Multiplex has stopped work on the upcoming $1.2 billion twin tower skyscraper project in Melbourne following structural issues in the construction.

Designed by New York-based SHoP Architects and Melbourne-based Woods Bagot and known as the 'Pantscraper', the mixed-use Collins Arch project located on 447 Collins Street is being built on a 6000sqm city block right in the heart of Melbourne CBD.

Work was halted at the project site on detection of movement in the precast structural concrete columns. A statement released by Multiplex and project developers Cbus Property and ISPT, says that a few minor column settlements were identified, following which the builder, Multiplex began a detailed investigation into the issue with structural engineers conducting inspections of the columns.

Work has been temporarily paused while the investigation is carried out.

Though resumption of work is not expected to be delayed, the problem in the twin tower is likely to have been caused by incomplete grouting in some of the precast columns leading to crumbling.

The liquid grouting solution between the column and the floor slab didn’t penetrate fully, leading to minor spalling of the column edges.

The problem has since been remediated and a full audit is being carried out for all the structural columns to rule out further issues.

Image: © SHoP Architects/Woods Bagot