Tauranga Harbour Link - Stage Two
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.