The North Sydney Investment and Tramway Company or the North Shore and Middle Harbour Land Company made major investments in the area and planned to build a tramway and a bridge across Long Bay gully in order to open up the area for sales of residential land.

[5] In 1912 the bridge was handed over to the NSW Government as a gift, on the condition that a tramway be extended to the north side and no toll charged.

Water had been allowed to accumulate around the suspension rods as they passed through the cross girder ends in small, undrained reserves that had originally been filled with a bituminous mixture, which had not stood the test of time.

From several options, it was decided that a large concrete arch span to support the deck of the old suspension bridge was the most satisfactory solution.

The towers themselves were in very good condition and were recognised by the DMR as having local significance as a landmark and tourist attraction and as having considerable historical value.

The bridge was closed to tram and vehicular (but not pedestrian[10]) traffic and work began at the beginning of June 1937.

An interesting innovation, however, was employed in the form of steel cylinders with base plate partly filled with a fine dune sand and fitted with a hardwood piston.

The pistons bore the weight of the girders until it was time to strike the falsework when two small screw plugs on the cylinders could be opened to a carefully prepared schedule, with a large team of operators working to signals, and sand released so that the crown and then, gradually, the whole arch took up its own load.

The process of the design and construction of the arch is illustrative of an era in the history of bridge building in the Department of Main Roads.

The use of the concrete arch solution to support the older bridge and to allow its landmark features to be retained was a creative and heritage-sensitive response to an infrastructure problem in an era long before heritage values and processes were enshrined in legislation.