Downer NZ

CATEGORY 2: Projects with a value between $1 million and $10 million

Working at heights

KiwiRail needed to replace a 40-metre high, 166-metre long bridge on its Midland Line in South Canterbury that was built over 120 years ago. Downer won the job and on November 16 last year started with the task of replacing the existing timber rail-beams (critical bridge beams that support the rail track) with prefabricated steel rail-beams on spans 1 – 6 of Bridge 28 Mid, and without delaying any train movements on the line. This involved about 146 metres of beam replacement. KiwiRail’s main objectives were to replace the existing timber rail-beams in the safest and most efficient way possible.

CATEGORY KiwiRail, through a tendering process, HIGHLY COMMENDED 2 CATEGORY 2 asked for contractors to propose methodologies and processes for the replacement of the rail-beam units to carry out the work in the safest, most efficient and environmentally friendly manner as possible, and Downer developed a methodology to allow this. The works included removal of the existing rail-beams and sleepers, installation of new steel rail-beam units and associated new steel members, and resleepering of the bridge.

Health and safety planning was critical to the success of this project, which was full of risks that included working within the rail corridor, working at heights, and in a remote location. “If any incidents occurred, we were a long way from help,” says Downer.

“So, as well as taking extra care and attention when performing all tasks, as a precaution, we communicated with Garden City Helicopters / Westpac Rescue Helicopter, in case of emergencies.”

Suffice to add, stringent planning was essential to the project, and the Bridge 28 Mid project was completed with zero significant incidents and zero injuries.

The completion due date was February 19, 2016, but the project was finished April 19 2016 after work scope changes and variations that were included and approved throughout the contract. These included replacement steel walkways to supersede the existing timber structures. In the end, “We met all targets for practical completion,” says Downer.

The original tendered value was $1,374,000 and the final delivered value was $1,488,680 with the variations. l