01 November 2017

Canadian Bridges: 4. Capilano Suspension Bridge, Vancouver

I mentioned previously that Lion's Gate Bridge is Vancouver's best known bridge, but the Capilano Suspension Bridge must run it close. Spanning 137m long, 70m above the Capilano River, it's also one of Vancouver's major tourist attractions.

Scottish civil engineer George Grant MacKay bought 6000 acres of wilderness from the Crown for 1 dollar per acre. In 1889 he worked with local First Nations people to connect both halves of his property with a suspension bridge. An information board at the site states his assistants to have been August Jack Khatsahlano and his brother Willie, but Wikipedia indicates August Jack to have been aged only 12 at the time of bridge construction. The new span was built from cedar wood and hemp rope, secured to trees on one side of the deep gorge, and to a buried tree on the other.

Engineer William Farrell replaced the original span with a bridge using wire cables in 1903. It was always a tourist destination, although in the early part of its life, it was a considerable trip from the main part of Vancouver via a ferry and a six-mile hike. Increasing visitor numbers meant that additional support cables were added in 1914.

The bridge that can be seen today is the result of a complete replacement in 1956, on the instruction of the owner at that time, Douglas McRae Mitchell. It was reportedly designed by Art Williams, the engineer, to carry 1,333 persons. Steel cables were anchored into 13 tons of concrete at each end, which I have to say doesn't sound like very much, and an information board at the bridge notes that the current anchors are 24 tons, which is a little more reassuring.

Today the entire site is a tourist mecca, with plenty to do beyond just walking across the bridge. It crosses a scenic canyon where reportedly bears and eagles can sometimes be seen, although I was not so lucky. It's surrounded on all sides by huge cedar and fir trees, including several very impressive forest giants.

The structural form is a simple suspended span, with the main cables secured into anchorages hidden out of sight below timber platforms. Short hanger cables connect to timber cross-beams which carry the walkway.

The views from the bridge are spectacular. It doesn't feel unsafe under moderate loading as seen in the photos, but it does sway quite noticeably. I've provided some videos of the sway below, seen from different angles.

I found it awkward to walk on, but not to the extent of feeling unsafe, although clearly anyone with vertigo or balance problems may not be able to cross the bridge (the whole tourist attraction is best entirely avoided in this circumstance!)

The Capilano bridge is small beer when compared to other long-span pedestrian bridges, including the new record-breaker near Zermatt, but I found it very impressive.

The suspension bridge park also features a treetop walkway, and a suspended cliffwalk, both of which I'll cover in my next two posts. The cliffwalk can be seen in the first photograph below.


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