TECHNICAL NOTES NOTES AND PROPOSED GUIDELINES ON UPDATED SEISMIC CODES IN ETHIOPIA IMPLICATION FOR LARGE-SCALE INFRASTRUCTURES

In light of recent expansion in the planning and construction of major building structures as well as other infrastructures such as railways, masshousing, dams, bridges, etc, this paper reviews the extent of seismic hazard in Ethiopia and proposes a review and update of the current out-dated and - in most cases - non-conservative seismic code. In specific terms, the last three seismic codes are reviewed and a comprehensive set of discussions on seismic zoning and PGA (peak ground acceleration), special provisions in concrete and steel beams and columns design, and seismic analysis are provided through a comparison with major international building codes. Sets of recommendations in updated and conservative seismic zoning, need for separate seismic codes for non-building type structures, a choice of 475 years as return-period instead of the current 100 years, and a revisit of the basic seismic design philosophy to focus on performance basis are provided. Key-words seismic design, building code, seismic hazard, earthquake, infrastructure, codes and standards.