1.1 Steel grid structure.The installation method of the grid frame shall be determined comprehensively according to the characteristics of the grid frame and structure, under the conditions of satisfying the quality and safety, schedule and economic effect, and in combination with the construction technical conditions of the construction unit.
1.2 After the installation method is selected, check and calculate the reaction force of the lifting point, deflection, internal force of the rod, stability of the supporting column during lifting or jacking and horizontal thrust of the grid under wind load, etc., and reinforce the grid when necessary.
1.3 No matter what construction method is adopted, trial assembly and trial installation shall be carried out before formal construction, and formal construction can be carried out only after confirmation.
2.1 The high-altitude bulk method is commonly used for grid rack installation, which requires load-bearing scaffolding during installation. Scaffolding installation shall be calculated and approved by the competent authorities before installation.
2.2 Steel tube fastener scaffold shall be used for platform construction, with the distance between vertical poles not less than 1.5m×1.5m, and the distance between horizontal poles not less than 1.5m; Face bar spacing 0.4m, foot board full shop and tie, foot board net distance < 0.1m, the pole out of the platform height must be < 0.1m, the platform must be equipped with two-way scissors support and sweeping rod, the front of the platform with protective railings.
2.3 Height of the platform: the height of the top of the platform is about 0.3m.
2.4 There must be safety protection facilities, safety nets and safety railings around the platform, as well as passage or escalator for construction workers to get up and down.
2.5 Re-test the axis deviation, relative elevation and surface smoothness of the buried parts. Each buried part must indicate the corresponding elevation, put the axis, the grid construction before the axis retest, more than the provisions to be amended.
3.1 According to the number of the installation drawing, pad the plane of the lower string ball, connect the lower string rod and the ball and tighten it in place at one time.
3.2 The belly rod and the upper chord ball should form a downward four Angle cone, the connection between the belly rod and the upper chord ball must be tightened in place at one time, the connection between the belly rod and the lower chord ball cannot be tightened in place at one time, mainly for the installation of the upper chord rod release service.
3.3 The installation sequence of the upper chord rod is transmitted from inside to outside. Tightening the upper chord rod and the ball should be followed by tightening the belly rod and the lower chord ball.
4.1 In the whole installation process of the grid, special attention should be paid to the padding of the lower string ball, the accuracy of the axis, the tightening degree of high-strength bolts, the control of deflection and geometric size.
4.2 During installation, the support must have enough strength and stiffness, and the string ball node under the pad can reach the specified elevation, which can be slightly higher than the specified value.
5.1 Handle the height difference of embedded parts carefully and control it within the scope of regulations and design;
5.2 After the installed grid becomes a stable body, the support vertex shall be removed at the same time and at the same speed as possible; Or according to 5.3 grid weight deflection curve partition in proportion, about 10mm drop each time.