Brief introduction of steel structure installation sequence

(1) Installation process

The target state of the steel structure installation in the vertical direction is: after the completion of the installation of the steel structure section, the civil construction unit will immediately lift the profiled steel plate of each floor of this section into place, and lay the profiled steel plate of the upper layer, so that the upper steel structure lifting and the lower profiled steel plate laying and civil construction process are effectively isolated. Vertical installation sequence (take a section of three layers as an example) : steel column installation → lower frame beam → middle frame beam → upper frame beam → measurement correction → initial screw bolt, measurement correction, and final screw high-strength bolt → laying of upper compression steel plate → laying of lower, middle and upper steel ladder and platform installation.

(2) Installation of steel columns

1) Installation sequence of steel column: the inner cylinder is installed first, then the outer cylinder is installed, the middle and then the four sides are constructed according to the hoisting partition, and the installation sequence of the bottom and then the top is installed first. 2) Selection of lifting point: the lifting point of the steel column is set on the top of the steel column, and temporary connecting plates are directly used (at least 4 connecting plates). A hoisting hole is arranged on the temporarily connected ear plate. 3) Lifting and unhook: use the selected lifting point to wear the clasp, tie the wire rope, and start lifting after checking everything. After the steel column is initially in place, pull the cable and wind rope, and then unhook. 4) Steel column in place.

(3) installation of steel beam

1) Hoisting sequence: It is generally carried out in accordance with the installation sequence of steel columns. After the installation of adjacent steel columns, the steel beams between them should be connected in time to make the installed components form a stable frame in time. Moreover, the steel columns installed every day must be connected with steel beams, and the cables that cannot be connected in time should be pulled for temporary stabilization. The main beam is installed first, then the secondary beam, and the lower layer is installed first and then the upper layer in the installation sequence. 2) Selection of lifting point: Lifting lugs are generally set at 1/3 of the lifting point from both ends of the steel beam. 3) Hoisting and positioning of steel beams.

4. Connection process

With the adoption of high strength bolts and welding connection, the requirements of the connected parts are becoming more and more strict. Such as component displacement, verticality, levelness, grinding top tight close paste degree, connection gap, hole concentricity, plate overlapping friction surface processing, must be inspected and approved by the quality supervision department, in order to carry out the next step of fastening and welding, so as not to leave difficult to deal with the hidden danger.

The tightening of high-strength bolts can be divided into two steps: initial and final twisting, which can reduce the difference of pretension between first and last twisting of high-strength bolts. For large node should be divided into early twist, twist and finally shake three steps, increase after double twist twist at the beginning of is to reduce the excessive bolt pretension loss, in order to make the connected plate fold dense paste, in construction process should begin from the core in order to screw bolt group, in order to prevent the high strength bolt connection change the surface treatment of coating, and influence the phenomenon of strong, Requirements should be completed by the end of the day. Torque wrenches with high strength and large hexagonal head screw are generally used by electric fixed torque wrenches or manual torque wrenches. The torque wrenches used in the inspection are generally manual pointer type torque wrenches or torque wrenches with percentile standard. The tool needs to be strictly torque corrected before and after the shift. The torque of the wrench used for twisting is ± 5%, and that of the wrench used for picking and checking is ± 3%. The torsional shear type high strength bolt can be visually inspected to check whether the tail of the bolt is screwed off. High strength large hexagon head bolts can adopt the method of small hammers for inspection, in which a finger tight hold the nut side, 0.3 ~ 0.5 kg weight of small hammer knock the other side of the nut, if the finger slightly vibrate is unqualified, in the process of vibration larger because owe twist or twist leakage, no tremor is the super twist.