The Chesapeake Bay Bridge and Tunnel Commission has awarded the Dragados Team a contract to construct a new parallel tunnel at the Thimble Shoal Channel.
This award marks the end of a 3.5-year project development and procurement process that leveraged a lowest price, technically acceptable acquisition strategy. The Dragados Team, a joint venture composed of Dragados USA, Inc. and Schiavone Construction Company LLC, submitted the lowest price proposal at $755,987,318.
The Dragados Team’s proposal included a bored tunnel and construction will begin on Island 1 in the fall of 2017. Total construction of the parallel tunnel at the Thimble Shoal Channel is expected to take approximately five years.
According to Commission Chairman Frederick Stant, “This has been a well-managed project with a thoroughly competitive procurement. We look forward to working with the Dragados Team for the successful construction of this critical infrastructure.”
On May 27, 2016, the Commission invited each of the three teams that had submitted fully-compliant proposals by the original due date of April 29, 2016, to submit revised proposals for a re-scoped Project. The District determined that the best interests of the Project would be served by re-engaging with all of these shortlisted teams to re-scope the Project after all of the original price proposals exceeded the cost estimate for the Project.
The re-scoping of the Project was focused solely on the reduction of costs by reducing or eliminating non-critical elements of the Project without compromising the technical safety factor of the design, customer safety, and maintenance life cycle priorities that are specified in the technical requirements of the RFP documents.
The conceptual design for the Project RFP initially included the widening of the man-made islands 250 feet to the west of the existing islands to provide physical space for either an immersed tunnel or bored tunnel to transition to the existing trestle alignment of the CBBT. Jeff Holland, Executive Director of the CBBT, states that “The Project was originally envisioned with a substantial expansion of the portal islands. As such, the expanded southern island would have created space for the future public amenities at little additional cost. When all of the teams competing for the Project focused on reducing cost, it became apparent that island expansion could be very limited or non-existent. As a result, the inclusion of the space sizing for the public amenities of a restaurant, retail shop and 200 additional parking spots that would otherwise require substantial island expansion became cost prohibitive and not necessary to meet the basic mission of the CBBT: providing the traveling public with a safe, cost effective, and unique driving experience across the scenic Chesapeake Bay. This scope change, combined with others, allowed the Commission to substantially reduce the cost of the Project by nearly $260 million from the low price received during the first phase of design-build proposal prices.” The fishing pier at Island 1 will be renovated during the construction Project and will re-open to the public in 2022, upon completion of the Project.
The Dragados Team has proposed to construct a bored tunnel for the new Parallel Thimble Shoal Tunnel. Construction will begin on Island 1 with the construction of a large pit. The Tunnel Boring Machine will be delivered to the site in several large pieces and will be assembled in the bottom of the excavated pit. After assembly of the TBM, construction of the tunnel will begin.
The TBM will excavate and build the tunnel as the machine progresses from Island 1 to Island 2. As the machine excavates, the soil will be conveyed back to Island 1 for removal. At the same time, new precast concrete tunnel segments will be delivered to the TBM. After the TBM reaches Island 2, the machine will be disassembled and removed from the site. After the tunnel lining is installed, construction crews will install the final roadway, lighting, and mechanical systems.