Engineers at Transurban are investigating the causes behind the falling sign on the Tullamarine Freeway in January 2019.
The company has conducted an audit of all road signs installed as part of the CityLink Tulla Widening Project of similar size and structure to that which fell on the Tullamarine Freeway in an attempt to identify and rectify the issue.
It can confirm there are no signs of deterioration or stress in these audited signs.
Transurban’s preliminary findings into the cause of the fallen sign have found ‘stiffener plates’ inside the gantry, which provide additional support for the sign, had not been installed according to the approved design.
These stiffener plates were required for two other signs which have also been removed as a precaution. Stiffener plates were not required to support any of the other similar signs installed as part of the CityLink Tulla Widening Project.
Transurban said it will continue working with the builder, CPB Contractors, to complete the investigation and confirm its preliminary findings.
In addition to work to re-engineer and verify the signage designs and design calculations, further materials testing is occurring on the gantry where the sign fell. The gantry is being removed to facilitate this work and a new one will be fabricated to replace it.
Transurban said it is committed to completing a robust and rigorous investigation and will safely reinstall and support removed signage once it has the full findings.