Factors Affecting the Ultimate Condition of FRP-Wrapped Concrete Columns

Chen, Jian Fei; Li, S. Q.; Bisby, Luke

doi:10.1061/(asce)cc.1943-5614.0000314

Cited by 59 publications

(26 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These variations can be mainly attributed to concrete crack growth and variations in CFRP thickness where, as expected, it is evident that regions with fewer layers of CFRP experience proportionally higher hoop strains. These observation are in agreement with Lam and Teng [5], Lam et al [23], Smith et al [22], Chen et al [35] and Wu and Jiang [24], where a non-uniform distribution of hoop strains outside the overlap region was observed in NSC specimens. It can also be observed from Figs.…”

Section: Hoop Strain Development On Cfrp Shellsupporting

confidence: 90%

Influence of overlap configuration on compressive behavior of CFRP-confined normal- and high-strength concrete

Vincent

Ozbakkaloglu

2015

Mater Struct

View full text Add to dashboard Cite

This paper presents the findings of an experimental investigation on the effect of overlap configuration on carbon fiber-reinforced polymer (CFRP)-confined normal-and high-strength concrete. A total of 33 specimens were prepared and tested under monotonic axial compression. All specimens were cylinders with 152 mm diameter and 305 mm height and confined by CFRP tubes. Two different concrete mixes were examined, with average compressive strengths of 52.0 and 84.7 MPa. The effect of overlap configuration was examined by manufacturing the specimens with different properties at the overlap region including overlap length, continuity and distribution. Axial and lateral behavior was recorded to observe the axial stress-strain relationship and hoop strain behavior for concentric compression. Ultimate axial and lateral conditions are tabulated and stress-strain curves have been provided. Detailed plots of hoop strain development and lateral confinement pressure at ultimate are presented. The results indicate that FRP overlap length has no significant influence on strain enhancement ratio (e cu /e co ), but an increase in overlap length leads to a slight increase in strength enhancement ratio (f 0 cc /f 0 co ), with these observations equally applicable to both continuously and discontinuously wrapped specimens. The results also indicate that continuity of the FRP sheet in the overlap region has some influence on the effectiveness of FRP confinement. Furthermore, it was observed that the distribution of FRP overlap regions for discontinuously wrapped specimens can influence the axial compressive behavior of these specimens in certain overlap configurations. Finally, it is found that the distribution of lateral confining pressure around specimen perimeter becomes less uniform for specimens with higher concrete strengths and those manufactured with overlap regions that are not evenly distributed. KeywordsConcrete Á High-strength concrete (HSC) Á Fiber-reinforced polymer (FRP) Á Columns Á Confinement Á Overlap Á Hoop strain Á Confinement pressure List of symbols D Diameter of concrete cylinder (mm) E f Modulus of elasticity of the fibers (MPa) Eff 1 Effectiveness of a given confinement arrangement in enhancing the ultimate strength (m -1 ) Eff 2 Effectiveness of a given confinement arrangement in enhancing the ultimate strain (m -1 ) f 0 cc Peak axial compressive stress of FRPconfined concrete (MPa) f 0 cc f 0 co Ultimate strength enhancement ratio f 0 co Peak axial compressive stress of unconfined concrete (MPa)

show abstract

Section: Hoop Strain Development On Cfrp Shellsupporting

confidence: 90%

Influence of overlap configuration on compressive behavior of CFRP-confined normal- and high-strength concrete

Vincent

Ozbakkaloglu

2015

Mater Struct

View full text Add to dashboard Cite

show abstract

“…It is worth noting that validation experiments using the PIV code reported by White et al [53] have demonstrated that the precision of this measurement technique is typically better than 1/10th of one pixel and the strain precision of the technique is a function of the size of the image, the resolution of the cameras used, and the chosen gauge length. Recently, some researchers [54,55,56,57] employed PIV technique to catch axial and hoop strain distribution in FRP jacket of FRP-confined concrete columns because this technique is capable of measuring strains in a patch with a certain area simultaneously.…”

Section: Experimental Programmentioning

confidence: 99%

Behavior and Three-Dimensional Finite Element Modeling of Circular Concrete Columns Partially Wrapped with FRP Strips

2018

View full text Add to dashboard Cite

Fiber-reinforced polymer (FRP) jacketing/wrapping has become an attractive strengthening technique for concrete columns. Wrapping an existing concrete column with continuous FRP jackets with the fiber in the jacket being oriented in the hoop direction is referred to as FRP full wrapping strengthening technique. In practice, however, strengthening concrete columns with vertically discontinuous FRP strips is also favored and this technique is referred to as FRP partial wrapping strengthening technique. Existing research has demonstrated that FRP partial wrapping strengthening technique is a promising and economical alternative to the FRP full wrapping strengthening technique. Although extensive experimental investigations have hitherto been conducted on partially FRP-confined concrete columns, the confinement mechanics of confined concrete in partially FRP-confined circular columns remains unclear. In this paper, an experimental program consisting of fifteen column specimens was conducted and the test results were presented. A reliable three-dimensional (3D) finite element (FE) approach for modeling of partially FRP-confined circular columns was established. In the proposed FE approach, an accurate plastic-damage model for concrete under multiaxial compression is employed. The accuracy of the proposed FE approach was verified by comparisons between the numerical results and the test results. Numerical results from the verified FE approach were then presented to gain an improved understanding of the behavior of confined concrete in partially FRP-confined concrete columns.

show abstract

“…There is a consensus that the presence of the triaxial stress state in FRP affects the actual 281 rupture strain of the fiber (Chen et al 2013). In this experimental program, it is obvious that 282 the axial stress of the FRP jackets in the fully wrapped specimens is higher than that of the 283 non-uniformly wrapped specimens.…”

Section: Lateral Strain 267mentioning

confidence: 97%

Optimized FRP Wrapping Schemes for Circular Concrete Columns under Axial Compression

2015

View full text Add to dashboard Cite

This study investigates the behavior and failure modes of FRP confined concrete wrapped with different FRP schemes, including fully wrapped, partially wrapped and non-uniformly wrapped concrete cylinders. By using the same amount of FRP, this study proposes a new wrapping scheme that provides a higher compressive strength and strain for FRP-confined concrete, in comparison with conventional fully wrapping schemes. A total of thirty three specimens were cast and tested, with three of these specimens acting as reference specimens and the remaining specimens wrapped with different types of FRP (CFRP and GFRP) by different wrapping schemes. For specimens that belong to the descending branch type, the partially wrapped specimens had a lower compressive strength but a higher axial strain as compared to the corresponding fully wrapped specimens. In addition, the non-uniformly wrapped specimens achieved both a higher compressive strength and axial strain in comparison with the fully wrapped specimens. Furthermore, the partially wrapping scheme changes the failure modes of the specimens and the angle of the failure surface. A new equation that can be used to predict the axial strain of concrete cylinders wrapped partially with FRP is proposed. This study investigates the behavior and failure modes of FRP confined concrete wrapped 5 with different FRP schemes, including fully wrapped, partially wrapped and non-uniformly 6 wrapped concrete cylinders. By using the same amount of FRP, this study proposes a new 7 wrapping scheme that provides a higher compressive strength and strain for FRP-confined 8 concrete, in comparison with conventional fully wrapping schemes. A total of thirty three 9 specimens were cast and tested, with three of these specimens acting as reference specimens 10 and the remaining specimens wrapped with different types of FRP (CFRP and GFRP) by 11 different wrapping schemes. For specimens that belong to the descending branch type, the 12 partially wrapped specimens had a lower compressive strength but a higher axial strain as 13 compared to the corresponding fully wrapped specimens. In addition, the non-uniformly 14 wrapped specimens achieved both a higher compressive strength and axial strain in 15 comparison with the fully wrapped specimens. Furthermore, the partially wrapping scheme 16 changes the failure modes of the specimens and the angle of the failure surface. A new 17 equation that can be used to predict the axial strain of concrete cylinders wrapped partially 18 with FRP is proposed. 19

show abstract

Factors Affecting the Ultimate Condition of FRP-Wrapped Concrete Columns

Cited by 59 publications

References 46 publications

Influence of overlap configuration on compressive behavior of CFRP-confined normal- and high-strength concrete

Influence of overlap configuration on compressive behavior of CFRP-confined normal- and high-strength concrete

Behavior and Three-Dimensional Finite Element Modeling of Circular Concrete Columns Partially Wrapped with FRP Strips

Optimized FRP Wrapping Schemes for Circular Concrete Columns under Axial Compression

Contact Info

Product

Resources

About