Disaster Mitigation in Health Facilities: Wind Effects Nonstructural Issues

Nonstructural elements to consider when assessing vulnerability ARCHITECTURAL EQUIPMENT BASIC INSTALLATIONS Façades Roof covers Parapets Chimneys Plaster Glass windows Attachments (signs, antennae,etc) Ornaments Canopies Railings Doors and exit routes Medical equipment Industrial equipment Supplies Office equipment Medical and industrial gases Air conditioning Electrical generator Hydraulic networks Electric networks

Nonstructural vulnerability assessment methods Previous experience Visual inspection Data collection Non-destructive tests Mathematical models Structural analysis and design Wind tunnel analysis Retrofitting recommendations Equipment classification

Standards and codes must cover components and claddings The trend for international standards is to adopt and adapt the ASCE-7 approach for components and claddings.

Design pressure for components and cladding and design force for special and open structures (ASCE-7) Design pressure p = qh [(GCp) - (GCpi)] Design force F = qzGCf Af Towers, signs, tanks, silos

Criteria for equipment classification Indispensable: Equipment that can not easily or economically be replaced and is essential for the provision of health services. Essential: Similar to indispensable equipment, except that it can be replaced easily or cheaply. Hazardous: Equipment that can injure people and damage objects. Chaotic: Equipment whose failure may cause disruption to its environs. Functional: Equipment that is not used for emergency health care.

Hipped roof recommended over flat roof

Gabled roof with slopes of 20 to 30 degrees are preferred against hurricanes Hatched area indicates where more frequent fixings are required PLAN ISOMETRIC Gabled roof

Connection details between metal sheet roof and purlins Metal sheet fixings and purlin-to-rafter connection Spacer block Self-tapping screw Metal sheeting purlin Galvanized hurricane strap fixed to rafter and purlin Rafter Ridge connection Valley connection

Typical connection system between metal sheet roof and masonry wall

Nonstructural elements are not designed to resist direct loads Failure of an unreinforced masonry wall without an adequate base anchorage Nonstructural elements are not designed to resist direct loads

Shutters protect against the penetration of flying objects and water

For a hospital it is essential to have protection against penetration of windborne debris and water

Anchorage of protective shutters on outside walls

Anchorage system of shutters on interior columns

Exterior doors must be protected against internal and external pressures through adequate anchorages

Window deformations due to the impact of windborne debris

Impact of windborne debris against louvre windows

An unprotected window is vulnerable in the event of a hurricane

Roll-up or permanent shutters are the best way to protect windows against hurricanes

Permanent window shutter details ELEVATION Storm shutter in open position when closed Surface bolts to secure PLAN fixed to frame Shutter panels

Details of roll-up shutter Housing chamber for ELEVATION CROSS SECTION Shutter guide roll-up shutter Details of roll-up shutter

Adequate anchorage of hospital equipment will ensure continuous service

An example of good anchorage on exterior hospital equipment

Exterior equipment should be anchored with special bands

External oxygen and gas tanks should not be loose

Correct anchorage of external oxygen and gas tanks to walls

Restraints and fasteners for larger external equipment

Failure of a metallic roof cover and an unreinforced masonry wall

Metal sheet roof of a health center was destroyed by hurricane-force winds

Damage to the façade due to failure of a neighboring building

Windborne debris on a structure A roof from a structure located 100 m away was violently thrown by the strong winds of a hurricane

Impact of windborne debris on a plywood hurricane shutter

Windborne debris perforates shutter and glass behind it

Health center damaged by a water tank thrown by hurricane winds

 Pan American Health Organization, 2005 These slides have been made possible through the financial support of the Disaster Preparedness Program of the Humanitarian Aid Office, ECHO (DIPECHO-III) Grupo de Estabilidad Estructural (Ge2) / INTEC Ave Los Próceres, Galá Apdo 349-2 Santo Domingo, Dominican Republic Ph: (809) 567-9271 Fax: (809) 566-3200 danielc@intec.edu.do www.intec.edu.do