Construction plan for steel structure (4)

(V) Installation of column base plate spacers and secondary grouting

When installing the steel column, it is necessary to adjust the elevation of the column and usually place the pad under the end plate at the bottom of the column, while the size of the pad is generally considered only to carry the weight of the steel frame itself. The difference between the elevation of the concrete surface of the foundation and the elevation of the bottom plate of the column is the thickness of the required pads, from which the number of pads required can be calculated. The column base pads should include 6 mm pads or wedge pads, and the wedge pads should be padded to the corner of the column base plate.

Grouting can be done only after the main steel structure is lifted and corrected, usually within three days after the correction is completed to avoid displacement of the structure due to other reasons. Preparation work before grouting, cut off the concrete surface too high so that the thickness of grouting is at least 4cm, remove the concrete surface of fine things, grease, soil and other undesirable substances, and maintain appropriate roughness. One end and both sides of the formwork should be higher than the surface of the slab and left at an interval with a slight inclination to allow the insertion of wooden rods or steel bars. The grout must be mixed with a mixing machine, if mixed by hand, it will lack fluidity and make the water easy to increase, causing the risk of shrinkage. Once grouted, the operation must be carried out continuously until the grout comes out from around, the grout must start from one side and cannot be interrupted before completion. After grouting, keep wet state maintenance for at least seven days.

(VI) High-strength bolt construction method

● The steel beam and column of this steel structure project are connected with large hexagonal high-strength bolts. The friction surface of the members should be protected dry and clean when installing the high-strength bolts and should not be operated in the rain. The order of tightening should be from the center of the anode plate to the edge (refer to chart No.5-H), the order of the two connections is the order of primary and then secondary, the order of H-beam members is the order of upper flange, lower flange and compound plate, the order of tightening of the beam and column nodes on the same section is the order of upper beam and column joints and then lower beam and column nodes, and finally the middle beam and column nodes. The tightening degree of high-strength bolts is controlled by a torque wrench. The exposed wire buckle is 2-3 wire, and each bolt pad two washers for common bolts used to connect purlin wall beams. All installation holes shall not be reamed by gas cutting. When the pinhole of the plate stack exceeds the allowable deviation causing the connection bolt to not pass through, the reamer can be used to trim, but the maximum diameter after trimming shall be less than 1.2 times the diameter of the bolt, and iron chips shall be prevented from falling into the gap of the plate stack when reaming. Meanwhile, all specifications of high-strength bolts of this project will be sent to the laboratory for testing after the supervisor witnesses the sampling.

● A team of 6 persons is to be prepared for the construction of high-strength bolts, including 4 persons for bolt installation, 2 persons for initial screwing and 2 persons for final screwing, and the bolts installed on the same day must be finished on the same day for final screwing.