They just had set up a concrete pumping unit and were ready to start. As soon as the concrete went through the piping system the load on the outriggers increased significantly with the result that the right front corner outrigger which was wrongly poistioned on top of a concrete cover plate collapsed with the result as shown in pictures below.
The concrete cover plate of the sewer pit was only 5 cm thick of non re-inforced concrete and obviously not strong enough to bear the load of the outrigger. They were lucky that no one got injured and that the end of the concrete pipe boom missed the top of the roof of the house with approx. 10 cms clearance.
They managed to stabilize the crane and get it in horizontal position again by retracting the outrigger and level the unit again.
LESSON LEARNED: WHENEVER A CRANE OR OTHER TYPE OF MACHINE IS PLACED ON OUTRIGGERS, MAKE SURE THE UNDERGROUND BELOW THE OUTRIGGER CAN SUPPORT THE LOAD!!!
At the botttom you can find another example of a badly positioned crane wich went through the deck completely
Here another example of a badly positioned crane.
Same priinciple applies: CHECK THE UNDERGROUND ON WHICH YOU POSITION YOUR CRANE OUTRIGGER!!
