How to make and install the roof truss of steel structure workshop?

Fabrication and installation of steel structure workshop roof truss. The following is a detailed introduction of Zhong Da Consulting for your reference.

Project overview

The building size of the workshop is 42m×34.5m.

The column spacing in the workshop is 6m.

The elevation of the column top is 20.4m,

The roof truss top elevation is 35.508 meters.

The ceiling elevation of skylight is 39.341m.

The roof truss is triangular,

Vertical support is provided between roof truss and skylight.

All steel structure materials adopt Q235AF,

When manual welding is used in covered electrode, it is E43~E50 series covered electrode.

The weld length meets the minimum length requirement.

The permanent bolt is Ф 22,

The diameter of the opening is 23.5 mm,

The mounting bolt is Ф16,

The diameter of the opening is17.5mm.

The paint adopts F06- 1 phenolic primer twice, and the color is light gray.

The roof panel adopts YX35- 125-750 color steel plate.

The installation quantity of steel roof truss in this project is about 79t.

The roof truss support has a safety capacity of about 24t,

The installation amount of steel skylight is about11t.

The safety degree of steel purlin is about 12t.

The construction difficulty of this project lies in the large span of roof truss and the difficulty of hoisting; There are many horizontal supports and vertical supports, and there are many unsafe factors in aerial work and cross work; In addition, the construction site is narrow and the production and assembly site is not easy to meet.

Main construction methods

1. Manufacture of roof system

Roof system production → component transportation → roof truss installation → purlin installation → top chord horizontal support installation → vertical support installation → bottom chord horizontal support installation → roof panel installation.

Roofing system includes roof truss, supports, purlins, etc. Its manufacturing method is represented by roof truss, which includes brackets and other components. Therefore, only the manufacturing method of roof truss is introduced here, and other components are used for reference. Due to the narrow space, the roof truss is planned to be made in different places, and each roof truss is made in two sections. Assemble on site before installation, and use roof nodes for assembly. After the assembly is completed, carry out hoisting.

Second, the production of operating platform

In order to ensure the production quality of steel structure members, there are two large platforms on the construction site. Among them, I platform is between ① and ⑦/,II platform is 25m× 15m, and the roof truss is assembled on I platform. ..

According to the requirements of construction drawings and the adopted specifications and standards, the drawings should be strictly reviewed during lofting. On-site construction lofting shall be carried out according to the audited construction drawings, and physical lofting shall be carried out according to the ratio of 1: 1, and templates and poles shall be made as the basis for blanking processing. Sample plates and sample rods shall be marked with work number, drawing number, part number, quantity, etc. They should be properly kept until the end of the project. When laying out and marking, the assembly mark, screw hole mark, position and direction of reinforcing plate, inclination mark, center line, reference line and inspection line shall be clearly marked, and samples shall be made if necessary. Pay attention to the reserved welding shrinkage allowance during fabrication and installation (consider 2mm); Cutting, edge planing and milling allowance; Installation reserved size requirements. Before marking, the bending and deformation of materials should be corrected.

Thirdly, blanking.

Cut according to the sample and ingredient list, save materials as much as possible and facilitate cutting. Steel is cut by gas, and profile cutting ensures the quality of cutting surface. Before cutting, rust and dirt should be removed from the surface of steel cutting area, and slag and splash should be removed after cutting.

Welding shrinkage allowance, cutting allowance, end face and edge machining allowance should be reserved when blanking.

When welding the edge of X-shaped V-shaped interface, flame processing is adopted, and it is smoothed by grinding wheel after processing, so the surface roughness is low.

Check by precise cutting. The error of groove plus size should meet the requirements of national standards and specifications. The end face of the component should be processed after the finished product is corrected, and the processed surface is perpendicular to the center line.

Fourth, assembly.

Before assembly, all parts shall be inspected to be qualified, and the connection contact surface and every 30 ~ 50 (mm) area along the welding edge shall be cleaned. Plates should be assembled after the profiles are spliced, and objects should be assembled after all parts are welded and corrected. The allowable deviation of axis intersection of truss structure shall not be greater than 3 mm. ..

Verb (abbreviation for verb) welding

Be familiar with the construction drawing before welding, and the welder must have a welder's operation certificate. Before welding, the joint quality of welded parts and the welder's operation should be checked repeatedly. When welding, the welder shall abide by the welding process, and shall not weld by himself or strike an arc on the second base material on the weld bead. All welds shall be welded continuously, and the welding slag shall be removed in time after each layer of welding, and the welding quality shall be checked.

Six, bolt connection

The roof truss and skylight, skylight bracket and skylight are connected by bolts on site. If you are sure in the construction, you can cancel some installation bolts and weld directly on site. The position deviation design of the mounting bolt hole is not clearly given, and should be carried out according to the specification.

Seven. Material splicing Material splicing includes the transverse joints (along the length direction) of cross-shaped beams and I-beams and the butt joint of steel products such as roof trusses. Butt welds of all factory materials are Class I welds.

1) beam and column reinforcement or steel plate, the allowable number of flat-fell joints shall comply with the regulations, and the shortest splicing length shall not be less than 500mm.

2) When assembling, the flat-fell seam of adjacent parts must be staggered, and the staggered distance between the center lines should not be less than 200mm.

3) Submerged arc welding is adopted for the preparation of the splicing groove, and semi-automatic cutting or edge planing is adopted for the preparation of the groove, and the groove type is 10 ~ 24 mm thick.

4) Before tailor-welding, there shall be no slag, floating rust, grease and other impurities affecting welding quality in the area to be welded; The surface of welding wire shall be free of oil stain, rust and other sundries; Flux must be dried according to the instructions; Instruments on welding equipment are in good condition and working normally; Add arc striking plate and arc extinguishing plate at both ends of flat-fell seam.

Steel structure installation project

The hoisting of components includes the hoisting of steel roof trusses and supports. For the installation of steel structure in this project, firstly, the axis of concrete column, the elevation of column top surface and the plane position and elevation of embedded M30 bolts should be checked, and the intermediate handover work should be completed with the civil engineering specialty; Secondly, the production of steel members should be qualified and complete.

1, steel roof truss hoisting

The roof truss of this project weighs about 7.2t, and the skylight weighs about 2.3t According to the hoisting capacity and construction safety of the crane, the skylight truss and the roof truss are hoisted separately, and then the skylight truss is hoisted after the roof truss and purlin are installed.

The hoisting sequence of steel roof truss is: assembly → hoisting → positioning → temporary fixing → correction → final fixing.

Before hoisting the steel roof truss, the steel roof truss shall be assembled first, and the assembly shall be carried out according to different models. After the same roof truss is assembled, the whole surface should be on the same plane, the center of the lower chord should be on the same straight line, and the welding between the assembled connecting plate and the lower chord reinforcement should be correct, firm and reliable.

After the steel roof truss is assembled, horizontally tie a φ48 steel pipe iron shoulder pole at the center line of the triangular steel roof truss to ensure that the components will not be deformed or broken during hoisting, causing accidents. As the span of the roof truss is greater than 18m, it is difficult to hoist at two points, so iron column hoisting is considered. The lifting point of the roof truss is within 300mm around the top chord node.

QY80 truck crane is selected as the crane. What is the walking route of the crane? Close to the axis, 8 meters away from the center line of the roof truss. After the crane selects the lifting point, it finds the binding point of the steel wire rope on the component, and the crane begins to overturn and lift. During the hoisting process, it should rise slowly, steadily and slowly, so as to ensure the smooth lifting and rotation of components in the air. Cable wind ropes are tied at both ends of the assembly to facilitate the control of the rotation of the assembly. After the component is hoisted to a height about 100mm higher than the installation position, it is slowly lowered. At the same time, the plane position and verticality of the component are preliminarily corrected by visual inspection or wire hammer. After confirmation, it can be temporarily fixed and the hook can be removed. Temporary fixation should ensure the safety of components and facilitate correction, including plane position, elevation and verticality. When the correction is accurate and meets the requirements, it can be finally fixed according to the connection method required by the construction drawing. When the second roof truss is fixed, it can be connected with the first purlin.

2, support system and purlin installation

After the roof truss and skylight are finally fixed, purlins are installed first, then the roof truss is fixed, and finally the roof truss and columns are connected. After the purlin is fixed, install the upper chord horizontal support and rigid-flexible pull rod, then install the vertical support, and finally install the lower chord horizontal support. Support should be in units. Lightweight supports are hoisted in place with artificial cables and wind ropes, while heavy supports are hoisted in place with cranes or chain block. During installation, attention should be paid to whether there is any cross between various supports and purlins. In this case, contact the designer in time and don't handle it at will.

3, roof panel and wall skin engineering

The roof of the workshop is YX35- 125-750 color steel plate, which is 0.3mm thick profiled steel plate. During installation, pay attention to the reliable connection between roof truss tile and purlin, and adopt the bottom-up installation sequence. The length of tiles under the upper gland should not be less than 300mm, and the joints between tiles should be along the dominant wind direction, overlapping by a wave width.

The wallboard is YX35- 125-750 color steel plate with a thickness of 0.3 mm. When installing, the board must be clamped according to the purlin position from one end, and then fixed with screws, and the joints of the wallboard are waterproof. When installing profiled steel plate, the position should be adjusted and fixed while laying.

4. Rust-removed steel surface in painting engineering.

Clean it up with brushes and other tools before proceeding to the next working procedure. The surface of steel after derusting is qualified. If it has returned to rust before priming, it needs to be derusted again.

Apply the first primer on the surface of the steel after the rust removal inspection is qualified. Generally, after derusting is completed, it is stored in the factory building and can be primed within 24 hours. If stored outside the factory building, the primer should be painted in shifts. Paint should be used according to the design requirements. After the first primer is dried, intermediate paint and topcoat should be painted to ensure that the coating thickness meets the design requirements. The paint should be uniform in the process of brushing and will not sag.

Process quality assurance measures

The first section steel structure production

(1) The selected steel must have the factory certificate and original data, and must be sampled for a second interview after entering the site, and can only be used after passing the test.

(2) Select processing equipment with good performance and full functions.

(3) covered electrode should have the factory certificate or material report, requiring covered electrode to dry in a drying oven before use, and the welding wire and flux selected for submerged arc welding must match the parent metal used.

(4) Steel members shall be derusted after fabrication, and primer shall be applied within 24 hours after derusting to ensure that the film thickness of paint meets the design requirements.

(5) All operators must strictly abide by the technical, quality and safety disclosure contents, and welding personnel must hold relevant certificates.

(6) In order to ensure the production accuracy, the shrinkage of steel members should be pre-released, and the pre-release amount depends on the size of the workpiece, according to the similar engineering experience of this enterprise and in line with the specification requirements.

(7) Make a reasonable welding sequence. When several kinds of welds are to be welded, the transverse seam with large shrinkage deformation should be welded first, then the longitudinal seam, or the butt weld should be welded first, then the fillet weld.

(8) The main weld of welded section steel shall be welded before assembling stiffening rib components. The welding sequence of main welds shall be staggered according to the requirements of post-weld deformation.

Section 2 Installation of Steel Structure

(1) The hoisting technology of steel structure shall strictly implement the Code for Construction and Acceptance of Steel Structures (GB50205200 1).

(2) Before hoisting, the vertical and horizontal axes, horizontal elevation, overall dimensions of steel members and welding quality of the foundation must be rechecked, and the construction can only be started if they are qualified.

(3) Technical disclosure must be made before construction.

(4) During the construction, the post holder of special type of work must hold the post certificate issued by the Labor Bureau.

(5) The measuring instruments can be used only after passing the metrological verification.

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

Section 3 Installation of profiled steel plate

(1) When transportation and hoisting permit, long-sized plates should be used to reduce joints and improve thermal insulation and waterproof effect.

(2) Fixed profiled steel plates, with every two steel plates overlapping in shear waves. The lap joint is sealed with sealant tape, then with waterproof sealant, and fixed with tapping screws and purlins.

(3) There shall be no less than 3 screws at the end of each plate, and at least one self-tapping screw shall be connected when the middle support is more than 3m purlin distance.

(4) Plates are overlapped on purlins to ensure the overlapping length. The overlapping parts are connected with rivets and coated with waterproof sealant, and the exposed nail heads are coated with sealant.

(5) The lap joint of wrapped steel plate shall be at the disadvantage as far as possible, the lap length shall be greater than 20 ~ 500mm, and the rivet spacing shall be less than 500mm. ..

(6) Self-tapping nails and rivets are arranged on the wave crest, which is waterproof.

(7) Once the color coating is scratched or rusted, it should be brushed with corresponding series of coatings.

Safety construction measures

(1) Full-time security officers shall be set up at the construction site to implement on-site safety measures, supervise and manage, and uniformly manage on-site construction personnel, on-site mechanical equipment and on-site electricity consumption. Operators of special jobs who are required to participate in the construction must be trained and hold relevant certificates. Conduct safety technical disclosure to all construction personnel before construction. Personnel entering the construction site must wear safety helmets and non-slip shoes, electricians and welders must wear insulating shoes, and safety belts must be fastened for aerial work.

(2) Before operation, the tools, machines and equipment used shall be inspected, and the safety devices shall be complete and effective.

(3) The operation surface shall be supported and insulated reliably, and the operation shall be carried out after inspection. The binding method of components is correct, the lifting point should have anti-skid measures, and the tools and materials used for aerial work should be placed in a safe place, and it is strictly forbidden to place them casually.

(4) When hoisting steel members, they should be lifted smoothly to avoid emergency braking or impact. Command by special personnel, and the signal is clear and loud. Illegal operation is strictly prohibited. Be sure to check the quality of the components after installation, and unscrew them only after they are safe and reliable. Before leaving work every day, work must reach a safe place.

(5) Mechanical and electrical equipment, brake boxes and electric welding machines on the construction site shall have reliable rainproof measures. Electrical operation must be carried out by professionals, and non-professionals are strictly prohibited. Electric welding machine shall be used in strict accordance with the safety operation regulations, the primary line shall not exceed 2m, and the secondary line shall not be exposed.

(6) Safety facilities shall be uniformly set by special personnel according to regulations, and others shall not dismantle them at will. If it is necessary to dismantle it due to work needs, it must be allowed by the relevant personnel, and it should be restored in time afterwards. The security officer should check it carefully.

(7) Do a good job in the safe use of electricity. All electrical equipment removal and site lighting should be carried out by professional electricians, and the electric tools used must be equipped with leakage protectors.

(8) Pay attention to aerial work. Drinking and playing are forbidden during work. Hand-held tools should be tied with safety ropes to avoid straight-line and vertical cross-operation.

(9) to do a good job of fire prevention, the operation should be used correctly in accordance with the provisions.

(10) When installing the roof, a safety net and a fence shall be set up.

(1 1) Adhere to the system of pre-shift safety meeting, and disclose the work arrangement and safety precautions of the day.

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

(13) The lifting command should be decisive, and the instructions should be concise and clear.

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

(15) A security cordon shall be set within the scope of hoisting operation, and non-operating personnel are prohibited from entering.

(16) All safety activity records and documents shall be complete.

For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd