Journal of the South African Institution of Civil Engineering
On-line version ISSN 2309-8775
Print version ISSN 1021-2019
WIUM, J A. Background to draft SANS 10160 (2009): part 4 seismic loading. J. S. Afr. Inst. Civ. Eng. [online]. 2010, vol.52, n.1. ISSN 2309-8775.
This paper provides a critical overview of the background to the revisions which led to the formulation of Part 4, Seismic Loads, of the South African Standard SANS 10160. The paper also presents a comparison to demonstrate the calibration of the standard against other international standards. Eurocode 8 was used as the principle reference for the formulation of the revised clauses. The clauses for seismic design of SANS 10160 are based on the concept of regular buildings with suitable detailing to allow the necessary ductile behaviour. The paper points out a need to review the use of a redundancy factor which makes provision for a possible lower design peak ground acceleration value and the behaviour factor for reinforced concrete shear walls. The damage limitation criteria also need to be based on Eurocode 8. It is shown that the revised formulation provides lower design forces for regular buildings than in the current standard. This is, however, dependent on the choice of a design nominal peak ground acceleration for the various regions in the country. The available information on nominal peak ground acceleration is presented, and it is pointed out that a decision is needed on the choice of this important parameter for the seismic zones of South Africa.
Keywords : Structural design standards; South African practice; seismic loads; actions on structures; Eurocode.