ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
Installation and measurement of Benxi Steel Structure Project includes: axis positioning of side truss, geometric dimension control of projection line, deformation observation of elevation control, installation and measurement of grid structure, etc. Because the installation of steel structure is mostly based on civil structure, according to this characteristic: the installation of measurement and control network of steel structure is based on the layout of measurement and control network of civil construction, and the measurement and control instruments are total station, theodolite and level instrument. Volume operation 1. Comprehensive review of civil survey control network and axis and elevation. 2. Re-measure the pre-embedded dimension, flatness and elevation of the pre-embedded parts of the foundation. Repeatedly measure the vertical and horizontal axis of the embedded bolt group and the vertical degree of the screw 4. Set up the cushion plate group and control the elevation and axis of the component installation. Fifth, measurement control measures (1), side truss assembly survey side truss assembly site should choose the horizontal hard place, while in order to reduce the side truss assembly process of tire formwork force point settlement, lay a layer of steel plate on the ground. Then the projection points of each node are measured on the steel plate according to the size of side truss.
All temporary fixing and tightening equipment should be removed when checking the leveling of the supporting stool and platform used in the pre-assembly. 1. Routine measurement is mainly used in the ground assembly of measurement methods, such as rectangular coordinates and Distance Intersection method. The main control line is released by theodolite, and then the projection points of each spherical node are made on the ground according to the relationship between the spherical nodes. In order to improve the accuracy of the marking, the projection points of each node are marked with steel needles on the steel plate; the corresponding relationship between the flatness of side truss and the elevation of upper and lower chords is controlled by leveling method, and the ground assembly leveling datum is used. Relative datum 2 and inspection method (1) The plane position of the joints is mainly composed of steel ruler and small vertical sphere to check whether the truss joints and the corresponding projection points conform to the limit difference. (2) Node elevation level and tower ruler check the elevation of each node. Because the node is spherical, the corresponding elevation is the center of the sphere. In order to reduce the difference, the lower end of the sphere is measured, and the tangent point of the sphere is held at the OM of the tower ruler, so that the lower part of the tower ruler is close to the projection point along the middle line. In order to better eliminate the error, the elevation of each node is measured several times.
(The elevation of this project is controlled by measuring three times at each node and taking the average value at last). According to the radius of different spheres and the measured elevation, the theoretical elevation of nodes is obtained. (The following nodal elevation control methods are the same.) 3. Ground assembling measurement accuracy requirements: the allowable error of side truss total length (total length is about 32 meters) is (+50 mm); the nodal location requires that the center of the nodal displacement be less than 1.0 mm of soil. In order to improve the accuracy of characterization, steel needle is used to characterize, and the competitiveness of characterization is less than 0.1 mm. 4. After the ground assembly of side truss, the truss should be checked comprehensively according to the above accuracy requirements, and the records should be made, so that the construction of next working procedure can be carried out after qualified. The geometric dimensions of the membrane frame must be checked before the next truss is assembled after a truss has been assembled.