Five Important Quality Control Points for Steel Structure Projects (2)

C.High-strength bolting project

High-strength bolt connection project is also one of the most important sub-projects of the steel structure project, and is also one of the weak links of the current construction quality, mainly in.

a.high-strength bolts have the phenomenon of filling good with bad, (using ordinary refined bolts instead of high-strength bolts).

b.High-strength bolt connection surface treatment does not meet the requirements of the specification, including surface treatment, flat and close, bolt hole quality, etc..

c.High-strength bolts are not screwed according to the specifications, such as not divided into the initial screwing, final screwing and finished at once, without torque wrench, all based on subjective estimates, etc. In order to ensure the construction quality of high-strength bolt connection project, the supervising engineer must be highly responsible, while supervising the contractor to improve quality awareness, strengthen quality management, and implement quality assurance measures, and actively use work methods such as side supervision and parallel inspection, so that the construction quality of high-strength bolt connection project can be under strict control.

D.Steel structure rust removal and painting project

Rust removal and painting of steel structure is a work that is easy to be ignored by steel structure contractors and is also a weak link in the construction of steel structure.

If this phenomenon is not corrected, the construction quality of steel structure will be greatly affected, because the quality of rust removal and painting directly affects the maintenance cost of steel structure during future use, and also affects the service life of steel structure project, structural safety and fire resistance time in case of fire (fireproof painting).

The root of this phenomenon lies in the lack of understanding of the importance of painting work by the personnel of the contracting unit, coupled with the lack of quality responsibility and even profit-oriented, which eventually leads to frequent problems in the quality of painting works.

Therefore, the supervising engineer must pay high attention to the rust removal and painting work, and conduct strict inspection and acceptance of each process, which is the basis and guarantee to ensure the quality of steel structure painting.

Regarding the painting quality of steel structure project, the following work should be grasped.

a.Strict acceptance of the quality of descaling of steel members according to the grade required by the design.

b.Checking the factory quality certificate of the painted raw materials, and the fireproof coating should also check the approval certificate of the fire department.

c.Thoroughly remove mud, oil and other debris from the surface of the members before painting.

d.The painting construction should be carried out in a dust-free and dry environment, and the temperature and humidity should meet the specification requirements.

e. The number of coats and coating thickness should meet the design requirements.

f.The damage of the coating should be handled carefully to ensure the quality of the coating.

g.Check the adhesion of the coating carefully.

h.Strictly check and accept the appearance to ensure that the quality of coating meets the specification and standard requirements.

E.Pressed Metal Panel Project　

Pressed metal plate project is mainly a color steel maintenance structure, which is a more emerging form of building maintenance structure. At present, the problems that appear in the actual project are mainly as follows

The construction unit does not develop the color plate (sandwich panel) construction plan, the color plate joints, the connection between the plate purlin, the color plate fittings production and installation and other node structure processing is not fine or not reliable, maintenance structure leakage, color plate sub-project perception quality exists uneven, not straight, not tight, deformation, scratches, pollution phenomenon, etc.

In view of the above situation, supervision engineers should pay attention to the following points in their work.

a.Before the production and installation of color board (sandwich board), the construction unit must be urged to develop a thorough and reliable construction plan for the color board project, especially to develop a detailed plan for the row of boards, building construction methods and quality assurance measures.

b. The process of production and installation should strengthen inspection, bystander supervision and parallel inspection, so that most quality problems can be eliminated before and during construction.

c.Strictly carry out inspection batch and sub-project acceptance, to ensure that the node structure is reasonable, reliable, no leakage, smooth, straight, tight, uniform and consistent color, no scratches, no rust spots, no pollution on the board surface.