27 January 2019

Johnson Street Bridge lawsuits

How time flies! I first covered Victoria, BC's Johnson Street Bridge some nine years ago, most recently writing about it again in January 2018.

Image courtesy Thedarkempire / Wikipedia

The project was initially controversial for the proposal to replace a 1924 historic heel-trunnion bascule bridge with a modern design. The new design was devised by MMM engineers with Wilkinson Eyre architects, and is a rolling bascule bridge, the largest such structure in Canada. Opposition from heritage groups was eventually defeated and the new bridge was completed and opened to traffic on 1st March 2018.

When I last reported, it was to discuss a dispute between contractor PCL, their client the City of Victoria, and the client's designers MMM. Wilkinson Eyre appeared to have long left the scene. There were also some really quite odd issues with the bridge's steel detailing.

The bridge has been back in the news again due to further legal disputes. These came to light late last year, with PCL filing a lawsuit against Victoria, MMM and design subconsultant Hardesty and Hanover. PCL have alleged that the designers provided a design which was late, incomplete, and contained errors; that the design was unreasonably changed; and they did not receive payments they were entitled to.

Some readers may recall that the contract was primarily traditional in nature, with the client responsible for providing the design, and the contractor building it. An odd feature of the procurement was that the contractor was obliged to value-engineer the client's design (PCL initially employed Hardesty and Hanover to help with this task).

Image courtesy Michal Klajban /Wikipedia

A key problem which seems to have haunted the project throughout its history is that the client's design was incomplete at the time that PCL tendered for the project, which is not normal practice in this kind of contractual arrangement. The contract setup is normally called "traditional" in the UK, or "design-bid-build" in North America, and the latter name indicates that the process is expected to be sequential, with the design complete before bids to build it are invited.

Local journalists suggest that PCL has merely lodged the lawsuit as a placeholder, a negotiating tool with the end aim of walking away from the project without any further liability on either side. This is based on a similar legal manoeuvre that took place in 2015/16.

A report in Focus on Victoria discusses the dispute but also draws attention to the general quality of the completed bridge. According to this report, some steelwork joints were sealed not by welding, but using a sealant material, which is already falling out. More interestingly, the bridge as-built is compared by Focus to the original design images from Wilkinson Eyre, such as the example below.

In the original design, large "ears" containing the bridge counterweights sit alongside the running rails on which the bridge rotates. However, both elements are blended smoothly together to give an organic appearance. With hindsight, it seems fairly clear that those flowing curves would be at best expensive and at worst impossible to fabricate, and likely to fall victim to the promoter's desire for value engineering.

Image courtesy Focus on Victoria

This picture shows what it really looks like, which is quite horrendous. There seems to be have been little thought about how to deliver a smooth curve in the steelwork, or even how to give the impression of one.

There's no manipulation here, either. The second image below shows just how disjointed the main steelwork trusses and counterweight ears actually are, with a physical gap between them on the outside face. To me, it looks quite bizarre.

Image courtesy johnsonstreetbridge.org

There are plenty of images on Google Streetview which show the issues as well.

Make no mistake: this is a remarkable bridge, with an interesting, exciting design. It's unfortunate that nobody was retained on the project with a brief to maintain the quality of the original design vision, and that the procurement process failed to find an acceptable balance between cost-cutting and quality.

Anyone who has worked on a complex landmark bridge project will know it can sometimes be a real battle to ensure an original idea isn't disfigured through messy compromise. Unless the client's commitment is there, it's difficult to resist negative changes. Even with a strong and imaginative client, success comes through all the team members pulling in the same direction, rather than being incentivised to do the opposite.


Unknown said...

Surely that isn't a rolling bascule? It doesn't roll, it is turning on a trunnion at the centre of the "wheel".

Also, surely, the ears are neither big enough not far enough back to help much with rotation. Indeed, since it isn't rolling, they are in the wrong place, reaching maximum leverage at about half lifted.

Unknown said...

Ahhh, I think I've got it. Not a trunnion. the whole gear/roller wheel sits in some sort of cradle. But it doesn't roll back like a proper rolling bascule. Those machines work hard!

The Happy Pontist said...

It is constrained by the rolling track to pivot about a virtual point in the centre of the "wheel". In this arrangement the bridge can retain pretty much the same front/back dead weight balance in all positions of rotation, unlike a Scherzer rolling lift bascule where the balance changes as it moves horizontally (usually to ensure it is front-loaded when closed, and back-loaded when open).

See also http://happypontist.blogspot.com/2011/08/london-bridges-12-bellmouth-passage.html and http://happypontist.blogspot.com/2009/06/bridge-competition-debris-part-15-foryd.html for similar designs.

Unknown said...

Thanks, So I understood the mechanism correctly but I find those weights and positions unbelievable. Are you happy that the balance is correct?

The Happy Pontist said...

Balance is less of a concern on moveable bridges than it was in the past, especially if they don't open frequently, so they're probably just designed hefty hydraulics and used the counterweights for a small saving. The power costs for operation are probably not significant.