The Second Phillip Island bridge

Last updated on 17 September 2016

A new 640m/2,100 feet long concrete bridge linking Phillip Island with the mainland at San Remo was officially opened on Friday 21st November 1969 by the Hon  M Porter, MLA, Minister for Public Works. The new bridge replaced the old suspension bridge constructed in 1938. The cost of the second bridge was $3.25m. The Country Roads Board felt this was justified due to many factors. The bridge it replaced was constructed when little finance was available and could cater only for loads up to six tons. Cables from the North Shore Bridge, Sydney, and cable hangers to support the wooden deck from the Victorian Tramways, all came second hand.

Rough weather and strong tidal currents took their toll on the old bridge from the foundations upward. Traffic density had increased following the 1939-45 war, creating a real need for a wider and stronger bridge. The CRB annual road count in March 1960 was 635 vehicles per day. In Decenber 4,730 vehicles per day with a miximum of 6,263 vehicles per day, a number of which were large tourist buses which were obliged to drive across unloaded whilst the passengers walked the third of a mile across. Heavier loads, therefore, needed to be catered for, and rumour has it they were going over at times. So when, in 1959, one of the end hangers supporting the deck from the main cables in the suspension span broke at the lower end, comprehensive examination was made and it was decided to build a new bridge.

The length of the second bridge and the difficult nature of the crossing which combines a large tidal range with fast currents posed many interesting design problems. Cowes, near the middle of the northern shore of Phillip Island is the main centre of the island, and Melbourne the main source of traffic. Alternative routes proposed for the new bridge were:

Via Somers, direct route (77km/48 miles from Melbourne) with a three-mile crossing over the potential deep water port area required high level bridge over main channel

Via Stockyard Point and French Island (113km/70 miles) giving access to French Island, but still involving a three mile sea crossing in shallower waters requiring provision for fishing vessels only.

Via San Remo-Newhaven, the present route with a length of about 135km/84 miles from Melbourne.

The first two proved too costly. The present crossing at the Narrows is the shortest distance between the mainland and the island. This site, east of the old bridge, has less tidal turbulence and for many reasons considered more suitable. It is of interest to note that this present site was the one suggested for the first bridge by Mr Richard Grayden who had talked about it in the early 1920s. Indeed he had thought of it because of his knowledge of tides and depth of water since rowing passengers across the Newhaven-San Remo passage from about 1908.

Preliminary investigations for the crossing included the following:

1. Hydrographic survey

2. Underwater inspection of the channel and sea bed

3. Seismic traverses

4. Core boring at each shore line

5. Penetrometer soundings

as well as provision for additional loading of bridge piers in case of a boat colliding with a pier.

The contract for construction was awarded to John Holland & Co Pty Ltd in April 1966, who elected to work from a temporary steel bridge. So began the tremendous task of building a reinforced concrete and pre-stressed concrete bridge 640m/2,100 feet long, consisting of  a central 61m/200 foot navigation span flanked by 46m/150 feet anchor spans and 30m/100 foot approach spans on each side.

The bridge is 8.5m/28 feet wide between kerbs with a five foot wide footway. Navigational clearance height at high tide is 12m/40 feet. Five sub-contractors and/or material suppliers were involved before completion of this beautiful bridge.

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