Repair and Retrofit of Concrete Columns with Fiber Composites

Fiber composite materials have been used for decades in certain industries such as aerospace, ship-building, sporting goods, etc. However, their application in civil engineering structures has received attention only in the recent years. The major advantage of fiber composites is their high tensile strength to weight ratio. Reinforced concrete columns constructed prior to mid 1970s usually have few ties; this lack of confinement results in various brittle modes of failure when the structure is subjected to lateral loads, e.g. during an earthquake. This paper presents the results of several reduced-scale column specimens that were constructed and retrofit by wrapping them with bands of glass fiber composites. The specimens were subjected to simulated earthquake type loading. The results indicate that this technique can be used very effectively in upgrading deficient columns in existing structures. A procedure is also presented to calculate the required thickness of composite materials to ensure a desired level of ductility in the column.