Tauranga Harbour Link - Stage Two

Tauranga Bridge

Project Delivery: Fletcher Construction

Consulting Design Engineers: BECA

Project Completion: December 2009

Application: Prestressed Concrete T-Roff Beams

Concrete Type: 60 MPa Self Compacting Concrete

Cement Type: EverFast™ (Type HE Cement), Microsilica 600 and EverPlus™ (Class C Fly Ash)

Concrete Supply: Firth Industries

Volume: Approximately 3,000m³

Concrete Durability Requirement: Construction of a concrete bridge with a specified life of 100 years exposed to extreme marine conditions.  These were in excess of the exposure classifications as detailed in NZS 3101:2006 where the concrete will not be exposed to the splash zone but is subjected to high wind blown salts.

Project Solution: A low water/binder ratio Self Compacting Concrete that contained a ternary cementitious blend of EverFast, Microsilica 600 and EverPlus was adopted.  Chloride profiles obtained from the concrete confirmed chloride life prediction modelling for a specified life of 100 years with a 40mm concrete cover.  This reduced cover depth allowed significant project cost savings as the weight of the T-Roff beams enabled greater spans while remaining within the lifting capacity of available site cranes.