Niagara walls

Fraco has custom—modified its mast climbers to meet challenging access requirements during renovation of the Robert Moses Dam at Niagara Falls on the US/Canadian border.

The hydroelectric dam began operation in 1961 and this US$ 13.3 million contract is the first major renovation of the structure. The project, which started in 2004 and should finish in 2006, is to remove and re—cast patches of deteriorating concrete covering approximately 10% of the 46500 m² dam face. The average depth of repair is 130 mm.

The main causes of access difficulties facing the contractors are the incline of the dam face and the presence of penstocks, structures that feed water from behind the dam to the power station below. Inclines vary from 44° to 51° over the bottom two—thirds of the otherwise vertical dam face, and the penstocks restrict access to two—thirds of its length.

The inclines meant Fraco had to re—mount the power unit so that it remained level during operation. The work at the dam wall was sub—divided into three sections, with one worked per year between mid—April and the end of October.