scholarly journals Repair of Block Masonry Panels with CFRP Sheets

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2363 ◽  
Author(s):  
Marco Corradi ◽  
Giulio Castori ◽  
Romina Sisti ◽  
Antonio Borri ◽  
Giovanni Luca Pesce
Keyword(s):  
Load Capacity ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Masonry Walls ◽  
Local Repair ◽  
Ultimate Load Capacity ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Wall Panels ◽  
Construction Defects

In the 1980s, block masonry started to be widely used for new constructions in Italy’s earthquake prone areas. However, recent seismic events demonstrated that block masonry buildings may need to be repaired after earthquakes due to cracking. Construction defects are the main cause for cracking of block work masonry. Carbon fiber reinforced polymer (CFRP) sheets have been used as a local repair method for non-defective and defective wall panels. An experimental program was formulated to investigate the shear behavior of block masonry walls repaired with CFRP sheets. A total of six wall panels were constructed in the laboratory and tested in shear (in-plane lateral loading). It was found that, although the control (non-defective) wall panels had a high ultimate load capacity, the use of CFRPs reduces the effects of construction defects and restores the lateral load capacity in non-defective walls. Overall, this research suggests that the use of epoxy-bonded CFRP sheets could be used for local repair of cracked wall panels.

scholarly journals Enhancing Stability of Thin-Walled Short Steel Channel Using CFRP under Eccentric Compression

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Hongyuan Tang ◽  
Canjun Wang ◽  
Ruijiao Wang
Keyword(s):  
Analytical Study ◽  
Ultimate Load ◽  
Load Capacity ◽  
Local Buckling ◽  
Fiber Reinforced Polymer ◽  
Actual Behavior ◽  
Thin Wall ◽  
Ultimate Load Capacity ◽  
Reinforced Polymer ◽  
Global Buckling

This paper presents the experimental and analytical results of eccentrically loaded short cold-formed thin-wall steel channels strengthened with transversely oriented carbon fiber reinforced polymer (CFRP) strips around their web and flange. Seven specimens, each 750 mm long, were fabricated; the main parameters were the number of CFRP plies (one or two) and the space between the CFRP strips (50, 100, or 150 mm). The application of the CFRP strips results in increases in ultimate load capacity and, with the exception of the most heavily reinforced (2 plies at 50 and 100 mm), local buckling was observed prior to global buckling. To extend and better understand the experimental work, a companion analytical study was conducted. Comparisons between experimental observations and computed results show that the analyses provided good correlation to actual behavior. In addition, the numerical results explained the observed phenomenon that flange local buckling was constrained to regions between the CFRP strips.

Strengthening of Masonry Walls Using Fiber Reinforced Polymer (FRP) Materials

2015 ◽  
Vol 660 ◽  
pp. 198-201 ◽  
Author(s):  
Eva Partene ◽  
Valeriu Stoian ◽  
Andrei Bindean ◽  
Luminita Fekete-Nagy
Keyword(s):  
Failure Modes ◽  
Shear Resistance ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Masonry Walls ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Earthquake Resistant ◽  
Ceramic Blocks

The paper presents the behavior of masonry walls built up using ceramic blocks with hollows tested in bear state and then strengthened using FRP materials. A number of two masonry walls are subjected to cyclic in-plane horizontal loads and constant vertical loads, in order to determine the efficiency of the strengthening solutions compared with the shear resistance of the walls in bear state. Also, the experimental program is useful to observe the failure modes of the strengthened walls and also to determine if such strengthening solutions is earthquake-resistant.

Numerical analysis of reinforced concrete beams strengthened in shear using carbon fiber reinforced polymer materials

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sabiha Barour ◽  
Abdesselam Zergua
Keyword(s):  
Finite Element ◽  
Ultimate Load ◽  
Load Capacity ◽  
Nonlinear Finite Element ◽  
Fiber Reinforced Polymer ◽  
Analytical Models ◽  
Ultimate Load Capacity ◽  
Content Type ◽  
Reinforced Polymer ◽  
The Difference

Purpose This paper aims to analyze the performance of reinforced concrete (RC) beams strengthened in shear with carbon fiber-reinforced polymer (CFRP) sheets subjected to four-point bending. Design/methodology/approach ANSYS software is used to build six models. In addition, SOILD65, LINK180, SHELL181 and SOLID185 elements are used, respectively, to model concrete, steel reinforcement, polymer and steel plate support. A comparative study between the nonlinear finite element and analytical models, including the ACI 440.2 R-08 and FIB14 models as well as experimental data, is also carried out. Findings The comparative study of the nonlinear finite element results with analytical models shows that the difference between the predicted load capacity ranges from 4.44%–24.49% in the case of the ACI 440.2 R-08 model, while the difference for FIB14 code ranges from 2.69%–26.03%. It is clear that there is a good agreement between the nonlinear finite element analysis (NLFEA) results and the different expected CFRP codes. Practical implications This model can be used to explore the behavior and predict the RC beams strengthened in shear with different CFRP properties. They could be used as a numerical platform in contrast to expensive and time-consuming experimental tests. Originality/value On the basis of the results, a good match is found between the model results and the experimental data at all stages of loading the tested samples. Load capacities as well as load deflection curves are also presented. It is concluded that the differences between the loads at failure ranged from 0.09%–6.16% and 0.56%–4.98%, comparing with experimental study. In addition, the increase in compressive strength produces an increase in the ultimate load capacity of the beam. The difference in the ultimate load capacity was less than 30% when compared with the American Concrete Institute and FIB14 codes.

scholarly journals ENHANCING OF FLEXURAL STRENGTH OF WEB OPENING REINFORCED GEOPOLYMER BEAMS BY USING FRP STRIPS

2021 ◽  
Vol 25 (Special) ◽  
pp. 4-135-4-149
Author(s):  
Oday H. Abbas ◽  
◽  
Hesham A.Numan ◽  
Keyword(s):  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Polymer Materials ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Normal Concrete ◽  
Web Opening ◽  
Reinforced Polymer

This study is devoted to inspect the flexural behavior of Geopolymer reinforced concrete beams with “large” web transverse opening and strengthened by three kinds of Fiber Reinforced Polymer materials. The implemented experimental program comprised casting eight beams under static and “one stage” repeated load, two of these are normal concrete beams and the others are Geopolymer beams. These beams are divided into two groups, the first comprised four beams of solid and beams “with transvers web opening” under static load for normal and Geopolymer concrete beams. The second group are of four Geopolymer beams that one of them is “un strengthened and having transvers web opening” while the others are also have transvers web opening but strengthened by different kinds of Fiber Reinforced Polymer materials sheets that installed vertically aligned and accompanied with the 90mm diameter large circular web opening. The strengthening materials included are Carbon Fiber Reinforced Polymer, Glass fiber Reinforced Polymer and Hybrid (one layer of Glass + one layer of Carbon) reinforced polymer sheets. The results showed that for the ultimate load capacity was decreased by 9.96% for holed normal concrete beam if compared with solid normal concrete solid beam while such capacity was decreased 2.25% and 11.89% for solid and holed Geopolymer beams respectively. In addition to that, the maximum load capacity is also decreased by 8.16%, 10.20% and 12.25% for Glass, Carbon and Hybrid fiber reinforced polymer strengthened beams if compared with reference beams “holed un strengthened beam” subjected to cyclic load.

Shear Failure Analysis of Concrete Beams Reinforced with Newly Developed GFRP Stirrups

2006 ◽  
Vol 324-325 ◽  
pp. 995-998
Author(s):  
Cheol Woo Park ◽  
Jong Sung Sim
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Shear Stresses ◽  
Fiber Reinforced ◽  
Shear Span ◽  
Reinforced Polymer ◽  
A New Technique

Even though the application of fiber reinforced polymer (FRP) as a concrete reinforcement becomes more common with various advantages, one of the inherent shortcomings may include its brittleness and on-site fabrication and handling. Therefore, the shape of FRP products has been limited only to a straight bar or sheet type. This study suggests a new technique to use glass fiber reinforced polymer (GFRP) bars for the shear reinforcement in concrete beams, and investigates its applicability. The developed GFRP stirrup was used in the concrete instead of ordinary steel stirrups. The experimental program herein evaluates the effectiveness of the GFRP stirrups with respect to different shear reinforcing ratios under three different shear span-to-depth testing schemes. At the same shear reinforcing ratio, the ultimate loads of the beams were similar regardless the shear reinforcing materials. Once a major crack occurs in concrete, however, the failure modes seemed to be relatively brittle with GFRP stirrups. From the measured strains on the surface of concrete, the shear stresses sustained by the stirrups were calculated and the efficiency of the GFRP stirrups was shown to be 91% to 106% depending on the shear span-to-depth ratio.

RETROFITTING PERFORMANCE OF REINFORCED CONCRETE ONE WAY SLAB

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Norliyati Mohd Amin ◽  
Nur Aqilah Aziz ◽  
Ilya Joohari ◽  
Anizahyati Alisibramulisi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Strength Performance ◽  
Concrete Crack ◽  
Reinforced Polymer ◽  
Structural Capacity

Cracks in concrete structure have always been a big threat on the strength of the concrete. Crack is one of the common deterioration observed in reinforced concrete beams and slabs. Concrete cracking is a random process, highly variable and influenced by many factors. To restore the structural capacity of the concrete damages, retrofitting and strengthening are required. There are several techniques that are used for retrofitting and strengthening reported in the literature [1], [2], [3]. This paper investigates the strength performance of retrofitting and strengthening methods of reinforced concrete one-way slab. Flexural bending test are performed on three different concrete slab of size 1000 mm x 500 mm x 75 mm. The methods that are used for retrofit are epoxy injection and patching and for the strengthening is lamination of carbon fiber reinforced polymer. The slabs were loaded to a certain stage where the cracks were formed for retrofitting and strengthening procedure. The achieved failure mode and load capacity of the concrete slab were observed. The repaired techniques for restoring and improving the structural capacity of cracked concrete slabs were analyzed. The ultimate load achieved for the epoxy injection laminate was 19.60 kN followed by CFRP laminate and patching that were 17.64 kN and 17.03 kN respectively. While the deflection value for the three specimens were 14.42 mm, 4.49 mm and 7.036 mm.  

scholarly journals An experimental study on flexural strengthening of RC beams using CFRP sheets

2018 ◽  
Vol 7 (4) ◽  
pp. 2075 ◽  
Author(s):  
Yasmin Murad
Keyword(s):  
Flexural Strength ◽  
Orientation Angle ◽  
Longitudinal Axis ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Rc Beams ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Cfrp Sheets ◽  
Reinforced Polymer

 The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.  

scholarly journals Seismic Retrofitting of Traditional Masonry with Pultruded FRP Profiles

2020 ◽  
Vol 10 (7) ◽  
pp. 2489 ◽  
Author(s):  
Francesca Sciarretta
Keyword(s):  
Maximum Load ◽  
Seismic Retrofitting ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Future Research ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Before And After ◽  
Basic Frame

This paper presents a study on the potentiality of seismic retrofitting solutions with pultruded Fiber Reinforced Polymer (FRP) profiles. This material can be used in connected frames providing lightweight, corrosion-free and reversible retrofitting of masonry buildings with the moderate requirements of surface preservation. In a hypothetical case study, an experimental program was designed; monotonic shear tests on a half-size physical model of the sample wall were performed to assess the structural performance before and after retrofitting with a basic frame of pultruded Glass Fiber Reinforced Polymer (GFRP) C-shaped profiles, connected to the masonry by steel threaded bar connections. During the tests, the drift, the diagonal displacements in the masonry and the micro-strain in the profiles were measured. The retrofitted system has proven very effective in delaying crack appearance, increasing the maximum load (+85% to +93%) and ultimate displacement (up to +303%). The failure mode switches from rocking to a combination of diagonal cracking and bed joint sliding. The gauge recordings show a very limited mechanical exploitation of the GFRP material, despite the noticeable effectiveness of the retrofit. The application seems thus promising and worth a deeper research focus. Finally, a finite element modelling approach has been developed and validated, and it will be useful to envisage the effects of the proposed solution in future research.

Experimental study on the behavior of carbon fiber reinforced polymer sheets bonded to concrete

2006 ◽  
Vol 33 (11) ◽  
pp. 1438-1449 ◽  
Author(s):  
Ayman S Kamel ◽  
Alaa E Elwi ◽  
Roger J.J Cheng
Keyword(s):  
Carbon Fiber ◽  
Failure Mechanism ◽  
Test Method ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This paper presents a study on the interfacial behavior of carbon fiber reinforced polymer (CFRP) sheets when applied to concrete members as external reinforcement. Two bond test methods that are detailed in the paper were used in separate test series to study the bond behavior and failure mechanism of CFRP sheets bonded to concrete. A modified push-apart test method was proposed and tested. It was concluded that there existed an effective length beyond which there will be no increase in the ultimate capacity of the joint. An experimental test method to determine the effective bond length was also proposed and tested. The strains at the edge of the CFRP sheets are consistently higher than those at the center. The anchorage requirements for the CFRP sheets were also investigated in this study. Anchor sheets placed at 90° to the primary test sheets and bonded underneath the tested sheet showed better or equivalent overall bond behavior compared with those bonded on top of the tested sheet. The distance at which the anchor sheet is placed from the crack does not appear to change the bond behavior.Key words: bond, concrete, debonding, failure mechanism, carbon fiber reinforced polymer (CFRP) sheets, anchor sheets.

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