Work on the Arsenal Street/Route 3 bridge over Interstate 81 resumed Monday night as construction crews began installing girders for the southern half of the bridge.

Interstate 81 under the bridge was closed Monday night and may be closed again tonight if crews need the second night to install the girders. All traffic on the interstate will be detoured onto the off and on ramps to avoid going through the construction zone.

"There has been other work on the project all along, but the bulk of the work this year will be on the western end of the project around the mall entrance and Ramada entrance and west as well as on stage two of the bridge," said Michael R. Flick, Region 7 state Department of Transportation spokesman.

He said some work will continue on the section east of the bridge, but it is mostly work outside the curbs.

On the bridge, the contractor will install the girders and pour the deck on the southern section. Then crews will close an 18-inch gap between the two sections.

The contractor, Lancaster Development Inc., Richmondville, finished and opened the northern half of the new bridge in November and removed the old southern half of the bridge during the winter. The northern half has four lanes for traffic and the southern half, when completed, will have three.

The project is scheduled to be completed in November and cost $34 million.