Briefly describe the precautions for the prefabrication and assembly of tower segments?

Before assembling the cylinder, each tower section is placed on a specialized fixture on a horizontal steel platform to check its dimensions and prefabrication quality. The size of the corners formed by the longitudinal welds after the cylinder is rolled is checked using an internal gauge arc plate with a chord length equal to D/6 and not less than 500 mm; after welding, this value should be no more than 0.1 times the thickness of the plate plus 2 mm, and in any case no more than 5 mm； For all tower sections, the difference between the maximum and minimum diameters in the same cross-section along the diameter direction shall not exceed 1% of the design diameter, nor more than 30 mm; the levelness of the ends of the cylinder sections shall be checked to ensure it remains within the specified error range ； When aligning the circumferential seams of the two cylinders, special alignment fixtures, supports, and tools for correcting misalignment are used to improve the quality and speed of alignment. During this process, the verticality of each cylinder section is checked from time to time using instruments such as theodolites and plumb bobs, to ensure high quality during the overall alignment process ； After the assembly of the 3 tower sections is completed, make proper markings and place them in sequence around the tower foundation at locations that do not hinder the operation of the tire crane, and that are also convenient for transportation and lifting (to be determined based on site conditions) ； And ensure proper protection of the finished product ； After the welding of the 4 tower sections is completed, a kerosene leak test on the welds is carried out in accordance with the design requirements ； And keep the corresponding records ； The misalignment variation during the alignment of the butt welds of the 5 towers (the amount of misalignment at the longitudinal and circumferential welding sites when two sections are aligned) must meet the specified requirements