforcement at the re-entrant region significantly affect the behavior of reinforced concrete beam with unequal depths in terms of first cracking, yielding level, ultimate load carrying capacity and mode of failure.

scholarly journals Investigation on Retrofitting of Reinforced Concrete Beam with Glass Fiber and Banana Fiber Mat

2021 ◽  
Keyword(s):  
Reinforced Concrete ◽  
Glass Fiber ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Ultimate Load ◽  
Initial Crack ◽  
Beam Specimen ◽  
Load Carrying Capacity ◽  
Banana Fiber ◽  
Load Carrying

Abstract. Concrete is the predominant material in the construction industry. To be sustainable, the old Reinforced Concrete (RC) buildings should be retrofitted, and the life of the building should be extended. Experimental study has been attempted to investigate the load carrying capacity of concrete beam strengthened with glass fiber and banana fiber mat. The primary aim of this study is to retrofit the RC beam specimen to enhance the load carrying capacity. All the beams were casted with the same grade of concrete (M30) and same structural detailing. Two-point symmetrical loading were given to the control beams to obtain load at initial crack and ultimate load. Then the beams other than control beams were loaded till it showes initial crack and then retrofitted with banana fiber and glass fiber bonded externally with resin. The retrofitted beams were tested for ultimate load performance. Load carrying capacity was higher for both retrofitting but the beam retrofitter with glass fiber showed significant improvement in the ultimate load carrying capacity.

scholarly journals Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
N. Aravind ◽  
Amiya K. Samanta ◽  
Dilip Kr. Singha Roy ◽  
Joseph V. Thanikal
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Fiber Reinforced Polymer ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Glass Fiber Reinforced Polymer ◽  
Flexural Strengthening ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Carrying

AbstractStrengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

scholarly journals Effect of Interfacial Debonding on the Strength of Composite Structure-Similarity Scale Model for the Wing-Box

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Shiyong Sun ◽  
Rui Yang ◽  
Zibin Yan ◽  
Wei Qian
Keyword(s):  
Carrying Capacity ◽  
Bonding Strength ◽  
Ultimate Load ◽  
Scale Model ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Box Structure ◽  
Ultimate Load Carrying Capacity ◽  
Composite Wing ◽  
Wing Box

Based on the wing-box structure, a model was established to analyze the strength of the scale model for the composite wing. Firstly, different failure criteria were set to determine damage onset of the components. The continuum damage variables were adopted in the stiffness degradation rule. Secondly, the interface elements were placed along the interface between the beam flange and the skin to investigate the effects of bonding strength on the ultimate load-carrying capacity of the wing-box. The failure modes of the wing-box structure were studied by using the nonlinear finite element method. The effect of flange’s width on the strength of wing-box was discussed based on the prediction method. The results indicated that the ultimate load-carrying capacity varied distinctly with the change of flange’s width. However, the bonding strength had limited effect on the model strength as the flange’s width increases to the critical value. The research methods and results of the study can serve as reference for the strength analysis on the scale model of composite wing as well as the determination of principles adopted in the design of the scale model for wing spar.

scholarly journals A Detailed Experimental Study on The Flexural Behaviour of Concrete Filled Steel Tube Beams

2018 ◽  
pp. 196-203
Author(s):  
Shaik Heena ◽  
Syed Rizwan ◽  
A.B.S. Dadapeer
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Steel Tube ◽  
Deformation Capacity ◽  
Load Carrying Capacity ◽  
Shear Connector ◽  
Steel Tubes ◽  
Load Carrying ◽  
Concrete Filled Steel Tubes

Concrete filled steel tubes (CFST) member have many advantages compared with the ordinary structural member made of steel or reinforced concrete. One of the main advantages is the interaction between the steel tube and concrete. Concrete delays the steel tube’s local buckling, whereas the steel tube confines the concrete and thereby increases the concrete’s strength. CFSTs are economical and permit rapid construction because the steel tube serves as formwork and reinforcement to the concrete fill, negating the need for either. The deformation capacity of the system is increased by the combined action of the concrete fill with the thin, ductile steel tube. The concrete fill significantly increases inelastic deformation capacity and the compressive stiffness and load capacity of the CFST member. In building construction concrete filled steel tubes are very widely used for columns in combination with steel or reinforced concrete beam. In this work totally 9 specimens were tested out of which 3 specimens were empty steel tubes and remaining 6 specimens were concrete filled with different bonding techniques. As it is prefabricated time consumption will be less in construction practice and due to confinement more ductility is expected which is very useful in earthquake resistant structures. Load carrying capacity of CFST almost doubled in comparison with empty steel tubes. Ultimate load carrying capacity of concrete filled steel tube beams almost doubled compared to empty steel tubes. Compared to empty steel tubes, strength increase of 67.19%, 97.48% and 114.84% was observed in normal CFST, CFST with sand blasting and CFST with diagonal shear connector beams respectively. Average ultimate load of EST was 105.66kN whereas average load of CFSTB, CFSTBWSB and CFSTBWDSC was 176.66, 208.66 and 227kN respectively. The maximum load was taken by the specimen CFSTBWDSC – 03 which was 231kN, it may be because of presence of diagonal shear connector inside the tube.

EFFECTS OF WEB OPENINGS ON SHEAR BEHAVIOUR OF NORMAL AND INTERNALLY STRENGTHENED CONCRETE BEAMS

2021 ◽  
Author(s):  
Burhan Ahmad ◽  
Muhammad Yousaf ◽  
Muhammad Irfan-ul-Hassan ◽  
Muhammad Burhan Sharif ◽  
Zahid Ahmed Siddiqi ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Shear Zones ◽  
Shear Behaviour ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Web Openings ◽  
Load Carrying

Web openings in reinforced concrete (RC) beams are provided to pass utility pipes and ducts through them. This causes high stresses (with local cracking) around the transverse web openings, which may lead to reduction in ultimate strength and stiffness of RC beams. Internal strengthening with shear reinforcement can increase ultimate strength of the beam with web openings. This paper presents an experimental study which was conducted to investigate load carrying capacity, mid-span deflection and failure modes of beams with web openings. A total of eighteen RC beams were included in the testing programme, which were tested under two-point loading. The beams contained both pre-planned and post-planned web openings. Experimental results showed that ultimate load of the beams decreased from forty-two to sixty-seven percent due to the presence of web openings in the shear zones. Shear strength of the beams with pre-planned web openings increased by thirty-six percent and one-hundred two percent as compared to the reference beam due to the increase of shear reinforcement by one-hundred twenty-two percent and three-hundred three percent, respectively. Similarly, increase in shear capacity up to six percent and fourteen percent was found for the beams with post-planned web openings due to the aforementioned increase in the area of shear reinforcement, respectively. The ultimate load carrying capacity was also compared with the theoretical models. Internal strengthening and pre planned opening were found effective for providing web openings in the beams.

Flexural Performance of Reinforced Concrete Built-up Beams with SIFCON

2020 ◽  
Vol 38 (5A) ◽  
pp. 669-680
Author(s):  
Ghazwan K. Mohammed ◽  
Kaiss F. Sarsam ◽  
Ikbal N. Gorgis
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Conventional Concrete ◽  
Flexural Performance ◽  
Load Carrying ◽  
Fiber Concrete

The study deals with the effect of using Slurry infiltrated fiber concrete (SIFCON) with the reinforced concrete beams to explore its enhancement to the flexural capacity. The experimental work consists of the casting of six beams, two beams were fully cast by conventional concrete (CC) and SIFCON, as references. While the remaining was made by contributing a layer of SIFCON diverse in-depth and position, towards complete the overall depths of the built-up beam with conventional concrete CC. Also, an investigation was done through the control specimens testing about the mechanical properties of SIFCON. The results showed a stiffer behavior with a significant increase in load-carrying capacity when SIFCON used in tension zones. Otherwise high ductility and energy dissipation appeared when SIFCON placed in compression zones with a slight increment in ultimate load. The high volumetric ratio of steel fibers enabled SIFCON to magnificent tensile properties.

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