Structural design for disaster risk reduction

The risk of loss from natural disasters, in terms of lives, livelihoods and social capital, is shown to be unacceptably high compared with acceptable risk from losses for which mankind is responsible. The collective loss is much worse than the sum of individual losses. The impact seems worst for non-engineered housing, fragile and vulnerable to natural hazards. The concept of Disaster Limit State (DLS) has been developed for structural engineers, above and beyond the Ultimate Limit State (ULS). Key to DLS is the recognition of post disaster function of the building or system being designed, combined with the recognition that heightened standards of design must be combined with non-engineering disaster risk reduction measures in a holistic way, with full community engagement. This is a challenge for structural and planning engineers, requiring an expanded vision and imagination.