Replacement of I-84 bridges over marion avenue bridge move

Steere Engineering, as the engineer for the Contractor, was the Structural-Engineer-In-Charge performing structural analysis and bridge monitoring for the accelerated bridge replacement of I-84 Eastbound and Westbound over Marion Avenue in Southington, CT.

The bridge superstructures consisted of precast/prestressed bulb tee beams made composite with reinforced concrete decks and were constructed offline on temporary shoring towers and moved into place using Self Propelled Modular Transport units (SPMTs). Demolition of the existing and transport of the new superstructures occurred over a single weekend shutdown which finished 9 hours ahead of schedule allowing the interstate to be reopened to traffic sooner than contractually required.

Steere used SAP2000 to perform a detailed structural analysis of the bridge using 3D solid elements. The results of the analysis were used to develop a Movement Monitoring Plan, which outlined the limits for allowable deflections, structural twist, and corresponding strains that the bridges could tolerate during transport. Steere performed real-time on-site monitoring during the bridge move used a combination of techniques to monitor these key limits in real time. The project received a 2015 ACEC/MA Engineering Excellence Bronze Award and a 2014 WTS Innovative Project Solutions Award.

Location: Southington, CT

Owner: Connecticut Department of Transportation (CTDOT)

Timeline: Design Completed in 2014; Construction Completed in 2014