Design Challenges of Bristol’s Castle Bridge

Bridging the River Avon between the new Finzels Reach development at the former Courage Brewery site in Bristol and Castle Park proved to be anything but straightforward.  Multidisciplinary engineering consultants Clarkebond worked with developer Cubex and architects The Bush Consultancy to develop a stylish bridge design that overcame numerous physical constraints posed by the site.

The Finzels Reach development is over 6 metres lower at the river edge than Castle Park directly opposite. Given the relatively short stretch across the water, that would be too steep a climb for most people, and would certainly not be wheelchair friendly.

The original plan by a previous developer was for a lift on the Finzel's side up to the bridge.  However, when new owners Cubex took over, it was decided that this was all too complicated and disadvantaged wheelchair users and cyclists. Also, what happens when it breaks down? How do you maintain it 24 hours a day?

The bridge also had to be sited away from the front of residential properties to avoid occupants being overlooked and the height of the bridge could be not less than that of Bristol Bridge further along the river.  In addition, the Harbour Master required a clear 20 metre wide channel to enable two rowing boats to pass each other and the structural bridge supports to be designed to withstand the impact from passing harbour craft.

The solution was a stylish curved bridge which stretches the distance to 90 metres across the river to a point where Castle Park is only 2.5m higher that the Finzels Reach site, and therefore lowers the gradient of the climb to a more acceptable level at no more than 1:20 across the entire span.  Clarkebond liaised closely with CTS, the bridge fabricator, and with the Harbour Master to confirm the final design brief and also designed the bridge supports with piled foundations into the harbour bed and a fender system around the supports to withstand impact from waterborne traffic.

John Pavey, Director of Clarkebond commented, “In solving the challenges of this site, the team has developed an iconic design which complements and enhances the high quality nature of the development.”

Architect:  Bush Consultancy
Contractor: Andrew Scott
Bridge Fabricator: CTS
Developer: Cubex

* image courtesy of Mark Small @thehistoryb0y