Calibre : Fiji bridge repairs withstand tropical depression in the lead up to sugarcane season

Recently completed repair works on the Penang Mill Bridge in Rakiraki, in the north of Fiji's main island Viti Levu, have been put to the test after a tropical depression hit Fiji early February, causing widespread flooding.

The Penang Mill Bridge was struck by large amounts of debris but the repairs, delivered by Calibre Consulting, withstood the flooding - a testament to Calibre's robust design.

When tropical cyclone Winston devastated Fiji in February 2016, Rakiraki was particularly hard hit, with around 2,000 people from the surrounding area losing direct access to the town when supporting piers on the Penang Mill Bridge were pushed sideways and rotated by the impact of flood flows and debris.

Penang Mill Bridge pier movements following Cyclone Winston in February, 2016.

The Fiji Road Authority (FRA) engaged Calibre to proceed with design and documentation of emergency bridge repairs, following success with earlier work on tender documentation and road maintenance activities, including the Denarau Bridge Replacement project.

The emergency repairs involved collaboration across the New Zealand and Australia offices, with Dave Chung, Business Unit Leader - Nelson, traveling to Fiji to inspect the site, while Melbourne-based Terry Leach, Senior Engineer, designed a braced piled steel support structure for the bridge.

The design presented a number of challenges, needing to be simple enough to be constructed in a remote area with limited resources and to be completed in time for the start of the sugar cane season as the bridge conveys the train tracks servicing the sugar mill.

'We were working to a very tight deadline and also needed to consider things like minimising work conducted in the waterway, as this would mean barges would be required, which would ultimately cause delays,' Terry Leach said.

'Additionally, there were no existing design plans available for us to refer to, nor did we have any geotechnical information, stream flow or stream height data. So essentially we had to work with conservative estimates and measurements taken by Dave on site.'

Repaired Penang Mill Bridge withstands flooding following tropical depression in February, 2017.

Acting General Manager - Capital Works for FRA, Rod Bridges, passed on his thanks to the Calibre team, noting, 'If we hadn't got in and repaired the bridge, it most probably would be down the river in pieces.'

Calibre completed the design and also prepared the tender documentation, which was then handed back to FRA who awarded the contract to a local construction business.

'It really was a case of 'a stitch in time, saves nine,'' Terry said.

'This is a salutary reminder of the importance of being responsive when clients seek our help and getting on with the job, particularly in vulnerable environments like the Pacific Islands. It is possible to fast-track delivery, especially when we draw on the wider resources of the Calibre network,' he said.