Reconstruction of I-95 over West River & Bridge Replacement

Reconstruction of I-95 over West River & Bridge Replacement

New Haven & West Haven, CT

Connecticut Department of Transportation

This section of I-95 is one of the most heavily traveled in CT, carrying over 135,000 vehicles per day across the West River. Middlesex value engineered an innovative demolition and construction approach for the north bound span that combined eliminated 105 days of lane closure impacts.

The existing I-95 NB and SB twelve span bridges over the West River were replaced with two new five span structures. The new bridges will have a combined total width of 141 feet including three lanes each direction. The new structures are on a new alignment, new ramps were constructed or partially constructed to tie in to existing ramps. The exiting I-95 SB ramp to Kimberly Ave. was removed. The existing Ella T. Grasso Blvd bridge was replaced.

The as-bid phasing called for installing the new I-95 NB structure to the east of the existing and removing the existing bridge using conventional demolition methods under nightly lane closures with equipment placed on the new inservice structure and the exiting I-95 SB bridge.

Middlesex re-engineered the approach to remove entire bridge spans using gantries mounted on SMPTs. Spans were removed to the median area off the bridge for processing during the day. To eliminate lane closures need for steel erection, construction was re-engineered to launch the fully assembled spans from the median. Over 105 nights of lane closure impacts were eliminated in total.

Scope of Work

Construct two new five span river bridges.
Remove the existing superstructure and substructure of the existing river bridges.
Demolish the existing ten span ramp from I-95 SB to Kimberly Ave, the majority over the river.
Replace the existing three span I-95 NB/SB bridge over Ella T. Grasso Blvd. with a new single span structure.
Reconstruct 4,650 feet of I-95 roadway.
Perform all work in phases maintaining three travel lanes on I-95 in each direction.
Design and install four temporary trestles for access in to the river.

Unique Challenges

Middlesex ran risk analysis and with CTDOT’s approval moved the I-95 NB bridge test piles so they could be driven ahead of demolition. The as-bid phasing called for removing the existing I-95 NB bridge and then driving test piles.
The existing soil conditions presented a risk that test piles would drive deeper than designed causing a revision to the piles, that needed to be ordered in advance of the testing based on theoretical design in order to meet schedule.
Middlesex performed a risk analysis on the project schedule using Monti Carlo simulation and determined that changes in pile length would cause a 60 day schedule impact. As a direct result CTDOT approved relocating the test piles outside the limits of the existing bridge allowing them to be driven early in the project.