Study of Various Local and Global Seismic Retrofitting Strategies - A Review

Abstract

Recent earthquakes, starting with the 1971 San Fernando Earthquake in California, left major destructions, damaged the infrastructure, and raised questions about the vulnerability and design practice of structures, especially concrete structures. Design codes have being updated to include seismic previsions but structures build before 1971 have to be retrofitted. The focus of this paper is reinforced concrete (RC) structures. Surveys done after earthquakes have shown that the major problem with concrete structures is columns. Other critical structural elements include, but are not limited to, gravity design frames, footings, shear walls, connections, and beams. There are two major categories of retrofit options for concrete structure; 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. Global methods concentrate at the structure level and retrofit to obtain a better overall behaviour of the entire structure. The different systems presented all have some advantages and disadvantages and the option chosen for the retrofit depends on the existing structure requirement. Finally a brief note is made on the development and use of Hybrid intervention schemes.