Breakfast Creek Green Bridge

In December 2018, the Kingsford Smith Drive upgrade celebrated a major milestone with the opening of the 1.2 kilometre Lores Bonney Riverwalk stretching from Bretts Wharf in the east to Cameron Rocks.  It is now an incredibly successful recreational and active transport route.

But, there was unfinished business at the western end at Breakfast Creek.

This hinged on the fact that the entire active transport network was trying to get around a right hand turn on the existing Breakfast Creek vehicular Bridge on an unprotected footpath less than 2.5m wide.

The opportunity was to provide a safer and more generous connection for pedestrian and cyclist movement between the City and the Northern Suburbs. Previous studies had identified no less than eight different crossing location options to resolve this.

COX were engaged in 2020 by SMEC and with Lat27 to resolve the alignment and propose a new bridge.

As we discovered, there were multiple challenges, including:

• The sensitive matter of interfacing with one of Brisbane’s most important historic places Newstead House and Newstead Park
• Accommodating a Creek that floods regularly and avoiding solutions that put more infrastructure in the Creek
• Dealing with an existing bridge that has major district services strapped to the outside of it that could not be modified

The first assessment established that we could not achieve a desired 6m corridor for bicycles and pedestrians on the existing bridge or via modification of the bridge. The second assessment was then for an appropriate new bridge alignment.

Analysis of the views to and from the Newstead House Peninsula meant even though there was a roughly equal distance to travel east (in front) or west (behind) Newstead House to continue on the network, that a river edge solution would not be appropriate for the historic setting.

Establishing a western route led to detailed investigations of an exact bridge alignment and resolving interventions in the park.

The northern launch point was constrained by maintaining the existing east west under bridge connection. This meant that a strong desire line solution rather than a perpendicular could be contemplated.

One of the driving matters was that the vertical clearance of the new bridge had to at least match the clearance of the existing bridge. This meant the bridge would land closer to the elevation of Breakfast Creek Road than to the Creek edge.

However, it still meant the bridge was landing next to the other bridge and in the Park; a Park that had already been reduced in size when the development of the existing vehicular bridge was built in 1958 replacing bridges built in 1858 and 1889.

The team worked to minimise this impact in four key ways,

• Integrating within the existing path network so that it is now possible to circumnavigate the Park without steps and with accessible grades
• Pushing the bicycle connection south of the bridge on to an underused road lane so that we didn’t need to modify paths amongst the Park’s significant Fig Trees and also avoid commuter traffic within the Park
• Promoting a connection underneath the bridge back to the west so that there can be connectivity to the Creek side development including the popular bakery
• Lastly, celebrating the historic existing avenue of Palms and provide new views of the Park

The remaining challenge was the bridge form.  We encountered early, the perception (that we shared) that the bridge could be a relatively modest structure given that the adjacent existing vehicular bridge had no structure above deck level.

As it turned out, the existing bridge is approximately sixty metres long comprising of three spans of 20m each, the new bridge would need to be closer to 90m long due to the angle across the creek and because of the potentially adverse flood impacts, a 90m clear span versus 20m span.

This put the bridge in significant span territory -much closer to that of the Goodwill Bridge and Kurilpa Bridge than the existing bridge.

Through analysis, a tied arch produced the least amount of visual structure and it allowed a framing of views between the Breakfast Creek Hotel and Newstead House as well as a modest marker as a northern gateway to the City.  Modification of the pier locations to reduce impact in the Park produced a bridge with two different arch spans- 67m and 89m inclined and supported together.

Within the Council’s green bridge program this was very much a functional piece, with the Kangaroo Point Green Bridge considered a far more significant city making piece.

The team focused significantly on increasing the experience of the Park and its connectivity.

The dominant Moreton Bay Figs within the park were a guide to bridge colour. The tree’s leaf has a different colour to its upper and lower side.  The resultant two tone bridge changes character through the day and is lit dramatically at night.  The bridge’s relationship to the Albion and Northshore Olympic Precincts means it will likely play a strong role in moving people around in 2032 and for many years to come.