In order to locate temporary objects and communication on the construction site, it is necessary to determine the exact position on the ground of the object being built. The professional geodetic service surveys the object, i.e. marks the footprint of the object on the ground through its characteristic points, which are marked with stakes.
At the same time, a fixed point on the construction site is marked as an absolute (elevation) height.
In this way, the object is completely determined in terms of its footprint and height.
In order to preserve the position of these stakes during the excavation of the construction pit, corner crosses of the target scaffolding are made.
The target scaffolding is erected at each corner of the object.
The target scaffolding consists of three stakes with two horizontal boards on which the edge of the foundation foot, the outer and inner face of the wall of the wide excavation are marked using notches. From the notch on the scaffolding from one corner (through the cross exactly above the stake), to the corresponding notch on the scaffolding on the opposite corner, a wire is stretched and the position is marked with a nail on the horizontal board, so the directions of the edges of the excavation are obtained. From the stretched wire, any point can be lowered to the ground using a plumb line.
The offset scaffolding consists of posts with dimensions 12 x 12 cm, mutually connected with beams with dimensions 4.8 x 16 cm. The horizontal beams must be perfectly horizontal, and pegs are attached to the plates ("beams") whose primary function is to correctly determine the width of the foundation and wall.
Later, after excavation, the offset scaffolding is executed around the entire (future) object, and the measurement or transfer of measurements from the drawing to the terrain is done from these end marks (pegs) that mark the corners of the building.
The offset scaffolding for marking the internal foundations and internal load-bearing walls of the ground floor is made of 2 posts and 1 beam according to the fronts of these foundations and walls.
The height of the scaffolding is 70 - 80 cm, or about 20 - 30 cm above the ceiling structure of the basement or the substrate of the ground floor of a non-basement building, if this height does not exceed 1.60 m. The posts of the offset scaffolding are embedded 1 - 2 m offset from the marked contours of the building.
