Hartford I-91 Bridge 43 N&S over US 5
Lateral Slide Project
Accelerated Bridge Replacement
The purpose of this project is to replace the existing bridges that carry Interstate 91 north and southbound over US Route 5 in Hartford, safely, efficiently, and with the least possible impact to road users and the surrounding community during the 2015 construction season. The structures were built in 1966; age, weather, and use have taken a toll on the concrete deck, beams, and abutments that make up the parts of the bridge called the superstructure and substructure.
In order to ensure the least possible impact to the road users and the surrounding community, VTrans is going to use accelerated bridge construction methods to build and install the new structures. By using accelerated bridge construction methods on this project, VTrans will be able to complete the project in just one construction season, approximately half the time that it would take using conventional construction methods. In addition, the use of accelerated bridge construction methods will allow the new superstructures to be moved into position during a short closure period over one weekend for each bridge.
In order to reduce construction-related inconvenience, VTrans is using an accelerated bridge construction method known as a lateral slide. This method allows for simultaneous construction of the substructure and superstructure while maintaining traffic on the existing bridge, minimizing impact to traffic on adjacent roadways and improving public safety.
The replacement superstructures (bridge deck and support beams) will be constructed next to the existing structures on temporary supports while the existing bridges remain in service. As opposed to the pictures shown below, the superstructures will be constructed to the east of the northbound bridge and to the west of the southbound bridge. Once the superstructures are constructed, VTrans will secure the workzone by closing a portion of the Interstate and reroute traffic onto the established detour route. Then the contractor will remove the existing bridge and slide the new superstructure into place by physically pushing or pulling the bridge into place along lubricated rails. Once securely in position, the bridge will be reopened to traffic.
|Lateral Slide – Step 1: Construct superstructure next to existing bridges|
|Lateral Slide – Step 2: Detour traffic and demolish the existing bridge|
|Lateral Slide – Step 3: Slide the new superstructure into place and reopen the bridge|
In order to replace the existing superstructures, VTrans will need to close the immediate bridge area for a short duration over a period of two weekends, one for each bridge structure. During this time, vehicular traffic on Interstate 91 northbound or southbound will be detoured around the work zone. The detour routes are under investigation and will be posted to this site at a later date.