BRADDOCK, Pa.—The Army Corps of Engineers says the main lock chamber on the Monongahela River in Braddock is closed for emergency repairs and could be down all weekend.

Commercial and recreational boaters should expect major delays at that point, some 11 miles from the confluence with the Allegheny River in Pittsburgh.

The corps closed the main lock chamber after discovering a crack in the steel that anchors a hinge on an upstream land wall gate.

Engineers are assessing the damage, and crews are breaking away concrete around the steel to help them determine the extent of the damage.

The lock chamber that is closed measures 110 feet by 720 feet. Another lock chamber that is 56 feet by 360 feet remains open and commercial vessels will be given priority for using it.