Location: New Haven, Connecticut
Owner: Connecticut Department of Transportation
Client: Connecticut Department of Transportation
Construction Cost: $574,000,000
- Bridge Replacement
- Construction Engineering Management
- Construction Engineering Inspection
- Quality Control and Assurance
- Progress Payments
- Project Schedule Monitoring
- Materials Testing
- Environmental Compliance Monitoring
- Erosion/Sediment Mitigation
- Utility Coordination
- Construction Change Order Coordination
- Bridge Rehabilitation
- Wetland Mitigation
- Constructability Review
- Construction Claims Analysis
- Contractor Compliance Monitoring
- Lighting Inspection
The Connecticut Department of Transportation (ConnDOT) I-95 New Haven Harbor Crossing Improvement Program is effecting extensive multimodal improvements on I-95 and the surrounding road network through New Haven. The centerpiece of the program is the replacement of the existing Pearl Harbor Memorial (Q) Bridge with a new 10-lane signature structure—the first vehicular extradosed cable-stayed bridge in the United States and, with stunning design and lighting, a distinctive landmark for the New Haven skyline.
The new Q-Bridge was split into three contracts for construction. Lochner was selected to provide construction engineering and inspection services for all three contracts, making the firm responsible for the oversight of a more than half-billion dollar construction program.
Sanitary Sewer Reconstruction
This project relocated twin sanitary sewer force mains that ran beneath the Quinnipiac River in the New Haven Harbor. The existing pipes would have been in conflict with the foundation of a temporary work trestle needed to construct the new Q-Bridge and, therefore, had to be moved before bridge construction could begin. Lochner oversaw the installation of two new 42-inch HDPE pipes, each approximately 1,900 feet in length, to the north of the construction site. To accelerate construction and minimize environmental impacts, horizontal directional drilling was used to place the pipes under the river. Drilling commenced with a 6-inch pilot hole from the west side of the river. The diameter was gradually increased in 6- to 12-inch increments until it reached 60 inches. The locations of the holes on the east side, after drilling, were accurate to within a few feet. The depth of the pipes reached up to 75 feet below the river bottom. Bentonite was used to maintain the integrity of the holes during this process. The pipes were fused together on the west side of the river in 400- to 450-foot sections that could be floated on the river. All sections were pulled across the river in two continuous 30-hour shifts—one shift per pipe. After the pipes were in place under the river, new ductile iron pipe was connected at the approaches on each end. Once the new pipes were active, the old pipes were filled with concrete and abandoned in place.
Main-Span Pier Foundations and I-95 NB Approach Structures
The main span foundations for the new northbound Q-Bridge and the west approach structures for I-95 NB were constructed “offline” because they were outside the existing highway footprint. Temporary work trestles were constructed on each side of the shipping channel to facilitate the construction of the main span. The trestle for the northbound bridge had to remain in place for the next contract and needed to handle the construction loads for both contracts. The trestle was founded on 24-inch pipe piles, driven into bedrock. Steel beams with timber decking comprised the superstructure, with concrete decking and counterweights used in crane turning and heavy-pick areas.
The four main-span foundations, constructed within the Quinnipiac River, adjacent to its navigable waterway, were founded on 8-foot diameter drilled shafts, ranging from 35 to 200 feet in length, with 10- to 30-foot rock sockets. The approach structures included I-95 NB connections to the new bridge, as well as ramps to I-95 NB from Route 34 EB, I-91 SB, and Wooster Street. The approach piers were founded on square precast prestressed concrete friction piles of 16- to 20-inch diameter and up to 120 feet in length. The approach superstructures—five spans of the I-95 approach and the nine-span Ramp I—were all steel plate girders.
Lochner also oversaw the reconstruction of several local roads in this contract: Hamilton Street, East Street, and Water Street on the west shore of the river and Forbes Avenue and Waterfront Street on the east shore. Roadway, drainage, and traffic signal improvements were also included. This project was completed under budget, one month ahead of schedule. All project milestones were met or exceeded.
Replacement of the Pearl Harbor Memorial (Q) Bridge
In the largest single construction contract ever awarded by ConnDOT, Lochner is providing construction engineering and inspection services for the new 4,600-foot, 23-span Q-Bridge. The extradosed cable-stayed main span has a cast-in-place concrete superstructure that uses balanced cantilever construction, and the bridge’s maximum span over the Quinnipiac River’s navigable channel is about 515 feet. The bridge construction includes two anchor piers and two tower piers, up to 140 feet above the river, as well as 128 stay cables that consist of 15-mm strands, individually sheathed in HDPE stay pipes, and LED aesthetic and memorial lighting. The approach spans are comprised of steel plate girders with a concrete deck. Latex modified concrete is used as a wearing surface on all spans for skid resistance and longer service life for the structure. Due to a widely varying depth of bedrock, the west approach spans are founded on precast concrete friction piles, and the main span and east approach spans are founded on end-bearing drilled shafts.
The demolition of the existing bridge was a challenging aspect of the project and had to be performed in accordance with stringent environmental permit requirements issued by federal and state agencies, such as U.S. Army Corps of Engineers and the Connecticut Department of Energy and Environmental Protection. Lochner was also in frequent communication with the U.S. Coast Guard, as channel closures were necessary for some construction and demolition operations. Close coordination was also needed with contractors from adjacent projects being constructed concurrently and with P&W Railroad in relation to work performed adjacent to, and over, an active freight line.
Other major components of this complex project—all overseen by Lochner inspectors—included the construction of tower and anchor piers and trestles in the water, the installation and testing of piles and shafts, the stressing of the stay cables, the geometry control associated with balanced cantilever construction, longitudinal and transverse post-tensioning, and the placement of concrete deck and the latex modified concrete wearing surface, all within an environmentally sensitive and regulated area.
The bridge’s northbound lanes were opened to I-95 northbound traffic in June 2012 and to southbound traffic in July 2013. The existing bridge was then demolished, and construction of the new southbound bridge began in its footprint. The southbound bridge was opened to four lanes of traffic in September 2015. Prior to opening to traffic, a community celebration and dedication ceremony was held on top of the bridge with over 9,000 people in attendance.