Early contractor involvement hastens Brighton Bypass up to 15months

By Rosemary Ann Ogilvie

Less than a year into construction, this initiative of the client – the Department of Infrastructure Energy and Resources (DIER) – has already netted huge benefits, with the project currently more than 12 months ahead of schedule. Expected completion date of the bypass is now early 2011, while the hub should be finished by December 2010. Original completion dates were June 2012 and September 2011 respectively.
"The earlier you involve the contractors in the project, the more benefit they can add in a value-management or cost-engineering sense," says JV communications spokesperson, Allistair Lindsay. "The contractors can also review 'build-ability' and advise the designers on construction methodology. Additionally, there are advantages in terms of construction scheduling."
For six months prior to the first works starting onsite, JV staff shared office space with DIER and the project designers, Pitt and Sherry. This enabled them to liaise with the designers and DIER to incorporate innovative ideas into the design. "Much of this was achieved through structured risk and opportunity workshops," says Lindsay. "External parties were engaged on several occasions to facilitate the sessions in order to minimise the risk of personnel becoming too narrowly focussed."
At the end of the ECI process, the team produced a comprehensive set of documents that had been reviewed in detail for constructability and project risk. Accompanying the documents were fully scheduled and itemised costings, which had been independently reviewed by a third party engaged by DIER.
By late October 2009 the scope was set, the cost was fixed and the program locked in.
As the contract documents went through the various channels for sign-off, the JV began mobilisation. Site compounds and accommodations were constructed and additional machinery was brought from the mainland. The JV was granted full possession of the site on November 23rd 2009.

Tasmania's largest civil project

A component of the larger Midland Highway Improvements Projects, which incorporates the Bridgewater Bridge refurbishment and several smaller projects, the Brighton Bypass was split into two separate parts – North and South – to spread the workload between two contractors. The $90m contract for the northern section was awarded to the VEC-Thiess Joint Venture. Land acquisitions pushed the total project cost to $255m, making this Tasmania's largest civil project to date.
By skirting Brighton and Pontville, the largely federally funded Brighton Bypass will result in safer, faster commuter and freight movement between the north and south of the state, and also significantly improve connection to the growing Brighton Industrial Estate. The 40ha state-government funded Brighton Transport Hub ($79m) is a modern road-rail freight distribution facility that will allow goods to be seamlessly transferred between road transport and rail.
Leading the JH-HB JV is project manager Gary Baird, who is highly regarded for his work in the Tasmanian construction industry. "A major benefit of a large project like this is that it helps retain key local talent," says Lindsay. "Of the 22 people John Holland has on the project, three-quarters are local, while the 182 Hazell Bros site-staff are all Tasmanian."
The project includes:

• Construction of a 3.5km dual carriageway from the East Derwent Highway Roundabout to a point just south of Brighton. "Two-thirds of this road is on a greenfield site," says Baird. "One third is a realignment of the existing alignment, in a mix of greenfield and brownfield sites."

• A 4km single-lane road, now called the Greenstone Road Diversion. "Main highway traffic is being diverted onto this road, allowing us to realign the new Midland Highway through an existing industrial area," says Baird.
• Two 34m single-span Super T bridges.
• The Brighton Interchange Rail Underpass, which is a 100m-long Bebo arch structure. "This required some drill and blast work to form the walls of the rail tunnel," says Baird. "They were shotcreted and rock bolted, so there were some challenges in getting that right in terms of accurate drilling and blasting to avoid too much over break to fill.”
• A second culvert-style rail underpass, which is a precast panel structure.
• A pedestrian underpass.
• 5km of rails including signals and Tasmania's first set of boom gates.
• Three operational buildings for the Transport Hub: an administration building, a locomotive maintenance facility, and a vehicle inspectors' building. Access areas will be laid with 1.2m brick pavers.

Engineering solutions`

The project team has had to engineer solutions to certain constructability issues associated with the fact that Tasmania is an island where resources are limited. "The JV negotiated with Van Ek Civil (VEC) to build an onsite precast-concrete yard to manufacture the beams for the bridge structures," says Baird. "As some beams are more than 30m long and 1500mm deep, it was impractical to source them from the only suitable precast yard on the island as it's 200km away. Apart from that, the local precast industry did not have the capacity to produce the required number of beams in the available time." 170 of these concrete Super T- beams, which weigh up to 55t, will be made for the new bridges.
Hazell Bros established a concrete batch plant onsite as well as a field workshop for equipment maintenance. 
A 350t mobile crane brought from the mainland, lifted the 30m bridge beams into position. Other significant items of equipment of the 54 pieces used onsite include a Caterpillar D11 dozer (the largest in Australia) and a fleet of scrapers, all provided by Collins Contracting, as well as 12 or more articulated dump trucks (Moxys), dry-hired from CatRent and Delta.
The entire one million cubic metres of earth moved was utilised onsite. "A significant exercise during the ECI phase was to balance the cut-to-fill quantities," says Baird. "A mutual arrangement between the two JVs allows for the exchange of material between projects."
Approximately 130,000t of sub base 2 (60mm) and 120,000t of sub base 1 (40mm) was crushed onsite from basalt excavated from the cut areas by blasting.
Heritage, environment
The JV had to deal with both Aboriginal and European heritage issues. Extensive Aboriginal archaeological research and excavations were undertaken, while a convict-built sandstone culvert, c.1835, was retained and incorporated into a new bridge. "We extended the culvert using new precast elements," says Baird. "We created a viewing chamber so you can see the end of the old structure, which is still functioning – provided you have the appropriate equipment and don't mind crawling along pipe structures in a confined space."
Environmentally, the JV has been involved in both the protection and propagation of endangered flora, and the eradication of introduced species of weeds. Constant attention has been paid to site run-off, including silt fencing and hay baling.

Risk assessment payoff

Another major benefit of the ECI initiative relates to the rigorous risk assessment undertaken, and the development of contingencies for each risk identified. "With every problem that has arisen, a plan was in place to deal with it. All the appropriate staff were trained in the mitigation strategies," says construction manager Jason Lennard.
"We've been very lucky with the project," says Baird. "Even when minor hiccups occurred, the JV model kicked in and with a concerted effort from everyone, each problem was solved."
He comments that a particularly beneficial aspect of the ECI process – apart from the substantial time and cost savings it has brought – was the building and strengthening of relationships that occurred during this period. "These relationships have helped administer the project as we move forward."