Old Public Trust Building - Heritage

Old Public Trust Building - Heritage

Cheops Holding Ltd
New Zealand
Dunning Thornton

Key Aspects

Design PT System

The ornate stone and brick Edwardian baroque style building on the corner of Lambton Quay and Stout Street is believed to be NZ's first steel framed office building and was completed in 1909. It is a category one heritage listed building with the NZ Historic Places Trust. The seismic strengthening works were some of the largest undertaken in Wellington, and generally consisted of installing two new full height reinforced concrete shear walls as well as extensive works to strengthen the floor slabs. 

Freyssinet were approached to supply Freyssibar to connect the new full height shear walls at each floor level. Freyssinet worked collaboratively with the design engineer and head contractor to redesign an alternative PT system using galvanised greased and sheathed strands, cast directly itno the floor slabs of levels 1-4. The alternative proposal was unique in that no conduits or ducts were used to house the PT strand due to tight space requirements of the floor slab. As a result, these strands were required to be temporarily stressed to a nominal load in order to keep them perfectly straight while the floor slabs were poured around them. 

Freyssinet were abvle to combine a mixture of flat slab anchorages as well as the C-Range anchorages to best suit the geometry of the project. The 15.7mm strands are designed to be replaceable after a major earthquake event.