The Central Artery/Tunnel Project, known unofficially as the Big Dig, in Boston was the most expensive highway project in the U.S. and consisted of countless errors. The project had errors throughout the plan and design that lead to escalating costs, scheduling overruns, leaks, design flaws, poor execution, substandard materials and even four deaths. The Central Artery/Tunnel Project (also known as the ‘Big Dig’) was a scheme to rebuild Boston’s elevated Central Artery expressway, which cut through the city center, in order to eliminate this disturbing element and relieve the persistent traffic problems in the center of the city. The expressway has been replaced with an underground road. The project was too extensive to describe all the …show more content…

As a result, it has been difficult, if not impossible, to assess whether the hired project managers did a good job. After the new system had been opened, some serious flaws were revealed. The tunnel under the downtown area was riddled with leaks requiring extensive repairs which may need to continue indefinitely. In addition to the use of inferior concrete, for which one supplier was prosecuted, the interfaces between several subsystems, such as that between slurry wall panels and between the slurry walls and the ceiling, also proved vulnerable. Moreover, a drop-ceiling in the connector tunnel on the I-90 route between downtown and the harbor tunnel collapsed, crushing a car and killing one passenger. The design for these drop-ceilings had been changed during the construction work because they were found to be vulnerable to strong vibrations. The new ceilings were heavier, but the outer tunnel shell to which they had to be riveted did not include steel beams capable of bearing heavy loads. According to the specifications, the chosen bolt-and-epoxy fixture should have been capable of bearing the weight, but this fixture required a very careful installation process. The work process had become much more vulnerable to failure. Although the cause of the incident has not been established unequivocally, forensic research has led to the conclusion that unrecorded deviance during the