Peering over the edge offers a dizzying view. The Long Gully Bridge stands before you. It is also known as Northbridge, Suspension Bridge, and Cammeray Bridge. This concrete arch road bridge carries Strathallen Avenue. It spans Flat Rock Creek and Tunks Park. The Long Gully Bridge connects Cammeray and Northbridge.
Originally, private developers built it. They wanted to promote residential development. The Long Gully Bridge opened in January 1892. It was a steel suspension bridge. Sydney sandstone finished it with crenellated turreted towers.
In 1935, the Department of Main Roads took over. By 1939, they rebuilt it. It became a reinforced concrete two-rib arch bridge. But the sandstone towers remained.
Back in the 1880s, land boomed north of Long Bay. The North Sydney Investment and Tramway Company invested heavily. They planned a tramway and bridge across Long Bay gully. This would open the area for residential land sales. The suspension bridge opened in January 1892. It took two years and nine months to build. The cost was A£42,000. With a 152-metre suspension span, it was a marvel. It became a major tourist attraction.
A toll was charged. It was threepence return for adults and one penny for children. The crash of 1892 bankrupted both companies. The 1890s depression slowed land sales. Northbridge did not develop as hoped. The tramway was never built. A fundraising dance and promenade concert occurred on the bridge in 1894.
In 1912, the bridge was gifted to the NSW Government. The condition was a tramway extension to the north side. Also, no tolls could be charged. The tramway extended over the Long Gully Bridge in 1913-14. Its terminus was in Sailors Bay Road.
The bridge suffered from poor maintenance. Repairs and strengthening occurred with the tramway construction. The Department of Main Roads took control in 1935. Inspections revealed serious corrosion in the steelwork and cables. Design defects contributed to this. Water accumulated around the suspension rods. The main suspension cables also weakened.
Replacement became necessary. A large concrete arch span supporting the old suspension bridge was chosen. The towers were in good condition. They had local significance as a landmark. They also served as a tourist attraction. They had considerable historical value. They were retained and repeated in the new design. The bridge closed in May 1936.
The arch was designed and tested using models. Hornibrook Bros. & Clark Pty. Ltd won the construction contract. Work began in June 1937.
The original suspension bridge had a 152-metre main span. Steel cables and hanger rods supported it. An undertruss stiffened the deck. Ornate sandstone turrets supported the steel cables. They anchored into bedrock at each end. The wooden deck carried two lanes of traffic, tram tracks, and footways.
Corrosion led to the 1930s replacement. The new arch has a 105-metre main span. It consists of two concrete ribs. These peak 51 metres above stream level. Columns supported on the arches carry the deck. There are 14 reinforced concrete beam slab spans. Expansion joints sit at the large piers over the arch springs. These transfer wind load to the foundations.
Concrete beam spans connect the towers. The concrete detailing reflects Victorian Gothic and Norman styles. The main piers sport Norman castle features.
Roadway openings through the towers increased to nine metres. Walkway openings cut through the towers. Light standards supported by concrete railings adorn the Long Gully Bridge.
In 1992, Sydney Electricity installed floodlighting. Safety fencing was installed in 2010. The Long Gully Bridge is intimately associated with residential development. The concrete arch is a fascinating part of its history. The design and construction illustrate bridge building history. The bridge is a creative response to an infrastructure problem. It occurred long before heritage values were enshrined in legislation.