Constructed in Wellington, the Montreaux Apartments are in a New Zealand region well known for seismic activity. The Engineers chose to use Speedfloor Suspended Concrete Flooring for its lightweight and ‘simply supported’ characteristics.
Most earthquake-resistant buildings in New Zealand are rectangular, but the one designed by Architect+, for 164 The Terrace, Wellington, had an unusual diaphragm; it was “H” shaped. The reason was that the “H” formation would optimise light and airiness for the apartment’s tenants.
Connell Mott MacDonald’s Design Engineer, John Finnegan, said this design solution is quite common in cities such as Hong Kong. “The system combines Eccentrically Braced Frames with a shear wall that has two service cores at either end. Although the torsional drift was quite high, this was kept in check by relatively light-weight K-frames.”
Architect Allan Wright commented: “The predominantly steel structure offered significant design flexibility and programme benefits, allowing earlier closure than would have been possible with concrete.
Once again, Wellington presented its unique challenges for MJH Engineering, who did the fabrication and the erection. In addition to the narrow site access, the location was adjacent to a bridge to the motorway, and mobile cranes could not be used on this. With no set down room for the fabricated steel being delivered, MJH had to erect directly from the delivery vehicle.
“We often have to do that in Wellington,” says MJH’s Malcolm Hammond, “getting in and out before the start of the morning traffic.” Commenting on the use of Speedfloor Steel Joists, he said: “The product worked well in providing light-weight, inexpensive support for a good quality concrete floor. It meant that a small, tower-crane was adequate for the job, and once again we struck a cooperative spirit among the follow-on trades, for which the C.A.S. Management team is to be commended.”
Structural Engineer: Connell Mott MacDonald
Steel Constructor: MJH Engineering
Project Managers: C.A.S. Management
The above article was printed in the SCNZ March issue and Speedfloor NZ thanks SCNZ for allowing the reprint.