Memo points to faulty construction for Big Dig

| Tuesday, September 19, 2006

The designer of the concrete ceiling panels in Boston’s Big Dig tunnels originally wanted to use four bolts on each anchor plate.

But, the Boston Globe has obtained a memo showing that project managers from Bechtel/Parsons Brinkerhoff, the firm behind much of the massive construction projects, convinced the designer to use only two bolts instead.

The Globe said those bolts were then safety-tested at a much lower standard than engineers typically required at the time.

Twenty of those same bolts came loose July 10, causing several ceiling panels to collapse on a car, killing its passenger.