LOCAL SEISMIC RETROFITTING OF RCC STRUCTURES USING CONCRETE JACKETING

Abstract

The Indian subcontinent has a history of earthquakes. Seismic Retrofitting Techniques are required for concrete constructions which are vulnerable to damage and failures by seismic forces. In the past thirty years. Moderate to severe earthquakes occurs around the world every year. Such events lead to damage to the concrete structures as well as failures. It is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. The biggest problem faced by structural engineers is a lack of standards for retrofitting methods – Effectiveness of each methods varies a lot depending upon parameters like type of structures, material condition, amount of damage etc. These techniques can be broadly classified as local and global methods. Local methods focus at the element level on a particular member that is deficient and in improving it to perform better. These methods include adding concrete, steel, or composite to the outside of the member. To evaluate the positive effect of concrete jacketing, a G+4 storied moment resisting frame was modelled in ETABS and response spectrum analysis was carried out for zone V. After the initial analysis, the concrete design was done as per IS:456-2000. It was observed that the most of the original columns were insufficient to withstand the applied loadings and were failing under flexure. So, to remedy that, a concrete jacket was proposed. Finally, a comparison was made between the performance of the columns pre and post retrofitting.