North Frame Pedestrian Bridge

A single-span steel arch carrying people and services across Christchurch’s Avon River

AO Architecture developed this competition proposal for a pedestrian crossing within Christchurch’s North Frame. The bridge had two jobs: carry people across the Avon River and take infrastructure pipes from one bank to the other. We brought those requirements together in a single steel arch, keeping the pipework within the structure rather than suspending it beneath the deck.

One arch for two jobs

The arch springs from the riverbanks in a single span, leaving the Avon clear of intermediate piers. Infrastructure pipework runs inside the arch, so the servicing requirement becomes part of the bridge’s structural idea and stays largely out of sight from the riverbanks.

AO Architecture worked with BUD Design as structural engineer and INOVO for project planning and management. Resolving the irregular steel geometry alongside the pipework it enclosed was a central part of developing the proposal.

A crossing that changes as you move

The deck does not cross the river as a straight line. It curves in plan as it passes over the asymmetrical arch, with long ramped approaches extending back into both banks.

As pedestrians approach, the bridge is seen obliquely before the route turns onto the crossing. The relationship between deck and arch continues to shift underfoot, so the structure reads differently from one side of the river to the other.

The asymmetrical geometry drew on the movement of the Avon below, giving the bridge a changing profile rather than a single symmetrical elevation.

The competition was subsequently cancelled, and the bridge remains unbuilt.