Project:
Lock No. 4 Allegheny River
Electrical and Mechanical Rehabilitation
Natrona Heights, PA

Owner:
Army Corps of Engineers

Lock No. 4, Allegheny River, was the first lock in the area to be rehabilitated with precast panels in the chamber. Also, the entire hydraulic system used to operate the lock was changed to electro-hydraulic machinery.

Innovative techniques were used in construction including blasting the existing lock face, grinding the lock walls, precast panel assembly and attachment, and temporarily operating the lock gates and valves. A major portion of the work was accomplished in two lock closures for one month each, in which the chamber was dewatered. If the time was exceeded, both closures had $25,000 per day in liquidated damages. Mosites completed both closures on time and opened the lock to river traffic without delay.