I-84 Bridge Move

Southington,  Connecticut

ConnDOT’s project goals were to replace the existing eastbound & westbound superstructures over Marion Avenue using rapid construction methods to minimize construction time, resulting in fewer road closures, and reduced disturbance to the traveling public on both the interstate and local roads.

Steere Engineering was the Structural Engineer In-Charge of the Accelerated Bridge Construction (ABC) for the 2014, I-84 Bridge Replacement Project located in the town of Southington, Connecticut. The project utilized a series of 12-line, 8 file PST Goldhofer, self-propelled modular transport units (SPMT’s) to move the proposed I-84 EB & WB bridges from the adjacent staging areas into final position on the existing rehabilitated abutments. The SPMT approach was also used to transport the existing I-84 EB Bridge from the abutments back to the temporary staging area for demolition at the same time the I-84 WB Bridge was demolished in place.  Transport of both the new and existing structures occurred over a single weekend shutdown period which finished 9 hours ahead of schedule and had the interstate reopened to traffic well ahead of the deadline imposed by the contract.

Steere Engineering, the bridge move engineer for Northern Construction Service, was responsible for the structural engineering associated with the accelerated bridge project located in Southington, Connecticut.  Specifically, Steere used SAP2000 to perform a detailed structural analysis of the bridge using 3D solid elements.  The results of the model were used to set limits for deflections and corresponding strains which Steere monitoried in real time during transport, by way of strain gages cast into the structures at key high stress locations. Steere’s other responsibilities on this $8-million project included the design of the temporary staging towers and foundations, erection procedures, demolition procedures, and assoicated concrete formwork and pour procedures.  In addition, Steere provided 3D modeling and animation of the proposed move sequences which included both the SPMT equipment and superstructures to ensure there were sufficient clearances, both horizontally and vertically, along the travel paths to perform the required turning and transport operations. The 3D modeling was completed in Rhino 3D, with the animation and rigging being completed in Modo.

Project Details

OWNER:  ConDOT/Norther Construction Service
REFERENCE:  Mr. Kenneth E. Fragnoli, P.E., Assistant District Manager
PHONE:  860.258.4604
PROJECT COST:  $8 Million