Retaining Wellington’s Roads, Chaytor St Case Study

Roads of Wellington city are often carved around steep greywacke rock terrain. Geotechnical engineers are faced with challenges to provide cost-effective solutions to retain the associated sidling fills, which often have marginal stability. This paper presents a case study of a tied back, concrete palisade wall that was constructed to retain a section of Chaytor St in Wellington.

The project was challenging given the significant depth of fill, site constraints and high seismic design accelerations. Significant effort was made during the development of the design to provide a cost effective solution that fulfilled both the requirements of the New Zealand Loadings Standard and the requirements of the client. The design that was adopted relied on the anchors resisting the majority of lateral load and avoided the more traditional approach of resisting part of the lateral loads through embedment of the wall piles into the underlying rock. The paper discusses the design philosophy of the tied back concrete palisade wall.