The development of this 10,000sqm site will change Subiaco landscape by creating a brand new precinct which will bring new life to this part of the city. The precinct will comprise of a 10-storey hotel, a 6-storey grade A office, 1500sqm of landscaped plazas and three levels of underground car parking.
Hera Engineering was appointed to perform Value Engineering of the existing structural design. Our solutions provided cost savings in excess of $2M and reduced total program significantly.
While the superstructure consists of structural steel and concrete metal decking, conventional structural systems stopped at grade. Site constraints ruled out open cut construction for the 12m deep excavation, making top-down construction necessary. Top-down construction, as the name implies, allows the permanent structure to be built simultaneously as the basement is excavated from top to bottom.
After installation of a contiguous pile wall and plunge columns, the highest basement slab was poured. Then excavation for the next slab down progressed. This allowed the slabs to act as diaphragms to brace the contiguous pile wall. Superstructure construction began while basement levels were still being excavated, which saved weeks of project construction time.
Innovative Steel Design
Hera Engineering worked on an alternative design for the steel composite superstructure with the aim of speeding construction to meet a very tight program schedule. With some innovative thinking, we were able to reconfigure the beams and reduce the number of columns on the typical floor plate from 90 to 30, with not net increase in steel quantity. This produced enormous savings in riggings costs and time. Another improvement we introduced was replacing the pre-fabricated trusses with standard steel beams, creating a saving of over $50k.
The Hera Engineering steel frame system designed for the main cores will be the first use of a system of this type in Australia. Furthermore, by implementing this system we were about to take off 12 weeks from the project program.