My latest project is a bridge in Top Ryde City, Sydney, Australia. Its 40m span across the busy Devlin Street is to ease the traffic flow around the precinct. It is also for an alternative access to the new Top Ryde Shopping Centre that was just opened for public on November 5th, 2009. It is now almost completely erected, leaving the 2 signage frames to be erected.
I must say that this was the most challenging project that I ever handled directly. The main chords were made in curves, and the “skeletons” (we called them lacings) were made in segmented curves. The beauty of this design is if we look at the bridge, it’s like the chords are twisted to form a helix shape.
The structure itself can be divided into 4 major parts, the main bridge, walkways, lift and stairs. The main challenge other than the nature of its geometry was the Engineer wanted every major part mostly being shop welded. So the team ended up detailed all those major parts only in 9 assemblies! Main bridge (1 assembly), belly frames (2), bridge-to-shops interface (1), external walkway (1), lift (1) and stairs (3).
It was obvious that it’s impossible, eg. detailing the main bridge (complete with the walkway inside) just in 1 assembly. It would be too crowded, full of details, many sheets and not to mention how long the BOM would be. So it was decided to use “sub-assembly” technique. For those who are not familiar with this, sub-assembly technique is to break down a complicated assembly into less complicated assemblies. In many cases, these less complicated assemblies could be separated again into simpler assemblies, and so on. So we will have a super assembly, and many sub-assemblies and many sub-sub-assemblies. Assemblies in an assembly. In this project, if the main bridge as a super assembly was a level-1 assembly, the “deepest” sub-assemblies were at level-5.
So it took a careful planning to decide an assembly at which level, to ensure it would be in line with the fabrication process later. The concept is pretty much the same as a supporting assembly should be in higher level than its supported assemblies. Maybe I should write about this later.
Anyway, following is some photos of the bridge that were taken by the Engineers. Oh, I just love this baby.
The Northern Distric Times (NDT), a local newspaper once wrote about this bridge on November and said “it would symbolise the vibrant and progressive comunity of Ryde”. And it will be named “Rita” after their first Mayor’s daughter. Anyway, I’m glad to be involved in this project. And I believe the folks in city of Ryde will be proud to have this beautifully designed bridge in their community. Next time I go to Sydney, surely I would visit her.
Southern Pedestrian Bridge, Top Ryde Shopping Centre
Owner: Beville Group
Architect: Bovis Lend Lease Pty Ltd
Structural Engineer: Arup Pty Ltd
Steel Fabricator: S&L Steel Fabrications Pty Ltd
Steel Detailer: Seacad Services Sdn Bhd
Steel Detailing team
Team Leader: MC Nugraha
Detailer: Suhaimi Hasan
Detailer: Nungki Martanto Adi
Detailer: Azhar Ibrahim
Checker: Youshij Yousefzadeh