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heated by open fires. The concrete aggregates were first obtained from a gravel pit, three-quarters of a mile below the work on the west side of the river. A temporary screening and mixing plant was erected near this work. In May 1914, the temporary plant was dismantled, and erection was started on the permanent mixing and screening plant on the east side of the river. The permanent plant was completed in August of that year. It consisted of machinery for crushing rock, rolling sand, and elevating aggregates into bins from which they could be dumped into the mixer hopper by gravity.

The crusher was of the gyratory type, which, with the sand rolls, was shipped from the Strawberry Valley project. The crusher was served with broken sandstone from the quarry, using a stiff-leg derrick with 40-foot mast and 60foot boom, handling a 5-yard skip. The output of the crusher and rolls was lifted by a 14-inch bucket elevator and discharged into a revolving screen over the middle of the bins. This screen was 24 inches in diameter and 8 feet long. The upper 5% feet consisted of a plate perforated with /s-inch holes while the lower 2% feet of the plate was punched with 2-inch holes. Sand went directly to the sand bin while the material passing the 2-inch holes was returned to the rolls

Bins were 32 by 24 feet, with the vertical portion 9 feet high, having a hopper bottom converging to the measuring

box about 12 feet below the vertical part of the bin. These bins had a capacity of 130 cubic yards of sand and 270 cubic yards of broken stone. The measuring boxes were of the extension type, adjustable from 7 to 9 and from 15 to 20 cubic feet capacity, and were provided with gates operated by levers discharging directly into the mixer hopper.

The mixer hopper was set flush with the cement-storage floor. On this floor was a 36-inch gage track running through the side of the building and about 50 feet downstream where it ended directly under the cableway. Cement was received at the siding on the west side of the river and unloaded on skips. The skips were carried across the river by the cable, deposited on flat cars on the 36-inch gage track, then taken to the storage room. About two cars of cement could be held in the storage room, and about five or six cars could be stored in the cement warehouse at the siding on the west side of the river.

The gasoline engine mixer used at the temporary plant was moved to the permanent plant. Just beneath the discharge spout of the mixer was placed a 36-inch gate track with a turnout leading to two tracks 6 feet apart, under the cableway. The mixer discharged into a 2-yard, tiltingdump, concrete bucket standing on a flat car. Three batches filled the bucket and it then was rolled under the cable, where it was picked up and transported where desired. Water was supplied to the mixer from an 800-gallon wooden

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tank on the hillside, 50 feet above the mixer. Water was pumped to the tank from the river. A 200-gallon boiler was used to prevent freezing; but as the weather grew colder this was inadequate and a 35-horsepower boiler, which had been used the previous season for pumping, was installed.

The main item of plant consisted of the cableway running across the river over the axis of the dam. In January 1914, excavation was started on the tail tower foundation and anchorage on the west side of the railroad tracks. In March the foundations and deadmen for both anchorages were placed and a 1-inch steel messenger cable was stretched between the two deadmen. Work on the two towers was begun in April. This work was completed in May, after which the main cable was placed. The cable was fastened to deadmen on the west end, and to six lines of 1-inch cable around two triple blocks between the head end and anchorage on the east side of the river.

A pile bridge was constructed across the river above the dam, running from the outer wall of the sluiceway to the east side of the river. A truss bridge was built across the sluiceway. This bridge was used in crossing the river for the construction of the main plant on the east side of the river and also for constructing the upstream cofferdam. Bents consisted of 3 piles, 8 by 14 inches, cross-braced, and surmounted by 10- by 10-inch caps, 16 feet center to center. Stringers were 4 by 8 inches. The piles penetrated the river bed from 5 to 10 feet.

A quarry near the east end of the dam furnished rock for riprap and concrete. The concrete plant was located near the quarry. Track was laid on the pile bridge and extended below the dam for handling paving rock and cofferdam material. A power plant was constructed at Cameo and power wired to the dam, the substation being completed in May 1914. Three 75-kilovolt-ampere transformers reduced the voltage from 16,500 to 2,200. The 2,200-volt line operated a 150-horsepower motor, direct-connected to a 100-horsepower, 250-volt, direct-current generator. On the west side of the river was located a cement shed, blacksmith shop, and warehouse; and at the east end of the dam, a pump house, machine shop, and hoist house.

The general method of construction was by unwatering certain areas of the dam site, digging trenches for the cut-off wall and curtain walls, and filling with concrete. Pier foundations were then prepared, and concrete poured up to elevation 4,774, or 4,778. Nose forms for the piers were then placed, lagging built up to elevation 4,794, and recesses for the roller crests, racks, and guards formed at the proper locations. Concrete was placed in lifts of 4 or 5 feet per shift up to elevation 4,794. Forms were removed in 2 to 4 days, and the concrete was pointed up and washed with thin grout. The aprons were usually poured in about three sections between piers. The work was done by Government forces.

INSTALLATION OF ROLLER CREST

The piers were constructed before the racks were received and recesses had been left for the racks and anchor bolts. By means of a transit and steel tape at each pier face, two marks were set on small plates attached to the concrete, one above the top of the rack and the other below the bottom of the rack, normal to the axis of the roller and 72 feet 6 inches apart. This is the distance between the face edges of the toothed rims on the rollers. A piano wire was stretched in this plane, 2 inches from the marks, as a reference line for the racks. A wire stretched horizontally from one pier to the other gave a reference line for the racks in the other direction. The racks were attached by adjusting bolts to iron bars, held in position on a wooden frame, and when in proper position a thin grout, proportioned 1 to 2, was poured around the steel support and anchor bolts and allowed to harden.

Rollers were shipped in five sections. The three rollers east of the west 70-foot roller were installed by the cableway. The two end sections were swung into place by cable and the proper teeth of racks and rims were engaged. Other sections were then brought into place, lined up, and the ends drawn together with pulling jacks. The roller was then tested with a wye level and riveting started. When the main roller was riveted it was raised about 8 feet and supported with 12- by 12-inch timber posts, one at each end. When these rollers were in place and raised, the cofferdam protecting them was demolished and the cofferdam needed for protection of the two rollers at the east end was repaired.

For the installation of the two east-end rollers a trussed beam, 8 by 18 inches, and 74 feet long, was placed between piers, 9 feet downstream from the sill. Six cables were dropped from the beam to hold sills for the false work. The beam was an improvement over the method used on the first three rollers.

The most westerly of the 70-foot rollers was next erected. This bay was protected by the sluiceway wall and by cofferdams built up and down stream from the first pier east of the sluiceway. The roller was assembled and raised, and after temporary sealing strips were attached the roller was lowered to cut the water off from the bay.

The last roller to be installed was the 60-foot sluiceway roller. On this work the false work for supporting part of the roller sections was built on flatcars running on a 36-inch track. This was possible because of the position of the sluiceway apron. It greatly facilitated the erection of the roller.

Erection of the service bridges was started in May 1915, before the installation of the rollers was completed. Anchor bolts for the cast-iron shoes at the arch ends had been set in the concrete for all spans except the sluiceway span. The arches were assembled on the west side of the river and swung into place by the cableway. Latticed handrailing was put up and a temporary floor laid. The floor, was later taken up, after which the permanent 3-inch plank flooring was laid.

COSTS

The table of costs in the next column covers the complete construction of the dam, headworks, power and battery station, and all operating mechanism. Charges listed for roller crests cover the cost of rollers, machinery, hoisting mechanism, and labor of erection, exclusive of the electrical machinery.

BIBLIOGRAPHY

Large Roller-Crest Dam, Grand Valley Project, Colorado. Engineering News, July 6, 1916.

Building the Rolling-Crest Dam Across Grand River. Engineering News, July 13, 1916.

Operation of Grand River Roller-Crest Dam Proves Satisfactory. Engineering News-Record, June 27, 1918.

The Construction of the Grand River Roller-Crest Dam. Reclamation Record, August 1919.

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EASTON DAM

KITTITAS DIVISION, YAKIMA PROJECT, WASHINGTON

BY L. K. MAIRES, ENGINEER, BUREAU OF RECLAMATION

THE EASTON DAM is located below the junction of the Yakima and Kachess Rivers, three-fourths of a mile northwest of Easton, Wash. It is situated on the eastern slope of the Cascade Range in a timbered country subjected to heavy snowfalls.

The diversion structure is unique in that it is capable of maintaining practically a constant lake level for diverting water into the Kittitas main canal while passing floodwaters or by-passing varying amounts of irrigation water over the crest of the dam. The irrigable area of the Kittitas division, for which the diversion dam primarily was constructed, comprises 72,000 acres.

Two transcontinental railroads, the Northern Pacific Railroad and the Chicago, Milwaukee, St. Paul & Pacific Railroad, traverse the southern shore of the lake. The Sunset Highway crosses a neck formed in the upper end of the reservoir.

Water entering the reservoir above Easton Dam is obtained from three sources, namely: the Keechelus Storage Reservoir, located on the Yakima River about 11 miles above the Easton Dam; the Kachess Storage Reservoir, located on the Kachess River about a mile above the Easton Reservoir; and the natural flow of the Yakima River between the Keechelus and Easton Dams.

The total drainage area is 185 square miles and the average annual run-off about 560,000 acre-feet. Floods in the Yakima watershed occur in the months of November to June, inclusive, and are caused by excessive rainfall rapid melting of snow, or a combination of these conditions. No discharge records are available at this point prior to the construction of the Kachess and Keechelus reservoirs, which very largely control the flood run-off.

The reservoir created by Easton Dam is 1 )" miles long and one-half mile wide, covering an area of 240 acres and containing 4,000 acre-feet of water. To prevent damage to the two transcontinental railroads, the maximum water surface is limited to elevation 2,181. Storage in the reservoir was started October 10, 1929, and raised to elevation 2,172 on October 11, 1929.

During 1924, the dam site was tested by drilling and was examined by Mr. Kirk Bryan, a geologist of the United States Geological Survey, who reported as follows:

The diversion dam is to be built in a narrow gorge carved in a massive, but impure quartzite that is a part of the

Easton schist. The rock is suitable for the foundations of any structure and its joints can be successfully grouted. * * * There is an old deep channel beneath the gravel plain north of the damsite and moderate leakage through this gravel may be anticipated. No danger to proposed or existing structures is involved. The Easton schist, as previously mentioned, is one of the older rocks of the Cascade Mountains. Normally, it is a silvery-gray or green rock with thin layers of quartzose material separated by micaceous minerals. In this form the rock is usually in thin crumpled plates gashed with quartz veins. At the damsite, however, the rock is a massive greenish gray quartzite composed mostly of quartz but contains also various accessory minerals to which the color is due. Immediately east of the damsite the normal schistose rock is found.

THE DAM

The dam is a straight gravity, overflow concrete structure, having an over-all length of 248 feet and a maximum height of 66 feet. It raises the water surface 43 feet above the normal low-river stage. To maintain a lake level sufficient to divert 1,320 second-feet into the Kittitas main canal and also to pass the varying amounts of water required for the lower divisions of the Yakima project, an automatically controlled, structural-steel drum gate is mounted over a float chamber on top of the spillway crest. The gate is 64 feet long and 14.5 feet high. A spillway capacity of 13,000 second-feet may be obtained for flood conditions when the gate is in its lowered position.

Two 12-foot-wide by 11-foot-high radial gates, placed in an intake structure located at the south abutment of the dam, regulate the flow of water into the Kittitas Canal. The intake structure is also designed to act as a transition to a 12-foot 3-inch diameter, concrete, horseshoe tunnel, 303 feet long, passing beneath the Northern Pacific Railroad. The tunnel is terminated by an appropriate transition connecting with a concrete-lined section of the canal.

For the purpose of sluicing and passing water through the dam at low reservoir stages, sluiceways were provided at each end of the dam near the bed of the river. The sluiceways are controlled by electrically operated 4.8- by 6-foot, air-vented, cast-iron gates, protected by trashracks. The trashracks are %- by 4-inch structural-steel bars placed 4% inches on centers and held together by bolts passed through the bars with pipese parators. The trashrack is 7 feet 3% inches wide by 45 feet 6 inches high.

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