2017 CCF WA EARTH AWARDS

CATEGORY 3 WINNER

The original timber Third Avenue bridge, constructed in the 1920s and approaching the end of its

design life, was replaced with a new concrete bridge. The deconstruction of the existing bridge and construction of the new structure needed to occur while maintaining pedestrian traffic along the existing Principal Shared Path (PSP) underpass and without impact on the busy Midland rail line in Maylands. BMD Constructions successfully delivered the project on time and within budget and recordable injury free, with positive feedback from the local community.

With train services every five minutes at peak times, the works were completed behind a general exemption fence and works within the rail corridor were completed during rail shutdowns and were achieved without impact to the rail operations.

Building the bridge over a live rail line inherently involved risks, including working at heights, placing large beams over a live rail corridor, traffic control, service locating and managing vibrations. As a highly experienced bridge contractor, BMD worked innovatively to overcome these risks.

Demolition works were carried out

over a single weekend rail shutdown, only seven weeks after contract award and four weeks after possession of site. The detailed planning undertaken by the project team included convening a number of planning workshops involving stakeholders and providing an hourly program for the shutdown duration. This led to the successful completion of the demolition, six hours ahead of schedule.

Careful planning and staging allowed for 435 (219 reinforced and 216 unreinforced) piles to be installed in a very tight corridor bordered by a live rail corridor and the PSP.

The bridge deck was constructed of precast concrete panels placed between four steel box girders. The girders and precast panels had to be installed within a pre-planned 48-hour rail shutdown. This shutdown had been planned in advance of all works commencing and was a critical milestone to the success of the project. The site space constraints meant that detailed pre-planning of the placement of the various components required for the assembly was critical to the swift execution of the works.

The project team were mindful of residents’ concerns due to the close proximity of private properties to the

project site. Proactive stakeholder engagement included regular updates via letter drops, planning workshops and individual contact when needed.

Main Roads Superintendent’s Representative Anthony Morrow said he was very impressed with BMD’s performance. “Their professionalism and detailed planning of the works has been exemplary, and their careful handling of the interface with Public Transport Authority (PTA) has been particularly important,” Mr Morrow said.

BMD CONSTRUCTIONSTHIRD AVENUE BRIDGE REPLACEMENTClient: Main Roads WA