During the first half of the 20th Century, in an endeavor to become one of the foremost tunnel and underground construction firms in the nation, Shea developed efficient, controlled blasting techniques, fine-tuned the performance of its rock drill machines, and advanced development in blasting agents and methods. Shea led the way in the development of tunnel heading and mucking machines using rail and specialized locomotives. Shea also worked with underground equipment companies to create specialized muck handling, ventilation, electrical power systems, lighting systems, and survey methods.

During the second half of the 20th century, changes in large diameter tunnel boring machines allowed for a more efficient and safer means of advancing tunnels in rock and soil, including high-productivity, cast-in-place concrete linings. Shea pioneered the design and use of the high-strength, segmental concrete, “one-pass” tunnel lining method now used throughout the world. 

In addition, Shea is experienced with frozen-earth shaft and chamber support methods that help prevent structures above from settlement. And, Shea’s Combined Sewer Overflow systems (tunnels, chambers and facilities to support the processing of raw sewage overflows into lakes, oceans and rivers) have had a positive impact on sensitive waterway environments. 

Today, Shea is working with highly-skilled engineers, designers, and American labor to lead the development of the pressurized-face Tunnel Boring Machine (for use in subaqueous tunnels beneath fragile infrastructure, historic buildings, and city streets) to minimize damage caused by underground construction. Shea participates in all forms of project delivery methods, including Design-Bid-Build, Design-Build, and Turnkey Private Public Partnerships.