Progressive bolt failure likely caused Boston’s massive water-main break in 2010 involving a 10-ft-dia, 1,400-lb steel pipe and insulated coupling in a reservoir supply tunnel, says a May 25 report by an independent panel appointed by the Massachusetts Water Resources Authority. The incident led to a 53-hour “boil water” edict that affected two million people. The report points to progressive failure based on bolt stresses that were significantly beyond code standards and to limited evidence retrieved from the site. MWRA suggests that pre-existing cracks in some bolt thread roots occurred during coupling installation or after initial pipe pressurization. Additional cracks
The 2016 Summer Olympics boating and swimming events have put an international spotlight on what has been a long-running problem in Rio de Janeiro—untreated sewage and trash are clogging up major bays and waterways.