Architect and Builder December 2016 | Page 68

uniform glass curtain wall, whilst providing opportunities to thermally control the building in an optimal way. Glazing specifications and colours were chosen with these thermal requirements in mind. The concrete structure has also been expressed in the building’s shell. Four stair-core shear walls run through the façades and it was decided to express them as the building’s primary supports, effectively holding the structure up, rather than hide them. 66 BUILDING STRUCTURE Seismic Integrity A hospital is considered a building for which structural integrity during earthquakes is of vital importance for protection and refuge. In the SANS 10160 design code this is ensured through the introduction of an importance factor which increases the design earthquake load by 40% compared to ‘ordinary’ buildings. This requirement resulted in significant base shear forces that were far too high to be resisted by the combined Christiaan Barnard