Strengthening of RC Circular Short Columns with Fibrous Jacket

Abstract

This research presented a wide study about the structural behavior and strength of RC circular short columns when strengthened with concrete jackets strengthened with steel fiber. A total of 17 circular columns were designed, fabricated, and tested experimentally under monotonic load. An experimental investigation was carried out to assess the efficiency of the fibrous jacket in the retrofitting of RC column. The parametric study was conducted which included using four columns as control specimens with different cross-section dimensions. The remaining 13 column specimens included strengthening the column by different parameters such as steel fibers ratio and type, jacket thickness, bond by epoxy, and full and limited jacket height. The ultimate stress and strain, crack pattern, failure modes, ductility, and toughness capacity of the specimens were studied. The experimental outcomes exhibited that the fibrous jacket enhanced the ultimate strength capacity, ductility, and changed the failure mode of columns. The increase in the steel fibers ratio (1%, 1.5%, and 2%) enhanced the ultimate load capacity by (194%, 71%, and 126%) respectively. Strengthened columns by FRC jacket with thicknesses (25, 35, and 45) showed enhancement in the stress carrying capacity by (126%, 242%, and 171%) respectively. Using epoxy appeared a different behavior in comparison with square columns. The use of epoxy showed lower stress capacity by (21% and 24%) for (1% and 2%) hooked steel fibers ratio respectively. Use of hoop jacket case enhanced the ultimate stress capacity better than composite case. straight fibers were better than hooked ones in the improvement of ductility and energy absorption.

Axial behavior of RC column strengthened with laterally reinforced FRHPC jacket

“…The accuracy of the load carrying capacity calculation based on Equation ( 26) should be appropriately checked. In Table 6, the experimentally observed values from this work and those of other scholars 19,20,22,26 are compared with the predicted results by the proposed model. The comparison between the experimentally observed data and predicted results by the model has been displayed in Figure 17.…”

Advanced Study of Columns Confined by Ultra-High-Performance Concrete and Ultra-High-Performance Fiber-Reinforced Concrete Confinements

“…Carbon fiber-reinforced polymer (CFRP) ropes were used for circular columns with various layers and spacings that were preloaded at different levels [15]. Several studies have been carried out to investigate the performance of short columns confined by fibrous 'jackets' [16], UPHFRC tubes [17], and FRPs [18].…”