In 2008, the Commonwealth of Massachusetts passed legislation that allowed for a historic $3 billion, eight-year Accelerated Bridge Program (ABP) to be implemented by the Massachusetts Department of Transportation, Highway Division.
The goal of this program is to expeditiously reduce the number of structurally deficient bridges across the commonwealth and prevent others from falling into this classification. According to the legislation, ABP will end in 2016 and the projects undertaken under this program must be completed.
The replacement of the historic Fore River Bridge, located between the cities of Quincy and Weymouth, and for which MassDOT selected STV to provide a planning study and preliminary designs, is one of the largest projects undertaken through the ABP program; and it exemplifies the benefits of an accelerated project delivery process. By streamlining, MassDOT and STV were able to halve the normal time it takes for approval of similar projects from roughly six years to just over three years.
How did we do this? MassDOT and STV adopted an innovative, collaborative process that included: integration of the planning, project development, environmental permitting and design-build procurement activities on a parallel track versus in a series; soliciting the feedback from all involved stakeholder groups at each phase in this process; producing preliminary designs that included details usually associated with final design; and providing a seamless transition of oversight from preliminary design to the final design-build process.
Keep it moving
The Fore River Bridge carries 32,000 vehicles on the Rte. 3A corridor over the Fore River between Quincy and Weymouth. A major thoroughfare for the region, the new bridge will be the third movable bridge at this location. An original swing-type bridge was built in 1902, and was replaced by a bascule bridge in 1936. In the late 1990s, this bridge was found to be badly deteriorated, and a temporary bridge was constructed. Traffic was directed over the temporary bridge in 2002. Two years later, the 1936 span was demolished. Though the temporary bridge is safe today and regularly inspected by MassDOT, it is rapidly reaching the end of its useful life. Through an expedited process, STV and MassDOT arrived at a decision to build a vertical lift bridge replacement.
In the fall of 2008, STV was selected by MassDOT to lead the efforts to assist with the evaluation of structural options for a new movable bridge and the approach structures, to coordinate with stakeholders and agencies and to select a preferred alternative for the replacement structure.
This evaluation included a complete environmental assessment and an active public-outreach program which presented the complex nature of the project to the community and a discussion of environmental issues early on.
The public-outreach program was initiated in the spring of 2009, and extended throughout the planning and preliminary design phase. Twenty meetings were held with the public, the local elected officials, the mariners and other stakeholders. Issues discussed included channel width, span-type selection, and the concerns of pedestrians, cyclists, motorists and mariners relative to the proposed bridge.
Bringing the public into the alternatives evaluation process very early on, as the preliminary design was being considered, not only saved time, but also informed the design of the Fore River Bridge. For example, at one of the early meetings with the public, it became clear that automobile drivers’ primary concern was to minimize the number of bridge openings—and therefore traffic delays. MassDOT and STV took this concern and incorporated it into the decision-making process evaluating the benefits of a vertical lift span vs. a bascule bridge.
A vertical lift bridge, even in a down position, would accommodate almost all pleasure craft passing beneath it on Fore River, therefore reducing the number of bridge openings and traffic snarls. A bascule bridge, on the other hand, because of lower clearances, would require more time in the open position, stalling traffic. While other technical considerations clearly informed the eventual decision for a vertical lift bridge, bringing the public in initially allowed their concerns to be heard and incorporated early in the process and prevented uninformed delays by the public later on.
Working concurrently
In addition to discussions about bridge types, construction-staging schemes and bridge aesthetics, STV identified environmental impacts and addressed them with several agencies concurrently, rather than one after the other.
For example, in designing the foundation elements of the bridge, STV conducted sediment sampling for toxins and sought U.S. Army Corps of Engineers environmental approval for construction that might stir up the toxins; STV and MassDOT were simultaneously negotiating with the U.S. Coast Guard about the need to widen the channel to accommodate large vessels. Channel width would have an impact on what movable bridge types were possible (vertical or bascule). Likewise, in meetings with the public, STV discovered that nearby residents were very concerned about noise levels (an environmental issue) associated with pile driving, so STV recommended drilled-shaft casings instead, which will substantially reduce construction noise levels. Normally these agency and public processes would be done in a series. Doing them concurrently saved considerable time, while not diminishing the importance of public participation.
As a result, an Environmental Assessment was submitted to FHWA in December 2010, and a Finding of No Significant Impact (FONSI) was issued in December 2011.
Easy for the mariners
Streamlining the selection of a bridge type (fixed bridge, bascule bridge, vertical bridge or a tunnel) to replace the torn-down Fore River Bridge occurred deliberately, based on a study of navigation requirements, engineering feasibility, prudence and costs. It was determined early on that a tunnel, for example, would be twice as expensive as any bridge type while a fixed bridge would have to be prohibitively high, up to 175 ft in height.
Any bridge type chosen had to be adequate for the mariners who regularly use the channel, most notably the Panamax class oil tankers that service the Citgo tank farm, which is located on the inboard side of the bridge. The bridge is located at a sharp bend in the Fore River, and the passage of the oil tankers and larger container ships through the area requires the assistance of two tug boats operating at low speeds.
Consequently, the planning study focused on two options, a bascule bridge, which would require a 225-ft-wide navigation channel, and a vertical lift bridge with a 250-ft-wide navigation channel. The 225-ft-wide channel selected for the bascule option represented the widest channel that could be reasonably achieved with a bascule, while also accommodating an independent fender system for each pier at this site.
The vertical lift option, which incorporated a Warren-type through truss for the lift span, presented one significant advantage over the bascule bridge. The vertical bridge provided improved clearance over the navigation channel when the bridge is in the closed, or down, position. With a vertical clearance of 62 ft, this bridge type can accommodate the passage of almost all pleasure craft without the need for a bridge opening, a key benefit to the driving public concerned about traffic delays when the bridge is raised.
The bridge study recommended that the vertical lift option be selected, and MassDOT accepted the recommendation in early 2011, directing STV to progress the design of the vertical lift structure to a level that was beyond 30% completion. Approach structures on either side of the movable span, approximately 2,000 ft in total length, along with the roadway, drainage and traffic elements were advanced just to the 30% level of design.?
Four for Fore
To choose a design-build team to complete the project, MassDOT and STV developed design-build procurement documents to establish performance-based criteria, minimum standards and visual quality, and define owner preferences associated with the movable bridge layout, operation and maintainability.
Some of these preferences were developed by STV in the preliminary design, another way it streamlined the design-build process. For example, using a “lessons learned” approach, STV interviewed bridge operators during preliminary design to understand where best to site the bridge tender’s house. STV located the house above roadway level where bridge tenders indicated it would improve sight lines and ease of operation. In other similar bridge projects, operators have been consulted after final design had been completed, when it is too late to get their knowledgeable input.
Using STV’s preliminary design template, MassDOT awarded the best value design-build contract to a joint venture of J.F. White Contracting Co. and Skanska Koch Inc. on Aug. 21, 2012, for a bid amount just under $245 million.
At approximately the same time, MassDOT awarded STV a contract to provide peer-review services, inspection oversight and construction support on behalf of the commonwealth through the duration of the design-build project. This provided continuity from STV’s role as preliminary design consultant to a new role as a single point of contact to coordinate agency and peer reviews of design and construction submittals, including quality-control documents. Thus, STV’s project-specific knowledge and experience—reaching back to the beginning of their preliminary design contract in 2008—minimized the potential for “knowledge loss” that can occur when a project transitions from a preliminary designer to a final designer.
Utilizing accelerated bridge techniques, construction of the Fore River Bridge is expected to be completed in 2016. Construction will occur in four distinct phases: off-line construction of the permanent movable bridge and connecting spans, rehabilitation of the retained approach roadways, connections between the new and rehabilitated structures, and demolition of the existing temporary bridge. Actual on-site construction efforts by the J.F. White and Skanska Koch team began in the fall of 2012.
MassDOT and STV helped substantially reduce the time required for the preliminary design phase of this elegant bridge project by gathering public input early on and considering bridge-type selection with an evaluation of environmental impacts. In addition, STV’s 30% design provided a technical template that will save time in the design-build construction phase. R&B
