Milford Marina Bascule Footbridge

The Milford Marina Footbridge (also called the Milford Marina Bascule Footbridge) is a 40m long architectural bascule lifting bridge in Auckland. Two hydraulic rams lift a 10m bascule span to allow boats to pass underneath when required. The bridge was initially conceived by North Shore City Council (now Auckland City Council) based on a commitment made to local residents for replacing a high level timber bridge that was removed in the nineties as it fell into disrepair. Following completion of the bridge and connecting cycleway it is now possible to walk, jog and cycle the Auckland waterfront from Mairangi Bay to Devonport without having to venture too far inland. In turn this project is enabling more access to parklands and waterfront helping people to maintain healthier and thus more productive lifestyles.

Dan was the lead bridge engineer and bridge architect for the Milford Marina Bridge whilst working at Beca. Beca are one of NZ’s largest engineering firms and we actively retain very strong relationships with their multi-award winning bridge team.

[quote author=”” source=””]A key to the success of this bridge is the adoption of simple but effective “architectural engineering” principles to incorporate bridge architecture and bridge engineering to deliver a functional but strong aesthetic.[/quote]

By Architectural Engineering principles we mean the careful consideration and selection of suitable structural form and materials that aim for a ‘perfect’ balance between engineering function, durability and architectural form. The purpose of this pursuit is to result in a refined and sometimes striking aesthetic. 

The main bridge lifting span is formed from steel rectangular hollow sections (RHS) combined into a simple deck form of two primary beams, three cross beams, and two members positioned diagonally as bracing. The rams are positioned to push directly in plane
with the primary members to eliminate unwanted eccentricities (which can cause structural issues). Over the steelwork a timber support system (joists) and hardwood vitex timber decking has been erected. The benefit of this arrangement is to reduce the overall weight but at the same time this enables a simple and pleasing aesthetic. The combination of the white steelwork with the timber deck create a simple and well placed nautical aesthetic. To further enhance the aesthetics of the bridge – with only a nominal cost premium – the timber decking has been arranged in a herron-bone pattern to suggest the scale and shape of a sail boat passing the channel when the bridge span is in the up position. The quality of this finish achieved by the carpenters has been outstanding in this finish.

Key Bridge Stats:

• Total bridge length =40m
• Lifting span length = 9.5m
• 3No concrete approach spans circa 10m each
• Bascule lifting span is powered by 2No. 600kN (60 tonne) hydraulic jacks
• Lifting span = steel + timber decking. Timber decking is arranged in a heron-bone pattern to suggest the sail of a boat when the bridge is erect
• Usable width = 3.0m shared cycleway
• All steelwork is zinc sprayed and painted with a polyurethane white top coat to fit with the maritime surroundings.
• Bridge operates on demand via a UHF radio. Marinas contact the remote operator to lift the bridge.
• Officially opened December 2015
• Client: Auckland Parks (part of Auckland City Council)