Clean engineering measurement is a very important part of work, how to do it? Ed Purification takes you to know about it.
(1) Establishment of construction control network. The Project Management Office dispatched the Surveying Section to accept the surveying control network delivered by the owner and set up the construction control network. In order to shorten the intermediate link, it is necessary to work with the surveyors of the participating units of the second-level companies.
According to the coordinate position, baseline and baseline of the proposed building (structure) on the general construction plan, and the relative elevation reference points specified in the urban leveling points or design drawings, the network points are measured by theodolite, leveling instrument and steel ruler.
(2) The measurement is carried out according to the working procedure of the whole and then the part.
(3) Establish a unified control network in the whole building site as the basis for the positioning and layout of the buildings.
(4) According to the construction control network, the positioning of each building is surveyed.
Closure error should be checked in the measurement of construction control network points. The error value is within 1/5000 and can be corrected proportionally. When the error exceeds the allowable error value, it should be retested.
_When using theodolite to measure the construction control network, the child should not be less than one test (round trip test is one test).
_When the construction level control network is established and measured with steel ruler, the two ends of the steel ruler should be kept at the same level as possible before the measurement can be carried out.

The unified construction control network, level point and the main axis of the building (structure) should be set firmly, stably, not sink, not displace, and be protected by concrete. Key signs and environmental protection needs can be fenced.

(2) Elevation control
(1) According to the relative reference points of the national leveling points indicated on the general plan or the surveying and designing drawings, the leveling instrument is used to accurately locate the corresponding positions near the construction site which are convenient for monitoring. The position of the leveling point used for monitoring should be firm, stable, non-sinking and non-deformable.
(2) Elevation survey should carry out a round trip survey, and its closure error value should not be greater than the value U for the number of stations. The closure error is within the allowable range and can be corrected in proportion to the horizontal distance.
(3) Location and calibration of axes of buildings in clean Engineering
The base points are determined according to the orientation and orientation indicated by the general plan or other plans. The children are positioned by theodolite, and the plane and opening dimensions are measured by steel ruler. The measurement begins at the intersection point of the main axis. The axes are measured. After Zui, the theodolite is moved to the diagonal point for checking and closing. After the overall size and opening size are confirmed, the axes can be extended to the axes outside the building, the gantry frame and the adjacent buildings (structures).
(2) The dimension of the opening of the sub-drawing axis should be checked by the total length dimension to minimize the accumulated error of the sub-drawing dimension.
(3) Axis piles and gantry frames with extension axes should be located 1 1.5 m away from the slope edge of excavation foundation pit, and axes should be marked with symbols of longitudinal axes.
(4) Axis pile, gantry frame and building (structure) marked by extension axis sign should be firm, stable, reliable and easy to monitor.
(4) Leveling and laying-out of clean Engineering Construction
(1) Building (structure) with pile foundation, according to the plan of pile and the axis of building (structure), the central mark of pile position of corresponding axis is determined. After checking, the mark of pile location is inserted.
(2) Foundation and pile foundation: According to the plan of foundation and the large sample drawing, locate according to the axis of the building (structure), connect the corresponding axis, calculate the slope of excavation (or the excavation degree of pit wall support), and determine the location of excavation side line.
(3) The corresponding elevation is indexed to the horizontal pile or axis pile with the level, and the elevation mark is drawn.
(4) After the foundation pit excavation is completed, the width of the foundation pit bottom excavation should be checked through the line, and the depth of the foundation pit should be checked by the horizontal marker, and the axis and marker should be moved to the foundation pit. In the foundation pit, the axis, the foundation side line and the elevation mark are set. A cushion should be laid on the cushion layer (elastic ink line) wall or foundation of the plane size.
_After the foundation template is completed, the geometric dimensions of the template installation shall be checked according to the requirements of the design drawings. The elevation lines of the foundation surface are set out around the formwork and marked with nails (marked with red paint on the vertical reinforcement). The axis and edge marks of the walls and columns should be extended to the outside of the foundation edge line for easy construction review.
_After the foundation construction of clean engineering is completed, the axis is measured to the foundation surface, and the relevant wall and column iso-sectional dimension lines are released according to the construction drawings. For ground beams, reserved holes, pipes and buried parts, the relevant markings (including the geometric dimensions of elevation and section) should be put out according to the construction drawings.
Edward Purification has been developing in the field of clean Engineering for many years, and has implemented a series of workshop purification projects. For some difficult projects, it has been perfectly completed through excellent technical strength and well-trained construction team of clean engineering.