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For details of embankment settlement installation, see Dwg 40-D-4414.
For details of foundation settlement installation, see bwa 40-D-463/.
Each installation placed as embankment progressed.
Crest settlement points located downstream from the axis of the
dam installed on 200' centers from Sta. 7+OOfo Std.63+OO incl.
Crest settlement points located upstream from the axis of the dam
installed on 200' centers from Sta. 8+00 to Sta. 84 #00 inclusive.
Crest settlement points adjusted to camber elevation.
Settlement point elevations recorded to nearest ool foot.
Elevations of each pipe extension on foundation settlement
installations recorded to nearest o.ol foot.
Elevations of all crossarms recorded to neares? 0.01 foot.
All settlement points designated by Axis Station and offset
upstream or downstream from axis of dam.
At Sta. 53400, Installation "A" installed as foundation settlement
apparatus from base of cutoff trench to El 2703+ and continued
as embankment settlement apparatus from El 2703 f to upstream
face of dam.
Original settlement point elevations established January and
February 1954 except the following, established Febuary 1952:
127.50 us- Stations 294.00 to 43+00, incl, and Stations 57+00
fo 71 + OO incl.
148.50 DS.-Stations 28+00 to 42+00, incl., and Stations 56+00
fo 68+00 incl.
263.5o D.S.-Stations 274 ooto 43+oo, incl., and Stations 57:00
to 71 too incl.


(Sheet 2 of 2.)


The holes were backfilled after installation. All tips were connected with plastic tubes to gages in a terminal well at station 54+00, 183.5 feet downstream from the axis of the dam. A terminal well is shown in figure 38. Pressures in the embankment are transmitted from the tip through the water-filled plastic tubes, and observed on the gage.

62. Settlement Installations. - An embankment settlement system was installed in a test pit at station 53+00, 99 feet upstream from the dam axis. The lowest crossarm of the system was placed on shale bedrock at about elevation 2649. Backfill was completed around the riser pipe from this crossarm at about elevation 2707, and nine additional crossarm units were placed at 5-foot intervals to the surface of the completed embankment.

Two standard-type foundation base plates (fig. 39) were installed at stations 15+00 and 21+00, 20 feet upstream from the axis, on the unconsolidated loessial foundation in the abutment of the dam. Also, four temporary plates, each consisting of a steel plate and riser pipe extending to the surface of the embankment, were installed at the following locations and elevations:

Station Distance from station Original elevation
30+00 200 feet downstream 2702. 10
45+00 170 feet downstream 2693. 62
54+00 162 feet downstream 2692.63
71+00 64 feet downstream 2693. 74

After the embankment had been completed above a plate, the plate was located by drilling and an access pipe was installed to the surface of the dam.

A total of 173 surface settlement points were installed at 200-foot intervals on the surface of the embankment and parallel to the dam axis (fig. 40). These points consist of 3/4- to 1-inch reinforcement bars ranging in length from 5 to 8 feet. These bars were driven flush with the ground surface and a concrete collar, approximately 15 inches thick and 15 inches in diameter, was placed around each bar within 3 inches from the top. As concrete was placed, the bars were alined and the upper end of each bar was center punched.

Shallow holes were drilled near the edges of the spillway floor slab and wall footing for use in determining elevations. The elevation of each hole was obtained by means of a level and leveling rod.

In the canal outlet works, a series of 3/8-inch-diameter brass bolts with round heads were placed at 25-foot stations in the invert for use in determining settlement. Vertical control was obtained with the aid of two permanent monuments located on the line center of the canal outlet works.

APPENDIX A Cost summary:

(A cost breakdown for Trenton Dam and Reservoir and the railroad and highway relocations, as of August 28, 1957.)

Major Construction Contracts

Total cost Specifications to the number Item, contractor, and contract number Government 2689 Foundation construction--Marshall, Haas and Royce, contract I2r-18601 $ 1,672, 398 3047 Construction of dam--United Concrete Pipe Corp., Vinnell Co., Inc., and Ralph A. Bell, contract I2r-19084 5, 570, 632 3112 Earthwork and structures except bridge structures, relocation of C. B. & Q. Railroad--Perry McGlone Const. Co., contract I2r-19157 2,786, 959 31.13 Superstructures for bridges, relocation of C. B. & Q. Railroad--American Bridge Co., contract I2r-19183 546, 345 4260 Spillway chute modification--Cass Co., contract 14-06D-1042 2, 329 VII-111 Constructing residence, combination garage and testing laboratory, water and gas supply, and sewage disposal systems for Government field construction facilities and caretaker's residence--Northwest Realty Co., contract I81r-1250 25,767 701C-200 Relocation of county road at Swanson Lake--Nichols Const. Co., contract I103r-1582 131, 232 701C-222 Clearing Swanson Lake--Asbell Brothers Const. Co., contract Il O3r-1611 63, 662 701C–250 Tree planting--Hitchcock County Soil Conservation District, contract I103r-1772 1, 366 701C-303 Planting trees and shrubs.--Hitchcock County Soil Conservation District, contract 14-06-701-456 4, 719 701C-345 Stream gaging station, spillway channel--Rentlor Co., Inc., contract 14-06-701-1345 6, 820 Subtotal, Major Construction Contracts $10,812, 229 APPENDIX A (Continued)

Minor Construction Contracts

Total cost Specifications to the number Item and contractor Government 701-03-733-52 Reconstruct four signal mounds and construct an earth cattle crossing on relocated C. B. & Q. Railroad, and salvage 40' x 40' CMP and install at new location-Perry McGlone Const. Co. $ 287 701C-03-3 Preparation of site for tree and shrub planting, Swanson Lake--A. H. Williams 495 701C-03-5 Cultivation of trees and shrubs, Swanson Lake--Forrest Quick 466 701C-03-9 Summer fallowing of areas to be planted to trees, Swanson Lake--Forrest Quick 119 701C-301 (SF) Preparation of replacement planting sites, Swanson Lake--A. H. Williams 470 701C-303(SF) Preparation of cultivated land for tree planting, Swanson Lake- -A. H. Williams 476 701C–305 (SF) Summer fallowing tree sites, Swanson Lake--John D. Williams 598 701C–314(SF) Electric power connection for irrigation outlet works, Trenton Dam --McCook Public Power District 135 701C–315(SF) Painting interior of caretaker's residence--L. C. Brown 247 701C-323(SF) Preparation of tree planting sites, Swanson Lake--A. H. Williams 257 701C–326(SF) Installation of automatic furnace blower unit on furnace in caretaker's residence--Stratton Supply Co. 135 701C–330 (SF) Construction of terraces, Swanson Lake--A. H. Williams 276 701C–357 (SF) Construction of terraces, Swanson Lake--James W. McCormick 338 Subtotal, Minor Construction Contracts $ 4, 299

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