Table 1
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In this paper, a detailed procedure for nonlinear finite-element analysis of fiber reinforced polymer (FRP) and textile reinforced mortar (TRM) upgraded reinforced concrete (RC) beam-column exterior joints is presented for predicting their seismic performance under simulated earthquake loading. The finite-element (FE) model was developed using a sm...
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Context 1
... of these four as-built specimens, one specimen was used as the baseline specimen (control specimen) and the other three were strengthened with TRM, CFRP, and GFRP sheets, respectively (Figs. 3 and 4). The nomenclature used for various specimens is shown in Table 1. All of these four subassemblages were subjected to quasi-static cyclic lateral load histories so as to provide the equivalent of severe earthquake damage. ...
Similar publications
Textile reinforced mortars (TRM), also known in the international literature as textile reinforced concrete (TRC) or fabric reinforced cementitious matrix (FRCM) materials, have been widely studied during the last two decades as they constitute a promising alternative to the fiber reinforced polymer (FRP) retrofitting solution for strengthening of...
The flexural behaviour of RC beams strengthened with TRM and FRP composites was experimentally investigated and compared both at ambient and high temperatures. The investigated parameters were: (a) the strengthening material, namely TRM versus FRP, (b) the number of strengthening layers, (c) the textile surface condition (dry and coated), (d) the t...
The objective of this study is to substitute carbon or glass fibber reinforced polymer composite by glass mineral matrix composites in order to improve the shear behaviour of short beams. The conclusion consists in evaluating the degree of correlation between the experimental results and the guideline formulations, with the objective to eventually...
This paper presents the first study on the performance of TRM and FRP jacketing in shear strengthening of reinforced concrete (RC) members subjected to ambient and high temperatures, including both medium-scale rectangular beams and full-scale T-beams. Key parameters investigated on the medium-scale rectangular RC beams include: (a) the matrix used...
The application of textile reinforced mortar (TRM) as a means of increasing the shear resistance of reinforced concrete members is investigated in this study. TRM may be considered as an alternative to fiber reinforced polymers (FRP), providing solutions to many of the problems associated with application of the latter without compromising much the...
Citations
... Nonlinear analysis can account for cracking in concrete and yielding in steel. Non-linear finite element analysis is thus necessary to evaluate concrete structural models and can provide reliable beamcolumn connection models [37][38][39]. To validate the experimental results, a non-linear finite element analysis was performed using ABAQUS-22 [40]. ...
In this paper, the structural performance of exterior fly-ash based concrete beam-column joints
reinforced with hybrid glass fiber reinforced polymer (GFRP) and steel bars was studied, to
inspect the hybrid concept efficiency under lateral loads. This paper studied two mixes of
concrete, normal strength concrete (NC) and fly-ash based concrete (FC), a 20% replacement
ratio of the cement weight with superplasticizer is considered in FC mix, which is considered
as an environmental-friendly and cost-effective alternative to ordinary Portland cement. Ten
joints were tested under the effect of monotonic lateral load experimentally. The studied joints
were divided into two groups based on their concrete type, in each group, five joints with
different GFRP to steel ratios “from 0% to 100% with an increment of 25%” were tested. The
obtained results showed that the fly ash presence in concrete resulted in an average increase in
both ductility and load capacity of 18% and 28.3%, respectively. Also, the average total energy
absorption increased by 35%, and the average initial and post-yield stiffness increased by 34%
and 41%, respectively. Moreover, the ductility index for each model was obtained, the FC
model with 75% GFRP to steel ratio achieved the maximum ductility index, so it was
considered as the optimum one. After that, the finite element analysis FEA was utilized to study
the performance of the tested beam-column joints. The FEA showed identical results compared
to the experimental ones concerning energy absorption, load capacity, and model stiffness.
Finally, using FEA, a deep parametric study on FC models reinforced with GFRP to steel bars
ranging from 60% to 90% was performed to obtain the optimum GFRP to steel reinforcement
ratio. Through the performed parametric study, it was found that the optimum range of the
reinforcement ratio was 68% to 82%. According to this research, the usage of fly ash in
concrete increased RC beam-column joints' efficiency especially when provided with hybrid
GFRP and steel reinforcement, in addition to the important environmental impact achieved
through the recycling process. It was recommended to utilize the composite reinforcement
ranging between 60% to 75% GFRP to steel bars in the presence of fly ash-based concrete for
the beam-column joints.
... The mortar contribution in the developed model was neglected due to its insignificant effect on the tensile response of the FRCM systems after cracking [21]. Most studies in the literature, such as Alhaddad et al. [38] and Moniruzzama [39], followed a similar procedure in their analysis and the reported results were in good agreement with the experimental results. Shell elements are often used to model structures with a thickness that is much smaller than their other dimensions. ...
This paper investigated both experimentally and numerically the flexural performance of two–span beams after being strengthened with polyparaphenylene benzobisoxazole (PBO) fiber–reinforced cementitious matrix (FRCM) systems at different hogging–to–sagging (H/S) strengthening ratios. The test results revealed that the enhancement in the flexural response of the strengthened beams was highly dependent on the strengthening configuration and the number of layers used in both the hogging and sagging sections. The H/S ratio had a notable effect on the failure modes of the hogging sections only whereas the sagging sections showed similar failure modes regardless of the H/S used. Strengthening the sagging sections governed the ductility of the tested beams with a slight effect of the H/S ratio on their ductility. Despite strengthening, the hogging sections were capable to redistribute up to 37% of their moments to the sagging sections, which represented 93% of the redistribution capacity of the unstrengthened sections. This finding suggests the revision of the CSA and ACI formulations that prohibit any moment redistribution in the design of externally–bonded strengthened elements. The developed finite element model accurately predicted the experimental results in terms of the failure modes, the load–carrying capacity, the ductility, and the moment redistribution ratios between the critical sections.
... Hou et al. [43] studied the effect of shear span ratios on the bonding behaviour between cementitious composite and reinforcement and concluded that the bond strength of slender beams is greater than short beams. Similarly, the response of columns, shear walls, and beam-column connections was studied under static and dynamic excitations [44][45][46][47][48][49][50][51][52]. Similarly, Abouhussien et al. [53] cracking behavior of ECC beam-column joints under cyclic loading. ...
... The experimental testing result of the ECC mix (a) averaged compression stress-strain curve and (b) averaged tensile stress-strain curve. developed on CSI ETAB, while Perform3D[51] was used for nonlinear modeling. The floor plan and finite 3D element model are shown inFig. 5. ...
Engineering Cementitious Composites (ECC) have received wide attention in recent years due to their enhanced mechanical properties and ductility. These properties offer an opportunity to design structures with significantly improved seismic performance having a low-damage and ductile response. However, existing research studies primarily focus on the performance of ECC at material and member scales, resulting in a knowledge gap regarding its response at the structural level. This study examines the system-level seismic response of buildings designed using ECC and compares their performance with those having conventional reinforced concrete (RC) members. For this purpose, two RC shear wall buildings (7-story and 24-story) were selected as a case study, and their elements were separately designed (for the combined gravity and lateral loads) as RC and ECC elements using the guidelines recommended by the Japan Society of Civil Engineering (JSCE) and ACI (American Concrete Institute) 318–19. The design results show that the requirement of longitudinal steel is reduced by a maximum of 24% in ECC flexural members and by 15% in compression members, in addition to a significant reduction in the required transverse reinforcement as compared to the corresponding RC members. Similarly, owing to improved tensile behavior, the ECC members also exhibited a higher shear capacity than RC members. The detailed nonlinear finite element models of the case study buildings (for both the design cases i.e., ECC and RC) were subjected to monotonic and reversed-cyclic pushover analysis, and nonlinear time history analyses (NLTHA) under a set of selected ground motions. It was observed that ECC structures exhibited significantly improved lateral capacity, revered-cyclic response, and overall seismic performance as compared to the corresponding RC structures. These results demonstrate that ECC can be effectively used to design various members for improved seismic performance of buildings.
... In assessing the above damages and analyzing the results of extensive research, some seismic codes have proposed several approaches showing the participation of masonry infill walls with the rest of the elements of reinforced concrete buildings to better evaluate the seismic behavior of how this type of building's infill walls contribute significantly to modifying the seismic behavior of reinforced concrete buildings [3,4]. It increases the stiffness and base shear of the building and reduces the natural time period of the building. ...
The direct modeling of masonry infill walls on many buildings, based on damage recorded by various past earthquakes, has become increasingly necessary in order to identify the seismic behavior of these elements, which constitute an important part of reinforced concrete buildings. In this paper, several 3D models were analyzed by the nonlinear static (pushover) method, when ignoring, and when considering, masonry infill walls. The finite element software SAP analyzed the proposed models. These models represent low and mid-rise reinforced concrete buildings infilled with double-leaf hollow bricks. The properties of materials used in Algeria, either in the frame elements or the infill elements, were used. The results obtained were compared according to two parameters, the natural time period of the building and the pushover curve, by varying the values of the dead load and the concrete compressive strength. The results were discussed according to the suggested parameters. The results showed that indirect modeling of such walls, either by taking assumptions embedded in the seismic behavior factor or by means of the macro-modal, can lead to a poor appreciation of the seismic behavior of such buildings. Consequently, direct modeling of walls by the infill of the real void showed acceptable results to some extent. This contributes greatly towards understanding the seismic behavior of this type of building.
... Based on the values used in the experiment of the carbon textile, the moduli of longitudinal elasticity were 240, 30, and 30 GPa in x, y, and z directions, respectively. The Poisson's ratios were assumed equal to 0.22, 0.22, and 0.3 for νxy, νxz, and νyz, respectively [33]. The moduli of transversal elasticity, Gxy, Gxz, and Gyz, were obtained using Equations (7) and (8), resulting in 13.2, 13.2, and 8.3 GPa, respectively. ...
... Based on the values used in the experiment of the carbon textile, the moduli of longitudinal elasticity were 240, 30, and 30 GPa in x, y, and z directions, respectively. The Poisson's ratios were assumed equal to 0.22, 0.22, and 0.3 for ν xy , ν xz , and ν yz , respectively [33]. The moduli of transversal elasticity, G xy , G xz , and G yz , were obtained using Equations (7) and (8), resulting in 13.2, 13.2, and 8.3 Gpa, respectively. ...
Sustainable solutions in the building construction industry promotes the use of innovative materials such as textile reinforced mortar (TRM) as a strengthening technique resulting in a reduced life-cycle cost. This paper presents a nonlinear finite element analysis (FEA) of TRM strengthened RC walls with cut-out openings under axial loading. FEA models were developed and validated with two experimental tests from the literature. Subsequently, a parametric study was performed to investigate the contribution of TRM in strengthening RC walls considering various opening sizes, types, numbers and orientations of window openings, and TRM strengthening configurations. The parametric study results revealed that strengthened models with smaller opening sizes had higher axial strength enhancement. Furthermore, the increase in the axial load capacities of walls with door and window openings were 34 and 26%, respectively, as compared to the corresponding control ones. TRM was more effective with a lower opening aspect ratio (Ho/Lo). In addition, confining the wall piers with U-shaped TRM jackets was the most effective configuration in improving the walls’ axial strengths with maximum enhancements of 16 and 22% as compared to the models strengthened with side-bonded sheets and strips, respectively. Finally, the axial strengths of the FEA models were also compared with the existing empirical solution and showed reasonable correlation with an average discrepancy of 15%.
... In TRM, textiles consist of woven, knitted, or even unwoven fiber rovings that are arranged in two directions (usually orthogonally). In the past, some interesting studies were conducted on the quasi-static response of RC members strengthened with TRM [17,18]. ...
The formulas available in the literature for predicting the projectile impact response of reinforced concrete (RC) targets are generally developed based on the results of impact tests. Recently, however, in order to avoid performing involved and challenging projectile impact tests, the impact response of RC targets was predicted using the quasi-static punching response of RC slabs. In this paper, the concept is extended to concrete slabs strengthened with textile-reinforced mortar (TRM) or carbon fiber-reinforced polymer (CFRP) sheets externally bonded to the concrete surface. In 16 groups, 96 slabs of 600 × 600 × 90 mm size were cast and tested under quasi-static and impact loads. The slabs were reinforced with two types of reinforcement: ϕ8@100 mm and ϕ4@25 mm. The singly and doubly reinforced concrete slabs with rebar spacing of 100 mm were strengthened using externally bonded CFRP and TRM on the back side of the slab specimens. Two mixes of concrete, representing normal and high-strength concretes, were used. The results of the present study reveal that the CFRP and TRM strengthening of RC slabs enhanced the energy absorption in punching by 57–130% and 20–59%, respectively. The use of WWM in singly and doubly reinforced slabs also resulted in a 30–42% and 41–63% increase in energy absorption in punching, respectively. An earlier proposed model was modified to incorporate the influence of strengthening (CFRP and TRM) in the estimation of the projectile perforation energy of the strengthened RC slabs with the help of energy absorbed in their quasi-static punching. This perforation energy was then employed for predicting the ballistic limit of CFRP- and TRM-strengthened slabs. The predictions show good agreement with the experimentally observed ballistic limits.
... They can be strengthened using various techniques such as applying externally bonded sheets, CFRP bars, near-surface mounted (NSM) bars/strips, or plates of high-strength materials. These high-strength materials could be fiber-reinforced polymer, polyester, steel plates, wire mesh, fiber-reinforced cement-based composites (FRCM), or textile fabrics and reinforced mortar (TRM) (Alhaddad et al. 2012;Ombres 2015;Al-Mahaidi and Kalfat 2018;Huang, Zhao et al. 2018;Zhang and Sun 2018;Siddika, Saha et al. Siddika et al. 2020;Mohammed et al. 2020). ...
In this study, the performance of shear deficient reinforced concrete (RC) beams with rectangular cross-sections, which were externally bonded reinforced (EBR) with high strength CFRP and GFRP strips composite along shear spans, has been experimentally and analytically investigated under vertical load. In the study, the minimum CFRP and GFRP strips width over spacing were considered. The shear beam with turned end to a bending beam was investigated by applying different composite strips. Therefore various arising in each of strength, ductility, rigidity, and energy dissipation capacity were obtained. A total of 12 small-scaled experimental programs have been performed. Beam dimensions have been taken as 100x150x1000 mm. Four beams have been tested as unstrengthened samples. This paper focuses on the effect of minimum CFRP and GFRP strip width on behaviours of RC beams shear-strengthened with full-wrapping, U-wrapping, and U-wrapping+longitudinal bonding strips. Strengthened beams showed significant increments for flexural ductility, energy dissipation, and inelastic performance. The full wrapping strips applied against shear failure have increased the load-carrying capacity of samples 53%-63% interval rate. Although full wrapping is the best strengthening choice, the U-wrapping and U-wrapping+longitudinal strips of both CFRP and GFRP bonding increased the shear capacity by 53%~75% compared to the S2 sample. In terms of ductility, the best result has been obtained by the type of strengthening where the S5 beam was completely GFRP wrapped. The experimental results were also compared with the analytically given by ACI440.2R-17, TBEC-2019 and FIB-2001. Especially in U-wrapped beams, the estimation of FIB was determined to be 81%. The estimates of the other codes are far from meeting the experimental results; therefore, essential improvements should be applied to the codes, especially regarding CFRP and GFRP deformation and approaches for longitudinal strip connections. According to the test results, it is suggested that GFRP, which is at least as effective but cheaper than CFRP, may be preferred for strengthening applications.
... The modulus of elasticity of the lightweight carbon textile mesh used in the experiment in the x-, y-, and z-directions were 225, 20, and 20 GPa, respectively. The ν were 0.22, 0.22, and 0.3 for ν xy , ν xz , and ν yz , respectively (Alhaddad et al. 2012). Elasticity relations [Eqs. ...
In this study, nonlinear finite-element analysis (FEA) will be employed to investigate textile-reinforced mortar (TRM) jackets for shear strengthened reinforced concrete (RC) beams. FEA models of TRM shear strengthened RC beams will be developed and validated against experimental study from the literature. Subsequently, a parametric study will be conducted on the validated FEA models to examine the effect of various beams' depths, load distributions, and orientations and stacking sequences of the textile's mesh layers. The results of the parametric study show that increasing the cross section depth improved the load capacity of the shear strengthened RC beams and reduced the shear contribution of TRM. In addition, the shear influence of TRM was more dominant when the beams were subjected to a uniformly distributed load. However, the strengthening the beams with one or three layers of textile mesh that had a 45° orientation was the most effective configuration to improve the shear capacity (VR). For stacking sequences, the improvement in the shear strength of all models compared with the control were between 68.6% and 77.4%, which indicated that the ply sequences had an insignificant impact on the RC beam's VR.
... Akgüzel and Pampanin [42,43] studied the response of non-seismically designed connections strengthened by GFRP. Alhaddad et al. [44] deliberated a comparison in the effect of connections before and after upgrading it with CFRP and mortar. Xiaobing et al. [45] have also studied square CFRP-strengthened connections using experimental procedures. ...
Nowadays, fracture mechanics modeling for strengthening structural members is a challenging issue for structural engineers. The developed fracture mechanics modeling was applicable for identifying propagation of a crack in concrete structural members such as beam-column connections. In the present paper, a numerical model derived from nonlinear fracture mechanics is developed to simulate the propagation of a crack in Carbon Fiber Reinforced Polymers (CFRP)-strengthened the connection. To validate the proposed model, two beam-column connections were made and tested. By using the proposed model, the outputs of the CFRP-strengthened connections show good agreement with the experimental results (8–12 %). It was also observed that propagation of the crack in the beam was prevented by the CFRP sheets. The average decrease was 36.9 % of the crack length compared with the control connection. The findings revealed that cracks formed in the connection area in the control specimen while extensive cracks appeared in the beam in the specimen strengthened by CFRP sheets.
... For almost two decades since the late 1990s, extensive research has been conducted on FRP-strengthened joints. Investigations were performed on the roles of various parameters on the effectiveness of externally bonded FRPs [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], analytical models were built to predict the shear capacity of FRP-strengthened joints [9,20,[24][25][26][27][28][29], and nonlinear finite element (FE) modeling approaches were developed for FRP-strengthened joints [30][31][32][33]. Nevertheless, most of the studies concentrated on two-dimensional (2D) joints, i.e., no transverse beams [34]. ...
... A perfect bond was considered between the steel reinforcements and the concrete and between the CFRP sheets and the concrete substrate. Similar conditions were considered in previous numerical investigations on CFRP-strengthened RC joints [30,32]. Especially, all specimens in the current study were designed such that failure would be due to shear in the joint, which ensured that the effect of a series of parameters on the shear capacity of joints can be investigated. ...
... The value of the shear transfer coefficient for open cracks (β t ) depended on the type of structure, type of load, effect of the dowel action of the reinforcement, and effect of aggregate interlock [45]. Previous researchers [30][31][32]45] selected values of β t between 0.125 and 1.0. Considering that the widths of the cracks in the strengthened joints were constrained by the externally bonded CFRP materials that possessed a linear behavior until they reached rupture, a value of 0.5 was used for β t , i.e., the same value was used in the FE simulation of CFRP-strengthened joints by Alhaddad et al. [30]. ...
To develop feasible carbon fiber reinforced polymer (CFRP) retrofit schemes for the shear strengthening of real three-dimensional reinforced concrete (RC) beam-column joints, a series of parameters in relation to the contributions of the CFRP sheets externally bonded to joint panels was numerically investigated in this study. The parameters include CFRP reinforcement ratio, CFRP layout, transverse beam-to-joint panel width ratio, transverse beam-to-joint panel height ratio, location of transverse beam, and number of transverse beams. Strengthening efficiency, a new dimensionless index, was introduced to evaluate the residual effect of a CFRP-strengthening system weakened by the presence of transverse beams in comparison with the increase in joint shear capacity in relation to the one-way counterpart. The results obtained from 44 nonlinear finite element models, which were calibrated against experimental observations, confirmed the effectiveness of the CFRP strengthening technique with regard to the relatively wide ranges of the parameters. The significant differences among the roles of the parameters were revealed, and the reasons behind the differences were analyzed. Furthermore, the shear mechanism of the CFRP-retrofitted joint panels was discussed with the proposed strut-and-tie model.
