The Army Corps of Engineers has recommended replacing the Bourne and Sagamore bridges. The Massachusetts Department of Transportation (DOT) has concluded that the two bridges be replaced with two much-wider bridges, revamping the roads leading to the bridges.
As the new bridges would be built off to the sides of the current bridges, none of the current roadway infrastructure lines up with the proposed bridges, so there would need to be land taking and infrastructure changes. In effect, the new bridges are bridges to nowhere until all the infrastructure changes and environmental impacts are resolved.
From my engineering experience on a new project, one should have an alternate project plan (Plan B) in case the hoped-for conceptual design (Plan A) runs into a snag as a result of more definitive data and analysis. Plan B is offered based on a modular approach that would result in the same number of travel lanes and lane width as those in Plan A, but would have a smaller environmental and infrastructure impact.
In Plan B the DOT bridge in Plan A would be divided into two modules at the center median, so in effect we have southbound and northbound bridge modules. The approach to construction would be to line up one module with the existing roadways. Initial construction would be to place the first module alongside the existing bridge. After the first module is completed traffic would be temporarily routed away from the old bridge using the new bridge. The next step would be to remove the old bridge and then replace it with the second module. Now the second module is in line with the existing roadways, and the necessary land taking and the impacts on the infrastructure are reduced.
Philip T. Levine
Harbor Hill Drive