Orca Offshore in cooperation with Saetech, has performed the technical investigation of the crane accident on request of the Dutch Safety Board (De onderzoeksraad voor veiligheid). The objective of the investigation was to evaluate the feasibility of the plan and to identify the root cause of this accident.
The accident involved a twin crane lift from two barges performed on inland water. The root cause of the accident has been identified and appeared to be a lack of stability of both barges.
It also appeared that a large part of the instability was related to an unaccounted effect related to the flexibility of the cranes. This effect resulted in a critical reduction of the stability which contributed to the incident. The next graph shows the shift of the load work point due to the flexing of the crane boom due to a barge heel which results in a stability reduction of the system.
Shift of load work point explained
Orca Offshore performed the stability analysis of the twin crane lift using a 3-D simulation model. Also a time domain analysis has been performed to simulate the effect of wind and crane actions. For the simulations MOSES from Bentley systems has been used. Below a video of the accident and the simulation of the accident can be found.
For a good summary in English of the Safety Board conclusions please visit: www.heavyliftnews.com
Technical NoteCrane barge stability using land based crane. Notification to Crane barge operators, owners and designers Download Dutch Safety BoardVisit the Dutch safety board website to download the official reports View Website
Download white Paper
Technical investigation of an inshore accident with a twin crane lift arrangement from two barges
Crane barge stability using land based crane. Notification to Crane barge operators, owners and designers
Dutch Safety Board
Visit the Dutch safety board website to download the official reports