Exploring the benefits of rocking shallow foundations

Abstract

Rocking foundations can offer significant benefits in terms of seismic performance, environmental outcomes and constructability. This paper explores the use of a simplified design procedure for rocking foundations and compares the design estimates to both displacement-based assessment and nonlinear time history analysis. Several simplifying assumptions were applied to the building design and modelling in this paper to isolate the role of rocking foundations. These assumptions are explicitly stated and would need to be addressed for the application on real buildings. However, this paper presents a pathway for adoption of rocking foundations in design. The simplified procedure that has been proposed for adoption in TS1170.5 is for low- to mid- rise buildings (less than 15 m to the uppermost floor or heavy roof), as well as other specific building criteria. However, by assessing both a 3-storey and 6-storey buildings, this paper shows how the procedure could be utilised for other structures provided appropriate validation is performed and constraints are assessed. The use of rocking foundations for multi-storey apartment buildings can enable more sustainable, cheaper, and easier to construct buildings and this paper provides support that the potentially higher initial design (and review) costs associated with this can be managed and justified.