Motorists face long wait for full use of Massachusetts Ave. bridge

Traffic on the busy span over the Charles River between Boston and Cambridge has been restricted for over a year and a half. Drivers face an indeterminate wait, and possibly a long-term detour, before a rebuilt, safer bridge eventually is opened.

The orange barrels that have closed off the two outside lanes of the Harvard Bridge for more than 18 months are not going to disappear anytime soon.

Also known as the Massachusetts Avenue Bridge, the span that carries one of the city's major thoroughfares from Boston into Cambridge is still awaiting reconstruction.

Robert J. McDonagh, chief engineer for the state Department of Public Works (DPW), says rebuilding the bridge is a very long process. So long, in fact, he is unwilling to predict when construction might start, when it might be finished, or what it will cost.

John Slater, a professor at the Massachusetts Institute of Technology, says that a year ago the reconstruction was projected to cost $9 million and take at least 11/2 years.

The bridge work is still in its early stages. Although some design work has been undertaken, and structural surveys done, the bulk of the project clearly lies ahead.

McDonagh says the DPW is tentatively planning to hold a public hearing about the bridge in early February. Public comments will be included in the environmental impact statement that the DPW must file before it can go ahead with any reconstruction work. Public concerns and environmental considerations could alter reconstruction plans or delay the design process further, McDonagh says.

The DPW proposes closing the bridge to traffic when work begins, says McDonagh, because if traffic were to use two lanes while work crews rebuilt the other two, the project would cost millions of dollars more and would take at least a year longer to complete. The DPW has already decided to allow pedestrian traffic on the bridge while it is under construction.

The Harvard Bridge, built in the 1890s, was designed to support little more than horse-and-buggy traffic and an occasional trolley car. Concern about the bridge and others across the state and country followed the June 28, 1983, collapse of the Mianus River bridge in Connecticut.

Bill Litant, a spokesman for the DPW, says special inspections of the Harvard Bridge at that time turned up cracks in some of the bolts that hold the structure together. David Lenhardt, senior civil engineer in charge of bridges for the Metropolitan District Commission (MDC), says the bolts were replaced and the structure was made safe. But it was clearly time to do something about the bridge.

The MDC closed the two outside lanes to traffic. The inside lanes are stronger because they were designed to support the trolleys. Buses and trucks were prohibited from using the bridge at all.

The DPW proposes completely rebuilding the superstructure. Only the bridge's pilings will be retained. The number of girders supporting the roadway will be increased from four to six or eight.

Mr. Lenhardt says the new girders will be made of steel, replacing the present wrought iron. This will be another improvement, he says, as the procedure for making iron at the turn of the century was ``not up to today's standards.'' And, he says, quality control was not as good in those days.

McDonagh says his department has been trying to balance several factors in designing a new bridge. A primary consideration, he says, was whether the old pilings could support the new structure. A team of marine consultants recently tied its barge to the pilings to test them. McDonagh says he has not seen the final report on the tests, but it appears the pilings will be strong enough.

Since the state Landmarks Commission has made the Harvard Bridge a registered historic landmark, its appearance cannot be substantially changed in the process of rebuilding.

Meanwhile, although only half of the bridge is usable, Lenhardt declares that it is quite safe. It is inspected weekly, he says, and occasionally the inspectors find a cracked suspension bolt, which is replaced immediately. -- 30 --{et