Presentations – MHX Bridges and Auckland Harbour Bridge Strengthening

When: March 2012

TALK #1: The Manukau Harbour Crossing Alliance Bridges - Bridge Design and Construction in a Successful Alliance Environment

Abstract: NZTA's Manukau Harbour Crossing project on Auckland's South-Western motorway was delivered by the MHX Alliance in late 2010 - on budget, open five months ahead of programme, to a high standard and with satisfied stakeholders. The project is notable for its bridges: all different, and ranging in scale from a timber boardwalk to the 13,800 m2 centrepiece of the project, the 100m span twin box girder balanced cantilever Duplicate Mangere Bridge.
This talk by Dr Andrew Dickson (Beca) briefly describes the Manukau Harbour Crossing bridges, and captures some thoughts on how the processes of concept design, community consultation, detailed design, temporary works design, construction, construction monitoring, quality closeout and handover were able to be successfully managed in the Alliance environment to achieve an outcome which has delighted the client and in which the Alliance takes great pride. A link is drawn between the benefits of the Alliance environment and the delivery of "Sustainable Bridges".

TALK #2: Auckland Harbour Bridge Box Girder Strengthening Design and Construction
Abstract: The economic vitality of Auckland depends upon the movement of people and freight around the city's motorways and the Auckland Harbour Bridge (AHB) is a crucial component of the network. Traffic loads derived from weigh-in-motion (WIM) data measured on State Highway 1 were found to have increased 50% since the last extension bridge assessment and upgrade in the 1980's. The bridge was found not to satisfy current standards and so to support the regional economic growth strategy major intervention was needed to upgrade the structure for current and future demands. The addition of extension bridges to the original truss bridge was an innovative achievement in 1969 increasing highway capacity from 4 to 8 lanes. Getting the most out of the existing steel orthotropic box girder structure to extend the service life of the crossing was the key challenge for this project.
This talk by Will Pank (Beca) will discuss the strengthening work completed in 2010 and highlight some of the innovative techniques used to deliver the required construction quality and fatigue endurance. More has been gained out of the AHB box girders than ever anticipated and the landmark bridge has been preserved for decades to come.