02 November 2017

Canadian Bridges: 5. Cliffwalk, Capilano, Vancouver

There are three main attractions at the Capilano Suspension Bridge Park. The Cliffwalk can be found a short distance to one side of the main bridge.

The Cliffwalk was opened in 2011. It was designed and built by Morrison Hershfield. The walkway is supported from the upper section of a 90m tall granite cliff face. It is some 213m long, with a 30m long cable-supported section, but it is claimed to have an environmental footprint of just 11 square metres. This is the amount of contact made with the cliff-face, which was carefully surveyed to identify suitable locations of rock anchors to be installed.

Over its length the cliff walk descends around 9m, before rising nearly twice as much, with a series of staircases. The main walkway is 0.5m wide at floor level, and 0.8m between handrails. Parapets are 1.2m high, which I found adequately reassuring. The parapet infill is a stainless steel mesh.

The narrow walkway is generally suitable only for passage single file, which requires a degree of patience when the crowds are visiting, but there are balconies and platforms at intervals to allow people to pass or stand for longer to admire the views.

The structure generally comprises galvanised steel, with stainless steel handrails. The floor is timber except for a couple of platforms with glass and grille flooring, deliberately inserted to make the whole experience more of a "thrill".

The whole assembly sits typically 3m off the cliff-face, intended to minimise the risk of damage due to rockfall.

The entire structure is reported to be able to carry 45 tonnes of load, which equates to a live loading of 4kPa. This seems ample given the restricted space provided.

Selected parts of the bridge were fully load tested to this level using water barrels, before the bridge was opened to the public. There's no mention of any analysis or testing for vibration in the paper published regarding the bridge's design and construction, but I didn't detect any significant movement.

The Capilano Cliffwalk is a well-designed and built structure, which strikes a good balance between a sense of fear and a sense of security. The detailing is pragmatic yet attractive, and it has certainly enhanced the value to be gained from a visit to the Capilano Suspension Bridge Park.

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