Effect of Confinement Level and Staggering on Seismic Performance of Lap-Spliced GFRP-Reinforced Concrete Columns
Publication: Journal of Composites for Construction
Volume 28, Issue 2
Abstract
In this study, we evaluate the seismic performance of concrete columns reinforced with lap-spliced glass fiber–reinforced polymer (GFRP) bars through simulated earthquake loads. Six 400 × 400 mm columns with an overall height of 1,850 mm were tested. Five columns were reinforced with lap-spliced GFRP bars and one was reinforced with continuous GFRP bars to serve as a reference for comparative purposes. The primary test variables were the transverse reinforcement spacing, tie configuration, and number of bars spliced at the critical section. The experimental investigation was followed by an evaluation of the provisions of related North American design standards on the effect of the confinement and staggering of the lap-splice length. The test results show that the level of confinement and staggering affected the hysteretic response, load-carrying capacity, and bond performance of the column specimens. The influence of the amount of transverse reinforcement on the deformability of the columns was found to be considerable. Staggering, however, did not significantly affect the deformability. A comparison of the results with existing design standards demonstrated that the current provisions in the CAN/CSA S6-19 and ACI 440.11-22 standards for monotonic loading need improvement in order to provide accurate results when considering confinement and staggering in predicting the lap-splice length of GFRP-RC columns under seismic loading.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
This research study was conducted with funding from the Natural Science and Engineering Research Council of Canada (NSERC–Alliance Program–ALLRP556942-20). The assistance received from the technical staff of the Canadian Foundation for Innovation (CFI) Structural Laboratory in the Department of Civil & Building Engineering at the University of Sherbrooke (QC, Canada) is also acknowledged.
Notation
The following symbols are used in this paper:
- Ab
- bar area;
- Atr
- reinforcement area within ld;
- db
- bar diameter;
- dcs
- shortest distance from the center of the bar being developed to the closest concrete surface or two-thirds of the center-to-center spacing of the bars being developed;
- EFRP
- modulus of elasticity of FRP bars;
- Es
- modulus of elasticity of steel bars;
- fcr
- concrete cracking strength;
- fFRPu
- specified (or guaranteed) tensile strength of an FRP bar;
- fy
- specified yield strength of steel reinforcement;
- k1
- bar location factor;
- k4
- bar surface factor;
- Ktr
- transverse reinforcement index;
- ld
- bar tension development length;
- n
- number of bars developing along the potential plane of splitting;
- Ps
- concrete spalling load;
- s
- maximum center-to-center spacing of the transverse reinforcement within a distance ld;
- Δe
- elastic deflection;
- Δe1
- deflection corresponding to the initiation of concrete spalling;
- Δe2
- elastic deflection in the second approach;
- Δu
- deflection of the column corresponding to a 20% decay in peak load or failure of the longitudinal bars, whichever occurs first;
- μΔ1
- displacement deformability calculated based on the first approach; and
- μΔ2
- displacement deformability calculated based on the second approach.
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Published In
Journal of Composites for Construction
Volume 28 • Issue 2 • April 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Jun 18, 2023
Accepted: Nov 29, 2023
Published online: Jan 11, 2024
Published in print: Apr 1, 2024
Discussion open until: Jun 11, 2024
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