Review of retrofitting methods to reduce seismic vulnerability of buildings, with particular reference to hospitals and medical facilities

Abstract

Seismic retrofitting consists of one or more structural interventions developed to improve the resistance of existing buildings to seismic loads. The seismic retrofitting of a building is usually the result of a process that, through analysis and evaluation of the current state of its structure, highlights shortcomings which prevent the building from performing as required by the local seismic standards. A structural intervention then needs to be designed and implemented to improve the seismic response of the building, often to the level required by the standard. Hospitals and health facilities are considered part of the critical infrastructure of a region due to their level of occupancy and their special use. Since these facilities need to remain operational after a destructive earthquake, special assessments are required to ensure that these buildings will be able to deliver the health care needed to the injured casualties. This implies that more stringent requirements compared to those considered for ordinary buildings should be applied to improve the response of hospital buildings to earthquakes. For a hospital to remain functional after an earthquake, the structure must still be erect, and the mechanical services and the medical equipment hosted by the building should also be undamaged. Most of the services and equipment are vulnerable to interstorey drift (the relative translational displacement between two consecutive floors), while some specific equipment might be vulnerable to lateral acceleration (see Review of non-structural considerations for seismic retrofitting of hospitals and medical facilities). For this reason it is required to define the seismic performance of hospitals by controlling and measuring their interstorey drift or lateral acceleration under seismic events. Following the introduction, section 2 of this report describes the methods for structural seismic retrofitting of reinforced concrete and masonry hospital buildings; section 3 provides an overview of guidelines and building codes for design of seismic retrofitting; section 4 gives recommendations for the Nepalese building stock; and section 5 gives examples of implementation in hospitals in Peru, Greece and Sudan. This report has been produced for Evidence on Demand with the assistance of the UK Department for International Development (DFID)