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2023-09-013.4、Temporary support
The review points are as follows.
(1) When using temporary supports (made of round tubes) for steel space frame installation, the arrangement (including quantity and location) should be strictly in accordance with the provisions of the construction organization design.
(2) The temporary support must be installed in place before the steel space frame is installed, and then the space frame is installed.
(3) Temporary support for steel space frame structure installation project is set on the ground floor concrete slab surface, before the construction of temporary support, the supervisor shall require the construction unit to carry out the load check on the upper part of the ground floor concrete slab, and the check shall be passed before the construction of the next process. If the value of the test exceeds the allowable load value of the slab, the temporary support construction can be carried out only after the reinforcement measures are taken for the bottom beam slab.
3.5、Unloading of space frame
The review points are as follows:
(1) Unloading principle: The program adopts the unloading method of “overall phased gradual” unloading.
(2) Unloading construction process.
3.6、space frame deflection measurement
Review points: the measurement method, calculation method and number of measurements of the space frame deflection.
3.7、Review of construction process test and evaluation
Focus on reviewing whether the test or evaluation methods of measurement correction, high-strength bolt installation, construction under negative temperature and welding process of the space frame installation meet the specification, and develop the corresponding construction process according to the test results and evaluation report.
4、Quality control of steel space frame structure installation project construction
4.1、Pre-control
(1)Review whether the practice qualification of the project department management personnel is in line with the type and scale of the project, and the project manager, full-time quality inspection personnel, safety management personnel, etc. should be on duty.
(2)Review whether the quality assurance system of the project department is established and sound, and whether the organizational and technical measures taken are real and effective.
(3)Review the operating qualifications of the steel space frame construction personnel, the relevant personnel are required to conduct training examinations, the issuance of certificates of competency, no permit personnel are not allowed to work. Where the induction of welders to unify the number, each weld finished a weld, the welders in the prescribed position to write the number. Inspection personnel should be each weld and welder’s name a – correspondence, recorded in the project data filed, so as to trace.
(4)before the start of the work, the production and installation of the net steel frame using the relevant measuring tools and testing instruments, must be certified by the measurement department, especially the manufacture and installation of steel ruler must be consistent, but also with the civil engineering unit steel tape measure for length, in order to unify.
(5) on-site review of steel space frame support and pad iron specifications, location and elevation is correct, support and column or frame beam contact is tight and smooth.
4.2、Control in the event
(1)、Bearing installation quality control. The supervising engineer shall measure and review the elevation and flatness of the pre-buried steel plate of the concrete structure. If there is a large deviation in the elevation and flatness of the pre-buried steel plate, the construction unit shall be notified in writing to correct the elevation and flatness of the pre-buried steel plate; the corresponding technical measures taken shall be kept in writing.
(2)、construction platform (scaffolding) erection of safety control. Construction platform (scaffolding) in the steel space frame assembly plays a role in supporting the space frame, controlling the elevation and as a platform for operation, etc. The quality of erection directly affects the quality and safety of steel space frame installation. Supervising engineers should strictly follow the provisions of the scaffolding construction program to control the quality and safety of scaffolding erection. If it is found that the construction unit is not erected in accordance with the requirements of the program, it shall be promptly ordered to rectify.
(3)、Quality control of temporary support construction. Before the installation of steel scaffolding, the supervising engineer shall check the construction quality of the temporary support system of the scaffolding in accordance with the requirements of the construction organization design, and the arrangement of the temporary support (including the number and location) shall be in accordance with the program. Before the installation of the steel space frame, the temporary support must be installed in place, and the page by the intermediate acceptance before the next process of construction
(4)、Installation of rods and ball nodes. The installation sequence should be determined before overhead bulking to ensure the accuracy of installation and reduce accumulated errors. Before the formal construction, test assembly and test installation should be carried out, and formal construction should be carried out only when the installation is really sure. The assembly process should pay attention to the following matters:
1） it is appropriate to start from the middle to both sides symmetrically;
2）first assembled into a small three-dimensional unit;
3）unit of the upper chord pivot point using casing-type movable table mold, the inner tube can be lifted;
4）inside and outside the tube with matching pin holes, hole distance according to the need to design, lift to the installation requirements of the elevation after the steel pin positioning fixed; ⑤ supervision engineer should follow up and acceptance of the installation quality of the rod and ball nodes, and make corresponding records.
4.3、Post-facto control of space frame installation quality
The construction party is responsible for inspection, and after passing the self-inspection, submit to the supervising engineer for acceptance. The supervising engineer, together with the inspector of the construction and installation unit on site, will check the sample by sample. The acceptance data related to the installation of the space frame is provided for review simultaneously.
5、Supervision methods of steel space frame structure installation project
During the installation of steel space frame, the supervising engineer should urge the construction unit to follow the relevant construction specifications and operating procedures and master the quality standards. Supervision work mainly includes: review the axis control line and elevation control point determined by the construction unit; check the correctness of the elevation and position of the pre-buried parts at the support; check the firmness of the scaffolding; urge the inspector to check the position of the reference axis, elevation and vertical deviation at any time, and correct the problems found in time. Supervising engineers can specifically take the following methods.
(1)、Actual measurement sampling: welding ball and bolt ball accuracy, specifications by number of sampling; structural surface, sampling by nodes and number of bars; installation accuracy, sampling by number of bars.
(2)、Side-station monitoring: measurement of deflection value after installation.
(3)、Subdivision acceptance: steel space frame subdivision project acceptance, organized by the supervision unit, the owner, general contractor, subcontractor, supervision, design, testing units to participate; comprehensive steel space frame subdivision of each sub-engineering inspection batch and concealed works quality acceptance, quality control information and acceptance records are complete and effective, the relevant safety and functional test results, assess the quality of steel space frame subdivision project.
(4)、documents and information acceptance, filing: supervision units should check the following documents and information, and require the construction unit to prepare the completion information, such as space construction drawings, as-built drawings, design change documents, construction organization design, quality inspection information, geometric dimensional error and deflection measurement records, acceptance information, etc.
space frame structure engineering as light steel structure will be more and more used to build large structural span buildings. As a result, construction management risks may arise during the installation and construction of the space frame structure, which should be given full attention by the supervising engineer. During the construction process, the supervising engineer should use the control method of supervision work to strictly manage and control the relevant process, so as to ensure the quality and safety of the space structure installation project and reduce the corresponding risk as much as possible.
