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<br />f <br />.. <br />~~ <br />;\t- <br /> <br />';.( <br />~ <br /> <br />c <br /> <br />(a) Jacking the pipe through the highway or railroad embankment as <br />horizontal excavation progresses. <br /> <br />(b) Installing metal tunnel-liner plates as horizontal excavation <br />progresses. The tunnel liner would be used as the conduit after installa- <br />tion. <br /> <br />(c) Installing double-barrel, small CMPA's by the open trench and <br />backfill method. <br /> <br />(d) Installing single-barrel, large CMPA's. <br /> <br />It was found that the single-barrel, large CMPA installed by the open <br />trench excavation and backfill method was the most economical of the <br />four conepts, and it was selected for use in both culverts. The <br />single-barreled CMPA under U. S. Highway No. 50 would consist of one <br />98" x 69" pipe-arch, 175 feet long. Reinforced concrete headwa1ls <br />would be provided at each end, and riprap would be placed at the <br />downstream end to protect the structure from scour. The culvert would <br />also pass beneath the gage station access road. During the installa- <br />tion operation highway traffic could be detoured over the gage station <br />access road for one phase and over U. S. Highway No. 50 for the other <br />phase. Seep rings wound not be installed, since no appreciable <br />hydraulic head could be expected on this non-gated structure. This <br />culvert would be designed by following such guides as CMPA <br />manufacturer"s load tables, the A.C.I. Building Code (318-63), and EM <br />lllO-2-2902. The single-barreled CMPA under the Arkansas Valley branch <br />of the A. T. & S. F. RY. would consist of one 12'-10" x 8'4" CMPA, 101 <br />feet long. Each end of the CMPA would be cut at a 1 on 2 slope. An <br />8" thick reinforced concrete blanket, conforming to the 1 on 2 slope of <br />the fill, would be applied to each end of the CMPA. The concrete <br />blanket and the CMPA would be bonded together through 5/8" x 10" hook <br />bolts, placed at 18" O.C. around the perimeter of the CMPA before the <br />pouring of the concrete. No seep rings would be required on this <br />structure due to low hydraulic head. This culvert would also be in- <br />stalled by the open trench method. Work would be scheduled for a time <br />when the least railroad traffic was anticipated, and the trains would <br />be re-routed at Lamar for a period of approximately one week during the <br />installation operation. <br /> <br />10-03. Corru~ated Metal Pipe Culverts. Two CMP culverts would be <br />placed under the county road. Both culverts would consist of two 36" <br />CMP's, 36 feet long. No seep rings or riprap would be required at <br />these locations. CMP manufacturer's load tables would be used in <br />determining the required gauge of metal for these pipes. Installation <br />of the culverts would be by the open trench and backfill method. <br /> <br />31 <br />