Page 24 - Modern Steel Construction (April 2019)

A new steel span provides safe pedestrian passage over

a busy street to a prominent gathering spot along the Charles River in Boston.

Take Me

to the River

BY WILLIAM GOULET, SE, AND MARIAN BARTH, PE

THE NEW FRANCES “FANNY” APPLETON BRIDGE, named for the
second wife of Henry Wadsworth Longfellow, is appropriately adjacent to Boston’s
historic Longfellow Bridge.
The bridge, which opened this past summer, replaces an existing decaying pedes-
trian bridge that, due to narrow switchbacks, did not meet current accessibility stan-
dards and could not accommodate the mixed use of people on foot and bicycles. The
bridge crosses Storrow Drive in Boston and provides an important connection for
pedestrians and cyclists from the adjacent Longfellow Bridge and Charles Circle to
the Esplanade parkland that extends along the Charles River. The Esplanade is the

location of the 4th of July reworks and Boston Pops concert, attracting hundreds of
thousands of people each year.
Undertaken as part of the Longfellow Bridge Rehabilitation Design-Build Proj-
ect by the Massachusetts Department of Transportation–Highway Division, the new
steel bridge—consisting of 280 tons of steel, all metalized and painted with a mid-coat
and a topcoat—provides a modern Vierendeel arch structure that contrasts with the
traditional arches of the historic Longfellow Bridge. The coating requirements were
changed from galvanizing to thermal sprayed metalizing, which eased shop assembly
of the larger parts.
Sporting a ribbon-like appearance, the 550-ft-long bridge superstructure, with 100-ft
ramp abutment structures at either end, runs through the existing park, weaving in between
the trees. The main span is a slender arch whose geometry was primarily determined by
site constraints, roadway clearances and the need to maintain accessibility standards. The
arch, spandrel columns and approach piers all use hollow structural sections (HSS) while
William Goulet (william.goulet@stvinc.com) a pair of continuous tub girders run from abutment to abutment. The bridge also incor-
is a senior structural engineer and Marian porates Y-shaped piers that branch out to support the two longitudinal tub girders. Steel
Barth (marian.barth@stvinc.com) is a project castings designed and supplied by Cast Connex Corporation (an AISC associate member)
manager, both with STV, Incorporated. were used to connect the vertical columns of the piers to the angled supports.

24 | APRIL 2019