acceleration (Ss) from 2% probability of exceedance in 50 years. Builders may refer to the Unified Facilities Handbook online for these values for some cities worldwide. These risk levels are based on ultimate strength, but deformation limits may require stiffer detailing or lower risk levels. Medium strength soil: unconfined compressive strength ±0.75 g risk if 2 separate pieces of rebar are inserted, overlapped 1.6 g risk if an entire internal rebar extends from base to bond beam Strong soil: unconfined compressive strength ±1.6 g risk if 2 separate pieces of rebar are inserted, overlapped ±2.1 g risk if a single rebar extends from base to bond beam Additional research and engineering analysis is needed to create valid CE manuals. References Natural materials Building materials