Debonding Limit of the Externally Glued FRP Reinforcements Applied on Clay Brick Substrate: Statistical Assessment of a Design Formula

2014 ◽  
Vol 624 ◽  
pp. 486-493
Author(s):  
Pietro Carrara ◽  
Francesco Freddi
Keyword(s):  
Design Procedure ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Clay Brick ◽  
Present Contribution ◽  
Clay Bricks ◽  
Reinforced Polymer ◽  
Alternative Formula ◽  
Testing Approach ◽  
Composite Fabrics

The present contribution aims to statistically assess a design procedure to estimate the bond resistance of composite fabrics externally glued on clay brick masonry substrates. Based on recent experimental campaigns a database of bond test results between fiber reinforced polymer and clay bricks is collected and an alternative formula is proposed starting from theoretical and experimental evidence. Then, its characteristic value is evaluated following the "Design Assisted by Testing Approach" suggested in the Eurocode 0. The capabilities of the proposed method are statistically evaluated and the advantages with respect to existing formulas are discussed.

Research on Static Load Tests of Damaged Bridge Strengthened with Pre-Stressed HFRP

2014 ◽  
Vol 1079-1080 ◽  
pp. 258-265
Author(s):  
Chen Ning Cai ◽  
Shan He ◽  
Li Na Liu ◽  
Shi Kun Ou
Keyword(s):  
Static Load ◽  
Flexural Rigidity ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Tests

Thispaper presents an experimental study to strengthen an existing bridge usingpre-stressed carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer(GFRP) materials. The method using pre-stressed hybrid fiber reinforced polymer(HFRP) to strengthened structural members is an emerging pre-stressed strengtheningtechnology. In this study, experimental data selected from result of staticloading test conducted to hollow slabs with CFRP/GFRP has been compared with specimenswithout strengthening. Test results showed that the strengthening methoddeveloped in this study could effectively reduce the stress in hollow slab,improving the flexural rigidity and inhibiting the concrete from fracture.

scholarly journals Punching Shear Strength of Reinforced Concrete Flat Plates with GFRP Vertical Grids

2021 ◽  
Vol 11 (6) ◽  
pp. 2736
Author(s):  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Test Results ◽  
Shear Reinforcement ◽  
Flat Plates ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Vertical Grids

In this study, the structural behavior of reinforced concrete flat plates shear reinforced with vertical grids made of a glass fiber reinforced polymer (GFRP) was experimentally evaluated. To examine the shear strength, experiments were performed on nine concrete slabs with different amounts and spacings of shear reinforcement. The test results indicated that the shear strength increased as the amount of shear reinforcement increased and as the spacing of the shear reinforcement decreased. The GFRP shear reinforcement changed the cracks and failure mode of the specimens from a brittle punching to flexure one. In addition, the experimental results are compared with a shear strength equation provided by different concrete design codes. This comparison demonstrates that all of the equations underestimate the shear strength of reinforced concrete flat plates shear reinforced with GFRP vertical grids. The shear strength of the equation by BS 8110 is able to calculate the punching shear strength reasonably for a concrete flat plate shear reinforced with GFRP vertical grids.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

Concrete Beams Reinforced with GFRP Plates

2017 ◽  
Vol 747 ◽  
pp. 220-225
Author(s):  
Alberto Pedro Busnelli ◽  
Ruben Edgardo López ◽  
Jorge Carlos Adue
Keyword(s):  
Glass Fiber ◽  
Carbon Fibers ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
The World ◽  
Critical Resistance

This is the presentation of the research carried out by the Faculty of Engineering at Universidad Nacional de Rosario on the use of pultruded Glass Fiber Reinforced Polymer (GFRP) plates to increase the flexural strength of reinforced concrete beams.Pultruded plates are the type of elements made of composite materials which are most widely used for this kind of strengthening. Although around the world the material used for these plates is carbon fibers, its high cost prevents its widespread use in our country.One of the aims of our research program is, precisely, to verify whether it is possible to substitute such plates for significantly cheaper glass fiber elements manufactured in Argentina. The test results have proved that this alternative is feasible.What's more, the greater thickness of the glass fiber plates allows the use of additional anchor bolts. These bolts provide the system with post-critical resistance and ductility-characteristics which are absolutely necessary, for example, in structures in seismic areas.

scholarly journals Sulfate and Calcium Chloride Resistance of Steel/Glass Fiber-Reinforced Polymer Hybrid Panel for Improved Movable Weir Application

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
S.-K. Lee ◽  
S.-Y. Yoo ◽  
C.-G. Park
Keyword(s):  
Glass Fiber ◽  
Calcium Chloride ◽  
Residual Strength ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Glass Fiber Reinforced Polymer ◽  
Sand Blasting ◽  
Steel Panel ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced

This study evaluated the performance of a hybrid panel that can overcome the current problem of corrosion of the steel panels of improved movable weirs when they are exposed to a sulfate and calcium chloride environment such as sea water. A hybrid panel with glass fiber-reinforced polymer (GFRP) layers on both sides of a steel panel means that the central panel is not exposed to the external elements, which can avoid corrosion problems. In this study, to maximize the hybrid panel’s strength and durability, the moisture absorption characteristics and the durability in an accelerated environment were evaluated. The test results were considered to indicate no durability issues as the final absorption ratio was approximately 2.0% or less in all environments. Also, from the accelerated deterioration test results when the steel panel processed by sand blasting was applied in all accelerated deterioration environments, it satisfied the residual strength level of 65% or more. However, in the case without surface processing, upon exposure to MgSO4 solution, it did not satisfy the standard residual strength level of 65%. These results show that sand blasting on the surface of a steel panel is adequate for hybrid panels for improved movable weirs.

Strengthening of reinforced concrete corbels with GFRP overlays

2011 ◽  
Vol 18 (1-2) ◽  
pp. 69-77 ◽  
Author(s):  
Sevket Ozden ◽  
Hilal Meydanli Atalay
Keyword(s):  
Reinforced Concrete ◽  
Reinforcement Ratio ◽  
Fiber Reinforced Polymer ◽  
Peak Performance ◽  
Test Results ◽  
Loading Test ◽  
Load Bearing Capacity ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Normal Strength

AbstractThe strength and post-peak performance of reinforced concrete corbels, strengthened with epoxy bonded glass fiber reinforced polymer (GFRP) overlays, were experimentally investigated. The test variables were the corbel shear span to depth ratio, corbel main reinforcement ratio, and the number and orientation of the GFRP fibers. In total, 24 normal strength concrete, one-third scale, corbel specimens, without hoop reinforcement, were tested to failure under quasi-static gravity loading. Test results revealed that GFRP overlays can easily be used for the enhancement of corbel load bearing capacity, depending on the fiber orientation. The main reinforcement ratio and the number of GFRP plies were found to be the two main variables affecting the level of strength gain in the corbel specimens.

EFFECT OF WET-DRY CYCLING ON BOND BEHAVIOR OF GFRP STRENGTHENED HISTORIC MASONRY STRUCTURES

2016 ◽  
Vol 78 (5-2) ◽  
Author(s):  
Meng Jing ◽  
Werasak Raongjant
Keyword(s):  
Research Work ◽  
Fiber Reinforced Polymer ◽  
Masonry Structures ◽  
Test Results ◽  
Bond Behavior ◽  
Historic Masonry ◽  
Water Permeation ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Cycling Condition

The objective of this research work is to determine the effect of wet-dry cycling on bond behavior of historic masonry structures strengthened by Glass Fiber Reinforced Polymer (GFRP). Shear bond testing was carried out through total 36 specimens exposed to dry, full moisture or wet-dry cycling conditions.  The selected samples were then tested at 0, 30, 60 and 90 days. Post-ageing test was also preceded on total sixty masonry prisms exposed to dry, full moisture or wet-dry cycling conditions. The compressive strengths of selected samples were then tested at 0, 40, 70 and 100 days. The test results showed an obvious decrease of the bond strength between GFRP sheets and bricks in the wet-dry cycling condition. For masonry prisms with or without GFRP strengthening, in the first 40 days, the compressive strength of GFRP bonded prism decreased quickly to the value near that of prism without GFRP. After 40 days the rate of decrease became slow, which means that, sheets retrofitted outside the masonry prisms helped to improve their durability by reducing water permeation. 

Theoretical Assessment of FRP Tendon Wedge Anchorage System

2010 ◽  
Vol 168-170 ◽  
pp. 1006-1009
Author(s):  
Ping Zhuge ◽  
Su Wei Hou ◽  
Shi Zhong Qiang ◽  
Ming Hu Liu
Keyword(s):  
Friction Coefficient ◽  
Carrying Capacity ◽  
Fiber Reinforced Polymer ◽  
Transverse Displacement ◽  
Test Results ◽  
Working Mechanism ◽  
System Effect ◽  
Reinforced Polymer ◽  
Anchorage System ◽  
Theoretical Assessment

In order to improve designing and well understanding the working mechanism for fiber reinforced polymer (FRP) tendon wedge anchorage system (FWAS), a theory for solving the anchorage system was presented in this paper. A designing guidelines of anchorage system was established. The theory was checked by comparing the analytical and test results of a Carbon FRP tendon anchrage system. Effect of presetting load and friction coefficient of sleeve-FRP tendon interface on anchorage performance were evaluated by the theory. The results show that, The theory was proved to be correct, it can be used to predict the carrying capacity of FWAS, and it can calculate the stress and transverse displacement of any point of the anchorage system. The presetting load and friction coefficient of sleeve-FRP tendon interface have great impact to anchorage performance.

Deflection Prediction of FRP-Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 243-249 ◽  
pp. 621-624
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Test Results ◽  
Structural Members ◽  
Modified Model ◽  
Reinforced Polymer ◽  
Service Load ◽  
Good Agreement

Bonding fiber reinforced polymer (FRP) laminates to the tension face of RC members has been proven to be an effective method to improve the flexural strength. However, structural members are not only needed to have adequate strength, but also to have adequate performance of deformation at service load levels. To evaluate the deflection of externally FRP-strengthened RC beams, a total of 18 RC beams, including 16 beams strengthened with CFRP laminate under different preload levels and 2 control beams, were tested. Based on the assumption that the section of the beam behaves a tri-linear moment-curvature response characterized by pre-crack stage, post-crack stage and failure stage and the test results, this paper presents a modified model to evaluate the deflection of CFRP-strengthened RC beams. The present modified model was verified by the similar test results, and shows a good agreement with the test results.

scholarly journals Experimental Investigation of the Fatigue Behavior of Basalt Fiber Reinforced Polymer Grid-Concrete Interface

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bo Wen ◽  
Chunfeng Wan ◽  
Lin Liu ◽  
Da Fang ◽  
Caiqian Yang
Keyword(s):  
Failure Modes ◽  
Fatigue Behavior ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Fiber Reinforced ◽  
Loading Level ◽  
Reinforced Polymer ◽  
Concrete Interface ◽  
Basalt Fiber Reinforced Polymer

Fatigue behavior is an important factor for mechanical analysis of concrete members reinforced by basalt fiber reinforced polymer (BFRP) grid and polymer cement mortar (PCM) and plays a critical role in ensuring the safety of reinforced concrete bridges and other structures. In this study, on the basis of the static loading test results of concrete specimens reinforced by BFRP grid and PCM, a series of fatigue tests with different loading levels were conducted on interfaces between BFRP grid and concrete to investigate the fatigue behavior of BFRP grid-concrete interfaces. The test results indicate that with high loading level, the fatigue failure mode of interface is interfacial peeling failure while it transforms to the fatigue fracture of the BFRP grid under low loading level. The fatigue life (S-N) curves of BFRP grid-concrete interface are obtained and fitted in stages according to different failure modes, and the critical point of the two failure modes is pointed out. The relative slip evolution of interface during fatigue is further revealed in different stages with two failure modes, and the law of interface strain is studied with the increase of fatigue times. The relation of effective bonding length of interface and fatigue times is also described.

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