Date: |
07 Oct 2026, 5.30PM – 7.30PM |
duration: |
2 hrs |
Venue: |
Te Manawaroa - Level 1 |
Address: |
University of Waikato, Tauranga Campus, Durham Street Tauranga |
Cost: |
Free event |
State Highway 29 is a critical link within the Auckland–Hamilton–Tauranga triangle. The project delivers a new three-span, 72m long piled bridge over the Ōmanawa River. Tauranga’s complex geology, including loose, sandy pumiceous soils, organic layers at variable depths, and founding rock deeper than 45m below ground level, posed significant challenges and strongly influenced the geotechnical design.
Key geotechnical elements comprise twelve top-driven piles of approximately 50m length, sleeved abutment piles, Mechanically Stabilised Earth (MSE) retaining walls, and soil-nailed slopes. At the western abutment, interactions between the piles, a 7m high MSE wall, and high-strength geotextiles were analysed. Static negative skin friction associated with construction of the adjacent abutment resulted in vertical pile settlements, confirming the need for pile sleeving.
The eastern abutment design mitigated risks from liquefiable layers, with soil nails meeting static and seismic slope stability criteria. Pier piles founded adjacent to the river channel were designed to accommodate seismic flow-induced loads.
The presentation outlines the design approach, construction considerations, and lessons learnt, to inform future bridge projects in similar challenging ground conditions.
Networking from 5.30pm, presentation will start at 6pm sharp.
Presenter Bio - Rhiannon Reardon (Beca)
Rhiannon is a chartered professional engineer with seven years of experience in geotechnical engineering. She is presently a senior Geotechnical Engineer at Beca, where she has worked since graduating from the University of Auckland. Throughout her career, she has been privileged to work on a diverse range of major infrastructure and land development projects. Elected to the New Zealand Geotechnical Society (NZGS) management committee at the end of 2025, Rhiannon is committed to fostering collaboration and innovation within the geotechnical community and serving its members.
Join the New Zealand Geotechnical Society (NZGS) and Engineering New Zealand's Bay of Plenty Branch looking at the Ōmanawa Bridge Replacement. This presentation looking at the initial phase of the Tauriko West Road of National Significance project, targeting improved safety, resilience, and freight efficiency along this key corridor.
State Highway 29 is a critical link within the Auckland–Hamilton–Tauranga triangle. The project delivers a new three-span, 72m long piled bridge over the Ōmanawa River. Tauranga’s complex geology, including loose, sandy pumiceous soils, organic layers at variable depths, and founding rock deeper than 45m below ground level, posed significant challenges and strongly influenced the geotechnical design.
Key geotechnical elements comprise twelve top-driven piles of approximately 50m length, sleeved abutment piles, Mechanically Stabilised Earth (MSE) retaining walls, and soil-nailed slopes. At the western abutment, interactions between the piles, a 7m high MSE wall, and high-strength geotextiles were analysed. Static negative skin friction associated with construction of the adjacent abutment resulted in vertical pile settlements, confirming the need for pile sleeving.
The eastern abutment design mitigated risks from liquefiable layers, with soil nails meeting static and seismic slope stability criteria. Pier piles founded adjacent to the river channel were designed to accommodate seismic flow-induced loads.
The presentation outlines the design approach, construction considerations, and lessons learnt, to inform future bridge projects in similar challenging ground conditions.
Networking from 5.30pm, presentation will start at 6pm sharp.
Presenter Bio - Rhiannon Reardon (Beca)
Rhiannon is a chartered professional engineer with seven years of experience in geotechnical engineering. She is presently a senior Geotechnical Engineer at Beca, where she has worked since graduating from the University of Auckland. Throughout her career, she has been privileged to work on a diverse range of major infrastructure and land development projects. Elected to the New Zealand Geotechnical Society (NZGS) management committee at the end of 2025, Rhiannon is committed to fostering collaboration and innovation within the geotechnical community and serving its members.
Presenters
New Zealand Geotechnical Society
Bay of Plenty Branch
