Column base installation problems

(1) Problems of embedded parts (anchor bolts): overall or layout deviation; wrong lifting; no protective measures for threaded fasteners.It directly causes the bolt holes at the bottom of the steel column to be misaligned, resulting in insufficient thread length.

Measures: steel structure construction unit and civil engineering unit cooperate to complete the work of embedded parts.The dimensions must be checked and firmly fixed before the concrete is placed.

(2) The phenomenon of bolt not vertical: the horizontal difference of frame column pedal, bolt not vertical, the horizontal error of buried bolt after foundation construction is large.After the column is installed, it is not in a straight line, which makes the appearance of the house unsightly, brings errors to the steel column installation, affects the structural stress, and does not meet the requirements of the construction acceptance standard.

Measures: during the installation of foundation bolts, the bottom plate and the lower adjusting bolts shall be leveled first, and then the non shrinkage mortar shall be used for secondary grouting. This method shall be used for construction in other places.In anchor construction, thick anchor or angle steel fixed anchor can be welded into the cage to improve support, or other effective measures can be taken to avoid the displacement of anchor when pouring foundation concrete.

(3) Problems of anchor bolt connection: the anchor bolt at the column base is not tightened, and the base plate is not welded with the ground; some anchor bolts are not exposed with 2-3 threads.

Measures: Guiyang steel structure shall adopt welding bolts and nuts, and thicken the fireproof coating and thermal insulation layer outside the chemical bolts to prevent the anchoring performance from being affected under fire, and supplement the foundation settlement observation data.

Connection problems

1）The equipment surface of the bolt does not meet the requirements, which makes it difficult to install the bolt, or the bolt fastening degree does not meet the design requirements.

Cause analysis:

(1) There are floating rust, oil stain, burr, welding nut and other impurities on the surface of bolt hole.

2。Although the bolt installation surface is still defective after machining.

measures:

(1) The surface of high-strength bolts of steel structure shall be cleaned of rust, oil stain and bolt hole defects one by one. The bolts must be rust proof before use. The bolts shall be kept and distributed by special personnel.

(2) The construction and installation sequence shall be considered for the processing and assembly surface to prevent repetition, and treatment shall be conducted before hoisting.

3）If the thread is damaged, the screw can not rotate freely into the nut, which will affect the bolt assembly.

The steel plate for door profile is very thin, the thinnest steel plate can be used for 4mm.In order to avoid flame cutting, it is best to use shear method.Flame cutting will produce huge wave deformation at the edge of the plate.At present, most H-type welding machines use submerged arc welding or semi-automatic welding.If the welding deformation is not well controlled, the parts will bend or twist.