Before the actual construction of highway can begin a great deal of investigative work has to be done. The final route chose for the highway reflects costs due to topography, rail highway, water crossing bridges to host of other considerations.
The highway designer con now insert horizontal and at each point, which the radius or degree of curve being controlled mostly by designed speed. At this point, the center line stations are adjusted to account for the curve alignment.
Horizontal control monuments and both parameters temporary BM one established at intercept of less than zoom. These control points are shown up on the plan with prepared.
The plan which prepared is upgraded in the field by the surveyor so that ambiguous or unknown features dimensions of structures, types of man holes (storm or sanitary), read and drive surfaces, and the like-on the plan are properly identified. Founding is taken at all water crossings, and soils tests are taken at bridge sites and the areas suspected of instability. All drainage crossings, water courses, ditches and soon are identified and tied in. utility crossing (pipe line conduits and overhead cables) are located with respect to horizontal and vertical locations.
Road crossings are requiring intersection angle and change, and track profiles asset distance right and left of the highways centerline.
Road and other highway crossings require intersection angles and chainages, together with their centering, profile left and right of main centerline.
Note: in our project at route design we completed the design portion and it already prepared for the civil engineer in order to contract the construction part of the design.
Highway construction layout
When the decision is made to proceed with the highway of construction, the surveyor goes back to the field to begin the stakeout. In some cased, months and even years may have passed since preliminary survey was completed, and some of the control parts (reference point) may have been destroyed.
However, if the primary survey has been properly sufficient horizontal and vertical control still exists for starting the stakeout. The centerline chainage is verified by measuring from referenced stations, by checking cross-road intersections and by checking into any cross road ties that were noted in the original survey.
Highways are laid out at stations begin established at all changes in horizontal direction (e.g. BC. EC, T.S, S.T) and all changes in vertical directions e.g. (BVC and EVC, low points tangents run out).
The centerline construction if staked out by using steel tape, total station or power set with specification designed. The necessary of centerline layout can be verified at reference parts, road intersections, and like. The motile grade, which is shown in the connect drawing, can refer to the top of granular elevation or it can refer to the top of asphalt (concrete) elevations. The surveyor ensures that he/she using proper reference before calculating sub grade evaluations for the required cuts and fills.
Placements of Slopes Stakes
The surface stare distance from centerline can also be scaled from cross section or top graphic plans. In addition, highway connect plans are now usually developed from plan maps. These plans show controls that are precise enough for most slope-stake purposes. One can usually scale off the required distances from by using either the cross section plan or the contour plan to the closest 1.0ft or 0.3m.
A slope point is mainly used in highway construction for making out cut and fills. It is done on the existing ground surface, one on each side of the centerline stake. These stake are placed where the edge of a cut or toe of a fill will come when earth work is completed
the centerline stake is in place and the stake on each side are slope stake. They are placed where the limits of the earth work must be located each slope stake must be marked with horizontal distance to the right and left of the centerline and the vertical distance plan the ground at the stake down to the elevation of bottom r cut or up to the elevation of the top of fill. All stakes must be marked with station number.
The position of stake will depend up on the following:
2. Width of the base
3. Slope of the sides
4. Elevation of the ground whole the stake is placed.
Shoulder and side work construction
The shoulder and side work construction are constructed adjacent to the centerline or some distance from the centerline. The shoulder is constructed for the purpose of safety for the track or vehicles. If the side walk is adjacent to the shoulder no additional layout is required because the work or shoulder itself gives line and grade for construction. In some cases, the concrete for this shoulder or sidewalk is placed in one operation.
When side walk is to be located at some distance from street line, a separate layout is required. Sidewalk located near the street line shoulder gives the advantage of increases safety and boulevard space for plowing water.