Hybrid Techniques for RC Column Strengthening

Abstract

Strengthening techniques of reinforced concrete structures have significantly changed in recent years. Such improvements happened mainly because of the development of new materials and their associated strengthening techniques. For example, polymeric composites of synthetic fibers (carbon, aramid, glass, etc.), high-strength concrete, and other high-performance cement-based composites have been introduced to construction market. The application of these materials in the strengthening of reinforced concrete (RC) columns implies a review of the design methods and the execution procedures, because if the strengthening materials change, the performance of the strengthened column also changes. This paper intends to characterize, even though in a superficial form, the main strengthening mechanisms associated with some rehabilitation techniques. Also, based on an exploratory experimental analysis, this paper reports the potential of hybrid strengthening techniques by combining different strategies. Six plain concrete short columns were strengthened using several combinations of high-strength concrete (HSC) and fiber-reinforced polymer (FRP) jackets, which resulted in so-called hybrid techniques. The columns had 150 mm diameter and 600 mm height as initial dimensions that, depending on the applied strengthening technique, had the diameter increased to 200 mm. The test results demonstrate that hybrid strengthening techniques are feasible and they can be used in different ways to optimize the rehabilitation strategy.