Investigation on strengthening of CFST members under compression using CFRP composites

Abstract

In the present era, the use of CFST members has become quite popular in the construction industry and at the same time, aging of metallic structures and member deterioration have also been often reported. Therefore, actions such as implementation of new materials and strengthening techniques have become essential to combat this problem. It has already been proved that FRP composites significantly improved the strength of reinforced concrete structures. The application of these materials is implemented in the high-performance steel structures. With this aim, an experimental study has been carried out to investigate the suitability of unidirectional CFRP fabrics in strengthening CFST members under axial compression. The size and height of the specimens used in this study are 91.5 Â 91.5 Â 3.6 mm and 600 mm, respectively. Out of 21 columns, 18 columns were externally bonded by CFRP strips having a constant width of 50 mm with spacing values of 20 mm and 30 mm and the remaining three columns were unbonded. The effect of CFRP layers on the load-carrying capacity of CFST columns was investigated. The strengthened columns exhibited FRP rupture failure due to outward buckling of steel tube. Experimental results also revealed that external bonding of CFRP strips considerably provides the confining pressure to the CFST column and as a result, CFRP-confined columns sustained higher ultimate load and larger axial deformation compared to control column. An analytical model was also proposed herein for predicting the axial load capacity of CFRP-confined CFST columns. The average percentage of difference between the analytical and the experimental loads was found as AE4%.

Behavior of Circular CFST Columns Subjected to Different Lateral Impact Energy

“…With the development of engineering technology, the concrete-filled steel tube (CFST) has been widely used in seismic-resistant construction, high buildings, industrial buildings, bridge piers and offshore structures owing to its high strength, good ductility, light weight and so on [1][2][3]. CFST has the capacity of high ductility and large energy absorption [4], which leads to the perfect seismic resistance of CFST [5].…”

Research on Dynamic Response of Concrete‐Filled Steel Tube Columns Confined with FRP under Blast Loading

“…is new structure could be used in high-rise buildings and bridges in seismic areas. Later, many researchers focused on the ultimate bearing capacity and working mechanisms, and compression and bending experiments were implemented [7][8][9][10][11][12][13][14].…”

Seismic performance of FRP-reinforced concrete-filled thin-walled steel tube considering local buckling

“…Composite structural columns formed by fully or partially enclosing a concrete-filled steel tube (CFST) in fiber-reinforced polymer (FRP) laminate wrappings have attracted increasing attention over the past decade. 1–6 Such a column is referred to as an FRP-reinforced CFST in this paper. The combinative technique of FRP-reinforced CFST offers many advantages.…”

“…Sundarraja and Prabhu 4,11,12 studied CFST members strengthened by CFRP composite under compression and bending. The results showed that external bonding of CFRP strips provides considerable confining pressure to the CFST column; as a result, CFRP-confined columns can sustain higher ultimate load and larger axial deformation.…”