L.B. Storie
NZ Transport Agency | Waka Kotahi, New Zealand, Auckland
M.D.L. Millen
Tonkin & Taylor Ltd., New Zealand, Christchurch.
University of Canterbury, New Zealand, Christchurch.
ABSTRACT
The recent release of the draft Technical Specification TS 1170.5 (2024) includes guidance for the design of rocking foundations. Despite the potential benefits of rocking foundations in terms of reduced seismic loads transferred to the structure, the nonlinear nature of rocking foundations has made it difficult to implement in typical design practice. The simplified rocking procedure in TS 1170.5 (2024) provides a means to more easily take advantage of rocking foundations. It also creates opportunities for rocking foundations to be implemented outside of the limitations of the simplified procedure, with some additional design effort.
This paper explains the simplified rocking foundation design procedure outlined in TS 1170.5 (2024) and the limitations to adopting that procedure. The procedure is structurally focused, generally not requiring significant geotechnical input. However, this paper will explain the important geotechnical considerations that should be included in rocking foundation design through collaboration between the geotechnical and structural engineer. These geotechnical considerations include the ground profile most suited to adopting rocking foundations, implications for foundation design and building deformations, and opportunities to implement ground improvement techniques to take advantage of rocking foundation design. Geotechnical engineers have a key role to play in promoting and implementing rocking foundation design for more efficient and seismically resilient structures.