Three tricks of the trade deliver a better building

When an ambitious program was proposed for the new Oracle Apartments in Perth, Michael Ruescher and his team at Wood & Grieve Engineers developed smart solutions that saved time and money.

The doors have recently opened on Blackburne Property Group’s 22-storey mixed use tower.

Part of the new Stirling Street precinct, Oracle Apartments features 137 apartments, three levels of car parking and street-level retail and commercial spaces.

Designed by DMG Australia and constructed by Probuild, the residential tower boasts a rooftop sky garden that maximises magnificent city views, as well as a fitness hub with gym, yoga room, sauna and pool.

A steady stream of residents is already moving in, thanks to a fast-tracked program driven by a talented project team.

Project engineer Ruescher (pictured) was involved from concept through to construction over a three-year period. He says three engineering solutions – 3D finite element modelling, post-tensioned floor slabs and full-height transfer wing walls – have helped to deliver a spectacular result.

3D finite element modelling, for example, uses computer software to predict how a building will react to real-world forces. Using this approach, Ruescher and his team were able to test out a range of design options.

“By modelling all the structural elements of a building – the concrete, the steel and design forces, for example - we get a more accurate picture of how the structure will react and move, and that allows us to design it more efficiently,” he says.

This type of modelling is becoming more commonplace as computer technology evolves, Ruescher explains.

“By modelling the building as a whole, rather than by isolating separate parts, we can see how each part interacts with the larger system,” he adds.

“In the case of Oracle, using the finite element modelling allowed us to propose a range of options to the architects, and to manipulate the design to get the best solution.”

Significant savings were also made by using post-tensioned floor slabs. This method of reinforcing concrete minimised the building’s weight.

“Tensioned steel tendons were cast into the concrete. This allowed us to span the concrete further and to reduce the slab thickness. This, it turn, reduced the weight, the foundations, the volume of concrete required and the cost,” he says.

“This approach is relatively new to Perth multi-residential construction, but can achieve significant savings, especially on a building of this height,” he adds.

Clever use of carefully-detailed “wing walls” on Level 5 of the Oracle Apartments meant that tower loads were distributed onto columns without the need for deep transfer beams.

“In any building, the transfer beams or slabs are the most complex and slow down the program of construction more than any other elements. At Oracle, we’ve used the walls as a structural element to transfer the weight of the building.

“This streamlined the structure, and also saved time and money, while delivering a better building.”

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