I-91 Springfield viaduct temporary works design

Steere Engineering, as the engineer for the contractor, was responsible for the temporary works designs associated with the Springfield Viaduct project. The Springfield Viaduct is a 4,200ft long, 48 span, elevated structure carrying I-91 NB and SB through downtown Springfield. The project consisted of a complete bridge deck replacement and associated steel repairs of the viaduct and connecting ramps utilizing a phased construction approach.

As part of the construction approach, the existing bridge deck required shoring support to be designed along the construction phase lines. These locations required support at the exterior overhangs resulting from the deck saw cutting which converted typical interior bays to exterior overhangs at the phase lines. Critical to this shoring design was the accommodation of the relative movement between framing located on each side of the phase line as the existing deck dead load was removed from half of the bridge while the cross frames remained intact.

Steere was responsible for the design of hold downs, which prevented the structure from overturning under the variety of road conditions. In addition to the shoring design, Steere was also responsible for the analysis and design associated with the contractor’s demolition procedure. This included stress analysis of multiple girders, under various states of composite and non-composite conditions as multiple pieces of construction equipment traveled across the 48-span structure, removing the deck. Spans 3 through 11 of the structure were comprised of pin and hanger spans requiring special analysis to accommodate the demolition sequence.

Location: Springfield, Massachusetts

Owner: Massachusetts Department of Transportation (MassDOT)

Timeline: Design Completed in 2015; Construction Completed in 2019