A. Lifting process
Positioning --- Fixing the elevation --- Pre-embedding the bolts at the top of the column --- Fixing the elevation ---- bullet line ---- column installation ---- steel beam installation ---- sub-structure installation ----- welding ---- patching paint ---- completion
B. Steel column installation process
a. Lifting of steel column
The base is remeasured, including the exposed length of anchor bolts, the displacement deviation of anchor bolt centerline to the reference line, anchor bolt spacing and base elevation, and the unqualified ones are processed before lifting.
In order to control the installation elevation of the column, a 500mm position is marked out on the visible section of the column in advance for fine adjustment and correction of the elevation during installation. Install the steel column on the basis of qualified retesting, firstly, tie the column with a single steel wire rope, and choose the position of the lifting point at 1/3 of the column length from the end of the column. Lift the column by rotating method and send the steel column to the installation position. The tying place should be padded.
b. Calibration of steel columns
Draw the centerline on the visible surface of the column in advance, and then adjust the verticality of the column in two mutually perpendicular directions with a latitude and longitude meter.
Control the verticality of the column by measuring the distance of the inner side of the column from the control line popped on the building.
Adjustment of column elevation, axis and verticality deviation is interlinked and balanced, and the correction work will be completed when all standards are met.
C. Steel beam installation process
The steel beams are unloaded to the vicinity of each column, sent to the floor level by car crane, and then installed by mast crane. The main beams with some heavy components can be platform craned with the car crane. Secondary beams can be installed by homemade tire type (5t) crane. Only when the bolts at both ends of the beam are tightened (or spot welded firmly), can the hook be released and other steel beams be lifted in turn. After passing the inspection, welding is carried out.
Steel beam tying lifting point is especially important, in the steel beam is too long can take steel flat bar, this project has many steel beam longest for about 20m, with triangle hanging plate to enlarge the wire rope spacing, to increase the wire rope angle in line with this lifting requirements. Steel beam tying diagram.
D. On-site welding process
Main components welding process
a.Butt penetration welding seam (flat welding position manual electric arc welding)
Applicable beam-column flange plate web butt welding seam, welding rod E4303. Welding process parameters:
b ≤ 12mm single bevel angle 60 degrees blunt edge 2mm
b>12mm double bevel angle 60 degrees blunt edge 2mm assembly gap: 2 --- 3mm
Welding current 140~~180A, welding voltage 24V, welding speed 375px /min
b.T-type welding seam (ship-shaped bit manual arc welding)
Applicable to beam-column tendon plate, connection plate, column top plate, column bottom plate, double-sided paste angle welding seam, welding rod E4303.
c.Welding process parameters.
Weld foot height: greater than the thickness of the thinner parts of the welded parts. Welding current 140 ~ ~ 160A, welding voltage 22V, welding speed 400px /min.
d.The appearance of the weld: with the naked eye and gauges to check the appearance of defects and weld foot size, should be in line with the requirements of the construction drawings and construction specifications, weld wave uniformity, there shall be no cracks, unfused, slag, weld tumor, biting edge, burn through, arc pit and pin-like pores and other defects, the welding area should be cleaned up, no spatter residue.
e.Full penetration weld as the focus of the welding process and key quality control points, quality inspectors should follow up on this part and do the corresponding quality inspection records.