Requesting safety technical measures for steel roof truss project construction

On-site installation part

(1) Steel structure installation

1. Construction method:

When installing the steel structure of this project, first review the axis line of the concrete foundation and the elevation of the top surface of the foundation. Use the piece-by-piece lifting method. First lift all steel columns. After correcting and fixing grouting, lift the first column in sequence. The steel beams from the first to fifth floors are hoisted and adjusted, then installed and fixed, and finally the roof supports and purlin systems are hoisted.

2． Construction sequence:

The on-site hoisting is divided into two construction units, each unit performs independent operations. The first unit uses a 50-ton crane to hoist from east to west from the 8th axis to the 1st axis. The second unit Use a 50-ton crane to lift from west to east from axis 9 to axis 15. The lifting sequence is shown in the lifting plan.

3. Preparations before installation

①. Construction of column foot bolts: Review the column foot positioning axis for civil foundation construction and bury the anchor bolts. In order to ensure the accurate positioning of the anchor bolts, the anchor bolts are positioned and fixed with steel formwork hole sleeves, and the concrete pouring construction can be carried out only after repeated verification. The exposed parts of the anchor bolts are wrapped with plastic sheeting to protect them.

②. Prepare installation plan and component supply plan, and organize construction.

③． Inspect steel components: Steel components should have factory certificates when they leave the factory. Check and review the components according to the drawings before installation. Transport the components to the installation range in accordance with the installation sequence. Try to place the components below the installation position without affecting the installation. , to ensure the convenience of installation.

④． Standard section installation process

⑤. Installation quality standards

Project name allowed deviation

Verticality of single-section column building overall H/100 and ≤10mm

Elevation beam surface L/1000 and ≤ 10mm

Column top ≤5mm

Building height ±n (△n △n △w)

4. Installation and construction technology

①. Steel column installation: Before hoisting, first determine the location of the lifting point of the component, determine the binding method, and take protective measures during hoisting. After lifting the steel column, straighten it when the column foot is about 30-40CM away from the anchor bolts, align the mounting holes of the column foot with the bolt, and slowly drop the hook into place. After preliminary calibration, when the vertical deviation is within 20MM, tighten the bolts and temporarily fix them to decouple.

②. Steel beam hoisting: The steel beam hoisting is carried out after the column review is completed. When the steel beam is hoisted, two-point symmetrical binding is used to lift and install it in place. After the steel beam is hoisted, it is slowly put into position when it is 100mm away from the column datum. After the steel beam is hoisted and in place, the docking adjustment and correction are performed, and then the connection is fixed. When hoisting steel beams, use theodolite to calibrate them as they are lifted, and any deviations can be corrected at any time.

③． Installation of wall purlins: The purlins have a small cross-section and are light in weight. They are hoisted using one hook for multiple hoisting or piece hoisting. The correction of purlins mainly involves the spacing size and their own straightness. The spacing check uses a sample rod to move back and forth between the purlin members. If there is an error, loosen or tighten the bolts to correct. The straightness is checked and corrected with guy wires and steel rulers, and finally fixed with bolts.

5. Installation and calibration

①. Steel column correction: Use a theodolite or a wire hammer to check the verticality of the steel column. When there is a deviation, use a jack to correct it. For elevation correction, use a jack to slightly raise the base, then increase or decrease the thickness of the pad. Tighten the column feet immediately after the correction is correct. Fix the anchor bolts. After the overall correction of the steel column is correct, pour fine stone concrete under the column foot plate to fix it.

②. Steel beam correction: Measurement and correction of the axis and verticality of the steel beam. The correction is carried out using jacks and reverse chains. Fix it immediately after correction.

6. High-strength bolt construction

①. High-strength bolts must have a material certificate (quality guarantee certificate) before construction and must be retested before use.

②. High-strength bolts must be properly managed by dedicated personnel and must not be thrown around. During the installation process, the bolts must not be damaged or contaminated with dirt to prevent the torque coefficient from changing.

③． High-strength bolts must be moisture-proof and corrosion-proof.

④. When installing bolts, use a bald crowbar and punch nails to align the screw holes of the upper and lower (or front and rear) connecting plates so that the bolts can be inserted freely.

⑤. If the error in the screw holes of the connecting plate is large, it should be checked and analyzed and dealt with accordingly. If the adjustment of the screw holes is ineffective or the remaining partial screw holes are not in the correct position, an electric reamer or a manual reamer can be used to drill the holes.

⑥. On the same connection surface, high-strength bolts should be inserted in the same direction, and high-strength bolts should be tightened at the end of the day after installation.

(2). Wall profiled color board installation

1. Pre-construction preparations

① Before the construction and installation of profiled steel plate enclosures, the corresponding construction drawings shall be customized, and the design shall be organized according to the preparation of design documents and the construction personnel shall be provided with technical training and safety production briefings.

②. Check the specifications and quantities of various materials in detail according to the documents. Damaged profiled steel plates and flashing plates should be repaired and replaced in time.

③. All types of construction equipment should be complete and functioning properly.

④. Review the installation accuracy of steel components related to the construction and installation of profiled steel plates, remove the installation weld coating and spatter of purlins, and apply anti-rust paint for anti-corrosion treatment.

2． Construction process of profiled color boards: Installation of wall panels starts from one end according to the position of the purlins. The boards must be tightened and then fixed with screws. The joints of the wall panels must be waterproofed. When installing profiled steel plates, their position should be adjusted and fixed while laying.

(3). Installation of floor pressure-bearing panels

Before the construction and installation of floor pressure-bearing panels, draw the corresponding panel layout and carry out construction according to the drawings. The profiled steel plates are laid starting from one end of the floor, and their position is adjusted and fixed while laying. If there is a hole, install the profiled steel plate first, and then cut the hole size according to the actual hole location. Bolts are connectors that serve as a combined connection between floor beams and reinforced concrete floors. The construction uses a drawn arc bolt welding machine (model: YD-200LS) and a welding gun (model: YS-223G), and uses a deoxidizing arc-resistant Thermal ceramic seat.

Welding method: Turn on the power of the welding machine's welding gun, put the cylindrical stud on the welding gun, and the anti-arc seat ring, start the welding gun, the current will fuse, the seat ring will generate arc light, and after a short time, the cylindrical stud will The end of the base material is pressed at a certain speed to melt, and the power supply is cut off and the cylindrical studs are welded and fixed to the base material.

Peg welding inspection: The quality of cylindrical studs is mainly hammered, supplemented by appearance and surface inspection. 1/500 of the daily output is taken for bending inspection. If there is no breakage at the weld, it is deemed to be qualified. , if cracks appear in the weld, the stud will be deemed scrapped and a columnar stud will need to be re-welded nearby as a supplement.

Seven. Quality assurance measures,

Our company adheres to the quality policy of "Customer is God, Quality is Life", and conscientiously operates the GB/T19002-9002 quality management model, and strictly controls different types of work and each process. Quality supervision is carried out to ensure that the quality of materials, semi-finished products and finished products during the construction process is under control, so that the quality of the project is fundamentally and effectively guaranteed.

(1) Establish a quality assurance system, and establish a top-down quality management network from the head office, branches to project management, so that project quality is under dynamic management.

(2) Formulate a project quality assurance plan, covering the entire process from the start of construction to post-completion service, from construction schedule planning, material procurement, equipment distribution, technical support, mechanical equipment management, and subcontracting unit quality control etc., and implement the operation of the GB/T19002-9002 series of national standards.

(3) The project manager carries out strict quality control in accordance with national quality management regulations. The project manager department conducts quality and technical briefings on the construction personnel, conducts actual measurement and monitoring during operation, and makes good records. .

(4) Material procurement: Strictly follow our company's material procurement procedures and documents. Important construction materials must be re-inspected and qualified before they can be used. Unqualified products are not allowed to enter the site.

(5) Process quality assurance measures

1. Steel structure production:

1.1 The steel materials selected for this structure must have factory certificates and original data. At the same time, the steel materials entering the factory are required to pass retests before they can be used.

1.2 Select processing equipment with good performance and complete functions. It is required that some H-shaped steel flange plates produced in the factory should be butted with a single-sided 45-degree groove, and the web should be connected with a single-sided 45-degree groove.

1.3 The welding rod should have a factory certificate or material report. It is required that the welding rod should be dried in a drying oven before use. The welding wire and flux selected for submerged arc welding must match the base metal used.

1.4 This steel component needs to be shot blasted and derusted after it is completed. It is required to apply primer within 24 hours after derusting. The primer should be sprayed. It is required to ensure that the paint film thickness meets the design requirements. .

1.5 All operators must strictly follow the technical, quality, and safety briefings, and welding personnel must hold certificates to work.

1.6 The butt welds required for this steel structure section must undergo ultrasonic flaw detection testing, and the testing level is Level 2.

1.7 In order to improve the accuracy of hole making, drill molding is used to make holes in steel structures. The drill sleeve is made of medium carbon steel and must be quenched. The diameter of the inner hole of the drill mold should be 0.3MM larger than the designed hole diameter. The thickness of the drill mold should not be too large, generally about 15MM.

1.8 In order to ensure the production accuracy, the shrinkage amount must be pre-shrunk when cutting steel components. The pre-shrinkage amount depends on the size of the workpiece. Generally, the workpiece is 40-60mm. Important, large and long workpieces must be pre-shrunk. 80-100mm.

1.9 It is essential to formulate a reasonable welding sequence. When several types of welds are to be welded, the transverse seams with larger shrinkage and deformation should be welded first, and then the longitudinal welds, or the butt joints should be welded first. Weld the seam and then weld the fillet weld.

1.10 The main welds of welded steel sections should be welded before assembling the stiffener plate parts. The welding sequence of the main welds should be staggered according to the need for post-weld deformation.

2． Steel structure installation:

2.1 The steel structure hoisting process strictly follows the "GB50205-95 Steel Structure Construction and Acceptance Code" and "GB50221-95 Steel Structure Engineering Quality Inspection and Assessment Form Standard"

2.2 Before starting construction, the vertical and horizontal axes and horizontal elevation of the foundation, the overall dimensions of the steel components, and the welding quality must be re-inspected before construction passes.

2.3 Technical briefing must be conducted before construction.

2.4 Special personnel employed during construction must have employment certificates issued by the Labor Bureau.

2.5 Measuring instruments must be qualified through metrological verification before they can be used.

2.6 Adhere to the three inspections (self-inspection, mutual inspection, professional inspection) system during construction, and strictly inspect process quality.

3. Installation of profiled steel plates:

3.1 Under the conditions of transportation and hoisting permission, long-sized plates should be used to reduce joints and improve thermal insulation performance and waterproofing effect.

3.2 The profiled steel plates are fixed, and every two plates have an overlap in the transverse wave. The overlapping surface is sealed with sealing tape, then sealed with waterproof sealant, and fixed with the purlins with self-tapping screws .

3.3 There should be no less than 3 screws at the end of each board. If the middle support is at a purlin distance greater than 3 meters, there should be at least one self-tapping screw connection.

3.4 The plates are overlapped on the purlins to ensure the required overlap length. The overlapping parts are connected with rivets and applied with waterproof sealant, and the exposed nail heads are coated with sealant.

3.5 The overlap of the edged steel plates should be in the leeward direction as much as possible, the overlap length should be greater than 20-50 mm, and the rivet spacing should be less than 500 mm.

3.6 Self-tapping rivets are installed on the wave crest for waterproofing treatment.

3.7 Once the colored coating is scratched or rusted, the corresponding series of paints should be used to repair it.

8. Safety construction measures

1. A safety foreman is appointed at the construction site to implement and manage on-site safety measures, and to conduct unified management of on-site construction personnel, on-site machinery and equipment, and on-site electricity consumption.

Special agents required to participate in construction must be trained and certified. Conduct safety technical briefings for all construction personnel before construction. Personnel entering the construction site must wear safety helmets and non-slip shoes. Electricians and electrical welders should wear insulating shoes, and safety belts must be fastened when working at heights.

2． Before work, all tools, machinery, and equipment used should be inspected to ensure that the safety devices are complete and effective.

3. The operating surface should have a reliable stand and protection, and it should be operated after inspection. The binding method of components should be correct, and anti-slip measures should be taken at lifting points. Tools and materials used for high-altitude operations should be placed in a safe place and are not allowed to be placed casually.

4． When lifting steel components, the lifting or lowering should be smooth to avoid emergency braking or impact. Dedicated personnel are responsible for command, and the signals are clear, loud, and unambiguous. Illegal operations are strictly prohibited. After the components are installed, their quality must be checked to ensure that they are safe and reliable before they can be unfastened. Work must reach a safe position every day before calling it a day.

5. The mechanical and electrical equipment, gate boxes, and welding machines at the construction site should have reliable rainproof measures. The operation of electrical appliances must be carried out by professionals, and operation by non-professionals is strictly prohibited. The electric welding machine uses strict safety operating procedures. The primary wire must not exceed 2 meters, and the secondary wire must not be broken or exposed.

6. Safety facilities are set up uniformly by dedicated personnel in accordance with regulations, and others are not allowed to dismantle them at will. When it needs to be dismantled due to work needs, permission must be obtained from the relevant personnel. It must be restored in a timely manner afterwards and the safety officer must carefully inspect it.

7. To ensure safe electricity use, professional electricians are responsible for the removal of all electrical equipment and on-site lighting. All power tools used must be equipped with leakage protectors.

8． The focus is on controlling high-altitude operations. Drinking and fooling around are strictly prohibited during work. Hand-held tools should be fastened with safety lanyards to avoid straight and vertical crossing operations.

9. Fire prevention must be ensured and all operations must be performed correctly and in accordance with regulations.

10． When installing the roof, safety nets should be arranged and railings should be installed.

11. Adhere to the pre-shift safety meeting system and explain the day's work arrangements and safety precautions.

12. Conduct regular safety inspections to prevent and control unsafe factors in accidents.

13. Lifting instructions must be decisive and instructions must be concise and clear.

14. Strengthen on-site security and pay attention to fire and theft prevention.

15. A safety cordon is set up within the hoisting operation range, and non-operators are prohibited from entering.

16. All safety activity records and documents must be complete.

9. Winter rainy season construction measures for steel structure projects

(1). Winter construction measures

1. Steel structure production and installation in winter construction are strictly based on the relevant steel structure construction measures. Structural winter construction regulations are implemented.

2. When steel components are produced at positive temperatures and installed at negative temperatures, the shrinkage of the components should be considered based on the difference in ambient temperature, and technical measures to adjust the deviation should be taken during construction.

3. Welders participating in the construction of negative temperature steel structures should undergo negative temperature welding technology training, pass the examination, and obtain the corresponding certificate.

4. Steel materials and related connection materials used at negative temperatures must be accompanied by quality certificates, and their performance meets the requirements of design and product standards.

5. Welding rods used at negative temperatures must not be exposed for more than 2 hours, and should be rebaked after 2 hours. The number of times the welding rod should be baked should not exceed 3 times.

6. The flux should be baked according to regulations before use so that its moisture content does not exceed 0.1.

7. High-strength bolts used under negative temperature must have product certificates, and retesting of torque coefficient and axial force must be carried out under negative temperature.

8. Water-based coatings must not be used for steel structures under negative temperatures.

9. When cutting components, a shrinkage allowance should be reserved, and the welding shrinkage and compression deformation should be coordinated with the shrinkage deformation of the steel at negative temperatures.

10. When assembling components, expand and assemble them from the inside out in the order specified by the process. When assembling at negative temperatures, conduct tests to determine the shrinkage value of the welds that need to be reserved.

11. When assembling components, remove rust, burrs, mud, oil, ice, snow and other debris remaining within 50mm of the joints, and keep the joints dry and without residual moisture.

12. When welding steel plates above 9mm under negative temperature, multi-layer welding should be used. The welds are welded layer by layer from bottom to top. Each weld is completed in one go. If the welding is interrupted, weld again. Remove welding defects before. It is strictly prohibited to strike an arc on the welding base metal.

13. When the steel structure is installed on site, if it is snowy or the wind speed is above 6m/s, a protective shed should be erected.

14. Unqualified welds should be removed and re-welded, and welding should be performed in accordance with the regulations on steel structure welding processes at negative temperatures.

15. When the ambient temperature is lower than 0℃, a painting process test should be carried out before applying anti-corrosion paint. When painting, the rust, oil stains, burrs, etc. on the surface of the component must be cleaned and the surface must be kept clean. dry. Painting work must not be carried out in snow or when there is thin ice on the components.

16. Take anti-slip measures when transporting and stacking steel structures in winter. The component stacking site should be flat and solid without puddles, and the ground should be free of ice. When components of the same model are stacked, the components should be kept horizontal and the pads should be placed on the same vertical line to prevent the components from slipping.

17. Before the steel structure is installed, its quality shall be re-inspected according to the requirements under negative temperature conditions. Components that have been missed during production or deformed during transportation and stacking shall be repaired and corrected on the ground.

18. When using steel cables to lift steel components, anti-slip spacers should be added, and the gusset plates that are lifted at the same time as the components, clamps required by the installers, etc. should be tied firmly with ropes.

19. Prepare a steel component installation sequence chart based on the temperature conditions, and install it in strict accordance with the prescribed order during construction.

20. When preparing the welding process for steel structure installation, both ends of a component must not be welded at the same time.

21. Before installation, remove ice, snow, and dew from the component surface, but the coating must not be damaged.

22. The columns and main beams installed at negative temperature should be corrected immediately, and the correct position should be fixed immediately and permanently. The components installed on the same day should form a stable spatial system.

23. When installing high-strength bolt joints, the friction surface of the components must not be covered with snow or ice, and must not come into contact with dirt, oil, and other stolen goods.

24. In addition to complying with the requirements of the "Steel Structure Engineering Construction and Acceptance Code" (GB50250-95), the installation quality of steel structures under negative temperatures should also be inspected and accepted according to the design requirements.

(2). Construction measures in rainy season

1. During construction on rainy days, temporary protective sheds should be set up to prevent rainwater from falling on the hot welds. If the welding parts are relatively humid, they must be Wipe clean with a dry cloth and dry with an oxyacetylene flame before welding to keep the joints dry and without residual moisture.

2. During hoisting, if there is water on the component, it should be cleaned before installation, but the coating should not be damaged. When installing high-strength bolt joints, the friction surface of the component should be clean, without water droplets, let alone Exposure to rain and contact with dirt, oil and other dirt.

3. Painting of weather components cannot be carried out on rainy days.

4. Roof insulation construction cannot be carried out on rainy days and strong winds above level 5.

5. Since the air is relatively humid on rainy days, welding rods should be stored in moisture-proof storage and baked. The same welding rod should not be baked more than twice, and management personnel should make baking records in a timely manner.

6. In case of strong winds, large components such as columns, main beams, supports, etc. should be corrected immediately. Once the positions are correct, they should be permanently fixed immediately to prevent unilateral instability. Components installed that day , a spatially stable system should be formed.

10. On-site civilized construction measures:

1. The internal industry requires that all materials and accounts (construction plans, safety education, safety briefings, safety inspections, electricians’ daily inspection records, pre-shift speech records, accounts), etc. be complete Keep records neatly, seek truth from facts, hold certificates for special operations, and have clear division of safety responsibilities.

2. Wear a safety helmet when entering the site, wear a safety belt when working at heights, the safety net is tightly supported in accordance with regulations, there are protective sheds at the entrance and exit, and there are safe passages in small sites.

3. Electrical equipment should be equipped with three levels of control and two levels of protection (main gate box, distribution box, switch box, and matching electric shock protectors in the distribution box and switch box). The gate boxes should be standardized and the lines should be standardized. There are records of electrician inspections and side shaking.

4. This project is equipped with colored calendered board walls with a height of not less than 2m, and civilized on-site construction management is carried out. There are clear publicity slogans on site and standard color signs hung at dangerous locations.

5. There are flat and clean channels on site that are not blocked or accumulated in water, and construction wastewater is properly discharged through drainage ditches.

6. Civilized construction will not disturb residents, strictly control construction noise, and stop construction after 10 p.m.

7. Do not occupy roads in violation of regulations, do not set up or stack objects illegally, do not cause fires or traffic accidents, do not damage public facilities in violation of regulations, and do not pollute the environment and related roads inside and outside the site. Departments and health supervision departments should cooperate.