Final placement of concrete for seal seat bellmouth to be made before installing bulkhead. Weld and radiograph halves of bulkhead to form a unit before installing ribbed bolts for connecting the hemispherical head and lifting beam to the stiffener ring. Filler valve seat shall be concentric with vertical axis of bulkhead. Stems to be in true alinament on vertical axis of bulkhead and operate freely in quide bushings. Rubber seals and clamp bars to be in even bearing on seal seat bellmouth. Ends of seals to be trimmed to butt tightly on assembly. End flanges of stiffener ring to be coated with white lead on assembly: For other notes, see Dwg3. 416-D-304 & 305. Top of filler Face of trashrack -Guide plate Guide 110-0 Normal travel of bulkhead. EI. 2095.88 Figure 62. --Trinity Dam outlet works--16-foot spherical intake bulkhead installation. 79. Stoplogs. Fourteen stoplogs were required for the outlet works diversion inlet structure to provide a bulkhead at the diversion inlet when practicable to conform to construction schedules. The 14 stoplog sections, each approximately 18 feet 6 inches long by 4 feet 8 inches high (fig. 63), were furnished under invitation No. H-33, 341-A. The stoplogs are installed in vertical guides on the face of the outlet works diversion inlet structure and are stacked seven logs high, two stacks being required for complete closure. Effective sealing is obtained by means of rubber strips bolted to the log sections. The estimated weight of the 14 stoplogs is 194,000 pounds. The stoplogs were designed for a 200-foot head at a safe stress. 80. Trashracks. (a) Outlet Works Intake Structure. --A total of 112 trashracks were required for the outlet works intake structure to protect the turbines from oversize trash. The 112 trashrack sections, each of which is approximately 11 feet 6 inches wide by 8 feet 7 inches high (fig. 64), were furnished under invitation No. DS-5036. The trashracks are installed in vertical slots of the outlet works intake structure. The racks consist of 2- by 5/8-inch trash bars supported by 10- by 1-1/2-inch horizontal load carrying members which in turn transmit the load to the side members. The 3-1/2-inch clear opening between trash bars is considered sufficient protection for the turbines. The estimated weight of the 112 trashracks is 588, 500 pounds, and they were designed for a 40-foot differential head at a stress of 33, 000 pounds per square inch. (b) Outlet Works Diversion Inlet Structure.--One trashrack is required for the outlet works diversion inlet structure to protect the 4- by 4-foot high-pressure gate from oversize trash. The trashrack section is approximately 5 feet 6 inches wide by 5 feet 10 inches high (fig. 65), and was furnished under purchase order No. H-33, 340-A. The trashrack is installed by means of anchor bolts. The rack consists of 4-1/2- by 1/2-inch trash bars attached to a 5- by 3-1/2- by 3/8-inch angle frame. The 4-inch clear opening between trash bars is considered sufficient protection for the high-pressure gate. The estimated weight of the trashrack is 900 pounds, and it was designed for a 40-foot differential head at a stress of 33, 000 pounds per square inch. 81. 4- by 4-Foot High-Pressure Gate, Hoist, and Control. One 4- by 4-foot high-pressure gate is installed in the base of the intake structure (fig. 66) at elevation 1952.00. The gate was provided to aid in diversion and care of Trinity River during construction. The gate was operated by a hydraulic hoist using lubricating oil as the operating medium. The oil pump and control valves were located on the intake stručture at elevation 2063.00. After the diversion inlet stoplogs were installed, water for downstream requirements was diverted through the high-pressure gate. When the reservoir water surface rose above the auxiliary outlet works intake, the high-pressure gate was closed and the conduit below the gate was plugged with concrete. gate control was then removed, as the gate had served its purpose. The gate, hoist, and control equipment were designed to operate at 146 feet of waterhead. The 82. Reservoir Level Gage. Reservoir level gage equipment (figs. 67 and 68) consisting of an inlet line, 20-inch floatwell, recorder, and transmitting equipment was provided to indicate, record, and transmit reservoir water-level information. The estimated weight of the inlet piping, gage well, recorder, and transmitting equipment is 24,000 pounds. The 1-1/4-inch-diameter inlet copper tubing was selected to withstand a head of 427 feet of water. The tubing was encased in a 2-inch standard steel pipe for protection during concrete placing. The inlet line from the intake structure to a low point at the gate chamber was installed on a uniform grade so as to avoid air pockets which would affect the accuracy of the gage. The 20-inch floatwell was designed for a head of 291 feet of water. 2. Outlet Works Gate Chamber 83. 10- by 20-Foot Fixed-Wheel Gate. (a) Requirements.--One 10- by 20-foot fixed-wheel gate, located in the outlet works gate shaft, is provided for emergency closure of the outlet works and power conduit in case of damage to the conduit, outlet works, or powerplant equipment, and also to permit unwatering the conduit for inspection and maintenance purposes. In normal operation, the gate will be closed only after flow through the conduit has been stopped by closing the turbine wickets and outlet valves. However, in an emergency, the gate has been designed so that it may be closed with water at full reservoir head flowing through the conduit. The gate will be opened only under balanced heads after backfilling the conduit through the filling line provided at the gate shaft for this purpose. The gate will be operated by a hydraulic hoist located near the top of the gate shaft. (b) General Description. --Some details of the gate installation are shown on figure 69. The frame and gate were furnished under invitations No. DS-4931 and DS-5132, respectively. The nominal gate size of 10 feet wide by 20 feet high represents the size of the gate opening in the tunnel at the gate structure. The gate normally operates in a vertical slot formed in the concrete and extending from the gate sill to the bottom of the bonnet. |