05.12.2007

Condemnation of that Tower crane

As we expected we have so far only received condemnation and even outrage at the makeshift tower crane counterweight that a contractor has installed on a crane on the prestigious Spencer Dock development in Dublin.

Hopefully someone will tip off the developer before something nasty happens?
In case you missed the photo here it is, Please register to see all images

Is this fit for purpose?

or you can go to the original story by clicking here
The following are just two of the more eloquent and printable responses we have had so far.

Hi
Re your photo of Comansa in Dublin with counter weights stacked, I have been erecting towers for 32 years and would never consider the likes of that. A sudden stop while slewing with a load on i.e. power failure and the slew brakes coming on I wouldn’t like to be driving it or below it depending on them straps.
regards

Dear Sir,

There are a number of problems here, as is obvious to most.

1. Ballast on tower cranes is placed in specific locations on the counter jib. It's not just randomly placed as ballast anywhere. An engineer must determine it's location if it deviates from the manual via back moment calculations.

2.During operation it's common that the beams supporting these counterweights can flex laterally while starting and stopping slewing motions. What is retaining their location?

Who approved of this? Only the manufacturer or engineer can accept a condition such as this. In the US no one outside of a professional licensed engineer or the manufacturer can accept this. Not even the leaser or contractor can make this decision. No manufacturer will put their name on this and don't hire an engineer whom would.

What is holding the weights in place laterally on top? I see one strap on a lower weight but none on top. Abrasion and compression may not be enough over time.

Finally is the weight loaded evenly side to side. In essence is the placement of the weight placing torsional loading on the counter jib and it's pendants beyond its intended design? Is one pendant taking more than 50 percent of the load?

The contractor could lower the other crane or maybe get reinforced tower to allow this crane to be taller. One or the other must be done. Later in the schedule of the job the cranes could then be tied in and climbed to allow for clearance of the building. It's not difficult only costly. If I were in a meeting and this were requested more than once I'd be less than polite about the intelligence of the requester.
Thanks for the information

Keep them coming and if anyone has any other news on this crane please do let us know.
Ed