Cinders, one of the projects I was involved in when I was in construction was the rebuilding and adding on to the Fort Worth Convention center which required a very large crane with a jib boom on top of the main boom to be able to deposit the roof top air handling units. Flat deck truck after flat deck truck arrived with steel ballast blocks for the crane....so many in fact that I took it upon myself to see exactly how much ballast they had to install. It was a staggering 225,000 lbs in all! I made sure I was no where near it when they started raising the AHU's lest something toppled.