System for Post Earthquake Building Evaluation, Bhutan

Atop the Himalaya, Bhutan faces a high risk of earthquakes. A major earthquake will damage hundreds, maybe thousands, of buildings all at once. People will need to know, quickly, which buildings are safe to use and which are not.

 

Can they live in their homes? Can the hospital stay open if it needs repair? Can school resume? We developed a field manual to guide trained engineers in making these evaluations. The goal is to improve safety and speed recovery after a disaster.

 

Working with the Bhutan's Departments of Engineering Services and Disaster Management, and Applied Technology Council, we assembled detailed descriptions, photos and drawings that show earthquake damage to local building types. It's the result of intensive collaboration and fieldwork.

 

The majority of buildings in Bhutan are constructed of traditional rammed earth, stone masonry, and adobe. Some have vernacular timber-based systems. Damage from moderate earthquakes in 2009 and 2011 indicates that stronger shaking will cause significant damage in rammed earth and stone buildings.

 

With this field manual, trained engineers will know how to assess which buildings might suffer additional, life-threatening damage in an aftershock as intense as the mainshock. 

 

They will post a red, yellow or green colored placard on each building to inform the public. Green means “Inspected” and the building is usable; it may be unscathed or need small repairs. Yellow means “Restricted Use” or access is limited. Red means “Unsafe” until repaired or demolished.

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Engineers may assess thousands of buildings in the first week after an earthquake. The ATC-20-1 Bhutan field manual, ready-to-go for Bhutan, will save precious time. Its use will support consistent evaluations that occupants can trust. 

 

Though specific to Bhutan, the manual could be used as a model for postearthquake building safety evaluations in nations with similar building types. It is based on the widely used ATC-20-1, Field Manual: Postearthquake Safety Evaluation of Buildings, 2nd Edition.

 

Funders: World Bank’s Global Facility for Disaster Reduction and Recovery (GFDRR), and the Applied Technology Council Endowment Fund