placed in the crests and piers of the left spillway intake. The first two lining placements were made in August 1962, from station 24+17.67 to 23+82.04, invert elevation 3196.90 to elevation 3224.33. A special concrete finish was applied to the lining through the elbow section as required by the specifications. A whirley crane was used to handle material and concrete for the lining and the intake structure, and it was placed on the rock ledge above the left side of the intake structure. In order to reach the right wall of the intake structure, it was necessary to extend the tracks. The left wall of the intake was started in October 1962, and was completed in February 1963. The tracks of the whirley crane were extended over the left wall of the intake structure in March 1963, and the right wall of the structure was started in that month. Meanwhile, the lining of the upper spillway tunnel was progressing and this work was completed in October 1963. The lower elbow section of the right spillway tunnel was excavated in March and April 1963. The first lining placement was made in the invert from station 26+11.72 to station 25+85.50 in September 1963. Two invert sections were lined and then one arch lining placement was made at the lower end of the elbow section. After four invert sections were placed, followed by the four arch lining placements, the remaining four placements were made by placing the entire circumference of the arch at one time. This work was completed in November 1963. The concrete work for the intake structure of the right spillway was completed in November 1963. The trunnion bases for the radial gates were placed, and assembly of the gates was started on the ledge above the intake. Hoist equipment was installed on the bridge of the intake structure, counterweights were installed, and the gates erected. Radial gate No. 3 was satisfactorily tested on February 27, 1964, and gate No. 4 was satisfactorily tested on March 10, 1964. Painting of all gates was completed in August 1964. 201. RADIAL GATES. The four 40- by 52.5-foot radial gates were furnished under invitation No. DS-5192 and manufactured by Vereinigte Osterreichische Eisen and Stahlwerke A.G. (VOEST). In the field erection, the workmanship was considered very good. Very minor drifting was required for assembly and no misplaced holes were found. A small omission was noted on the gate arms in that drain holes were not drilled and the holes for guide shoes on top of gates No. 3 and 4 were not drilled. This was a very small percentage of the holes required and the installation contractor made corrections in the field. Merritt-Chapman and Scott Corp. proposed several changes in the erection procedure shown on figure 268. The prime contractor had well-qualified survey crews and engineering supervision with recent experience on erection of large radial gates. As the erection procedure allowed some latitude in the method of erection, the contractor was allowed to proceed with erection of the first gate, subject to acceptable installation. The contractor's erection methods were sound and all operating checks were satisfactory. The remaining gates were also assembled without unusual difficulties and it was not necessary to use the final adjustment of babbitted joint allowed by design. The radial gate hoist is a two-drum electric-motor-driven mechanical hoist located on the radial gate operating deck. Two 1-1/2-inch stainless steel wire ropes from each hoist drum are connected to lifting brackets near the bottom of the gate. The four gate hoists installed on the left and right spillways were furnished by Moffett Engineering, Inc., of Berkeley, Calif., for a contract price of $104,000. The four radial gate hoists were installed by the prime contractor in the fall of 1962, and were accepted for operation on March 10, 1964. The hoists were placed on embedded anchor bolts and, by use of double nuts, the drum units and gear cases were alined and leveled. A transit was used for alinement and a precise machinist level was utilized on line shafting joining the drum units and gear cases. The various components and gearing were checked with the hoists running by using dial indicators. No significant difficulties were encountered and good operation of the hoists was obtained. E. PENSTOCKS AND OUTLET WORKS 202. PENSTOCKS. Water for power generation is delivered to the turbines through eight penstocks (figs. 129 and 130) having a common intake certerline elevation of 3470 feet, which is 245 feet below the crest and 330 feet above the turbine level. They descend through the dam on a 60° incline, bend at the base on a 60-foot radius, and cross over to the powerplant on concrete piers (fig. 269). Centerline length ranges from 406 feet in an outer unit to 449 feet in a center unit; the steel shell thickness ranges from 7/8 inch in the upper sections to 1-13/16 inches in the lower sections. The diameter of the upper, inclined portion is 15 feet, reducing to 14 feet for the lower, horizontal section. 10-foot sections, or cans, were shipped by rail to a Flagstaff, Ariz. plant which was established by Vinnell to complete the fabrication (fig. 272). At Flagstaff, the cans were welded into 30-foot sections. Before being shipped to the jobsite by truck, the welds were X-rayed and the sections were placed in an oven for relieving stresses from the welding and were hydrostatically tested. Installation began in December of 1960, with the lower horizontal sections to be embedded in the mass concrete of the dam. The mass concrete was at elevation 3127.5 when the sections were set in place. Figure 269.-View looking down on Glen Canyon Dam and Powerplant. Note penstock installation P557-420-7212, July 5, 1962. the penstock transition at the intake of penstock No. 2 at the face of the dam in block 16. between 203. PENSTOCK INSTALLATION. The eight penstocks, referred to as No. 1 through 8, are located in dam blocks 18, 16, 15, 13, 12, 10, 9, and 7, respectively. Installation of the penstocks was subcontracted to Chicago Bridge and Iron by the prime contractor, Merritt-Chapman and Scott Corp. The penstocks were furnished by Vinnell Steel of Irwindale, Calif., under invitation No. DS-5052. Initial fabrication was performed at the Irwindale plant. From Irwindale, dam During the initial installation of the horizontal and the lower vertical bend sections to be embedded in the and powerplant. máss concrete of the dam, a framework of angle iron was used to support these sections to line and grade until the girth seams could be welded. This supporting framework had been anchored in concrete before any of the penstock sections were brought to the installation site. For extra stability and protection against misalinement by possible concrete bucket collisions with the penstocks, this framework was embedded in the concrete along with the penstock sections. On sections installed on the incline, no supports were used other than the key plates holding two sections together and the actual welded joints as the work progressed. The sections along the incline were for the most part 20 feet in length and installed at a 60° angle from the horizontal plane. In general, no more than one penstock section and a portion of another section would be exposed above the mass concrete. In rare cases when the work was slack for the welders, there would be two complete penstock The penstocks intakes are protected from ice and debris by massive 200-foot-high trashrack structures (fig. 270). The lower intake section contains six reinforced concrete bays for an overall height of 75 feet. Each bay is a 15-foot inside-diameter, semicircular structure composed of five chords. Each chord constitutes a trashrack opening of about 9 by 12 feet, which is covered and protected by framed metalwork. Closure of the penstock intakes is accomplished by stoplogs and fixed-wheel gates. The respective sets of stoplogs are spaced several feet in front of the gates and have a total vertical height of 250 feet. Each set is divided into four groups: 9 lower logs, 7 intermediate logs, 7 top logs, and a final upper section of 20 smaller logs. The eight fixed-wheel gates cover only the intake bell of the penstocks. Each gate is 13.96 by 22.45 feet and weighs about 115 tons. Closure control is provided by a large hydraulic hoist. All of the mechanical features along the face of the dam are serviced by a 165-ton gantry crane. Figure 271 shows 10-foot sections, or cans, were shipped by rail to a Flagstaff, Ariz. plant which was established by Vinnell to complete the fabrication (fig. 272). At Flagstaff, the cans were welded into 30-foot sections. Before being shipped to the jobsite by truck, the welds were X-rayed and the sections were placed in an oven for relieving stresses from the welding and were hydrostatically tested. Installation began in December of 1960, with the lower horizontal sections to be embedded in the mass concrete of the dam. The mass concrete was at elevation 3127.5 when the the penstock transition at the intake of penstock No. 2 at the face of the dam in block 16. 203. PENSTOCK INSTALLATION. The eight penstocks, referred to as No. 1 through 8, are located in dam blocks 18, 16, 15, 13, 12, 10, 9, and 7, respectively. Installation of the penstocks was subcontracted to Chicago Bridge and Iron by the prime contractor, Merritt-Chapman and Scott Corp. The penstocks were furnished by Vinnell Steel of Irwindale, Calif., under invitation No. DS-5052. Initial fabrication was performed at the Irwindale plant. From Irwindale, sections máss concrete of the dam, a framework of angle iron was used to support these sections to line and grade until the girth seams could be welded. This supporting framework had been anchored in concrete before any of the penstock sections were brought to the installation site. For extra stability and protection against misalinement by possible concrete bucket collisions with the penstocks, this framework was embedded in the concrete along with the penstock sections. On sections installed on the incline, no supports were used other than the key plates holding two sections together and the actual welded joints as the work progressed. The sections along the incline were for the most part 20 feet in length and installed at a 60° angle from the horizontal plane. In general, no more than one penstock section and a portion of another section would be exposed above the mass concrete. In rare cases when the work was slack for the welders, there would be two complete penstock |