Project:  Central Motorway Junction

Date:  February 2006

Location:  Diaphragms in concrete box girder bridges (KPV Structure)

Contractor:  CMJ Joint-Venture

Engineer:  Beca

Concrete Supplier:  Firth

Type of Unit:  A new diaphragm, inside an existing cast-in-place continuous box-girder bridge, as part of a bridge widening contract.

Reason for choosing SCC:  Access was difficult inside the existing bridge.  Concrete had to be pumped the ful length of the bridge and formed up to the soffit of the bridge deck which was significantly easier to achieve using SCC.

Outcome:  Problems were intially encountered with the truck-life of the SCC mix due to delays on congested central Auckland roads.  The problem was overcome by rescheduling the pours to suit the traffic and re-dosing with admixtures on site as required.  The final outcome was an easily placed, high quality diaphragm integrally connected with the deck soffit.  SCC was a successful solution to a difficult strengthening job.

Submitted by:  Graham Frost, CMJ Joint-Venture