Woden construction wall collapse could have caused multiple fatalities

The dramatic collapse of earth, concrete and scaffolding at a major Woden construction site had the potential to cause multiple fatalities and has resulted in a guilty verdict for an engineering corporation involved with the site.

The Structural Design and Construction Company (SDCC) was found guilty of failing to comply with a health and safety duty, which is an offence under the Work Health and Safety Act 2011, by the ACT Magistrates Court last week.

On 6 August 2022, a 35-metre-long and 10-metre-deep section of a shoring wall collapsed into an excavated pit during the construction of a large residential and commercial building precinct in Phillip called WOVA.

“It only took a few seconds for the shoring wall to collapse, with the site fencing and scaffolding and the edge barrier to the driveway for the neighbouring multi-storey carpark (Sky Park) also falling into the excavation,” Magistrate Ian Temby said in his recently published decision.

“The debris from the collapsed part of the wall travelled around 15 metres from the side of the excavation.

“In addition, about five minutes after the shoring wall collapsed, a section of the Sky Park driveway collapsed into the excavation.”

He said it was fortunate no one was present at the site when the wall collapsed.

“If there had been any workers near where the wall collapsed, they would not have had time to evade the debris which fell into the excavation,” he said.

However, Sky Park was open, and three cars were recorded nearby in the 10 minutes preceding the incident.

One of these cars drove over the driveway less than a minute before it collapsed.

“If any of these cars (or any others) had been driving on the section of the driveway that collapsed at the time that it did, they would have fallen into the excavation,” the magistrate said.

He stated that SDCC was a corporation that, under the business name PTC Consulting Engineers, provided engineering services. At the time of the incident, its sole director and principal engineer was Wen Lu Zhang.

SDCC had been asked to provide a geotechnical investigation report for the site by WOVA’s principal contractor, Geocon Constructions (ACT). It was also subsequently engaged by subcontractors to complete the design work for the demolition and excavation of the site.

“SDCC was responsible for the design and associated drawings for the shoring wall,” Magistrate Temby said.

Prosecutors alleged SDCC failed to provide an adequate design for the shoring wall at the site between November 2019 and August 2022. It was also alleged the failure meant there was a risk the shoring wall would collapse and, in turn, this meant there was a risk anyone in the vicinity of the collapse could be exposed to the risk of death or serious injury.

Magistrate Temby said SDCC did not contest its charge, but prosecutors still had to prove its guilt.

WorkSafe ACT’s investigation could not conclusively determine the reason for the wall’s collapse, but identified contributing factors that may have included rainfall at the time, rock fractures, and the inadequacy of the shoring wall system.

Magistrate Temby ultimately found the design of the shoring system was non-compliant with Australian standards.

“In circumstances where the soil at the site contained fractures and defects, the likelihood of the risk eventuating at the site without adequate engineering control was obvious,” he said.

He accepted that the degree of harm from the risk was “potentially catastrophic” and multiple fatalities were a very real possibility.

“Given the regular attendance of workers at the site and the use of Sky Park by members of the public, multiple fatalities were a very real possibility as a result of the inadequate shoring wall design that SDCC prepared,” he said.

The sentencing hearing is scheduled for 8 December.