A $48 million project is under way to perform foundation and substructure repairs to the 10 concrete piers supporting the Thomas J. Hatem Memorial Bridge that carries Route 40 over the Susquehanna River between Havre de Grace and Perryville.
The Maryland Transportation Authority, which owns and operates the span, says the work zone, which is in the river because the repairs are mainly underwater, should have minimal impact on vehicular traffic over the bridge and on marine traffic in the river.
The project is funded by toll revenue, the MDTA noted in a news release announcing the start of the project.
Minimal daytime traffic impacts are anticipated around the equipment staging area, located in the 600 block of Water Street in Havre de Grace, and from delivery of materials, MDTA said,
No lane closures on Route 40 will be required. Intermittent concrete pours may occur during the night and result in higher than normal levels of noise, however, MDTA said.
The project will be done in stages:
Stage 1 consists of excavation of the river bottom surrounding the piers to remove stone and debris, followed by installation of steel cofferdams around the piers. A cofferdam is a temporary watertight enclosure that is pumped dry to expose the bridge foundations.
Construction of each cofferdam may take about one month to complete, after which earth will be removed inside the cofferdam to expose existing bridge foundations.
Concrete will then be placed inside the excavated cofferdam to create a protective layer for the existing sub foundation and to form a seal for the bottom of the cofferdam. The seal will allow the water inside the cofferdam to be pumped out, exposing the foundation of the bridge so repairs can be made.
Stage 2 consists of repairing piers inside cofferdams, including removing and replacing deteriorated concrete, reinforcing steel, repairing cracks, strengthening columns and constructing a protective reinforced concrete encasement around the repaired foundations.
Stage 3 consists of removing the cofferdams and restoring the river bottom to its original condition.
Excavated material will be transported and disposed of at the Maryland Port Administration's Cox Creek Disposal site in Anne Arundel County, the MDTA said.
Environmental restrictions will be in effect between Nov. 1 and April 1 on work that could disturb the river's bottom. To the extent possible, the project was designed to minimize the disturbance or loss of submerged aquatic vegetation beds, the MDTA said
The project's anticipated completion date is fall 2014. McLean Contracting Company of Glen Burnie is the general contractor.
A similar project began last fall on the Millard E. Tydings Memorial Bridge on I-95.
For more information visit http://www.mdta.maryland.gov.Copyright © 2014, The Baltimore Sun