Axial compression performance of concrete filled double skin (SHS outer and CHS inner) steel tubular columns strengthened by CFRP

Self Cite

This paper focuses on the axial compression performance of 15 concrete-filled double skinned tubes CFDST columns with different CFRP reinforcement schemes. The design of this test used an outer square steel tube with a square steel tube inside, with concrete poured at the sandwich and the inner steel tube kept hollow. The structure is both cost effective and allows the hollow to be used for utility access. However, in recent years damage to CFDST has occurred due to fire, earthquakes, corrosion etc. Therefore, research into the reinforcement and repair of this structure is crucial. Compared to other reinforcement methods, FRP has the advantage of being lighter and more robust and does not significantly alter the original structure. In this study, the mechanical properties of the specimens were further analyzed from the data of load displacement, peak load and ultimate displacement by mainly observing and analyzing the damage mechanism of the specimens through the strengthening effect of different strengthening schemes for different hollow ratios. The results show that when the hollow ratio is not bigger than 0.33, the CFRP reinforcement effect is relatively obvious, especially the three-layer CFRP wrapped CFDST specimens have a substantial increase in bearing capacity and stiffness. Finally, an analytical study was carried out based on previous research and the experimental results agreed well with the calculated results.

“…According to several now available strength models for FRP-steel-confined concrete, Park et al 28 take the following form …”

Section: Simplified Formulatementioning

confidence: 99%

Section: Simplified Formulatementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Axial compression performance of square concrete filled double skin SHS steel tubular columns confined by CFRP

Wang

Liang

et al. 2023

Self Cite

“…The conventional techniques to strengthen the deficient RC members include the external wrapping of the potential plastic hinge regions using concrete 10 or steel jackets 11 . The key disadvantages of these techniques include labor-intensive and time-consuming 12 – 14 . Further, the concrete jacketing results in enlarged sections and imparts noticeable weight to the structure, whereas the steel jacketing is prone to inner surface corrosion and involves difficulty in its handling 15 .…”

Section: Introductionmentioning

confidence: 99%

Stress and strain relations of RC circular, square and rectangular columns externally wrapped with fiber ropes

Hussain,

Ruangrassamee,

Jirawattanasomkul

et al. 2024

This study explores the potential use of low-cost natural fiber reinforced rope polymers (FRRP) to improve the compressive behavior of circular, square, and rectangular reinforced concrete (RC) specimens. A total of 42 specimens were tested under monotonic axial compression in three groups. Groups were formed to differentiate specimens with different cross-sectional shapes such as circular, square, and rectangular. The findings demonstrate that FRRP can effectively boost the compressive behavior of RC columns. Circular specimens with three-layer hemp FRRP exhibited a 200% increase in compressive strength and a 270% improvement in corresponding strain. Cotton FRRP provided a 117% boost in compressive strength and a 233% enhancement in strain. In square specimens, three-layer hemp FRRP resulted in a 110% rise in compressive strength and a 186% increase in strain, while cotton confinement yielded improvements of 95% and 144%, respectively. For the square and rectangular specimens, the improvement in the compressive behavior was reduced compared to the circular specimens because of stress concentrations near corners. Moreover, the study showed that the hemp FRRP confinement outperformed the cotton confinement. The investigation also revealed that the existing analytical models were inadequate in predicting the mechanical properties of RC confined with natural FRRP. Therefore, the study introduces novel equations to predict the compressive strength and corresponding strain for both hemp and cotton confined concrete in various cross-sectional types. These proposed equations exhibit a good level of accuracy in predicting the compressive strength and corresponding strain.

Axial compression performance of partially encased concrete columns with web opening

Liang,

Wang,

Zou

et al. 2024

The objective of this study is to comprehensively assess the behavior of partially encased concrete (PEC) columns with web openings under axial compression. The primary objectives of this study are to analyze damage patterns and investigate the influence of key parameters, such as concrete strength, opening rate, and opening shape, on the ductility index and ultimate load-carrying capacity. The study employs experimental testing to examine the response of the PEC columns, with a particular focus on the mechanisms of concrete fracture and flange flexing. Notably, the study reveals a significant impact of the opening rate on the bearing capacity, while the effect of opening shape is comparatively minor. Furthermore, computational analyses are conducted to deepen the understanding of structural behavior. The study builds upon existing research to propose a novel method for calculating the bearing capacity of PEC columns with web openings. This method introduces two discount factors to enhance predictive accuracy.