Project overview

********Workshop 3: workshop, the construction area of the project is 12779 square meters, and the height of the main workshop is 16.55 meters.The main structure is steel frame structure, which is divided into two layers. The height of the first floor platform is 6m. The floor adopts profiled metal plate as permanent support formwork, and works with cast-in-place reinforced concrete structure layer to form the permanent composite structure of the building.It is often called structural floor bearing plate.

The floor bearing plate also includes baffle, sealing plate, edge closing plate and other auxiliary components.The floor bearing plate is laid and connected with the steel beam, the end of the plate is welded with the steel beam by penetration welding, and the middle part is welded with the steel beam through the stud.Steel bearing plate is an important supporting product of steel structure building. It has the advantages of simple construction, short construction period, replacing traditional formwork, reducing material cost as part of structural strength, easy construction of reinforcement, wiring and piping, clean and beautiful appearance, light weight, high strength, large bearing capacity and good seismic resistance.Yx-344-688 type steel bearing plate is used in the project, the thickness of the plate is 1.0 mm, the welding nails are? 16, the spacing is 200 mm, and the height is 30 mm higher than the floor bearing plate.The concrete strength grade is C25.

2.construction technology

The process flow of floor bearing plate is as follows: snapping line → layout and blanking → hoisting → profiled steel plate installation → plug plate and edge plate installation → welding and fixation → acceptance → reinforcement arrangement → embedded parts → pouring → maintenance.

3.Construction method of main items

1.The center line of the steel beam is first popped out in the slab laying area. The center line of the beam is the control line for laying the floor support plate to fix the main position.The center line of the main beam controls the lap width of the overlapping steel beam of the floor support plate, and determines the position of the welding point of the floor support plate and the steel beam.The center line of the beam will determine the welding position of the stud of the penetration weld.Since it is difficult to observe the specific position of the secondary beam flange after the floor bearing plate is laid, the center line of the secondary beam and the width of the secondary beam flange are bounced back on the center line of the main beam, and the center line and flange width of the secondary beam shall be rebounded to the floor bearing plate on the surface of the secondary beam when fixing the stud.

2.According to the lap length, position, spacing and span size of the main and secondary beams required by the drawing design, layout and blanking can be divided into standard cross profiled steel plate layout drawing, non-standard cross profiled steel plate layout drawing, standard node construction detail drawing, individual node construction detail drawing, profiled steel plate number, material list, etc.The overlapping size of profiled steel plate and main beam of the project shall not be less than 50mm.

3.Hoisting:

1）When the profiled steel sheet manufacturer supplies, the profiled steel sheet shall be transported to the site in bundles with the installation unit as the unit, and the profiled steel sheet shall be stacked orderly according to the layout plan provided by the manufacturer.2) Before lifting the profiled steel sheet, check the plate type, size, number of blocks and the location according to the design and construction drawings. After confirming that the ingredients are correct, the profiled steel sheet shall be hoisted to each construction section according to the installation sequence and progress of the main structure.Stacking should be done in strips.When the profiled plate is suspended on the beam, it should be lowered at a slow speed, and rough lifting action should be avoided.3) During the loading, unloading and installation of profiled steel sheet, it is strictly prohibited to use steel wire rope for direct lifting. Soft sling shall be used or rubber shall be added at the corner of contact between steel wire rope and plate or cushion wood shall be used under steel plate. Transportation and stacking shall have enough fulcrum to prevent deformation.The lifting should be stable and there should be no inclination to prevent people from falling down.4) When the profiled steel sheet is stacked in bundles, it should span multiple steel beams. When a single span is placed between two beams, attention should be paid to the support width at both ends to avoid falling accidents caused by dumping.5) When the wind speed is greater than or equal to 6m / s, construction is prohibited. The disassembled profiled steel sheet should be re strapped. Otherwise, the profiled steel sheet is likely to be blown by strong wind, causing safety accidents or damaging the profiled steel sheet.

4.Installation

1）The bending deformation shall be corrected before laying.2) The top surface of the steel beam shall be kept clean, and the damp and wet paint shall be strictly prevented.3) Before installing the profiled steel sheet, the position line of the profiled steel plate should be marked on the beam.When laying profiled steel sheet, the corrugated notch of adjacent two rows of profiled steel sheet end should be aligned.After hoisting in place, the phase plate shall be placed in place along the laying direction from the starting line of the steel beam, and the slab joint shall be adjusted appropriately after reaching the control line.4) The plate should be scattered and adjusted in strict accordance with the requirements of the drawings and specifications. The maximum deviation of the plate straightness is 10 mm for a single span, and the plate stagger requirement is less than 5 mm. It can be connected with the main beam after passing the inspection.5) The laying direction of profiled steel sheet the laying direction of the project shall be perpendicular to the direction of small secondary beam, and it shall be disconnected at the main beam, and the lap joint shall not be less than 50 mm.6) The laying of irregular panel is based on the layout of the steel beam on site. The center line of the steel beam is set out, and then the control line is set out to obtain the actual area of profiled steel plate to be laid, and then the layout is carried out according to the width of profiled steel plate.After that, the profiled steel plate is lofted and cut.The profiled steel plate is pre assembled on the platform on the ground, and the parts with loose bite and loose tightness shall be adjusted.Lay according to the actual layout, connect and fix.

5.The installation of baffle plate, edge closing plate and edge sealing plate is to prevent slurry leakage during concrete pouring of floor slab, and to keep the floor bearing plate tightly sealed and the structure size of four sides.The thickness of baffle, edge closing plate and edge sealing plate shall not be less than 4mm.The construction sketch is as follows:

6.Welding fixation

1）The groove bottom on both sides of each profiled steel sheet shall be fixed with the steel beam with 16mm diameter welding nails, and the average maximum spacing of welding points is 20cm.The welding material should penetrate the profiled steel plate and have a good fusion joint with the steel beam material.If the penetration stud is directly welded to the steel beam through the profiled steel plate, the stud can replace some of the above welding points.

2）The welding with steel beam includes not only the supporting steel beam at both ends of profiled steel sheet, but also the secondary beam between spans; if the welding current of stud is too large, which causes the profiled steel plate to burn through and loosen, the welding spot should be added beside the stud.

3）On site opening and cutting: plasma cutting machine shall be used for cutting profiled steel plate required on site, such as beveled edge, cutting angle, super length, hole reservation and some irregular surface, so as to avoid damaging the coating treatment on the steel plate surface.If oxygen acetylene is used for cutting, zinc rich antirust paint shall be applied on the edge of the cutting opening to avoid corrosion; during the construction of water, electricity and ventilation pipeline, profiled steel sheet construction personnel shall cut the hole.After cutting, the hole shall be protected according to the requirements.

4）After the profiled steel plate is positioned, the cutting line will be popped and cut along the line.The position of the cutting line shall refer to the floor hole drawing and layout drawing for details, and shall be checked; the general holes shall be cut after the concrete pouring as far as possible. If the pre cut holes in the vertical direction of the slab rib damage the groove rib of the profiled steel plate, it must be reinforced according to the regulations.The reinforcement measures are shown in the detail drawing of opening reinforcement construction

6）The profiled steel plate shall be installed, straightened, compacted and spot welded according to the drawing.

The requirements are as follows: ① the corrugation shall be aligned to facilitate the reinforcement to pass through the wave; ② the beam shall be overlapped at the groove to facilitate welding; ③ each groove must be welded firmly, with no less than one spot for each groove, and the diameter of the welding point shall not be less than 25px.④ After the profiled steel plate is laid, straightened and fixed, the mouth locking machine shall be used to lock the mouth in time to prevent the separation of the bite of the profiled plate due to the stacking of construction materials or personnel traffic.⑤ After installation, the construction waste shall be cleaned in time before the reinforcement installation, and the leftover materials cut off shall be collected on the ground for centralized stacking.

7.The reinforced concrete part of the construction floor can be constructed only after the profiled steel plate and stud are accepted.The construction technology of the concrete part of the composite floor is basically similar to that of the pure concrete floor. When pouring the concrete, because the unsupported profiled steel plate is used as the floor formwork in the project, care should be taken to avoid the excessive accumulation of concrete and the impact caused by the dumping of concrete

4.Quality assurance measures

1.Main control items

1）The anchorage support length of profiled steel plate and main structure shall meet the design requirements and shall not be less than 50 mm.2) Inspection quantity: spot check 10% along the longitudinal length of the connection and not less than 10m.3) Inspection method: visual inspection and steel ruler inspection.

2.General items

1）The profiled steel plate should be installed flat and straight, and there should be no construction residue and dirt on the plate surface, and there should be no untreated wrong drilling holes.Inspection quantity: spot check 10% according to the area and no less than 10m2.

Examination method: observation.Quality control points: 1) the construction quality of profiled steel sheet requires the corrugation to be straight, all openings and node cutting shall not be constructed with oxyacetylene flame to avoid burning off the zinc coating; 2) the distance between the bite points of the plate joint shall not be greater than 1 / 2 of the width of the plate and shall not be greater than 400mm. If the whole seam is occluded, the bite shall be smooth and the bite depth shall be consistent; all the gaps between plates and between plates and components shall not be direct Light transmission, all joints with width greater than 5mm shall be blocked with mortar and tape to avoid slurry leakage.

5.Key requirements of occupational health and construction safety

1.Before the construction of profiled steel sheet, the safety technical disclosure shall be done according to the requirements of sound safety production management, and the safety production responsibility system shall be implemented layer by layer.

2.Regular and irregular safety inspection and regular safety education activities are carried out to improve the self-protection ability of all employees.

3.The power supply on site must be in strict accordance with the provisions of GB 50194-93 and JGJ46-88. The connection port of construction power supply should be provided with rain proof and leakage proof protective measures to prevent construction workers from getting electric shock at high altitude.Safety helmet must be worn when entering the construction site. Safety belt and anti-skid shoes must be worn when working at height.Do a good job in the safety protection work of high-altitude construction, lay special traffic berm, install safety rope above the steel beam of workers’ construction, and hang the safety belt on the safety rope during construction to prevent workers from falling from high altitude; before the construction, physical examination shall be conducted for high-altitude workers, and personnel suffering from diseases not suitable for high-altitude operation (heart disease, hypertension, anemia, etc.) shall not be arranged high Empty job.During the construction of profiled steel sheet, both ends should be picked up at the same time, and handled with care to avoid sliding or warping. The material head cut by construction should be placed safely and collected at any time to avoid falling.

Non construction personnel are not allowed to enter the construction floor, so as to avoid eye burn or eye shaking caused by welding arc, and avoid welding. Auxiliary construction personnel shall wear sunglasses to cooperate with the construction.Reliable fall prevention measures shall be taken to prevent the construction personnel from falling from high places; both ends shall be picked up at the same time and handled with care to avoid sliding or warping; the material head cut by construction shall be placed stably and collected at any time to avoid falling; necessary personnel traffic horse way shall be laid during construction; non construction personnel shall not enter the construction floor to avoid eye burn or eye dazzling caused by welding arc light.In case of falling injury, auxiliary welding construction personnel shall wear sunglasses to cooperate with the construction; special personnel shall be assigned to monitor the next floor to prevent other personnel from entering the construction area and welding sparks falling and causing fire.