Australian construction firm McConnell Dowell has used Fugro's O-Cell technology to assess the ground condition and validate the design of the bridge piles for a new bridge across the Fangaʻuta Lagoon, in Tonga.
The 720m twin lane road bridge is part of a major US$$97m infrastructure project linking Nukuʻalofa and Tonga's main island of Tongatapu.
Once completed, the bridge will reduce travel times and traffic congestion, while also serving as a critical emergency evacuation route for local communities.
Fugro carried out the testing within coral formations, an environment where traditional pile testing methods are often impractical due to access, load limitations, and constructability constraints.
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The O-Cell tests, however, enabled direct measurement of pile performance under high loads, providing critical insights into pile-soil interaction within the coral strata.
The data helps reduce geotechnical uncertainty.
Testing was carried out on two different pile diameters to support design optimisation, with Fugro's APAC personnel working with the McConnell Dowell "to bring the project in on time and on budget".
O‑Cell or Osterberg Cell technology is a bi‑directional load testing device developed to meet the construction industry's need for a reliable method of testing high-capacity, deep foundations.
Installed within the foundation element, the tool applies pressure both upward and downward simultaneously, enabling full‑scale static load testing without the need for massive reaction systems.
During a site visit in March by officials from the New Zealand and Tonga Administrations
McConnell Dowell Managing Director Fraser Wyllie said: "We are not just building a bridge, we are helping build futures."
McConnell Dowell has invested US$10m in Tonga through local employment, equipment procurement, and capability development, including a new concrete batching plant, a materials testing laboratory, and delivering more than 3,000 hours of training and development.
The Fanga‘uta Lagoon Bridge project (below) is being delivered in partnership with the Tongan Ministry of Infrastructure, with investment support from the Asian Development Bank.
