A large crane is moved into position yesterday to lift a supporting section in the Route 195 bridge project onto a dolly to be moved into position.

THE PROVIDENCE JOURNAL / Kris Craig

PROVIDENCE — Using a pair of cranes that together can lift more than 600 tons, contractors for the state Department of Transportation last night started installing the beams that will carry traffic from Route 195 over Route 95.

With much of the night’s work still ahead of them, officials said they expected to have the highway open for traffic by 5:30 this morning, before traffic picks up for the morning rush hour.

Last night, a crew from Atlantic Bridge & Engineering was installing the first of two bents — heavy beams that will bridge Route 95 — across the highway’s northbound lanes. It, and a second bent to be installed tonight over the southbound lanes, will support the girders that will support the concrete roadway.

The ramps under construction will carry westbound traffic on Route 195 to Route 95 southbound, and also to an exit on Eddy Street at Rhode Island Hospital. The construction is part of the DOT’s relocation of a section of Route 195 and its interchange with Route 95.

The DOT started closing lanes on the highway at 8 p.m., with the whole road closed at 11 p.m. By that time, traffic could already been seen backing up on the north-bound lanes of Route 95.

Similar closings will affect one or both sides of Route 95 Sunday through Thursday nights through May 15.

The project tests the DOT’s elaborate and heavily publicized detour plans intended to avoid traffic jams during the night.

The work is scheduled to prevent the much worse traffic jams that could result if the construction work intrudes into the morning rush hour. The DOT doesn’t have much choice about closing the highway, since building the new interchange where Route 195 meets Route 95 involves dangling heavy steel beams over the travel lanes.

Frank Rice, the Atlantic Bridge superintendent, said that there was nothing particularly tricky about last night’s project, and that he expected to have the job finished on schedule.

The bents have been sitting on the ground off Eddy Street, near the highway and the hospital. As the sun went down yesterday, the Atlantic Bridge crew used one of the cranes to lift one end of the 105-ton bent to be installed last night. With that first end blocked up with wooden cribbing, the crew was to pick up the other end and slide a multi-wheeled, self-propelled transporter under the beam.

Later during the night, with the highway closed, the transporter was to haul the beam north along the highway, up the Eddy Street exit ramp in the opposite direction that traffic normally flows to leave the highway at the hospital, and onto Route 95’s southbound lanes. The transporter was then to carry the beam south and across the median, to the pair of concrete piers that will support it.

The two cranes, one positioned beforehand, and the other driving up on the highway after putting the beam on the transporter, were to hoist the beam and set it in place on the piers.

The project meant closing both the north and southbound lanes of Route 95 last night. The same thing will happen tonight, when Atlantic Bridge will install the second, even heavier bent, this one across the southbound lanes.

Atlantic Bridge, of Salisbury, Mass., is working as a subcontractor for Cardi Corp. the general contractor on that part of the $600-million Route 195 relocation project.

The two cranes have a capacity of 300 and 360 tons, respectively.

blandis@projo.com