Final Environmental Impact Report - Whittier Bridge/I-95 ...

Whittier Bridge/I-95 Improvement Project FEIR
Chapter 2.0: Response to Comments on the Environmental Assessment/Draft Environmental Impact Report
design, with spans twice the length of the Whittier and trusses proportionally larger, seventeen years older, subject to
the same, if not worse weather conditions, is still functioning smoothly and is well-maintained, while the Whittier is
undoubtedly in need of a major overhaul or , replacement. WHY IS IT THAT THE SAGAMORE WAS
REHABILITATED IN THE 1980'S, INCLUDING DECK AND CABLE REPLACEMENT, FOR $20 MILLION, CLOSING
ONE LANE AT A TIME, WHILE THE DOT CLAIMS THIS IS IMPOSSIBLE FOR THE WHITTIER
Response: Although similar, the environmental winter conditions are very different for the Whittier
Bridge and the Sagamore Bridge over the Cape Cod Canal. The weather on Cape Cod is relatively
more temperate then the Merrimack Valley, and this requires less deicing salts which are
problematic for the lattice built-up truss members. During the winter months the Whittier Bridge
experiences almost daily freeze and thaw cycles, while the Sagamore Bridge experiences far fewer
freeze and thaw cycles. In addition, I-95 has a higher operating speed and a higher volume of truck
traffic than US Route 6 over the Sagamore Bridge. All of these issues contribute to the deterioration
of the structure resulting in the structural obsolescence of the Whittier Bridge. The Whittier Bridge
underwent a complete deck replacement in the 1970s when traffic volumes were much lower and a
lane could be taken out of service to perform this work. Hanger modifications were made in the late
1990s to further extend the life of the structure. The structural problems with the Whittier Bridge go
beyond the need for deck replacement and include deterioration to the arches with widespread pack
rust occurring at the riveted connections which increases the long-term structural risk to the
structure. Structurally non-redundant bridges like the Whittier Bridge require a more conservative
engineering approach since the tragedy of the I-35W bridge collapse in Minneapolis in 2007.
JH-6: Secondly, the Sagamore comparison begs the obvious question which the DOT should also address: How is it
that between the yearly inspection process and the Department's budget and maintenance procedures the Whittier
ended up in the decrepit condition it is in today The DOT's own inspection reports claim they have no idea when the
bridge was last painted. Is this really possible (Neighbors don't recall it being painted since the early 1970's.)
Shouldn't the DOT be looking for 'lessons learned' here so we don't end up in the same situation down the road with
a new bridge Obviously, if the bridge had been properly maintained all these years, this discussion wouldn't even be
taking place.
Response: MassDOT‘s bridge and structural engineers for the project have determined that the
Whittier Bridge cannot be safely rehabilitated.
The Whittier Bridge is a steel-riveted built-up truss bridge built in 1951. Truss bridges comprise
multiple non-redundant members. A failure of one member, in either tension or compression, could
cause the bridge to collapse. The bridge was originally designed to carry only two lanes of traffic in
each direction with full breakdown lanes. In the 1960s, it was reconfigured to three lanes without
shoulders in each direction, and traffic volumes have increased the fatigue loading by 50 percent.
Significant corrosion has also occurred to structural elements of the bridge, including truss floor
beams and stringers, bracing, wind chords, and gusset plates, with the most severe deterioration
occurring to members exposed to deicing salts at the edges of the bridge and in the open medians
between the northbound and southbound roadways. Substantial recent repairs have been completed
to maintain the bridge in a safe condition for existing traffic and to ensure public safety. However,
these repairs are temporary and address only the immediate load-carrying needs of the bridge; they
neither provide permanent repairs nor do they address long-term fatigue-life considerations.
Because of the extensive deterioration of the existing structure, the temporary nature of the near-
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