Rehabilitation of Old Naga-hammady Barrage Bridge

When the Old Naga Hammady Barrage has been constructed in 1930, it had a navigation lock on the western side of the barrage. In 1993, a new navigation lock has been constructed in the western side of the old lock. Each lock has a movable bridge to allow the high ships to pass from north to south and vice versa. The bridge of the new navigation lock is suffering from technical problems pampering the bridge movement and makes it out of work. This paper studies the problems, causes and the factors affecting these problems. During this study, field inspection and measurements were carried out as well as analytical study was performed. The study concluded that the main factor affecting the bridge and causing the major problem is that the bridge is subjected to overloading due to passing heavy trucks over it although the original design is performed to carry the loads less than thirty tons. The other important factor is the bad installing of the concrete bases in the four corners. As it plays an important role for instability causing misalignment where in turn leading to breaks the various elements of the operating system in the lifting and the rotating mechanisms. To overcome the problems affecting the bridge, the study recommends a new design must be performed to the bridge and girders must be added to enable the bridge to carry seventy ton Lorries. The cam supporting system should be replaced by a sliding supporting system in the lifting mechanism and the damaged axis shafts, bearings and pinion should be replaced by new ones. Also, a good alignment and stability should be carried out for all mechanical parts. The recommended design helps safety, durability, and stability of the system.