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: 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 Specifications number 2689 3047 3112 3113 4260 VII-111 701C-200 Item, contractor, and contract number Construction of dam--United Concrete Pipe Corp., Vin- Superstructures for bridges, relocation of C. B. & Q. Constructing residence, combination garage and testing Relocation of county road at Swanson Lake--Nichols Const. Total cost to the Government $ 1,672,398 5,570,632 2,786,959 546, 345 2,329 25,767 131, 232 Stream gaging station, spillway channel--Rentlor Co., Inc., 6,820 Subtotal, Major Construction Contracts $10,812, 229 701C-330(SF) 701C-357 (SF) Construction of terraces, Swanson Lake--A. H. Williams Construction of terraces, Swanson Lake--James W. Subtotal, Minor Construction Contracts 135 276 338 $ 4,299 3002 3080 3121 3129 3148 Outlet pipe for dam--Keys Tank Co., contract I2r-19114 19083 High pressure gates for spillway river outlets--Hardie- Structural steel for underpass on relocated C. B. & Q. Total cost to the Government $ 20,380 5,707 5,916 53, 125 3,302 49,389 3321 Radial gates for spillway--Johnson Machine Works, con- 138,259 3420 Radial gate hoists for spillway--Northwest Marine Iron 119,523 3573 Trashracks for canal outlet works, intake structure, 5,445 Subtotal, Major Supply Contracts $ 898,996 701-67,217-A Pipe and expansion anchors--contract I103r-1187 701-67,216-A Oil pump units--contracts I103r-1188 and I103r-1189 701-67,218-A Oil pump units--contracts I103r-1194 and I103r 1, 128 1,314 505 833 701-67,222-A 1195 Pipe--contract I103r-1222 420 3,310 701-67,224-A Level gage piping--contracts I103r-1231 and I103r1232 696 975 731 18,570 701-67,229-D Air piping, ice preventative system--contract I103r-1405 1,387 701-9391-B Asphalt--contract I103r-1460 450 701-67,247-A Spillway metalwork--contract I103r-1441 |