03.12.2019

Flat top snap

The top of a flat top tower crane – jib, cab, counter jib - broke free from its tower at a site at Smeaton Grange near Campbelltown on the southwest side of Sydney, Australia on Sunday.

The entire episode was captured on video – see below - watching it you might be forgiven for initially assuming that the incident occurred while the crane, a Comedil CTT561 was being erected.
But no it has been working on the site at Smeaton Grange since July. The failure is down to a connection pin/bolt or other failure between the tower and slew ring section. How or why it failed like this when out of service and calm days is the focus of an investigation by the rental company operating the crane - Reds Global and the authorities.



Thankfully no one was injured in the incident, more to due to the fact that the site was closed than anything else.

SafeWork NSW is investigating the incident and checking similar crane models for any similar issues along with Reds Global which has issued a statement which is published in full below, followed by a full and detailed bulletin.

“Yesterday afternoon a tower crane under Reds Global’s control had partially collapsed on a construction site at Smeaton Grange. Our management team were on site until late last night, and the team is there again today, discussing the next steps. At this stage, access to the affected areas are restricted as we establish a safe methodology to remove the crane. There are many different stakeholders working together and as such, it will likely be a lengthy process. While it is too early to determine a cause, we can confirm that the issue is limited to this model of crane and we do not manage any other units of this model.”

It has followed this up with a more comprehensive statement as follows:

“Reds Global has been alerted to a number of assertions regarding the collapsed tower crane at Smeaton Grange. Some of these assertions have been incorrect. Although the matter is subject to ongoing investigations, we draw your attention to the following facts:
• This particular crane is cross hired, meaning it’s not owned by Reds Global
• The construction site at Smeaton Grange was shut at the time of the incident
• There was no wind at the time of the incident
• This is not a new crane as has been reported
• 100% of the bolts were non-destructive tested (NDT) by a certified third party prior to installation, meaning all the bolts passed inspection
• The crane was certified by a third party as fit for operation on the day of commissioning
• The counterweight configuration installed complied with manufacturer’s specifications
• The crane was serviced every month by Reds Global since installation in July 2019”

“In order to provide further clarity, this model crane is a Comedil CTT561 which has a specific connection assembly from the slew mast to the slew mount which is the point at which the crane separated. To our knowledge, there are three similar cranes in Australia manufactured by Comedil with this same connection assembly and we have reached out to the crane owners individually.”

“Reds Global does not have any other cranes with this slew mast assembly design in our fleet.”

“In the crane, the slew mast is connected to the slew mount by 8 x M39 x 592 bolts. Newer versions of this model crane, subsequently called CTT561A, replaced the vertically installed bolt connections with 4 x 90mm horizontal pins. Appendix A shows the depiction of CTT561 version (Smeaton site) and Appendix B the current CTT561A redesigned version.”
Appendix A – the section that failed

The later design


“Reds Global would like to thank all those who’ve shown support and made offers of assistance. It is very encouraging and greatly appreciated. It shows the strength of the industry, that we can pull together in times like this.”

Comments

Mike74
Well, earlier this year, a Terex-Comedil flattop belonging to a Corleonis company (yep, the name IS real, and the company is not italian ;-) snapped exatly the same way on a powerplant construction site in Warsaw, Poland, right after the operator parked it at the end of the work and was packing his stuff to exit the crane. He survived because in case of such accident the cab, which is attached to the turntable at a lower point, actually remains attached to the tower, but I hardly envy the guy for the experience. I am unable to confirm that the crane in question was of exactly the same model, but it surely was a heavy Terex-Comedil flattop. And the reason were broken vertical bolts. I think it tells a tale.

4 Dec 2019
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