The Delaware River Turnpike Bridge was reopened  to traffic Thursday night.

Shortly before 10 o'clock, the bridge, which had been closed since late January, began allowing eastbound traffic,  Pennsylvania Turnpike Commission spokesman Carl DeFebo said. Westbound traffic was to follow.

About 42,000 vehicles a day use the span between Bucks and Burlington Counties.

Commission officials had anticipated that the bridge would remain closed until April, but unseasonably warm conditions expedited repairs, they said.

"Everyone feels very sure it's going to be able to support weight," DeFebo said.

The bridge had been closed since Jan. 20 after a worker on a painting crew found a crack in a truss on the underside of the bridge. Engineers confirmed Thursday that the crack was caused by two holes erroneously drilled into the beam and then improperly filled with a weld. The holes were each about an inch in diameter. Engineers have said an unusual weight on the bridge and cold weather in January may have also contributed to causing the crack.

Officials did not find any evidence of other welds, called plug welds, in an inspection of the 1.2-mile-long span. A review of the structure included hands-on inspections, ultrasonic testing, and metallurgical analysis from three different laboratories, the turnpike commission said. While engineers have said plug welds were once a common repair for unneeded holes, it's rare for one to be the catalyst for such significant damage.

When the truss cracked, the bridge shifted by two inches, and the first step to repair it involved installing hydraulic jacks beneath the structure to hoist it back into position during the last week of February. Repair crews used post-tensioning rods to pull the two sides of the cracked beam close enough to build a permanent splice to repair it last weekend. Eight tri-axle dump trucks collectively carrying 40 tons were driven over the bridge to test the sturdiness of the repairs.

At least two dozen contractors, consultants, and other entities have participated in the repair work. There were at least $10 million in contracts associated with the repair, but the final cost of the work has not been tallied. Temporary sensors installed during the work will remain in place, officials said, and they expected to install a more permanent monitoring system in the coming months to observe the bridge.

State police monitor carrier vehicles on the turnpikes in both states, DeFebo said, and if weight is confirmed as a factor in the crack, officials would consider adjusting police enforcement to prevent trucks that exceed the bridge's weight limits from crossing.

The bridge first opened to traffic May 23, 1956. It is jointly owned by the Pennsylvania Turnpike Commission and the New Jersey Turnpike Authority.