Country: New Zealand
Key Area: Transportation
Services: Architecture,Civil Engineering,Environmental & Social Impact Assessment,Environmental Planning,Geotechnical Engineering,Heritage,Landscape Architecture,Land Surveying,Structural Engineering,Traffic Engineering,Traffic Modelling,Transportation Infrastructure Design,Transportation Planning & Engineering

The Wellington Inner City Bypass has won the INGENIUM Excellence Award for projects over $1million. This is the sixth in a line of awards presented for the bypass to Opus, along with the clients, Transit NZ and the Wellington City Council, and the contractor, Fulton Hogan.

The $55m Wellington Inner City Bypass (WICB) is Wellington’s largest roading project in recent times.  It provides a cross-city link between the end of the Wellington Urban Motorway and the Basin Reserve and consists of a double lane one-way arterial route in each direction, partly along existing streets, partly along a new road that includes a 450m long below grade trenched section.

The trenched section of new road posed design and construction challenges in view of the variable soil conditions, high seismicity of the area, complex groundwater regime and confined site.  A cost-effective solution here has involved a propped trough section flanked by sections with soil nailed retaining walls.  The soil nailed walls are some of the largest of their type in New Zealand and incorporate a post-grouting technique to enhance bond strength.

While most of the quantifiable benefits of the new road network are related to reduced travel times for motorists, the project also provides other benefits.  It has reduced the impact of motorway traffic coming into and leaving the city on local residents and businesses, catered for the needs of cyclists and pedestrians and, something rare for a roading project, it has helped preserve an important part of Wellington’s building heritage.  Incidentally, the project provided the impetus for the upgrading of a major stormwater diversion and provided cut-to-waste soil to cap a city landfill.  The WICB is a good example of the integration of a transportation solution with the needs of the local community.  The complexity of the project called for a collaborative approach in its delivery, the success of which owes much to a ‘partnering charter’ established from the outset by the two clients, consultant and contractor.

Although wide public consultation was held during the ‘investigation and reporting’ phase of the project, the WICB polarised public opinion and was the subject of heated challenge and protest.  “Destruction of the Te Aro – Cuba St culture and historic buildings and lack of information” were cited as the main reasons for opposing the bypass with those in Central Wellington divided three ways - 33.2% in favour, 33.3% opposed and 34.2% undecided.

It is pleasing to note that since the WICB was opened in mid 2007 there has been very little debate over the benefit provided by the project, with most feedback being very supportive.  The engagement of the public, attention to mitigation of adverse environmental effects during construction, the quality of the finished project and the benefits it has brought to Wellington have largely silenced criticism.