Engine Arm Lifting Bridge

Tags: infrastructure, steel, bridge

Related projects: Bath Quays Bridge

  • Client: Complex Development Projects
  • Value: Confidential
  • Start Date: September 2015
Engine Arm Lifting Bridge Approach GIF Interrobang
Engine Arm Lifting Bridge Plan Interrobang
Engine Arm Lifting Bridge GIF Interrobang

As part of a wider development of the Smethwick Rolfe Street area, we have designed a lifting bridge over a canal that provides a pedestrian and cycle route between two development areas while allowing boaters to continue to navigate the waterways.

The Engine Arm is a feeder canal that crosses the Birmingham New Mainline canal via the Grade I listed Thomas Telford Aqueduct. It is home to a number of boaters with residential moorings. The design of the lifting bridge therefore needed to respond to a raft of complex constraints including the setting of the listed aqueduct, ease of use for boaters, safety of pedestrians and cyclists, longevity of a moving structure, and the robustness required to withstand both accidental impact as could be caused by a narrowboat striking the structure, and vandalism.

The key challenge to overcome was to create a structure light enough to lift easily but robust enough to withstand potential impact from a narrowboat. This is achieved by creating a structure that decelerates a boat over a distance of approximately 600mm. This therefore requires that the design accommodates a substantial deflection. This is achieved with two outriggers that can slip laterally in case of impact. The force of the impact is absorbed by a tuned flexible truss running centrally along the underside of the deck. This solution allows for a very light structure that can be lifted with two hydraulic pistons.

The intention is for the bridge to be locked in the open position overnight. It is therefore designed to contribute to the urban fabric as much as a local landmark as a bridge.