scholarly journals Flexural Behaviour of RC beams using GFRP Composites

2018 ◽  
Vol 7 (3.12) ◽  
pp. 744
Author(s):  
S Sivasankar ◽  
T Bharathy ◽  
R Vinodh Kumar
Keyword(s):  
Minimum Cost ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Gfrp Composites ◽  
Flexural Behaviour ◽  
Rc Structures ◽  
Strain Behaviour ◽  
Load Carrying ◽  
Long Time ◽  
Ultimate Load Carrying Capacity

Reinforced Concrete (RC) structures damaged by sudden accidental loads due to earthquake and severe environmental exposure. Traditional strengthening methods are not meeting the service life of the structure for long time. Recently, FRP strengthening is used successfully in all kind of exposure with minimum cost and less duration. In this paper RC beams were strengthened by GFRP sheets in two different orientations. Two specimens are control beams, two specimens are wrapped with U wrapping and the remaining beams are bottom wrapping. The size of the beam is 1700mm long, 150mm  wide and 250mm depth. The test specimens consit of 2 nos of 10mm dia rods as longitudinal reinforcement in compression zone and 2 nos of 10mm dia steel rods in tension zone. 2-legged stirrups of 8mm diameter were used with a centre-to-centre spcaing of 150mm. All beams were tested under four-point loading. Experiments will be undertaken until beams fails so that the influence of GFRP characteristics on the Flexural behaviour of beams which includes Flexural behaviour, Ultimate load carrying capacity, Deformation and Stress-strain behaviour. Evaluation of the results will lead to optimum GFRP jacketing /wrapping arrangements for the concrete beams are considered here. 

scholarly journals Studies on stress-strain behaviour of concrete mixes confined with BFRP rebars

2021 ◽  
Vol 309 ◽  
pp. 01049
Author(s):  
K Ajay Kumar ◽  
A Venkat Sai Krishna ◽  
S Shrihari ◽  
V Srinivasa Reddy
Keyword(s):  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Basalt Fibre ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Strain Behaviour ◽  
Load Carrying ◽  
Fibre Reinforced Polymer ◽  
Ultimate Load Carrying Capacity ◽  
Steel Rebars

In the present study, the stress-stain behaviour of confined concrete made with basalt fibre reinforced polymer bars (BFRP) were taken up. The stress-strain behaviour was studied for the concrete mixes confined with steel rebars and BFRP rebars. The confinement was given in the form of steel hoops in the cylinders, 3 hoops (0.8%), 4 hoops (1.1%), 5 hoops (1.3%) and 6 hoops (1.6%). The addition of basalt fibres along with confinement of concrete with steel and BFRP hoops enhanced the compressive strength, indicating further confinement effect in the concrete. It is observed that the addition of fibres is helpful in lower confinements only. Beyond 1.1% confinement, the addition of any type of basalt fibres doesn’t show any effect on compressive strengths. From the stress-strain behaviour of all types of concrete mixes, it is concluded that the ultimate load-carrying capacity and strains at peak stresses are more in concrete with BFRP hoops for mixes up to 1.1% confinement. The addition of basalt fibres to concrete has increased the ductility in both confined and unconfined states

scholarly journals Studies on stress- strain behaviour of fibre reinforced self-compacting concrete in confined state

2021 ◽  
Vol 309 ◽  
pp. 01054
Author(s):  
Gorla Jayasri ◽  
V Siva Prasad Raju ◽  
V Srinivasa Reddy ◽  
M Mounika
Keyword(s):  
Compressive Strength ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Confinement Effect ◽  
Load Carrying Capacity ◽  
Self Compacting Concrete ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

In the present study, the stress-stain behaviour of self-compacting concrete (SCC) and fibre reinforced self-compacting concrete (FRSCC) were taken up. The stress-strain behaviour was studied for the SCC and FRSCC mixes in unconfined and confined states. The confinement was given in the form of steel hoops in the cylinders, 3 hoops (0.8%), 4 hoops (1.1%), 5 hoops (1.3%) and 6 hoops (1.6%). The addition of fibres along with confinement of FRSCC with steel hoops enhanced the compressive strength, indicating further confinement effect in the FRSCC. It is observed that the addition of fibres is helpful in lower confinements only. Beyond 1.1% confinement, the addition of any type of fibres doesn’t show any effect on compressive strengths. From the stress-strain behaviour of all types of FRSCC, it is concluded that the ultimate load-carrying capacity and strains at peak stresses are more in SFRSCC and HFRSCC for mixes up to 1.1% confinement. The addition of fibres to SCC has increased the ductility in both confined and unconfined states

scholarly journals Stress - strain behaviour of confined nano silica-based concrete

2021 ◽  
Vol 309 ◽  
pp. 01048
Author(s):  
Kakara S J Kumar ◽  
M V Seshagiri Rao ◽  
V Srinivasa Reddy ◽  
S Shrihari
Keyword(s):  
Carrying Capacity ◽  
Ultimate Load ◽  
Confined Concrete ◽  
Load Carrying Capacity ◽  
Nano Silica ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity ◽  
Steel Rebars

In the present study, the stress-stain behaviour of confined concrete made with nano-silica (nano-SiO2) were taken up. The stress-strain behaviour was studied for the M30 and M50 grades nano-silica (nano-SiO2) concrete mixes confined with steel rebars. The confinement was given in the form of steel hoops in the cylinders, 3 hoops (0.8%), 4 hoops (1.1%), 5 hoops (1.3%) and 6 hoops (1.6%). The addition of nano-silica (nano-SiO2) along with confinement of concrete with steel hoops enhanced the compressive strength, indicating further confinement effect in the concrete. It is observed that the addition of nano-silica (nano-SiO2) is helpful in lower confinements only. Beyond 1.1% confinement, doesn’t show any effect on compressive strengths. From the stress-strain behaviour of all types of concrete mixes, it is concluded that the ultimate load-carrying capacity and strains at peak stresses are more in nano-silica (nano-SiO2) concrete with steel hoops for mixes up to 1.1% confinement. The addition of nano-silica (nano-SiO2) to concrete has increased the ductility in both confined and unconfined states

scholarly journals Experimental Study on RC Beams Using High Volume Fly Ash

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
R. Thangaraj ◽  
R. Thenmozhi
Keyword(s):  
Fly Ash ◽  
Carrying Capacity ◽  
Carbon Dioxide Emissions ◽  
High Volume ◽  
Load Carrying Capacity ◽  
Environmental Friendliness ◽  
Rc Structures ◽  
High Volume Fly Ash ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

The aim of this paper is to examine the flexural behaviour of structural beams made of high volume fly ash (HVFA) concrete with confined stirrups introduced in compression regions.Generally concrete is low tensile strength and poor ductile property. By confining compression regions introduced with closed stirrups which improves the ductility and load carrying capacity of beams. The introduction of stirrups to these regions would suppress the development of tensile stresses.Fly ash (FA) has been used in concrete and identified such a product as Eco smart or green concrete. In earth quake regions it becomes essential to construct the structures as a ductile one. Sudden failures due to poor workability of RC structures can be avoided, if critical sections are able to undergo large plastic deformations and to absorb large amount of strain energy.The results indicated that the confinement in the form of stirrups improves the ultimate strength and ductile behaviour of the concrete. It has been suggested that, the effective use of fly ash minimizes the disposal of fly ash , this HVFA concrete is easy to pump, consolidate and finish the surface, free from cracks, reduces carbon-dioxide emissions, superior environmental friendliness, reduction in stone mining since consumes less volume of Portland cement. The methodology adopted above which improves ductility, thus improving the ultimate load carrying capacity.

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 Behaviour of RC Beams with a Circular Opening at the Flexural Zone and Shear Zone Strengthened Using Steel Plates

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
J. Branesh Robert ◽  
R. Angeline Prabhavathy ◽  
P. S. Joanna ◽  
S. Christopher Ezhil Singh ◽  
Sivaraj Murugan ◽  
...  
Keyword(s):  
Shear Zone ◽  
Carrying Capacity ◽  
Steel Plate ◽  
Steel Plates ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Circular Opening ◽  
Control Beam ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

In this paper, an investigation on the behaviour of RC beams with circular openings in the flexural zone and shear zone strengthened using steel plates is presented. Totally seven beams were cast: a control beam, one beam with a circular opening of size of one-third the depth of the beam (100 mmϕ) in the flexural zone, one beam with opening strengthened using the steel plate, one beam with a circular opening of size of 100 mmϕ in the shear zone, one beam with an opening in the shear zone strengthened using the steel plate, one beam with two circular openings of size of 100 mmϕ in the shear zone, and another beam with two openings in the shear zone strengthened using the steel plate. The experiments were conducted in a loading frame of 400 kN capacity. The beams were subjected to two-point loading. The ultimate load carrying capacity reduced marginally by 1.78% and 2.8% compared to that of the control beam when a circular opening of 100 mmϕ was provided in the flexural zone and shear zone, respectively, and when the opening was strengthened with steel plates, it reduced by 3.04% and 25%, respectively, but the ductility increased when steel plates were provided. Beams with an opening of size of one-third the depth of the beam (100 mmϕ) in the flexural zone strengthened with the steel plate can be provided, as the load carrying capacity is only marginally reduced compared to the control beam, and the ductility is more when compared with beams with unstrengthened openings.

scholarly journals Strengthening of Reinforced Concrete Beams Weak in Shear Using GFRP

2018 ◽  
Vol 7 (2.20) ◽  
pp. 306
Author(s):  
Qudhan Shaik ◽  
P Polu Raju
Keyword(s):  
Carrying Capacity ◽  
Shear Behavior ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Existing Structures ◽  
Load Carrying ◽  
Lateral Strength ◽  
Ultimate Load Carrying Capacity

Due to lateral forces acting on the structure, stresses are generated in the beam which causes beam failure. To overcome those stresses in the existing structures, retrofitting is one of the techniques to increase the lateral strength. In this study, an experimental investigation was done on RC beams to check the shear behavior by comparing control RC beams with strengthened RC beams. To observe the shear behavior considered RC Beams were made weak in shear and then Retrofitted. Two sets of beams were considered, out of which, set-1 consists of three control specimens with shear reinforcement of 100%, 50%, and 30%. Set-2 consists of three retrofitted specimens with GFRP Strips with shear reinforcement of 100%, 50%, and 30%. GFRP strips were provided around the beam with different spacing. The results concluded that the retrofitted specimens have more load carrying capacity compared to control specimens. Thus, the retrofitting is a feasible solution to overcome the stresses developed in the structure. The study also involves the behavior of shear having several GFRP layers and orientation of ultimate load carrying capacity, failure mode and crack pattern of the beam are also investigated.  

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

2021 ◽  
Vol 16 ◽  
pp. 155892502110203
Author(s):  
Mohammad Iqbal Khan ◽  
Galal Fares ◽  
Yassir Mohammed Abbas ◽  
Wasim Abbass ◽  
Sardar Umer Sial
Keyword(s):  
Strain Hardening ◽  
Environmental Conditions ◽  
Carrying Capacity ◽  
Flexural Behavior ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Curing Conditions ◽  
Flexural Members ◽  
Load Carrying ◽  
Curing Regime

Strain-hardening cement-based composites (SHCC) have recently been developed as repair materials for the improvement of crack control and strength of flexural members. This work focuses on strengthening and flexural enhancement using SHCC layer in tensile regions of flexural members under three different curing conditions. The curing conditions simulate the effect of different environmental conditions prevailing in the central and coastal regions of the Arabian Peninsula on the properties of SHCC as a retrofitting material. In this investigation, beams with SHCC layer were compared to control beams. The beams with SHCC layer of 50-mm thickness were cast. The results revealed that the flexural behavior and the load-carrying capacity of the normal concrete beam specimens under hot and dry environmental conditions were significantly reduced, lowering the ductility of the section. However, compressive strength is comparatively unaffected. Similarly, the hot curing conditions have also led to a notable reduction in the loading capacity of the beam with SHCC layer with a slight effect on its stiffness. On the other hand, steam-curing conditions have shown improvement in load-carrying capacity and a reduction in section ductility of the beam with SHCC layer. It was found that the structural unit retrofitted with SHCC layer was a curing-regime dependent as the tensile and strain-hardening properties of SHCC are highly sensitive to the alteration in the cement hydration process. A normal curing regime was found effective and satisfying the practical, cost, and performance requirements. Accordingly, a normal curing regime could be implemented to retrofit reinforced concrete (RC) beams with SHCC layers as recommended in the study.

scholarly journals Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3468
Author(s):  
Zbigniew Kolakowski ◽  
Andrzej Teter
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Equilibrium Path ◽  
Load Carrying Capacity ◽  
Nonlinear Buckling ◽  
Elastic Range ◽  
Load Carrying ◽  
Thin Walled ◽  
Ultimate Load Carrying Capacity

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.

Flexural strengthening of pre-cracked RC slabs with prestressed NSM CFRP laminates and evaluation of strain loss

2021 ◽  
pp. 136943322110105
Author(s):  
M.R. Mostakhdemin Hosseini ◽  
Salvador J.E. Dias ◽  
Joaquim A.O. Barros
Keyword(s):  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Transfer Length ◽  
Rc Structures ◽  
Cracked Concrete ◽  
Flexural Strengthening ◽  
Cfrp Laminates ◽  
Load Carrying ◽  
Rc Slabs

The strengthening intervention of RC structures often involves already cracked concrete. To evaluate the effect of the level of damage prior to the strengthening (pre-cracks) on the behavior of the flexurally strengthened RC slabs with prestressed NSM CFRP laminates, an experimental research was carried out. Two pre-cracking levels of damage were analyzed and, for each one, three levels of prestress were tested (0%, 20% and 40%). The obtained results showed that the strengthening of damaged RC slabs with prestressed NSM CFRP laminates results in a significant increase on the load carrying capacity at serviceability limit states. Pre-cracked RC slabs strengthened with prestressed NSM CFRP laminates presented a load carrying capacity almost similar to the corresponding uncracked strengthened slabs. To determine the effective prestress level in CFRP laminates, the variation of strain over the length of the CFRP and over time was experimentally recorded. The prestress transfer length was also evaluated. The experimental results revealed that the transfer length of CFRP laminates was less than 150 mm, and the maximum value of strain loss out of transfer length (around 14%) was measured close to the cracked section of the damaged RC slabs. Significant part of strain loss in CFRP laminates occurred during 24 h after releasing the prestress load.

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