Modern Steel Bridge Complements Historical 1900's Landmark

Location:	The Gap, Brisbane, Queensland
Country:	Australia
Project Size:	A$1.5 million
Client:	Brisbane City Council
Fabricator:	Emersteel Fabricators Pty Ltd 144 Lavarack Avenue Eagle Farm, QLD, 4009 Ph: 07 3268 5811 Fax: 07 3268 7190 Email: emersteel@ozemail.com.au
Products Used:	AS/NZS 3678 - 400 XLERPLATE®

High strength 400 grade XLERPLATE® hot rolled steel from BlueScope Steel was recently used in the construction of a new single arch steel bridge over Enoggera Creek in the north west Brisbane suburb of The Gap.

Duplication of the existing two lane Walton Bridge was necessary as part of Brisbane City Council's (BCC) Waterworks Road Transit Lane Project, which provides additional lanes for the operation of peak time transit lanes between The Gap and the city.

The Waterworks Road Transit Lane Project is an integral part of BCC's Integrated Transport Strategy, to encourage the use of public transport by making it more efficient, convenient and accessible.

The Transit Lane Project, currently being constructed between Settlement Road, The Gap and Enoggera Terrace, Red Hill, commenced in July 1999 and is due for completion by December 2003.

A key design requirement for Brisbane City Council was that the new bridge complement the visual appeal of the existing historically significant bridge.

Commenting on the project, the BCC's Transport Committee Chair, Councillor Maureen Hayes, said: "Walton Bridge, which opened in 1900, provides a lasting example of bygone construction techniques with its twin arch earth-packed concrete design. The arches, which can be viewed from both sides of the parkland reserve surrounding the bridge, are an important landmark in The Gap'.

The new A$1.5 million bridge was designed by BCC's City Design business unit.

"The new steel bridge, built from high-strength steel, minimised the visual impact on the existing bridge because its structural elements were able to be kept as slim as possible', Cr Hayes said.

"Thinner, lighter deck beams and raked columns were used to provide a clear line of vision from the reserve to the historic twin arches of Walton Bridge.

"In fact, the unobstructed view of Walton Bridge has been further enhanced by the framing effect created by the raked columns'.

The new bridge substructure was constructed from 400 grade XLERPLATE® steel to provide greater strength, cost effective construction and ease of fabrication and welding. The single arch design allowed bridge footings to be placed outside the creek bed, eliminating the environmental impact that would have resulted from driving footings into the creek bed.

Brisbane based Emersteel prefabricated all of the steelwork for the bridge.

Company principal, Nigel Emerson, said the project had been both challenging and rewarding.

During design, careful attention was paid to accurate identification of the dimensions of the prefabricated steel work, to ensure each of the steel columns would fit exactly into the cast in situ footings and headstocks.

"This meant we had to use the best quality steel for the job we could, which is why we opted for XLERPLATE® from BlueScope Steel', said Mr Emerson.

"It is dimensionally accurate and, as long as the proper steps are taken, it doesn?t warp or distort during welding'.

In total, Emersteel used more than 150 tonnes of 400 grade XLERPLATE® in the construction of the structure, which was named New Walton Bridge 2002.

"The end result is a new structure which not only meets its functional objectives, but does so while helping to preserve and enhance the heritage significance of the 103 year-old Walton Bridge', said Mr Emerson.