Steel structure project construction 8 quality control points

When the project meets the requirement of short construction period, steel structure project may be the best choice. Steel structure construction is fast, short cycle, high strength, easy to prefabrication, installation. However, the quality problem of steel structure project is the premise to play these advantages. Therefore, it is of great practical significance and necessity to strengthen the quality control of steel structure project.

1、Construction preparation

Construction preparation is to create necessary conditions for construction. Doing construction preparation work carefully, meticulously and thoroughly plays an important role in giving full play to human positive factors, reasonably organizing manpower and material resources, accelerating project progress, providing construction quality, saving investment and materials, and successfully completing the steel structure construction task.

Steel structure project

1.1 Do a good job of reviewing and handing over the construction drawings seriously

Drawings are the basis of engineering construction, and the technical person in charge of the project should organize the relevant technical personnel to review and digest the drawings by division of labor, the purpose of which is, firstly, to make the construction unit and each participating unit familiar with the design drawings, understand the engineering characteristics and design intention, find out the technical difficulties that need to be solved, and formulate the solutions; secondly, in order to solve the problems in the drawings, reduce the errors of the drawings, and nip the hidden quality problems in the drawings in the bud. Nip in the bud. At the same time, do a good job of technical briefing, do a good job of the combination of construction and design, do a good job of the combination of steel structure lifting and civil construction, steel structure and concrete structure prefabrication.

1.2 Prepare the construction organization design of steel structure project carefully.

Construction organization design is an important comprehensive technical document compiled by the construction unit to guide the activities of the whole process of construction, which is a scientific management method. When the construction unit prepares the construction organization and construction plan, it should make practical and feasible specific implementation rules from the five aspects of man, machine, material, law and environment, implement the plan, implement the organization personnel, implement the self-inspection, mutual inspection and special inspection, and put all the quality problems that are likely to appear into the controlled state, and ensure that the technical measures of the plan are powerful and feasible. In the process of preparation and implementation of construction organization design, it should do extensive and in-depth research, and hand over to the construction personnel, so as to achieve everyone's gatekeeping. The steel structure project should prepare the production process and installation construction organization design for the production stage and installation stage respectively. The content of production process should include the quality standard and technical requirements of each process and each item in the production stage, as well as the specific measures formulated to ensure the quality of products. The content of construction organization design of steel structure installation project includes the establishment of quality assurance system and technical management system, measures and methods of quality and progress control, and the arrangement of construction period.

2、Emphasize the quality control of steel structure foundation project

The quality control of steel structure foundation project generally refers to the quality control of steel structure foundation pre-embedded bolts, and the pre-embedded bolts are the first step of the whole project construction, which is also a very critical step, and is the foundation of the whole project. When constructing foundation pre-embedded bolts, first familiarize yourself with the drawings, understand the intention of the drawings, and should make the installation template. Pre-embedded bolts with two installation templates and rebar positioned on the main reinforcement and template of the column, to ensure that the pre-embedded bolts are not displaced by the civil pouring concrete construction. In this way, the spacing and height between each group of bolts can be controlled within the permissible error; at the same time, the bolt wire fasteners are protected from damage during concrete pouring. After the completion of civil engineering, use the latitude and longitude instrument and level meter to review the elevation and axis of the ground bolt and make records. And hand over the next process for acceptance.

3、Quality control of steel structure production project

The construction of steel structure project usually goes through two stages of factory fabrication and on-site installation. Most of the time of steel structure project is carried out inside the factory workshop, because the quality of steel structure components processed and manufactured in the factory is crucial to the on-site installation of steel structure project and the safety and stability of the overall structure. Therefore, the steel structure production manufacturer must have the corresponding enterprise qualification, production scale, technical ability, mechanical equipment and advanced technology level.

Steel structure processing general production process is divided into: sample rarr; material rarr; splicing rarr; cutting rarr; assembly rarr; submerged arc welding rarr; drilling rarr; assembly rarr; corrective molding rarr; riveting parts and components under the material rarr; production and assembly rarr; welding and welding inspection rarr; antirust Processing, painting, numbering → Acceptance of the components to leave the factory. In the steel structure production, the key process should be seized for quality control according to the steel structure production process, such as controlling the processing of key parts, the process of main components, measures, processing equipment used, process equipment and so on.

Steel structure engineering processing

4、Emphasize the quality control of welding project

Welding project is the most important link in steel structure production and installation engineering project, and it is necessary to pay attention to welding project quality control. At present, most of the steel structure in the production process with automatic submerged arc welding machine, part of the semi-automatic gas shielded welding machine, individual parts of the manual welding.

Welding quality problems exist more in the manual weld, these problems are: weld tumor, slag, porosity, not welded through, biting edge, wrong edge, weld size deviation, not use the arc plate, welding deformation is not corrected, spatter cleanup is not clean, and so on. In view of this situation, before welding steel structure, the certificate of conformity of the welding rod should be checked, and used in accordance with the requirements of the manual, the welder must be licensed to work permit, the weld surface shall not have cracks, weld tumors, one or two welds shall not have pores, slag, arc crater cracks, one level of weld shall not have biting edges, not full weld and other defects, one or two weld nondestructive testing in accordance with the requirements of the provisions of the weld and the part of the welder should be checked for the welder's steel seal. Unqualified welds shall not be handled without authorization, set out to modify the process and then deal with the same part of the weld should not be reworked more than 2 times.

5、Quality control of steel component installation

The steel structure enters into on-site installation after the project production is finished. Before installation of steel structure, the quality of components should be checked, and the permanent deformation and defects of components should be processed when they exceed the permitted value. Steel column installation should check whether the pad iron under the column base plate is solid and flat to prevent the ground bolt under the column base plate from being unstable; control whether the column is vertical and whether there is any displacement, and in the installation project, temporary support measures should be taken before the structure has formed a stable system. When the steel structure is installed to form a fixed unit in space, and after acceptance, the construction unit is required to pour the space between the column base plate and the top surface of the foundation in a timely manner with expansion concrete for the second time to make it dense. Finally, it is also necessary to check the verticality of the main structure of the steel structure and the overall plane bending and so on.

6、Quality control of steel structure fastener connection

The quality control of steel structure fastener connection mainly emphasizes the quality control of high strength bolt connection. The control of construction quality of high-strength bolt connection project is accomplished from the following aspects:

First of all, the steel structure project must pay attention to the processing quality of the friction surface of the high-strength bolts and the protection before installation to prevent pollution and rust. And before installation, carry out the anti-slip coefficient test of the friction surface of high-strength bolts, check the factory certificate of high-strength bolts, batch number, and do the axial force test of high-strength bolts with different batch numbers on a regular sampling basis.

The installation of high strength bolts requires free penetration, no hammering and reaming; therefore, a certain amount of frame mold should be prepared to control its deformation during the production of steel structure, and practical fixing measures should be taken to ensure its dimensional stability during the transportation of the components.

In the process of steel structure installation, the contact surface of plate stack should be flat, the contact surface must be more than 75%, and the edge gap should not be more than 0.8mm. the installation process of high strength bolts, including the operation sequence, installation method, fastening sequence, initial screwing, final screwing should be strictly controlled and checked, and the torque wrench for screwing bolts should be calibrated, etc. The final screwing should be checked one by one, and the final screwing should be completed. The final screwing should be checked one by one, and the under-screwed and over-screwed ones should be replenished or replaced.

7、Steel structure descaling and coating project

Descaling and painting of steel structure is the most neglected part of steel structure project at present. Descaling of steel structure is divided into manual descaling and mechanical descaling, and the construction personnel should adopt different descaling methods according to the requirements of drawings and descaling grade. The quality control of painting project should be done that before the steel structure is painted, the surface of painted components should not have foreign objects such as welding slag, oil, water and burrs, and the number of times and thickness of painting should be in accordance with the design requirements. The painting material must have certificate of conformity, and the fireproof coating painting project must be constructed by the construction unit approved by the fire protection part.

 

8, color steel plate construction quality control

Color steel plate project is another important part of steel structure project. The good or bad quality of its construction directly affects the use of steel structure project. At present, there are many kinds of color steel plate. But color steel plate construction problems are more concentrated, such as: color plate joints, color plate accessories production and installation of node processing is not fine, unreliable, maintenance structure leakage, color plate perception quality is not flat, deformation, scratch, pollution phenomenon and so on. Therefore, the quality control of pressure type color plate installation mainly includes: after the pressure type color plate enters the field, it is necessary to carry on the appearance and the certificate of conformity inspection, and review the installation accuracy of steel components related to the construction and installation of pressure type plate, clear the welding seam flux skin and spatters during the installation of purlins, and brush the antirust paint for anticorrosive treatment. When installing the color plate, prepare a reasonable installation process sequence and so on.