Arup expertise highly commended by SAICE

21 August 2017

The South African Institution of Civil Engineering (SAICE) recognised Arup with a Highly Commended Award in the Structural Engineering Project Division for their work on the PwC Tower, at the Most Outstanding Project Awards ceremony hosted by SAICE, Johannesburg Branch.

“Our unique contribution to the PwC Tower located in Midrand, north of Johannesburg, was to make the complex, spiralling tower design buildable and economical. Our advanced parametric modelling software and systems enabled us to make quick assessments of a number of different structural and façade geometries – enabling us to offer optimised and integrated solutions,” said associate director Richard Lawson at Arup and project manager for the PwC Tower.

“We believe the key to the success of this award-winning development is the industry collaboration coupled with embracing technology that facilitates that collaboration”, Lawson concluded.

The biggest structural challenge is the spiralling form of the tower that caused the gravity loads to create a clockwise torsional load on the building. This is balanced by columns along the façade that counter that twist.

Tall building construction is relatively rare in South Africa. The core was constructed using slip forming. Internationally this construction method is relatively common for buildings over ten storeys, but until recently in South Africa, it has generally only been used for forming chimneys and cooling towers.

The façade also posed technical challenges. It was decided to wrap flat glass around a twisting structure, and the optimisation of this included factors such as glass utilisation, aesthetic alignment with the structure and integration of blinds with a sloping, slanting façade.

Because the PwC façade is concave and twisting, concentrated solar reflections were identified as a risk. A purpose-built script was developed to assess intensities of solar reflections. It calculated the magnitude of the solar concentrations in the open areas surrounding the tower. It then tested feasible and practical solutions to mitigate the impact of the solar reflections.

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