21.10.2014
Tree work takes another crane
Here is another example of a crane overturning while helping remove a tree, this time in Largo, Florida, on Sunday.
This time it involved a 20 tonne boom truck painted in the livery of A-OK Crane Service of Tarpon Springs. The company specialises in tree work and knows how tricky it can be. It seems that in this case the crane was lifting a substantial section of the tree and had started to slew when the crane overturned. The outriggers remained solid, so it looks as though it was a classic overload – either actual or dynamic as the section twisted and moved out of radius.
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The operator escaped unhurt, while the crane also brought a street light down
The crane operator working from the side of the vehicle saw the crane begin to go and managed to dive and a roll away from the falling boom. Thankfully no one was hurt, although a number of cars, a van and an RV/camper trailer were seriously damaged, while a street light was pulled down and a house opposite was hit. The crane was working for Sustainable Tree Service and we are not certain if the operator was employed by that company or by A-OK Crane which normally supplies its own operator.
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The crane crushed an RV/camper trailer
A-OK knows the tree business well and has the following statement on its web site: “A-OK Crane Service owns top of the line Terex cranes, and employs professional crane operators who work the tree business daily. This provides an advantage over our competitors. Having crane operators that do tree business every day is very important because they have the expertise needed to get the job done right Companies that contract out and hire crane operators are at a disadvantage. Using a crane for tree service and removal is much more complex compared to standard crane operating usage. A climber who is cutting down a tree must maintain highest communication with the crane operator. Large tree limbs, especially Oak trees are very heavy, and when the cut is made a branch sways. A tree removal crane operator must possess the necessary skills needed to complete a large tree removal job in a safe and reliable manner”.
We couldn’t agree more.
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The boom landed on a people carrier almost certainly writing it off
UPDATE
The crane was recovered using a large wrecker truck, and the tree company was back on the scene the following day with its own bucket truck. A man used the lift cut small sections off tree letting them drop to the ground. In spite the scare the team had on Sunday he was not wearing a harness or lanyard. This in spite of the vulnerability that tree cutting brings - with the possibility of a limb hitting the boom and creating a catapult effect.
An OSHA inspector was on site to investigate.
2sleepy4u
This looks like a National boom truck. It may or may not have had a continuos boom rotation feature that would cause the operator to go that direction over the front. There are no capacity charts for over the front lifting on this type of boom truck, once past the stabilizer you are operating by the seat of your pants. It seems to me there was poor planing for the lay down area the way the truck was parked in the driveway. Some boom trucks have a front bumper stabilizer which could give you an over the front capacity/radius chart. I would have set up parallel to the street and taken the load over the rear bed of the truck instead of over the front. In the old days on truck cranes before the addition of a fifth front bumper stabilizer we would try to keep the front wheels just touching the ground or use dunnage and cribbing under the front wheels to prevent tipping, but that was still a "seat of the pants operation" too since they weren't any radius or capacity charts to work over the front of truck cranes either. This is just another great example of how unpredictable and dangerous tree work really is. It's very easy to underestimate the weight of the load and once cut you can't put it back. You own it after its cut loose. There are a lot variables in tree work that are very hard to estimate, like the species, weight of leaves, nuts, hard or soft wood density all add to the difficulty of estimating the actual load. I think the best way to do tree work is to use a fifty percent reduction on the posted capacity chart similar to when using a clam bucket which can also easily overload a crane too. That's my "two cents" worth on this accident. I am a retired crane operator with forty years of experience on many different cranes and configurations including a National boom truck very similar to this unit.
Tmayes
still not learning from there mistakes.