For background on the Johnson Street Bridge project, we are posting relevant articles from our old website. This article, from October 24, 2010, was also published in Monday Magazine — which prompted a letter (reprinted below) from MMM's Joost Meyboom, asserting that the design of the new bridge is “tried, tested and proven”.
The attention came because Cowing, a prominent Cleveland engineer, had previously registered his design for a new type of bascule bridge [drawing at left] – in which the hinge point would be a huge wheel, turned by a cradle of gears and bearings – and this was his chance to put it to the test. Cowing opened his rolling bascule bridge with great fanfare in 1907, and went on to a good career in Chicago, where he died in 1926.
Alas, Cowing’s patent wasn’t quite so successful. In 1916, an international congress said his bridge “ha[d] not commended itself for further adoption,” and others like it were never built. Although the Cleveland bridge continued operating, by the 1940s it had become a mechanical nightmare. Due to the stresses on its bearings and gears, the bridge repeatedly broke down, often closing for weeks at a time as Cleveland frantically machined new parts from scratch. In 1957, the city finally decommissioned it, deciding it wasn’t worth the ongoing headaches. (To see some old news clippings about the bridge’s problems, click here.)
Earlier this month, the City of Victoria rolled out its $50,000 taxpayer-funded campaign to convince residents to vote in favour of borrowing $49,200,000 for a new “one of a kind” Johnson Street Bridge, to be “built for the next 100 years”. But as Cowing’s bridge should remind us, a novel design does not always live up to long-term expectations.
Bridge historians have noted similarities between Cowing’s patent and two bridges at London’s Canary Wharf, which were created by the UK firm Wilkinson Eyre and built in 2001. Both designs lift on a wheel resting on roller bearings and gears, but in the Canary Wharf bridges the wheel is an open ring [photo right], allowing pedestrians to walk through it. This was the novelty that enticed Victoria’s council to select a similar design, also by Wilkinson Eyre, to help extend the sightseeing walkway along the Inner Harbour.
But was novelty a good criterion to use for a structure that’s supposed to last 100 years? Recently, I spoke with a veteran movable bridge engineer who had seen plans for Victoria’s bridge, and its rolling-bascule design “raised questions” in his mind. “I don’t see any great advantage to it,” said the engineer, who asked to remain anonymous.
The Canary Wharf bridges are only 23 metres long, whereas the lift span of Victoria’s bridge will be 57 metres long and at least 30 metres wide. Will the larger size magnify any issues with the mechanical design? “Greatly,” the engineer said.
“They’re going to need a lot of counterweight,” he continued. “What I’ve seen of Victoria, you’d have to have it extended quite a distance.” The separate pedestrian and multimodal pathways hanging off the lift span will further increase its complexity. “If you’re going to do this, it’s going to take a lot of engineering work.”
(That work will be even more complicated if rail is included, as the weight of a train demands a far stiffer span. On October 13, the Capital Regional District endorsed the City’s application for federal gas-tax money to help pay for rail on a new bridge, but Victoria’s council won’t decide whether to include rail until December, and the gas-tax application won’t be heard until April – making it hard to know whether we’re voting on a bridge with rail, or not.)
This is encouraging, but it still suggests that we’re considering a mechanism that’s unique for a bridge. The existing Strauss bridge certainly has its own issues – its hinges can’t be replaced without dismantling the structure, which MMM said would be required to give it another 100 years of life – but at least it has functioned for 86 years without significant failures. According to engineers, the typical warranty on new bridge construction lasts one year from opening. [2017 note: the new bridge has a two-year warranty.] So, if a decade from now our “one of a kind” bridge requires ongoing and expensive repairs, well, that’s our problem.
Certainly, engineering has changed dramatically since Cowing’s day, and computer-aided design has enabled the construction of some remarkable machines. But if someone tried to sell me a new car that’s “one of a kind” – and then promised, even though there are no other examples of it, that it would last for “100 years” – I’d be inclined to look for another dealership.
COMMENTS ON ORIGINAL ARTICLE
The new bridge will be one span only, and is longer and wider. This huge area will present more windage when in the raised position, which could present a problem in the strong westerly storms that blow into the harbour in the winter.
In the above photo the design shows a walkway going through the large rolling gear. This is an obvious safety issue with the type of guard rail shown, that will not prevent a small child or pet from becoming injured, not to mention the easy access to vandals. Workmans Compensation will have something to say about exposed gears. The next thing you will have is the whole design being changed, with barb wire and chainlink fences to keep people out.
I believe this new design is flawed and will end up being changed, thus increasing the final cost. And why are we building a bridge for “the next 100 years”, when in a few decades we may not be using transportation infrastructure as we know it today?
Instead of going with a new design, the city needs to reconsider rehabilitating the tried and true Johnson Street Bridge, that has survived for 86 years.
world famous blue bridge? Why cant we fix it, and save it? It should be a crime to tear down something so well loved by the people of Victoria.
I will be so sad if they do. And it will tie up traffic downtown for 2 years, whereas a refurbishment can be done in stages, and the downtown businesses will not have to suffer. Please answer me, I really want to know. Why?
The sight of three independent spans raising up would also add to the spectacle of the current bridge.
I just heard Ross Crockford debate Dean Fortin on CFAX Radio this morning, and he did an excellent job poking holes in the mayor’s nonsense.
Ross encouraged Victoria voters to vote NO on the referendum to borrow almost $50,000,000 to destroy and replace the JSB.
That was great, but he forgot to mention the one candidate who is likely to be able to do anything about this mess, Barry Hobbis.
I would like to endorse Barry Hobbis also, but can’t understand why Ross Crockford and Yule Heibel haven’t yet endorsed him.
After all, one of the three directors of the JohnsonStreetBridge.org group, Mat Wright, is Barry Hobbis’ campaign manager.
In Mr. Crockford’s recent article “Mechanical Questions”, he compares the mechanical system
proposed for the new Johnson Street Bridge that is “tested and proven” with that for a bridge
designed more than 100 years ago before the advent of modern metallurgy, computer-guided
fabrication and computer aided engineering design. This is not an appropriate comparison
and may unfortunately mislead readers of your magazine regarding this important project.
I would like to clarify some of the points made in Mr. Crockford’s article in order to present “the complete story,” so that your readers are not accidently mislead. In this regard, I would like to note the following:
1. While Mr. Crockford acknowledges that engineering design is significantly more
sophisticated today than in the early 1900’s, what is equally or maybe more important are
the advances that have been made in the past century in metallurgy and computer-guided
fabrication. These advances allow the use of significantly higher strength/grade steel and
very accurate fabrication of precision machinery that dramatically improves reliability and
lowers maintenance cost for a moveable bridge. Engineering design, metallurgy and
computer-aided fabrication are vastly superior (and not even comparable) to the technology
being referenced by Mr. Crockford which are from the industrial revolution.
2. Mr. Crockford repeatedly refers to the mechanical system of the new bridge as “one of a
kind”, “novel” and “unique”. This is far from the truth. The mechanical system proposed for
the Johnson Street Bridge has been tried, tested and proven. The proposed mechanical
system is based on solid engineering principles, has been peer reviewed, and has been
used in previously designed/constructed structures and applications from heavy industry
such as foundries for decades under conditions that are much more aggressive and
demanding than anticipated at the Johnson Street Bridge.
3. Cowing held a patent for a rolling bascule bridge system which was considered by many
lead bridge engineers of the day to be a direct infringement on another patent held by
Montgomery Waddell. Waddell was the original inventor of the rolling bascule system and
his patent reflected a higher quality, more sophisticated design than Cowing’s. For example,
Cowing’s system used solid rollers rather than a compound roller, a system that mimics a
set of ball bearings. The failure of the Cowing design was in part because of the use of solid
rollers.
In closing, I wish to reiterate that the mechanical system for this new bridge is “superior” to the
system referenced in Mr. Crockford’s article and has been “tried,” “tested” and “proven” and will serve the city for the next 100 years.
Thank you for considering this response and to correct any inaccurate information being portrayed in the public as part of this important community project.
Yours very truly,
MMM Group Limited
Joost Meyboom, Dr.sc.tech., P.Eng.
Partner
Regional Manager – Western Canada
Project Delivery and Management
as an independent designer and a certified CAD technician. I can honestly say that in the last twenty years computer drafting and modelling has come such a far way. Even in my short lifetime i have seen plans go from the drafting board to the computer screen. I have seen a 3D model take two days to render that was 5 years ago now its under two minutes. To say that the new bridge is not superior is more than a joke its an insult to anyone who knows what computer drafting has added to out world.
And to the writer below who said there’s an “obvious safety issue” with the exposed gears… all I can say is, how about you do some research. You are judging from a picture, and your opinion is biased.
With time the gears would have to be replaced and large delays will occur.
Mention is made of superior metals being available today. those very same metals can be used on the Blue Bridge as individual struts,beams and girders are replaced with very little traffic disruption
Have we considered building a permanent fixed bridge similar to the Bay Street bridge?
Please come to the meeting at Alix Goolden Hall tonight for some answers to your questions.