Recent Advances in Seismic Retrofit of RC Frames

Carbon Fiber Reinforced Plastic (CFRP) is a promising new technology for repair and strengthening of reinforced concrete structural members. It is being increasingly used in concrete structures damaged due to deterioration of concrete and corrosion of reinforcement in concrete structural members. Reinforced concrete structures when subjected to fire, loses its strength rapidly resulting initially in spalling of concrete cover. At higher temperatures and for a longer duration of exposure to fire the strength steel reinforcement in the concrete also decreases significantly leading to collapse of the structure. CFRP laminates and wraps can be used effectively to strengthen the structures distressed by fire. This paper presents a case study on rehabilitation and strengthening of a reinforced concrete bridge which was subjected to a high intensity fire loading, resulting in severe damage to columns and moderate damage to girders. Prior to repair and strengthening a detailed investigation was carried out to assess the extent of damage due to fire and the possibility of repairing and strengthening it. Laboratory and field investigations indicated that the concrete elements were amenable for repair and strengthening by CFRP. Strengthening of the girders and slabs in the structure was carried out using CFRP laminates and wraps and columns of the bridge were repaired by concrete jacketing

Keywords:

RC frame , bracing , seismic retrofitting , HPFRCC , Behaviour factor