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.

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.

Relationship between Half-Cell Potentials and Load Carrying Capacity of Corroded Reinforced Concrete Beam-Column Joints

2013 ◽  
Vol 351-352 ◽  
pp. 939-944
Author(s):  
Ming Li ◽  
De Jian Shen ◽  
Jie Yang ◽  
Zheng Hua Cui
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Rc Beam ◽  
Load Carrying Capacity ◽  
Half Cell ◽  
Load Carrying ◽  
The Relationship

This paper aims at detailed investigation on the relationship between half-cell potentials and load carrying capacity of corroded RC beam-column joints. There are four specimens in the test with the corrosion rate to 0%, 3%, 9% and 15%. Results show that the potentials of normal joint are larger than that of corroded damaged joints. As the corrosion rate of joints increases, load carrying capacity and half-cell potentials decrease. Analytical method based on the values of half-cell potentials to evaluate the load carrying capacity of corroded joint is presented. Comparing the analytical and experimental results, the proposed method can predict the load carrying capacity of corroded reinforced concrete beam-column joints.

scholarly journals Flexural Behaviour Of Reinforced Concrete Beams Containing Expanded Glass As Lightweight Aggregates

2015 ◽  
Vol 23 (4) ◽  
pp. 1-7 ◽  
Author(s):  
Jamal Khatib ◽  
Adrian Jefimiuk ◽  
Sammy Khatib
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fine Aggregate ◽  
Load Carrying Capacity ◽  
Flexural Behaviour ◽  
Structural Concrete ◽  
Load Carrying

Abstract The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand) replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume) expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.

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.

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 Flexural Behavior of Damaged Lightweight Reinforced Concrete Beams Strengthened by CFRP

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Ali I. Salahaldin ◽  
◽  
Muyasser M. Jomaa’h ◽  
Dlovan M. Naser ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Load Carrying Capacity ◽  
Normal Concrete ◽  
Load Carrying

One of the most common methods of strengthening, rehabilitation, or repairing of structural lightweight concrete (LWC) elements is the external carbon fiber reinforced polymer (CFRP) strips. This paper presents an experimental study on the flexural behavior of reinforced concrete beams which comprise lightweight aggregate concrete, in different proportions, strengthened by CFRP sheets. The experimental program included six specimens with a 1500mm effective span. Two of the specimens were normal concrete beams. Another two samples were lightweight beams with a 50% aggregate replacement with pumice. The last two specimens were lightweight concrete beams with a 75% aggregate replacement with pumice. These beams were casted and tested twice under a two-point load application, once before strengthening and the other after that. The experimental results show that full strengthening of the beams along with their entire length, increase in load-carrying capacity by 75%, 113%, and 107% for normal concrete beam, (50% aggregate replacement) LWC beam, and (75% aggregate replacement) LWC beam respectively. While the middle-third strengthening of the beams shows an increase in load-carrying capacity by 64%, 72%, and 57% for normal concrete beam, (50% aggregate replacement) LWC aggregate beam, and (75% aggregate replacement) LWC beam respectively. The strength of the two types of LWC beams was almost the same and it is about 85% of the concrete beam with normal weight.

scholarly journals Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange

2018 ◽  
Vol 4 (7) ◽  
pp. 1595
Author(s):  
Nibras Abbas Harbi ◽  
Amer F. Izzet
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reference Beam ◽  
Effect Of Temperature ◽  
Load Carrying Capacity ◽  
Prestressed Concrete Beam ◽  
Load Carrying

The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high temperature flame of 300, 500, and 700°C, and the remaining beams were left without burning as reference specimens. Then, the burned beams were cooled gradually by leaving them at an ambient lab condition, after which the specimens were loaded until failure to study the effect of temperature on the residual beams serviceability, to determine the ultimate load-carrying capacity of each specimen in comparison with unburned reference beam, and to find the limit of the temperature for a full composite section to remain composite. It was found that the exposure to fire temperature increased the camber of composite beam at all periods of the burning and cooling cycle as well as the residual camber, along with reduction in beam stiffness and the modulus of elasticity of concrete in addition to decrease in the load-carrying capacity.

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