Upgrade 2 : A design and construction measure taken to increase the resistance of structures, systems, and components for the effects of natural phenomena hazards. Upgrade, strengthening, and retrofit are equivalent terms
Department of Energy AREA SDMP, DOE Handbook, Glossary of Environment Safety and Health Terms, DOE-HDBK-1188-2006, D.C. 20585, USA 2006. http://www.hse.niordc.ir/uploads/86_24_dictionary_ 2006.pdf, (Envir Hlth and Sfty - Amer) {44}