Experimental investigation on the use of glass fiber reinforced polymer reinforcement in hollow‐core circular concrete columns

Fiber reinforced polymer (FRP) has been widely used in repairing and strengthening of damaged concrete columns due to its excellent material properties. Most of the existing compressive strength models for FRP-confined concrete columns have been established through regression analyses of experimental data, and only a few models were established based on theoretical derivation. Therefore, to extend these compressive strength models based on theoretical derivation, a new strength model based on the Drucker-Prager yield criterion was established in this article, which is suitable for predicting the strength of FRP-confined circular and square concrete columns with loaddamaged, fire-damaged and strain rate. To study the strength model of FRPconfined concrete columns, the author collected 675 test data from published literature and built a large database containing cross-section type, damage type, damage degree and strain rate. In this database, most of the existing strength models in the published literature and the model proposed in this article were evaluated. The evaluation results show that the model can accurately predict the compressive strength of FRP-confined circular and square concrete columns with undamaged, load-damaged, fire-damaged and strain rate.

Section: Introductionmentioning

confidence: 99%

Analysis of a compressive strength model for FRP‐confined damaged concrete columns based on the Drucker–Prager yield criterion

Zhang

Xiong

Musa

et al. 2022

Axial and bending behavior of GFRP bar‐reinforced hollow‐core polypropylene fiber concrete columns

Ahmad,

Sheikh,

Hadi

2024

This study reported the axial (concentric and eccentric) and bending (four‐point bending) loadings behavior of glass fiber‐reinforced polymer (GFRP) bar‐reinforced hollow‐core polypropylene fiber concrete (HC‐GFRP‐PFC) columns. The confinement effect of HC‐GFRP‐PFC columns with different center‐to‐center (c/c) spacing of GFRP spirals was also investigated. Twelve hollow‐core circular specimens with an outer diameter of 214 mm and an inner (circular hole) diameter of 56 mm were experimentally investigated. Four reference specimens were cast with nonfibrous (normal) concrete, whereas the remaining eight specimens were cast with polypropylene fiber (0.15% by volume of concrete) concrete. It was found that, with a similar ratio of reinforcement, the HC‐GFRP‐PFC specimens gained 2%–4% higher maximum load (PMaximum) and 9%–19% higher ductility (μ) than the GFRP bar‐reinforced hollow‐core nonfibrous concrete (HC‐GFRP‐NFC) specimens under concentric axial loading and four‐point bending. The HC‐GFRP‐PFC specimens with a 30 mm c/c spacing of the GFRP spiral gained 6%–36% higher PMaximum and 4%–59% higher μ than the HC‐GFRP‐PFC specimens with a 60 mm c/c spacing of the GFRP spirals under different loading conditions.

Experimental, theoretical and numerical study on flexural behavior of hybrid steel‐GFRP reinforced concrete slabs

Meghdadi,

Khaloo

2024

This paper presents the experimental results of six full‐scale one‐way reinforced concrete slabs with variations in reinforcement detailing. Test specimens consisted of two reference concrete slabs reinforced fully with glass fiber reinforced polymer (GFRP) rebars or with steel rebars and four hybrid‐reinforced slabs. The variables included the arrangement of rebars, mechanical reinforcing ratio, and the ratio of steel rebar area to GFRP rebar area. The fabricated specimens were subjected to four‐point loading until failure in the strong floor laboratory. Experimental results indicated that hybrid reinforcement enhances stiffness compared to FRP reinforcement and provides a higher load‐bearing capacity than steel reinforcement. Also, it was observed that FRP bars placed as tensile reinforcement, similar in number and diameter size to steel bars placed as compressive reinforcement in a slab result in the highest ultimate capacity. Moreover, it was observed that while the mechanical reinforcing ratio contributes to the overall behavior of hybrid‐reinforced concrete slabs, the ratio of steel rebar area to GFRP rebar area is not considerably effective. Furthermore, image processing was employed to determine the exact crack widths of specimens after failure. Finally, finite element modeling results showed good agreement with the experimental results.