Recall Chicago’s John Hancock Building!
In the summer of 1966, a 12-ton column was placed on the base plate at the top of one caisson, and the plate tipped slightly. A foreman wisely ordered the column lifted....
Six months later, at an estimated cost of $1 million, the caissons had been thoroughly inspected and repaired. A large void had been discovered in two concrete caissons, and earth, sand and other foreign material in three others.
What was the cause? ``Careless pouring of concrete (and) inadequate or missing caisson liners,
http://articles.chicagotribune.com/1985-03-24/features/8501160598_1_caissons-john-hancock-center-architectural-history
A friend was involved on this project.
They had to jack out the concrete on a bunch of the caissons $$$.
I will say that Forensic Investigation is a fascinating field. Having spent about 45 years managing various aspects of construction I have had the chance to provide expert testimony, participate in investigative teams, law school mock trials, and similar items. I have seen some astonishing events and incidents that initially baffled me. Early on in my career I spent three years with a manufacturer of building components settling claims after investigating them.
I was fortunate to get to attend some seminars given by the forensic teams involved in the Twin Tower disaster and it was truly great to see that poster Two-Thirds Vote Aye and my armchair analysis of much of the collapse and clean up occurred as we theorized at the time of the events.