Laserfiche WebLink
<br />2-12 <br /> <br />Supplementing Planning Surveys <br /> <br />e <br /> <br />Field survey data obtained in the planning phase must be supplemented <br />to provide basic design data. In fact, budgetary considerations will <br />often preclude much of the detail described above for the planning <br />phase so that the survey data used in preparing preliminary drawings <br />may be of little value as design data. <br /> <br />Supplemental data needed to establish the visual resource design may <br />be determined by the outlines shown in Chapter 2, Appendix A. <br /> <br />Bench levels must be checked and supplemented. Damaged BM's should <br />be reestablished and additional bench marks should be set and tied in <br />as needed. <br /> <br />Coordinate control should be established by traverse and closed within <br />third order accuracy. Triangulation may be used to establish control <br />on large, complex projects, if desired. <br /> <br />Topographic strip maps of the area will be needed for layout and design. <br />Data for these maps may be secured either by plane-table or transit <br />topography tied to the traverse. Strip map data must be secured to <br />provide accurate location of contours, fences, buildings, bridges, culverts, <br />roads, utilities, the edges of woody vegetation areas, large trees, orchards, <br />existing drainage or irrigation ditches and structures, and all other <br />physical or man-made features within the probable limits of work. <br /> <br />e <br /> <br />Test pits and borings should be accurately located and the elevation <br />should be established on a reference hub adjacent to the site. <br /> <br />Preparation of Strip Maps and Profile <br /> <br />Strip maps should be plotted to the same scale as that intended for <br />final drawings - usually I inch = 40 ft. to I inch = 200 ft., depending <br />on the detail needed. For convenience, strip maps should be plotted <br />on transparent paper or cloth sheets not exceeding 42 inches in width <br />and 20 ft. in length. This provides sufficient length for proper selection <br />of long tangents and curves for the "paper location." <br /> <br />Trial locations complete with stationing and curve data are then superimposed <br />on prints of the strip maps and profiles are plotted on equally long profile <br />sheets to permit selection of long tangent grades. <br /> <br />As the hydraulic design progresses and design cross sections are selected <br />one of the alternate locations will usually emerge as apparently superior. <br />The best apparent alternate including right-of-way requirements should <br />then be drawn on the strip maps. Design grades and cross sections should <br /> <br />e <br /> <br />,--.----- <br />