Client name: Clendon, Burns & Park Limited

Duration: January 2012 – February 2012

Location: Wellington, New Zealand

Coffey brought an understanding of the local geological and geotechnical conditions to assess design parameters for the St Patrick’s College Silverstream Gymnasium.

Geotechnical investigation of seismic activity and liquefaction prone area 

This new gymnasium is positioned on an existing embankment and is the first stage of a larger sports hub including an aquatic centre and state-of-the-art all-weather track.

The site is located in an area prone to seismic activity and liquefaction. To assess the feasibility of the project, our client required a greater understanding of the site’s seismic response, liquefaction potential and foundation and retaining wall requirements.

Our client also needed assurances that the chosen site for their gymnasium wouldn’t be compromised by 1 in 100 year flood events on the Greater Wellington Hutt River Corridor.

On completion of preliminary designs, our client decided to reposition the development by approximately 10m. While the repositioning of the project was not in response to geotechnical factors, it did mean a further assessment was needed to ensure the new project area was also suitable for development.

Subsoil capacity and risk mitigation report built on historical geotechnical data and new investigations

We reviewed historical geotechnical information and carried out site investigations to confirm the existence of acceptable founding materials for our client’s development. 

We provided our client with a detailed understanding of the subsoil capacity and presented a report on the requirements needed to mitigate the risk of settlement and rotation of foundations.

Clear knowledge of conditions meant our client could include adequate provision for foundation design and construction in their project budget.

We found that the existing ground levels were above the 1 in 100 year flood level. This meant we could focus on delivering a foundation and retaining wall design that would lessen the impact of flooding should any future seismic activities cause lower ground levels. This was a cost effective solution for the client.   

Our understanding of the original site meant we could complete the additional investigation with decreased scope and reduced costs.

Results indicated that ground conditions were similar to the previous site, allowing the design to continue as planned.

Cost-effective solution

Our involvement in the early stages of design ensured geotechnical risks were identified quickly and efficiently. Our client was able to use traditional, more cost effective foundation options for their development, as our findings proved that more conservative foundation options weren’t necessary.