The hole diameter after trimming or reaming shall not exceed 1.2 times the bolt diameter, and then steel plate cushion block shall be added on it for fixation.
In the above three cases, communicate with the design and obtain its consent before treatment.
Others” in Appendix 1, the hoisting and installation of steel structures are dangerous projects.
② For bolts with slightly larger displacement offset, a small hole can be drilled at the root of the anchor bolt to leak out the part that has been embedded in the concrete, and then heated with oxygen acetylene.
According to Article 3 of “III.
Photo 3 the concrete is too high and chiseled.
Here, it is highly recommended to control in advance.
3、 Preparatory work 1 Re measurement and correction of anchor bolt position (1) prior control of bolt position as mentioned in “part I”, anchor bolts are generally fixed in concrete independent columns with supports in advance, and then concrete is poured.
Manual pulling and wooden prying can be used for correction.
After each bolt is corrected, the quality of most bolts can be guaranteed to be qualified.
Snap the positioning axis ② the reserved space for secondary pouring of column foundation.
In the figure, no butter is applied, only waste engine oil is applied, and it still rusts after being washed by rain.
When the civil engineering team pours concrete, the steel structure installation team needs to arrange special survey technicians to set up a total station or theodolite on the previously protected control pile (mentioned in part I) to correct the anchor bolt offset caused by concrete pouring in real time while the concrete is not completely hardened.
Therefore, as long as the installation of steel structures, special construction schemes must be prepared according to the requirements.
hoisting and hoisting and hoisting machinery installation and disassembly works” and Article 2 of “VII.
Figure 2.
Figure 1 plasma reaming (unqualified) the reaming hole diameter is too large.
During column base installation, the accuracy of column elevation can be controlled by adding adjusting nuts to the anchor bolts under the base plate.
If the anchor bolt is not controlled in advance or poorly controlled, resulting in excessive deviation of the anchor bolt, the bolt needs post-treatment.
Post treatment is forced.
(2) The main contents of the special construction scheme for large and dangerous projects shall include: (1) project overview: overview and characteristics of large and dangerous projects, construction layout, construction requirements and technical guarantee conditions; （2） Preparation basis: relevant laws, regulations, normative documents, standards, specifications, construction drawing design documents, construction organization design, etc; （3） Construction plan: including construction schedule, material and equipment plan; （4） Construction technology: technical parameters, process flow, construction methods, operation requirements, inspection requirements, etc; （5） Construction safety assurance measures: organization assurance measures, technical measures, monitoring measures, etc; （6） Construction management and operation personnel allocation and division of labor: construction management personnel, full-time safety production management personnel, special operation personnel, other operation personnel, etc; （7） Acceptance requirements: acceptance standards, acceptance procedures, acceptance contents, acceptance personnel, etc; （8） Emergency response measures; （9） Calculation sheet and relevant construction drawings.
This method is especially suitable for crawler cranes with convenient movement..
(3) Other precautions ① while retesting the anchor bolts, snap the positioning axis of the building on the concrete column with an ink bucket (see Figure 2).
31″ document, special construction scheme shall be prepared for projects with high risk, and expert demonstration shall be conducted for projects exceeding a certain scale.
Of course, the correction accuracy shall comply with article 10.2.2 of gb50205-2020 acceptance standard for construction quality of steel structures, that is, the bolt center offset shall not exceed 5mm.
Before secondary concrete pouring at the column bottom, the base plates shall be welded and fixed.
31.
Generally, it can be carried out about 30min after the pouring is completed according to the temperature (it should also be adjusted according to the season, early in summer and late in winter).
(2) Post control of bolt position.
When the column base is hinged, it should not be greater than 50mm, and when the column base is rigidly connected, it should not be greater than 100mm.
If it is corrected as soon as the pouring is started, because the plasticity of concrete is still great, and the bolts are easy to return, If it is pulled too late, it is difficult to pull, so the specific time should be determined according to the site conditions.
Generally, there are the following methods for post-treatment: ① for those with small deviation, ion machine or reamer can be used to enlarge the bolt hole of column bottom plate into an ellipse (see Fig.
③ If you want to offset the displacement too much, you can cut the bolt, weld the root bolt on the embedded steel plate, attach a steel plate with the same thickness as the embedded steel plate, then weld it on the embedded steel plate by rivet plug welding, and then weld a new bolt according to the design requirements.
4、 Hoisting of columns and beams 1 Installation sequence (1) general hoisting sequence during the construction of single-layer steel structure installation project, the single piece flow method is generally adopted for column, inter column support and crane beam.
The column can be installed and corrected at one time, and then the inter column support, crane beam and other components can be installed.
③ The anchor bolt shall be protected from damage, corrosion (greasing) and pollution.
See Appendix 1 and Appendix 2 of the document for dangerous and large projects and dangerous and large projects exceeding a certain scale.
http://www.mohurd.gov.cn/gongkai/fdzdgknr/tzgg/201805/20180522_236168.html Note: the above contents refer to jbz [2018] No.
The purpose of this is because the initial setting time of cement shall not exceed 45min at the fastest.
After the soft temperature rises and softens, the anchor bolt can be slowly pulled to the corresponding position with steel pipe.
2 Special construction scheme for steel structure installation and hoisting (1) according to the requirements of the Ministry of housing and urban rural development’s “jbz [2018] No.
This step needs the cooperation of civil engineering discipline and installation discipline.
The special construction scheme of steel structure shall not only include the installation of steel structure, but also include the lifting and hoisting, including the model selection of crane, the setting of lifting points, calculation sheet, etc.
1).
