scholarly journals Evaluation of Effective Polymer Fiber Length on Energy Absorption Capacity of Reinforced Beams by EBR and NSM Methods

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Komeyl Karimi-Moridani
Keyword(s):  
Energy Absorption ◽  
Crack Nucleation ◽  
Absorption Capacity ◽  
Rc Beams ◽  
Energy Absorption Capacity ◽  
Near Surface ◽  
Cfrp Sheets ◽  
Reinforced Beams ◽  
Cfrp Sheet ◽  
Externally Bonded

This study presents a comparison of two methods used for retrofitting Reinforced Concrete (RC) beams, namely, the Externally Bonded Reinforcement (EBR) and the Near-Surface Mounting (NSM) methods. A parametric analysis was carried out using variables such as the retrofitted, the retrofitting method (EBR and NSM), and the thickness of the Carbon Fiber-Reinforced Polymer (CFRP) sheets. To achieve this goal, the finite element method and ABAQUS software were employed. An un-retrofitted beam was also simulated as the control specimen for comparison. Beam responses were compared through load–displacement and energy absorption capacity diagrams. Results show that the higher energy absorption capacity in all CFRP-retrofitted RC beams, which was 1.69–5.54 times higher than in un-retrofitted beams. In the case where half of the beam was reinforced using CFRP sheets, the entire beam assembly and the CFRP sheet contributed to load-bearing, thus delaying crack nucleation in the beam and increasing its energy absorption capacity. As a result, the energy absorption capacity of the beam, in this case, was less than that obtained in the previous one where half the span of the beam was retrofitted.

STRENGTHENING OF RC BEAMS USING NEAR SURFACE EMBEDDED-FRCM

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Usama Ebead ◽  
Hossameldin El-Sherif
Keyword(s):  
Experimental Evidence ◽  
Masonry Structures ◽  
Rc Beams ◽  
Near Surface ◽  
Flexural Strengthening ◽  
Reinforced Beams ◽  
Concrete Layer ◽  
Test Parameters ◽  
Externally Bonded ◽  
Strengthening Technique

Fibre reinforced cementitious matrix (FRCM) systems are mostly externally bonded (EB) for the strengthening of reinforced concrete (RC) and masonry structures. In this paper, the relatively new concept of near-surface embedded (NSE) FRCM, has been introduced for the flexural strengthening of beams. The process of the application of NSE-FRCM strengthening technique involves the removal of the concrete layer at beam soffit, being the most deteriorated in actual practices. Experimental evidence of the flexural strengthening efficacy of this technique is provided here. Eight RC beams were prepared and tested under four-point loading with the consideration of two test parameters: (a) FRCM material (polyparaphenylene benzobisoxazole (PBO)/carbon/ glass); and (b) the reinforcement ratio (0.5% representing flexure-deficient beams and 1.28% representing typical under-reinforced beams). The strengthening led to gains in ultimate loads that ranged between 31.4% and 84.3%.

scholarly journals Energy Absorption Evaluation of CFRP-Strengthened Two-Spans Reinforced Concrete Beams under Pure Torsion

2019 ◽  
Vol 5 (9) ◽  
pp. 2007-2018 ◽  
Author(s):  
Ammar N. Hanoon ◽  
Ali A. Abdulhameed ◽  
Haider A. Abdulhameed ◽  
Saad K. Mohaisen
Keyword(s):  
Reinforced Concrete ◽  
Energy Absorption ◽  
Concrete Beams ◽  
Absorption Capacity ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Rc Beams ◽  
Pure Torsion ◽  
Energy Absorption Capacity ◽  
Strengthened Beam

For more than a decade, externally bonded carbon fiber reinforced polymer (CFRP) composites successfully utilized in retrofitting reinforced concrete structural elements. The function of CFRP reinforcement in increasing the ductility of reinforced concrete (RC) beam is essential in such members. Flexural and shear behaviors, ductility, and confinement were the main studied properties that used the CFRP as a strengthening material. However, limited attention has been paid to investigate the energy absorption of torsion strengthening of concrete members, especially two-span concrete beams. Hence, the target of this work is to investigate the effectiveness of CFRP-strengthening technique with regard to energy absorption of two-span RC beams subjected to pure torsion. The experimental program comprises the investigation of two groups; the first group comprises eight un-strengthened beam specimens, while the second group consists of eight strengthened beam specimens tested under torsional forces. The energy absorption capacity measured from the area under the curve of torque-angle of twist for tested beams. Two parameters were studied, the influence of concrete compressive strength and the angle of a twist. Experimental results indicated that all beams wrapped with CFRP sheet display superior torsional energy absorption capacity compared to the control specimens. The energy absorption may consider as a safety index for the torsional capacity of two-span RC beams under service loadings. Therefore, it is possible to avoid structural as well as material damages by understanding the concept of energy absorption that is one of the important experimental findings presented in this study.

scholarly journals Effects of RC beams reinforcement using near surface mounted reinforced FRP composites

2010 ◽  
Vol 8 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Slobodan Rankovic ◽  
Radomir Folic ◽  
Marina Mijalkovic
Keyword(s):  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Near Surface ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Reinforced Beams ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Basic Characteristics ◽  
Frp Bars

This paper analyzes application of modern reinforcement methods for reinforced concrete (RC) beams using fiber-reinforced polymer (FRP) materials. Basic characteristics of FRP materials and the method of mounting the FRP bars within concrete, that is, near the surface of the beams (NSM method) are presented. The properties of this method and its advantages in comparison to externally bonded reinforcement laminate method (EBR) have been analyzed. The results of measured deflections and width of the cracks of the beams reinforced by FRP bars, depending on the load are presented and discussed, in comparison to the results obtained from the non-reinforced beams. The experimental research was published at the Faculty of Civil Engineering and Architecture of Nis in 2009.

scholarly journals Torsional Strengthening of Reinforced Concrete Beams with Externally-Bonded Fibre Reinforced Polymer: An Energy Absorption Evaluation

2020 ◽  
Vol 6 ◽  
pp. 69-85
Author(s):  
Mahir M. Hason ◽  
Ammar N. Hanoon ◽  
Ahmed W. Al Zand ◽  
Ali A. Abdulhameed ◽  
Ali O. Al-Sulttani
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Energy Absorption ◽  
Structural Damage ◽  
Absorption Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Concrete Compressive Strength ◽  
Externally Bonded ◽  
The Impact

The impacts of numerous important factors on the Energy Absorption (EA) of torsional Reinforced Concrete (RC) beams strengthened with external FRP is the main purpose and innovation of the current research. A total of 81 datasets were collected from previous studies, focused on the investigation of EA behaviour. The impact of nine different parameters on the Torsional EA of RC-beams was examined and evaluated, namely the concrete compressive strength (f’c), steel yield strength (fy), FRP thickness (tFRP), width-to-depth of the beam section (b/h), horizontal (ρh) and vertical (ρv) steel ratio, angle of twist (θu), ultimate torque (Tu), and FRP ultimate strength (fy-FRP). For the evaluation of the energy absorption capacity at different levels, Response Surface Methodology (RSM) was implemented in this study. Also, to fit the measured results, Quadratic and Line models were created. The results show that the RSM technique is a highly significant tool that can be applied not only to energy absorption-related problems examined in this research, but also to other engineering problems. An agreement is observed between Pareto and standardized charts with the literature showing that the EA capacity of the torsional FRP-RC beams is mostly affected by the concrete compressive strength, followed by the vertical reinforcement ratio. The newly suggested model in this article exhibits a satisfactory correlation co-efficient (R), of about 80%, with an adequate level of accuracy. The obtained results also reveal that the EA acts as a safety index for the FRP-strengthened RC beams exposed to torsional loadings to avoid sudden structural damage. Doi: 10.28991/cej-2020-SP(EMCE)-07 Full Text: PDF

scholarly journals Cyclic Loading Behaviour of Externally Bonded CFRP Reinforced Concrete Beam-Column Joint

2021 ◽  
pp. 1310-1321
Author(s):  
Harsh N. Bhutwala ◽  
Prof. Vishal B. Patel ◽  
J. D. Rathod ◽  
Prof. A. N. Desai
Keyword(s):  
Cyclic Loading ◽  
Energy Absorption ◽  
Failure Modes ◽  
Reinforced Concrete Beam ◽  
Absorption Capacity ◽  
Rc Beam ◽  
Energy Absorption Capacity ◽  
Externally Bonded ◽  
Column Joint ◽  
Strengthening Technique

Cyclic loading behaviour of RC beam-column joints strengthened with externally bonded Carbon Fiber Reinforced Plastic (CFRP) was analysed through Abaqus CAE software. Effect of the number of CFRP layers and the strengthening technique on failure modes, hysteretic curves, skeleton curves, ductility, and energy dissipation capacity were studied. The results show that the strengthening of RC beam-column joints by externally bonded CFRP can effectively improve the cyclic loading behaviour. Strengthening the joint by fiber bands enhances ductility and energy absorption capacity. The increase in the number of CFRP layers leads to enhance energy absorption capacity significantly as compared to ductility.

scholarly journals FLEXURAL BEHAVIOR OF RC BEAMS STRENGTHNED WITH CFRP SHEETS USING DIFFERENT STRENGTHENING TECHNIQUES

2019 ◽  
Vol 16 (1) ◽  
pp. 35
Author(s):  
Sherif El Gamal ◽  
Ali Al-Nuaimi ◽  
Abdullah Al-Saidy ◽  
Khalid Al-Shanfari
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Hybrid Technique ◽  
Rc Beams ◽  
Ultimate Capacity ◽  
Near Surface ◽  
Cfrp Sheets ◽  
Four Point Bending ◽  
Externally Bonded ◽  
Strengthening Technique

Due to the advantages of Fiber Reinforced Polymer (FRP) materials, they have been utilized to strengthen several reinforced concrete (RC) elements such as slabs, beams and columns. In this paper, five RC beams (200 mm width, 300 mm height, and 2750 mm length) were constructed. Four of these beams were strengthened with CFRP sheets whereas the last beam was used as a reference. Test parameters include the amount of FRP and the strengthening technique. Three strengthening techniques were used including the externally bonded technique (EB), the near surface mounted (NSM) technique using folded CFRP sheets inserted in near surface grooves, and a hybrid technique. All beams were tested under four point bending setup until failure. The control beam failed by the yielding of the tension steel followed by concrete crushing. The strengthened beams failed by steel yielding followed by either rupture or debonding of CFRP sheets at higher loads compared to the reference one. The stiffness after steel yielding and the ultimate capacity increased as the amount of CFRP increased. The strengthening technique affected the ultimate capacity of the strengthened beams. The NSM beam showed the lowest increase in the ultimate capacity (25.2%) whereas the hybrid beam showed the best performance with the highest increase in the ultimate capacity (58%) compared to the reference beam.

Investigation on Energy Absorption Capacity of Reinforced Concrete Beams by the Near-Surface Mounted Technique Using Ductile Materials

2016 ◽  
Vol 8 (8) ◽  
pp. 1536-1546 ◽  
Author(s):  
Md. Akter Hosen ◽  
Mohd Zamin Jumaat ◽  
A. B. M. Saiful Islam ◽  
M. Obaydullah ◽  
Kh. Mahfuzud Darain ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Energy Absorption ◽  
Concrete Beams ◽  
Absorption Capacity ◽  
Reinforced Concrete Beams ◽  
Energy Absorption Capacity ◽  
Near Surface ◽  
Ductile Materials ◽  
Near Surface Mounted

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

scholarly journals Dynamic crushing behavior of closed-cell aluminum foams based on different space-filling unit cells

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
S. Talebi ◽  
R. Hedayati ◽  
M. Sadighi
Keyword(s):  
Surface Area ◽  
Dynamic Behavior ◽  
Energy Absorption ◽  
Peak Stress ◽  
Absorption Capacity ◽  
Unit Cell ◽  
Lattice Structures ◽  
Energy Absorption Capacity ◽  
Closed Cell ◽  
Unit Cells

AbstractClosed-cell metal foams are cellular solids that show unique properties such as high strength to weight ratio, high energy absorption capacity, and low thermal conductivity. Due to being computation and cost effective, modeling the behavior of closed-cell foams using regular unit cells has attracted a lot of attention in this regard. Recent developments in additive manufacturing techniques which have made the production of rationally designed porous structures feasible has also contributed to recent increasing interest in studying the mechanical behavior of regular lattice structures. In this study, five different topologies namely Kelvin, Weaire–Phelan, rhombicuboctahedron, octahedral, and truncated cube are considered for constructing lattice structures. The effects of foam density and impact velocity on the stress–strain curves, first peak stress, and energy absorption capacity are investigated. The results showed that unit cell topology has a very significant effect on the stiffness, first peak stress, failure mode, and energy absorption capacity. Among all the unit cell types, the Kelvin unit cell demonstrated the most similar behavior to experimental test results. The Weaire–Phelan unit cell, while showing promising results in low and medium densities, demonstrated unstable behavior at high impact velocity. The lattice structures with high fractions of vertical walls (truncated cube and rhombicuboctahedron) showed higher stiffness and first peak stress values as compared to lattice structures with high ratio of oblique walls (Weaire–Phelan and Kelvin). However, as for the energy absorption capacity, other factors were important. The lattice structures with high cell wall surface area had higher energy absorption capacities as compared to lattice structures with low surface area. The results of this study are not only beneficial in determining the proper unit cell type in numerical modeling of dynamic behavior of closed-cell foams, but they are also advantageous in studying the dynamic behavior of additively manufactured lattice structures with different topologies.

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