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The production of components

The panels used in portal steel frames are very thin, up to 4mm. Multi - sheet blanking should be preferred shear mode and avoid flame cutting. Because cutting with flame will make the edge of the plate produce a lot of wave deformation. At present, most h-beam welding manufacturers adopt submerged arc automatic welding or semi-automatic welding. If the control is not good, welding deformation should occur, so that the members of the bending or distortion.

Second, the column foot installation problem

(1) problem of embedded parts (anchor bolt) : overall or layout deviation; Wrong elevation; The thread is not protected. It directly causes the hole misalignment of bolt on the bottom plate of steel column, resulting in insufficient screw length.

Measures: steel structure construction unit and civil construction unit work together to complete the embedded parts work, before concrete pouring and ramming. Relevant dimensions and fastening must be checked.

(2) the anchor bolt is not vertical: the horizontal degree of the bottom plate of the frame column is poor, the anchor bolt is not vertical, and the horizontal error of the embedded anchor bolt after foundation construction is large. The column is not in a straight line after installation, which makes the appearance of the building very ugly, brings errors to the steel column installation, and the structure stress is affected, which does not meet the requirements of the construction acceptance code.

Measures: anchor bolt installation should adhere to the bottom of the bottom plate with the adjustment of the bolt level, and then use non-shrinkage mortar grouting fill, foreign method construction. Therefore, when the anchor bolt construction, can use reinforcement or Angle steel and other fixed anchor bolt. Welded into a cage, perfect the support, or take some other effective measures to avoid pouring the foundation concrete anchor bolt moved one.

(3) connection problem of anchor bolt: anchor bolt of column foot is not tightened, and the backing plate is not welded with the bottom plate; Part of the anchor bolt without 2-3 screws.

Measures: welding bolt and nut should be adopted; In the outside of the chemical anchor bolt, should be thickened with fire retardant coating and heat insulation treatment, to prevent fire affect the anchorage performance; The observation data of foundation settlement should be supplemented.

3. The surface of bolt equipment does not meet the requirements, resulting in bad installation of bolts or the degree of bolt fastening does not meet the design requirements.

Reason analysis:

(1) the surface of floating rust, oil and other impurities, bolt hole wall burr, welding, etc..

(2) the bolt mounting surface is still defective after treatment.

Solution:

(1) the surface of high-strength bolts floating rust, oil and bolt hole hole problem, should be cleaned one by one. Before use, anti-rust treatment must be carried out, so that the bolts used for assembling shall not be used for formal assembling. Bolts shall be kept and distributed by specially-assigned person.

(2) processing assembly surface should take into account the construction and installation sequence, to prevent repetition, and try to deal with before lifting.