Ep 9. The Big Dig

The Big Dig episode of Modern Marvels season 9 takes viewers on a journey through one of the most ambitious and expensive construction projects in American history: the Central Artery/Tunnel Project, also known as the Big Dig. This massive infrastructure project was undertaken to address the traffic congestion and safety issues caused by the elevated Central Artery that ran through downtown Boston.

The episode begins by providing an overview of the Big Dig's scope and scale, including its budget of $14.6 billion and its estimated duration of 10 years (which ended up taking over 15 years to complete). Viewers are introduced to some of the key players in the project, including project manager Ed Pesce and tunnel engineer Dennis Switzer.

Next, the episode delves into the challenges associated with the Big Dig, starting with the need to excavate and remove the elevated Central Artery while still keeping traffic flowing through the heart of the city. This required the construction of temporary ramps and lanes, as well as the use of massive cranes and other heavy equipment to demolish the elevated roadway.

As the project progressed, engineers faced an even greater challenge: constructing the underground tunnel system that would replace the Central Artery. This involved boring massive tunnels through bedrock, constructing enormous concrete segments to line the tunnels, and installing sophisticated ventilation, lighting, and fire safety systems. Viewers get an inside look at the construction techniques and equipment used to accomplish these feats, including the use of a massive tunnel-boring machine nicknamed "The Thing".

The episode also explores some of the innovations and breakthroughs that were developed specifically for the Big Dig. This includes the use of precast concrete segments to line the tunnels, allowing for much faster construction times and improved safety. Furthermore, a new method of tunnel excavation was used, called "Pilot Tube Microtunneling," which allowed the construction team to take advantage of new technology and further increase safety.

As the project neared completion, the focus shifted to the restoration of the surface areas above the tunnels. This involved the construction of new public spaces, such as the Rose Fitzgerald Kennedy Greenway, as well as the installation of new infrastructure for utilities, bike paths, and pedestrian walkways.

Overall, the Big Dig episode of Modern Marvels season 9 provides viewers with a fascinating glimpse into one of the most ambitious and complex engineering projects in modern history. From the early planning stages to the final restoration work, viewers will gain insight into the many challenges and triumphs associated with this iconic American infrastructure project.