Experimental Research on Seismic Performance of Pre-Damaged RC Frame T-Beam Strengthened with Sprayed BFRP

2014 ◽  
Vol 507 ◽  
pp. 209-216 ◽  
Author(s):  
Rui Gao ◽  
Qian Gu ◽  
Cheng Fang Sun ◽  
Yu Jia Peng
Keyword(s):  
Seismic Performance ◽  
Peak Load ◽  
Basalt Fiber ◽  
Experimental Program ◽  
Rc Frame ◽  
Reinforcement Effect ◽  
Cyclic Shear ◽  
Shear Loads ◽  
Reinforced Polymer ◽  
T Beam

This experimental program was designed for investigating the seismic performance and reinforcement effect of pre-damaged RC frame T-beams reinforced with sprayed basalt fiber reinforced polymer (BFRP). Four RC frame T-shape beams specimens, among which one was unstrengthened , one was undamaged and strengthened , and the other two were pre-damaged and strengthened, were tested under an incremental loading procedure of the pseudo-static, cyclic shear loads. The test results including the failure mode, ultimate bearing capacity, load-displacement hysteresis curves and ductility of specimens were obtained and analyzed. It indicates that spraying BFRP reinforcement can effectively increase the peak load and energy dissipation performance of damaged RC frame T-beams, ultimate lateral deformation and ductility of damaged RC frame T-beams can be improved obviously. Increasing the reinforcement thickness of sprayed BFRP can effectively improve the seismic reinforcement effect of T-shaped beams damaged by the earthquake.

Experimental Research on Seismic Behavior of Seismically Damaged RC Frame Column Strengthened with Sprayed Hybrid BF/CFRP

2014 ◽  
Vol 501-504 ◽  
pp. 1592-1599 ◽  
Author(s):  
Yu Jia Peng ◽  
Qian Gu ◽  
Rui Gao ◽  
Getahune Bitewlgn
Keyword(s):  
Energy Dissipation ◽  
Load Capacity ◽  
Experimental Program ◽  
Strengthening Effect ◽  
Rc Frame ◽  
Cyclic Shear ◽  
Concrete Frame ◽  
Shear Loads ◽  
Seismic Behaviors ◽  
Frp Retrofit

This experimental program was designed for investigating the seismic behaviors and strengthening effect of pre-damaged RC frame columns retrofitted with sprayed BFRP and hybrid BF/CFRP. Four RC frame column specimens, among which one was unstrengthened and three was pre-damaged and strengthened with sprayed FRP, were tested under an incremental loading procedure of the pseudo-static, cyclic shear loads combined with constant gravity loads. The test results including the failure mode, ultimate bearing load capacity, load-displacement hysteresis curves and ductility of specimens were obtained and analyzed. It indicates that spraying hybrid BF/CFRP strengthening scheme can effectively improve the ductility and energy dissipation ability of pre-damaged concrete frame columns. Although the improvement of the peak loads and ultimate lateral deformation of damaged frame columns were not obvious compared with those of the reference column, but it should be pointed out that the strengthened columns were pre-damaged seriously with yielded steel bars and the recover of load bearing ability resulted from spraying FRP retrofit can not be neglected. It also shows that increasing the thickness of spraying overcoat can effectively improve the energy dissipation ability of damaged frame columns.

scholarly journals Numerical Modeling of Earthquake-Damaged Circular Bridge Columns Repaired Using Combination of Near-Surface-Mounted BFRP Bars with External BFRP Sheets Jacketing

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 258 ◽  
Author(s):  
Xing-Gui Zeng ◽  
Shao-Fei Jiang ◽  
Xin-Cheng Xu ◽  
Hai-Sheng Huang
Keyword(s):  
Numerical Modeling ◽  
Numerical Models ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Near Surface Mounted ◽  
Damage Accumulation Model ◽  
Good Agreement

This paper reports the numerical simulation of earthquake-damaged circular columns repaired with the combination of near-surface-mounted (NSM) basalt fiber reinforced polymer (BFRP) bars with external BFRP sheets jacketing at quasi-static loading. The numerical modeling was carried out with the nonlinear OpenSees software platform by using the BeamWithHinges element. In the simulations, the effect of the previous earthquake damage on the behavior of the repaired columns was taken into account, and a simple and effective material damage-accumulation model is proposed to modify the constitutive of materials in the unrepaired regions of the repaired columns. The developed numerical models were validated by comparing their quasi-static findings with those obtained from a previous experimental program, and a good agreement can be observed. Furthermore, the efficiency of the repair technique used in tests is evaluated via the developed numerical model.

scholarly journals Flexural Behavior of a Novel Textile-Reinforced Polymer Concrete

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 176
Author(s):  
Daniel Heras Murcia ◽  
Bekir Çomak ◽  
Eslam Soliman ◽  
Mahmoud M. Reda Taha
Keyword(s):  
Peak Load ◽  
Basalt Fiber ◽  
Flexural Behavior ◽  
Image Processing Technique ◽  
Polymer Concrete ◽  
Textile Reinforced Concrete ◽  
Polymer Resin ◽  
Reinforced Polymer ◽  
Structural Applications ◽  
Textile Fabric

Textile reinforced concrete (TRC) has gained attention from the construction industry due to its light weight, high tensile strength, design flexibility, corrosion resistance, and remarkably long service life. Some structural applications that utilize TRC components include precast panels, structural repair, waterproofing elements, and façades. TRC is produced by incorporating textile fabrics into thin cementitious concrete panels. Premature debonding between the textile fabric and concrete due to improper cementitious matrix impregnation of the fibers was identified as a failure-governing mechanism. To overcome this performance limitation, in this study, a novel type of TRC is proposed by replacing the cement binder with a polymer resin to produce textile reinforced polymer concrete (TRPC). The new TRPC is created using a fine-graded aggregate, methyl methacrylate polymer resin, and basalt fiber textile fabric. Four different specimen configurations were manufactured by embedding 0, 1, 2, and 3 textile layers in concrete. Flexural performance was analyzed and compared with reference TRC specimens with similar compressive strength and reinforcement configurations. Furthermore, the crack pattern intensity was determined using an image processing technique to quantify the ductility of TRPC compared with conventional TRC. The new TRPC improved the moment capacity compared with TRC by 51%, 58%, 59%, and 158%, the deflection at peak load by 858%, 857%, 3264%, and 3803%, and the toughness by 1909%, 3844%, 2781%, and 4355% for 0, 1, 2, and 3 textile layers, respectively. TRPC showed significantly improved flexural capacity, superior ductility, and substantial plasticity compared with TRC.

scholarly journals An Anchorage Technique for Shear Strengthening of RC T-Beams Using NSM-BFRP Bars and BFRP Sheet

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Hesham M. Diab ◽  
Ahmed M. Sayed
Keyword(s):  
Reinforced Concrete ◽  
Basalt Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Shear Strengthening ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Anchorage System ◽  
Near Surface Mounted

Abstract This study presents a detailed experimental program for reinforced concrete T-beams strengthened in shear with near-surface mounted (NSM) basalt fiber-reinforced polymer (BFRP) bars. This paper aims to introduce and evaluate a nonmechanical anchorage technique for shear strengthening using NSM-BFRP bars. T-beams were strengthened using manually manufactured closed or U-shaped hybrid BFRP stirrups (BFRP bars and BFRP sheets). The experimental program was developed to study the effects of these anchorage techniques. The results showed that the shear capacity increased by 8%–46% for beams strengthened with NSM-BFRP bars without anchorage. However, the presence of the proposed anchorage system increased the shear capacity of the strengthened beams by 39.6%–81.6%. Moreover, the maximum strains induced in the BFRP bars ranged from 27 to 59% of their ultimate strains according to the spacing between the NSM and the presence of the anchorage. The proposed anchorage technique prevented the premature debonding of the NSM-BFRP bars.

Bond performance of basalt fiber-reinforced polymer bars in conventional Portland cement concrete: a relative comparison with steel rebar using the hinged beam approach

2017 ◽  
Vol 24 (6) ◽  
pp. 909-918 ◽  
Author(s):  
Muhammet Seis ◽  
Ahmet Beycioğlu
Keyword(s):  
Basalt Fiber ◽  
Bond Stress ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Steel Rebar ◽  
Reinforced Polymer ◽  
Embedment Length ◽  
Bar Diameter ◽  
Basalt Fiber Reinforced Polymer

AbstractThis paper reports the results of an experimental investigation carried out to evaluate the bond stress behavior of basalt fiber-reinforced polymer (BFRP) bar and steel rebar (SR) in conventional C30-type concrete. The experimental program was conducted on testing 16 hinged beam specimens that were prepared according to BS 4449:2005+A2:2009 standard. Conventional C30-type concrete was used to produce hinged beams. In beam tests, bar diameter and embedment length were used as experimental variables. The bond performances of BFRP bar and SR were compared with the help of the load-slip results of hinged beam bending tests conducted on produced beam samples after 28 days of curing. Results showed that much higher bond stress values were obtained from BFRP bars compared to SR for both 12 and 8 mm bar diameters. Besides, the maximum bond stress values decreased with increasing bar diameter and embedment length for both BFRP bar and SR.

scholarly journals A Monotonic Smeared Truss Model to Predict the Envelope Shear Stress—Shear Strain Curve for Reinforced Concrete Panel Elements under Cyclic Shear

2021 ◽  
Vol 2 (1) ◽  
pp. 174-194
Author(s):  
Luís Bernardo ◽  
Saffana Sadieh
Keyword(s):  
Shear Stress ◽  
Reinforced Concrete ◽  
Shear Strain ◽  
Peak Load ◽  
Strain Curve ◽  
Fiber Reinforced Polymers ◽  
Shear Stresses ◽  
Cyclic Shear ◽  
Concrete Panels ◽  
Truss Model

In previous studies, a smeared truss model based on a refinement of the rotating-angle softened truss model (RA-STM) was proposed to predict the full response of structural concrete panel elements under in-plane monotonic loading. This model, called the “efficient RA-STM procedure”, was validated against the experimental results of reinforced and prestressed concrete panels, steel fiber concrete panels, and reinforced concrete panels externally strengthened with fiber-reinforced polymers. The model incorporates equilibrium and compatibility equations, as well as appropriate smeared constitutive laws of the materials. Besides, it incorporates an efficient algorithm for the calculation procedure to compute the solution points without using the classical trial-and-error technique, providing high numerical efficiency and stability. In this study, the efficient RA-STM procedure is adapted and checked against some experimental data related to reinforced concrete (RC) panels tested under in-plane cyclic shear until failure and found in the literature. Being a monotonic model, the predictions from the model are compared with the experimental envelopes of the hysteretic shear stress–shear strain loops. It is shown that the predictions for the shape (at least until the peak load is reached) and for key shear stresses (namely, cracking, yielding, and maximum shear stresses) of the envelope shear stress–shear strain curves are in reasonably good agreement with the experimental ones. From the obtained results, the efficient RA-STM procedure can be considered as a reliable model to predict some important features of the response of RC panels under cyclic shear, at least for a precheck analysis or predesign.

scholarly journals Compressive Strength of Modified FRP Hybrid Bars

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1898
Author(s):  
Marek Urbański
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Basalt Fiber ◽  
Test Method ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Free Length ◽  
Compression Properties ◽  
Reinforced Polymer ◽  
Frp Bars

A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.

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