Q+A:When it comes to bridge design, what is the balance between structural integrity, architectural beauty and usability?
Two individuals, from different professional backgrounds, and from different parts of the globe, give answers to our question of the week.
Stuart Nielsen, is a bridge engineer, adjunct faculty member and owner of the blog, tallbridgeguy.com. He grew up in Calgary and now lives in the United States:
Getting the obvious out of the way first, any engineer worth their T-square will ensure that a bridge is safe for the intended loads it will face. Functional usability is also mandated by design codes, meaning traffic lanes are wide, deck grades are accessible for pedestrians and all the corners are rounded to prevent injuries. Aesthetic usability, the idea that a bridge is more than just a conduit between roads, is a challenge for any designer.
So the question actually becomes, how much beauty does a bridge deserve? All bridges are beautiful in their own way (is that a song?). Looking at how an engineer has solved the forces through giant pieces of concrete and steel creates a subtle internal dynamic.
As Gustave Eiffel said “Can one think that because we are engineers, beauty does not preoccupy us or that we do not try to build beautiful, as well as solid and long lasting structures? Aren’t the genuine functions of strength always in keeping with unwritten conditions of harmony? Besides, there is an attraction, a special charm in the colossal to which ordinary theories of art do not apply. “
We do hate bridges that have to twist and bend to make a visual statement without regard to the underlying structural needs of the bridge.
The famous engineer Hardy Cross wrote, “A bridge must be structurally sound, correct in form, adequate in detail, of good materials properly used; but it should also fit into the landscape and with grace and dignity carry the roadway over from street to street or from hill to hill. The distinction between architect and engineer is quite recent and in bridge architecture it is almost impossible to enforce it. One who would design a beautiful bridge must have correct concepts of structural action; the artist must be something of an engineer, the engineer an artist and planner.”
Stephen Leopold is the Founder and President of Leopold Montreal Real Estate and the Founder and President of AudaCité Montréal www.audacitemontreal.com :
Structural integrity should be a basic requirement of building a bridge. Is promising that a bridge will not fall down really something to aim for? If so, the bar is set way too low.
There should be no balance between structural integrity and aesthetics. A bridge is suppose to stand up, period. Such a basic trait shouldn’t be up for discussion.
Is it up for discussion that a quarterback can throw a football?
Is it up for discussion that a chef can use a knife?
No, because quarterbacks should know how to throw a football and chefs should know how to use knives. Just the same, bridges should stand up.
What is up for discussion are specialties, like a heated road bed or a bicycle bath. And of course, what the bridge will look like should definitely be up for discussion.When the Brooklyn Bridge was built, they constructed a beautiful structure and made sure that it stood up. Same for the Golden Gate Bridge.
Here in Montreal, we have the busiest bridge in Canada, the Champlain Bridge, that will be replaced by a new bridge. Instead of having a discussion centered on the structural integrity of the new bridge, more emphasis should be put on building something iconic for Montreal and for Canada,like the Sydney Opera House or the Eiffel Tower. We have all of this hydro electric power in Quebec, why not build a bridge that showcases our process in this energy sector.
Of course a bridge should have structural integrity, but while we’re at it, why not built something special.
Ask any San Franciscan if the Golden Gate cost just one penny too much, compared to the billions that it has brought into San Francisco each decade for almost a century. Ask the same question of any person from anywhere in Australia about the Sydney Opera House, or anybody from France the same question about the Eiffel Tower. We are not building something on a whim. We have no choice but to build something. We can pretend that we are third world or we could plant the icon for Montreal and all of Canada for the 21st century. And with a completely transparent decision making and bidding process, the greatest bridge in the 21st century should come in at less cost than any of the numbers that have been thrown around to date.
So what do you think?
When it comes to bridge design, what is the balance between structural integrity, architectural beauty and usability?