Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
Under the dual influence of the environment and the longevity of the application requirements, the effectiveness of the space frame steel structure will gradually diminish and is an irreversible objective fact. If the regularity and ability of such damage can be scientifically identified, and corresponding proper treatment precautions can be taken immediately, then the operation process of structural destruction can be delayed by time, and it can be done to enhance the service life of the structure to put it bluntly.
The inspection of cracks includes the area of the crack, the orientation of the crack, and the size and total width of the crack. The inspection of the total width of the crack is important to use 10-20 times high magnification, crack comparison card and micrometer and other common tools. Crack length can be measured with a tape measure, and crack height can be measured roughly with the help of inserting to ultra-thin carbon steel plate in the seam. It can also be cored along the direction of the crack or examined with ultrasonic instruments. In order to easily identify whether the cracks are developing or not, the plaster paste method can be applied. A plaster cake with a thickness of about 10 mm and a total width of 50 to 80 mm is firmly pasted over the gap, and a gap in the plaster is observed.
The most common laboratory instruments and common tools used to measure the deformation of structures or prefabricated elements include levels, horizontals, hammer balls, hot rolled steel strips, cotton threads, laser generator displacement meters, infrared range finders, RTKs, and so on. There are many types of structural deflections such as beams, roof truss deflection values, roof truss tilt, column lateral movement and depending on the overall objective of the inspection different methods and experimental instruments must be used. In measuring the deflection values of small span beams and roof truss structures, a simple method of pulling a line can be used, as well as the option of selecting points for horizontal measurements. Slope and displacement measurements of roof truss structures are usually made directly above the roof truss structure from the top chord to the strong axis, and tilt values are measured and the direction of tilt is recorded.
Steel performance inspection is mainly to check cracks, holes, fly ash and dirt, etc., and welding welding is mainly to check fly ash and dirt, bubbles, undercut, burned through, welding welding lack of welding, melting the deep layer is not in place and welding holes in the specification of the model is not enough. For the ground bolts or ground screws important to check whether the lack of riveting, checking neglect, not biased, not pointing and turning. Inspection methods are mainly estimated, X-ray, B ultrasound inspection, magnetic particle flaw detection regular maintenance penetration to the inspection. Ultrasonic method used in metal materials inspection to high frequency, power need not be very large, so the inspection is highly sensitive, inspection accuracy is good. Ultrasonic testing is generally applied in two ways: longitudinal wave non-destructive flaw detection and transverse wave flaw detection (key application in welding flaw inspection).
