Requirements for winter construction of steel structures
The construction of Shandong steel structure project in winter will be much more difficult than before, and the focus will also increase. For example, when installing steel members at positive and negative temperatures, the shrinkage of members should be considered according to the difference in ambient temperature. Technical measures to adjust deviation are taken during construction; The exposure time of welding rods used under negative temperature shall not exceed 2 hours, and the re baking time shall not exceed 2 hours. The baking times of welding rods shall not exceed 3 times. When installing the steel structure on site, if it snows or the wind speed is above 6m/s, please set up a protective shed. In windy weather, large components, such as columns, main beams and supports, shall be corrected immediately, and shall be fixed for a long time immediately after correcting the correct position to prevent unilateral instability. Components installed on the day shall constitute a space stable system.
During the inspection and acceptance of Shandong steel structure members under negative temperature, the influence of current temperature shall be considered for their overall dimensions. The joints and welds of equal strength that need to penetrate must be subject to 100% ultrasonic inspection, and the remaining welds must be inspected by 30% - 50% ultrasonic sampling. The probe used for ultrasonic flaw detector under negative temperature shall use non frozen oil-based lotion between the surfaces in contact with steel. Unqualified welds shall be re welded.
Before applying anti-corrosion coating on Shandong steel structure members below 0 ℃, the painting process test shall be carried out. When brushing, the rust, oil stain, burr on the edge hole, etc. on the component surface must be removed, and the component surface must be kept dry. In order to accelerate the drying rate of the coating, hot air and infrared radiation can be used for drying, and the drying temperature and time need to be determined through experiments. Paint spraying is not allowed in rainy or snowy days or when there is thin ice on the parts.