Gravity Test

Rick Raef

Rick Raef is a heavy construction safety consultant for Willis Group Holdings, San Francisco, Calif., a global insurance broker. Raef has been with Willis since 1996, during which time he developed a crisis management program called, "Character Based Crisis Management: A Contractor's Survival Guide." He is currently the editor of WCSN-The Willis Construction Safety Network, an electronic safety bulletin distributed to contractors in the United States and Australia. You can contact Rick Raef at raef_ri@willis.com.

 

December 1, 2004—Improper outrigger set-up accounts for at least 50 percent of crane accidents. Common mistakes include failure to extend outriggers fully, not extending all outriggers, and failure to get completely off-rubber. Three recent accidents from around the world serve as an excellent reminder about the proper use of outriggers.

In Winstead, Conn., a crane set up next to a concrete roadside barrier tipped, bringing down power lines with it. While some cranes feature partial outrigger extension options for setting up next to obstructions, operators must follow the appropriate load chart to avoid a tip-over. To learn more about this accident and to view photos, go to http://www.rep-am.com/story.php?id=11226

 

Enlarge Image A lattice boom crane tipped while disassembling a tower crane.

In mid-November a lattice boom crane in Sydney, Australia, tipped while disassembling a tower crane's horizontal jib. The operator's injuries included a broken arm and lacerations. The building under construction

Enlarge Image Rescue workers clean up debris in Syndey, Australia.

and the crane were both damaged in the incident. Outriggers are one of several areas investigators are considering as they continue their inquiry into the cause of this accident.

 

And, in Connemara, Ireland, in September, a truck-mounted crane called in to remove a car from the harbor got into a bit of trouble of its own. The recovery truck, likely undersized for the job, began to lift the car heavy with water without deploying the outriggers. What's more, the boom was positioned over the cab of the truck—the so-called “No-No” zone.

Enlarge Image Recovery truck fails to deploy outriggers.	Enlarge Image Crane tips over into water while attempting to retrieve submerged car.	Enlarge Image A proper sized mobile crane arrives to save the day.

With two vehicles now in the water, a proper sized mobile crane arrived to save the day. Note the correctly deployed outriggers. Yet, even after witnessing the toppling of the first crane, a crowd continued to gather under the loaded boom within full view of the operator.

Photos for the accidents in Australia and Ireland came from a public internet bulletin board and were provided to Lift and Access 360 by WCSN.
 

Editor's Note: Tray Prejean, a safety professional, shares that “accidents commonly occur because the operator is lifting from only one side of the rig, with only two outriggers extended. Then, later in the day, this same operator is asked to swing the boom to the other side of the rig for pick. He does this without thinking and topples the crane.”

 

Additional safety tips addressing mobile crane outriggers can be found at www.toolboxtopics.com. Go to the General Industry Topics and click on Mobile Crane Outriggers.