Johnson Street Bridge, Victoria
Subsequent to Somerset Engineering performing the erection engineering for the installation scheme for this bascule bridge, PCL awarded the structural steel and mechanical machinery erection to KWH Constructors.
The bridge is a single leaf, modified trunnion type, Bascule Bridge with a 50’ diameter ring that the turning rack and pinion systems are mounted on. It is amongst the largest bascule leafs in the world.
The drive machinery and the structural steel are set to very tight tolerances on the site, with 3D alignment dimensions of a few microns.
The ring support wheels and equalizers are installed first, see gallery photos from site. The span counterweight box is then set on falsework, with the two circle track sections spliced to them one at a time using a large capacity floating crane. The main roadway leaf is erected in one piece during a weekend closure using the same barge crane. Sidewalks and bicycle lanes are erected separately.
Other items KWH installed include the main machinery, CPU, room, stairs, handrail, platforms and a separate pedestrian bridge.