Tullamarine Freeway sign falls – Was it a weld Failure?

A highway sign and support gantry collapsed and crushed a car during peak hour on Melbourne’s Tullamarine Freeway on Tuesday.

Fortunately, the woman driving sustained only minor injuries.

The four-metre by five-metre sign and gantry were installed as part of the CityLink-Tulla Widening project about 12 months ago.

Graeme Chambers, Major Road Projects Authority director admitted, “Clearly something has gone very wrong”. He explained, “The gantry would have been designed by an engineer, proof-engineered, independently reviewed and quality certified so we are going through all that documentation as part of the investigation.”

According to Mr Chambers, the signs were visually checked once every six months and received a more thorough, structural check every two to four years.

As the sign and gantry were only installed 12 months ago, presumably the first post commission structural check at 24 months had not been undertaken.

Article by Melissa Cunningham, originally published in The Age

Comments from AWS

Our welding engineer team have raised the following commentary in response to this story

Compliance in the Welding of Safety Critical Structures

Over the last 12 years, we frequently encounter non-compliant steelwork.
Providing documented evidence for weld design and production is critical for compliance. We see many organisations that are building safety-critical structural steel, yet they are unable to provide this evidence.

The new federal government procurement guidelines require compliance auditing for all federal government spending.

That said, compliance auditing is not a box ticking exercise, especially for welded structures. Welding is an advanced empirical science, mis-understood my many. It is imperative that very experienced, suitably qualified welding engineers are engaged in any technical audit looking at compliance.

An audit need to start with actual in process welding, and step through the technical, the technique and the application to arrive at an outcome in terms of compliance. Any less rigour and you have signs that fall down.

The ‘Weld Integrity’ Myth

Many in construction are misinformed about NDT Testing. They believe that simple non-destructive testing of a completed weldment will provide assurance of safety-critical structures.

Non-destructive testing alone will not provide this assurance.

This form of testing does not examine the mechanical properties of the weld and heat-affected base metals, nor the physical properties of welded joint.

The tensile strength, toughness, hardness, and elongation are all determined in the design of the weldment.

Non-destruction techniques are all different, and sometimes cannot locate some of the most common weld defects; defects that may lead to structural failure.

Weld design

The design and empirical validation of Welding procedures is a complex design process. Correct weldment design then has to be applied to the appropriate joint consistently, by experienced competent personnel.

These personnel include:

• the Welder
• the Responsible Welding Coordinator
• the Welding Supervisor
• the Welding Inspector(s)

In fact each of the Persons Conducting a Business or Undertaking (PCBU) for the project all have a duty of care.

The weld design begins at the correct and compliant welding procedure design.

The impact of skills declining

From engineer, manager, trainer to welder, the decline in Australian heavy steel manufacturing has resulted in a wholesale decline in welding industry knowledge and skills.

This includes a loss of:

• Sound understanding of the welding process technologies
• The shortcomings of process and filler metal selections
• Gas type variations, and so on.

The weld must be designed, and then that design consistently deposited by a qualified and competent welder, supervised by qualified and competent persons with authority to act, with suitable quality systems in place to assure quality and maintain evidential records.

The ISO 9001 system alone does not provide this assurance in welding of structures.

To help bridge this knowledge gap the AWS training team in collaboration with The University of Adelaide has for 9 years now delivered a course on the science of welding (Topics in Welded Structures) to Engineering students.

It is the only course of its type in Australia and is now available as a CPD program for engineers everywhere.

Follow this link for more information.