Niagara Falls 100.000-Hp. Development

30 ] Niagara Falls 100,000 Hp. Development Manufacturers of all machinery were requested to ship in pieces not heavier than 50 tons, also that each piece must pass through a door 12 ft. wide and 16 ft. high. The equipment for the power house was carried below the bank by means of a large 50-ton crane which is a permanent structure built in 1906 and was used in the construction of old Station No. 3. This 50-ton crane is operated over a crane runway, the westerly end of which is a cantilever extending 53 ft. over the edge of the cliff and running back easterly over the switchtracks which are about 200 ft. from the edge of the cliff. The crane has a 50-ton and a 5-ton hook with a total lift of 235 ft. By means of this crane all equipment was lifted from the railroad cars upon the switchtracks, carried out to the end of the cantilever and lowered 225 ft. below unto a car which runs on a standard-gage track into the south end of old Station No. 3 and there turns into the new station. Within the new station are two electric cranes of 100 tons each. By means of these cranes all parts of the equipment were easily carried from the car and dis- tributed to their proper place in the power house. In the erection of the turbines and generators it was necessary as the parts were assembled to make lifts from 150 to 200 tons. This was accomplished by using the two cranes together by means of a large whiffle tree, which was a 200-ton capacity box girder beam arranged so that the two cranes should be readily- hitched at each end with a large lifting hook in the middle of this beam. Tunneling and Lining the Penstocks Method of Driving Tunnels Up Through 350 Ft. of Rocks and Placing Penstocks Steel and Johnson Valve By G. W. Hewitt Field engineer Niagara Falls Power Company, Niagara Falls, N. Y. THE three penstocks of Station No. 3 extension are identical, and except for a few minor details dur- ing the construction, the conditions met were the same. Each tunnel was driven from the lower portal up through the rock to the top, a distance of 350 ft. Excavation started at the face of the deep excavation of the power house and ended at the face of the excava- tion of the forebay. The excavation of the bell-mouth section inside the limits of the forebay gatehouses was open excavation and was part of the excavation of the forebay. The center line of tunnel was level at El. 353 to the P. C. of the lower curve, the P. I. of which was 86 ft. from the portal. At this point the line turned 18° 19' to the right and 45° to the vertical, making the actual intersection angle 47° 50'. The two tangents were connected by a 40-ft. radius curve. The inclined section of tunnel was 45° to the vertical until the upper curve was reached, which also had a 40-ft. radius, and then into the open excavation of the bell-mouth section, the center line of which was El. 538, or a vertical dis- tance of 185 ft. from center of lower horizontal section to horizontal section of bell-mouth. The diameter of finished tunnel is 15 ft. 6 in. and the plans called for a minimum of 18 in. of concrete, making the excavation 18 ft. 6 in. in diameter theo- retically, although sunflower cross-sections showed that the diameter of excavation averaged 20 ft. Excavation was started at the lower portal, using four water Leyner column drills,, and the entire head- ing, or upper half of the tunnel, drilled and shot. Disposal was made on the horizontal section by shovel- ©A = l'x9'Drift D -Ribs and 50% of Dench C -Remainder of Bench FIG. 42—STAGES IN PENSTOCK TUNNELING OPERATION'S ing the rock into 4-yd. cars, which were hauled out by steam dinkeys. After the bench had been uncovered, it was then drilled and shot and the material disposed and the track run back. At the end of the horizontal section a heavy timber hopper was built under which the cars could be run and loaded so that after shoot- ing the rock would roll down the 45° slope onto the hopper. Above this point and for the remainder of the tunnel, the drilling and shooting were done in three operations, as can be seen from the sketch shown above. FIG. 41—COFFERDAM AT FOREBAY OF EXTENSION TO STATION NO. 3, NIAGARA FALLS POWER COMPANY