Residual behaviour of glass FRP bars subjected to high temperatures

This research study investigates the flexural behavior of fiber reinforced polymer (FRP) bars after being subjected to different levels of elevated temperatures (100, 200 and 300°C). Three types of glass FRP bars (ribbed, sand coated, and helically wrapped) and one type of carbon FRP bars (sand coated) were used in this study. Two testing scenarios were used: a) testing specimens immediately after heating and b) keeping specimens to cool down before testing. Test results showed that as the temperature increased the flexural strength and modulus of the tested FRP bars decreased. At temperatures higher than the glass transition temperature (Tg), significant flexural strength and modulus losses were recorded. Smaller diameter bars showed better residual flexural strength and modulus than larger diameter bars. The immediately tested bars showed significant strength and modulus losses compared to bars tested after cooling. Different types of GFRP bars showed comparable results. However, the helically wrapped bars showed the highest flexural strength losses (37 and 60%) while the sand coated bars showed the lowest losses (29 and 39%) after exposure to 200 and 300℃, respectively. The carbon FRP bars showed residual flexural strengths comparable to those recorded for the GFRP bars; however, they showed lower residual flexural modulus after being subjected to 200 and 300℃.

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Bond Strength of Glass FRP Bars in Concrete Subjected to Freeze-Thaw Cycles and Sustained Loads

Advances in FRP Composites in Civil Engineering ◽

10.1007/978-3-642-17487-2_80 ◽

2011 ◽

pp. 368-371 ◽

Cited By ~ 1

Author(s):

Juliana Alves ◽

Amr El-Ragaby ◽

Ehab El-Salakawy

Keyword(s):

Bond Strength ◽

Freeze Thaw ◽

Sustained Loads ◽

Glass Frp ◽

Frp Bars

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Designing and Testing of Concrete Bridge Decks Reinforced with Glass FRP Bars

Journal of Bridge Engineering ◽

10.1061/(asce)1084-0702(2006)11:2(217) ◽

2006 ◽

Vol 11 (2) ◽

pp. 217-229 ◽

Cited By ~ 77

Author(s):

Brahim Benmokrane ◽

Ehab El-Salakawy ◽

Amr El-Ragaby ◽

Thomas Lackey

Keyword(s):

Bridge Decks ◽

Concrete Bridge ◽

Concrete Bridge Decks ◽

Glass Frp ◽

Frp Bars

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Sensing Properties of Fused Silica Single-Mode Optical Fibers Based on PPP-BOTDA in High-Temperature Fields

Sensors ◽

10.3390/s19225021 ◽

2019 ◽

Vol 19 (22) ◽

pp. 5021

Author(s):

Jiahui Shen ◽

Ting Li ◽

Hong Zhu ◽

Caiqian Yang ◽

Kai Zhang

Keyword(s):

High Temperature ◽

Optical Fiber ◽

High Temperatures ◽

Optical Fibers ◽

Large Strain ◽

Single Mode ◽

Fused Silica ◽

Thermomechanical Coupling ◽

Temperature Fields ◽

Frp Bars

The strain of fiber-reinforced polymer (FRP) bars at high temperatures is currently difficult to measure. To overcome this difficulty, a method of smart FRP bars embedded with optical fibers was proposed and studied, in which an ordinary single-mode optical fiber was applied as a distributed sensor. In this paper, both the distributed temperature and strain-sensing characteristics of optical fiber were studied based on pulse pre-pump Brillouin optical time-domain analysis (PPP-BOTDA) under high temperature. The temperature and strain coefficients were investigated under a thermomechanical coupling environment with consideration of large strain levels. The experimental results show that the temperature and strain coefficients decreased as the temperature increased, because the properties of silica and coating materials changed with temperature. Then, the formulas for determining the temperature and strain coefficients at high temperatures were introduced and discussed. The excellent sensing performance of the optical fiber indicated that smart FRP bars have the potential for use at high temperatures.

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Evaluation of FRP Bars under Compression and Their Performance in RC Columns

Materials ◽

10.3390/ma13204541 ◽

2020 ◽

Vol 13 (20) ◽

pp. 4541 ◽

Cited By ~ 2

Author(s):

Laith AlNajmi ◽

Farid Abed

Keyword(s):

Mechanical Properties ◽

Cross Sections ◽

Total Force ◽

Compression Tests ◽

Rc Columns ◽

Static Compression ◽

Compression Members ◽

Different Diameters ◽

Glass Frp ◽

Frp Bars

The behavior of fiber-reinforced polymer (FRP) bars under compression is not fully understood yet due to the limited research in this area. However, the long-term durability, weathering resistance, and exceptional mechanical properties of FRP bars justify the need for their use in compression members. The main objectives of this study are to evaluate the mechanical properties of glass FRP (GFRP) and basalt FRP (BFRP) bars under compression and examine their performances as main longitudinal reinforcements in reinforced concrete (RC) columns. In the first part of this research, a series of static compression tests were conducted on GFRP and BFRP bars of different diameters. The second part of this research numerically investigated the behavior of FRP-RC columns under concentric and eccentric loading using the mechanical properties of the FRP bars obtained experimentally. Nonlinear finite element models were developed to simulate the compressive behavior of the concrete columns reinforced with GFRP and BFRP bars. The FE models were verified with the experimental results conducted previously. The verified FE models are then utilized to conduct a parametric analysis considering two different column geometries and cross-sections, five reinforcement ratios, two concrete compressive strengths, three types of ties materials, and several loading eccentricities to develop a set of interaction diagrams that may provide valuable data for design purposes. The results indicated that the FRP bars could have a significant contribution to the overall capacity of FRP-RC columns by up to 35% of the total force at failure, depending on the reinforcement ratio. The performance of both the GFRP- and BFRP-RC columns was almost similar in terms of capacity, deflection, and bar strength contribution.

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