Quality Control in Grid Structure Engineering
Quality Control in Grid Structure Engineering
1. Quality control during grid construction
(1) The quality control of bolt ball grid structure: The bolt ball is composed of bolts, pipe sleeves, pins, cone heads or sealing plates, and is connected by high-strength bolt balls with steel bars to form a spatial truss structure. The structure is loaded with a baseball grid. Any component with quality issues will endanger the overall safety structure. This should be a high-quality component. Strictly control the quality of grid components before assembly, eliminate unqualified components, and ensure the quality of the most important part of the project network structure. The entry of grid structure components requires inspection of the factory certificate of conformity, keeping records of entry acceptance, and conducting sampling testing between each group according to regulations. In addition, rod inspection and testing cannot be ignored.
(2) The quality control of grid assembly and hoisting requires pre assembly work to ensure the correctness of formal construction. During pre assembly, the site should be leveled and compacted, and accurately set out. The specifications of the bolt ball and the correct position of the compression rod should be carefully determined by comparing the design model of the drawing to prevent errors in the position of the tension and compression rod. When assembling, the lower chord should be assembled first, and then the elevation and axis of the lower chord should be corrected and tightened for positioning before connecting the web member and assembling the upper chord. During this period, it should be prevented from being too loose or too tight to avoid residual stress during assembly.
(3) Quality control of accessory installation: When installing the roof panel purlin support, it is necessary to connect and fix it on the bolt ball with bolts. Welding method should never be used to fix the purlin support on the bolt ball. It is necessary to prevent the reduction of thread shear and sliding resistance caused by high temperature during welding, as well as the problem of cracking caused by the hardening and embrittlement of cold steel after welding, which can lead to a decrease in performance. For suspended ceilings, fire pipelines, raceways, heavy equipment, and temporary construction installations that require decoration and decoration, bolt connections should be used to suspend them on the ball nodes (it should be noted that all suspended objects need to be designed and calculated, and weight and quantity cannot be arbitrarily increased), and welding connections are not allowed. It is very dangerous to prevent equipment weight from directly hanging on the pole, especially heavy equipment suspended in the middle of the pressure pole. If the equipment is suspended in the middle of the pole, it is equivalent to adding a concentrated force in the span of the pole. The heavier the force, the greater the corresponding concentrated force, and the greater the harm to the pole. It may cause bending failure, causing instability of the grid and overall collapse failure.
