01 scaffolding collapse at a construction site in Hong Kong January 12, 2021 scaffolding collapse at a construction site in Kai Tak Development Zone, Kowloon, Hong Kong! Everyone is responsible for work safety! Illegal operation is strictly prohibited
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02 Chengdu scaffold collapsed at about 8 am on January 9, when the external wall decoration scaffold of three units located at No
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1, North Lane 2, Dongfeng Road, Chengdu City was demolished, the external wall scaffold from the 5th floor to the 1st floor was demolished and collapsed when it was demolished to the 2nd floor
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It is understood that the urban management department, the electric power department, the construction party and the maintenance unit have all arrived at the scene
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Combined with standard! Detailed explanation of common safety hazards in scaffold construction: safety hazards (1) the quality of materials used in scaffold construction does not meet the specification requirements 1.1 the quality of steel pipe model is not standardized, there are corrosion, deformation, drilling and other phenomena jgj130-20118.1.1 the inspection of new steel pipe shall meet the following requirements: 1 there shall be product quality certificate; 2 there shall be quality certificate According to the inspection report, the inspection method of steel pipe material shall comply with the relevant provisions of the current national standard tensile test method for metallic materials at room temperature (GB / t228), and its quality shall comply with the provisions of article 3.1.1 of this specification; 3 the surface of steel pipe shall be straight and smooth without cracks, scabs, delamination, dislocation, hard bending, burr, indentation and deep scratch; 4 the deviation of outer diameter, wall thickness and end face of steel pipe 5
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The steel pipe shall be coated with antirust paint
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[strong bar] 9.0.4 it is forbidden to drill holes on steel pipes
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1.2 if the fastener quality does not meet the requirements, and the bolt tightening torque of the fastener does not reach 65N · m, it will destroy jgj130-20118.1.3 of the safety technical code for steel tubular scaffold with couplers in building construction
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The acceptance of the fastener shall meet the following requirements: 1
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The fastener shall have the production license, the test report of the legal testing unit and the product quality certificate
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When the quality of fasteners is in doubt, sampling inspection shall be carried out according to the current national standard “steel pipe scaffold fasteners” gb15831
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2
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Both new and old fasteners should be treated with anti rust treatment
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3
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The technical requirements of fasteners shall comply with the relevant provisions of the current national standard “steel pipe scaffold fasteners” gb15831
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[strong article] 8.1.4 when the fastener enters the construction site, the product certificate shall be inspected and the sampling retest shall be conducted
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The technical performance shall comply with the provisions of the current national standard “steel pipe scaffold fastener” gb15831
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The fasteners shall be selected one by one before use, and those with cracks, deformation and sliding bolts are strictly prohibited
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2.2.2 in jgj130-20113, the fastener shall not be damaged when the bolt tightening torque reaches 65N · M
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7.3.11 the tightening torque of the second bolt shall not be less than 40n · m, and shall not be greater than 65N · M
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8.2.5 the tightening torque of fastener bolts after installation shall be checked by torque wrench, and the sampling method shall be carried out according to the principle of random distribution
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The number and quality standard of sampling inspection shall be determined according to table 8.2.5
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The unqualified ones shall be re tightened to qualified ones
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1.3 the safety net that does not conform to the current standard shall be used, and its quality and impact strength do not meet the requirements
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1.1 the selection of safety net for building construction shall meet the following requirements: 1
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The material, specification, physical properties, fire resistance and flame retardancy of safety net shall meet the current national standard safety net gb5725; 2
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Dense mesh safety net The mesh density should be 10 cm x 10 cm, and the area should be greater than or equal to 2000 mesh
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Hidden danger of safety (2) the frame structure does not meet the requirements of the specification 2.1 the foundation bearing capacity does not meet the requirements jgj130-20115.5.3 for the scaffold erected on the floor and other building structures, the bearing capacity of the building structure supporting the frame should be checked
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When the bearing capacity requirements cannot be met, reliable reinforcement measures should be taken
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7.1.4 the debris in the erection site shall be removed, the erection site shall be leveled, and the drainage shall be smooth
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7.2.1 the construction of scaffold foundation and foundation shall be carried out according to the load on scaffold, erection height, soil condition of erection site and relevant provisions of current national standard code for acceptance of construction quality of building foundation engineering (GB 50202)
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2.2 the frame structure is wrong (the distance between the vertical poles is too large, the vertical and horizontal poles do not intersect, and the position of the vertical and horizontal poles is wrong) 6.2.3 in the safety technical code for steel tubular scaffold with couplers in building construction (jgj130-2011 [strong article]) 6.2.3 a horizontal bar must be set at the main node, which is connected with right angle couplers and is strictly prohibited to be removed
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Chapter 8 inspection and acceptance table 8.2.4 Item 9 fastener installation: the distance between the center points of each fastener at the main node a ≤ 150 mm
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2.2 frame erection structure error (high and low place erection error) 2.2 frame erection structure error (parapet position erection height error) jgj130-20116.3.7 safety technical code for steel tubular scaffold with couplers in building construction jgj130-20116.3.7 the top rail of scaffold pole should be 1m higher than the upper end of parapet and 1.5m higher than the upper end of cornice
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2.3 the connection and stress of the vertical pole of the scaffold body do not meet the requirements of 6.3.5 in technical code for safety of steel tubular scaffold with couplers in building construction (jgj130-2011) [strong article], the vertical pole of single row, double row and full hall scaffold must be connected with butt fastener except the top step of the top layer
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Article 1 of technical code for safety of steel tubular scaffold with couplers in building construction (jgj130-20116.3.6) when the vertical pole is butt lengthened, the butt couplers of the vertical pole shall be staggered, the joints of two adjacent vertical poles shall not be set in synchronization, the staggering distance of two separated joints separated from one vertical pole in the height direction shall not be less than 500mm, and the distance between each joint center and the main node shall not be large 1 / 3 of the step
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2.4 the structure of the sweeping pole does not meet the requirements of jgj130-20116.3.2 the scaffold must be equipped with vertical and horizontal sweeping poles
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The longitudinal sweeping pole shall be fixed on the vertical pole not more than 200 mm away from the bottom of the steel pipe with right angle fasteners
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The horizontal sweeping pole shall be fixed on the vertical pole close to the bottom of the longitudinal sweeping pole with right angle fastener
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The longitudinal sweeping pole shall be fixed on the vertical pole not more than 200 mm away from the bottom of the steel pipe with right angle fasteners
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The horizontal sweeping pole shall be fixed on the vertical pole close to the bottom of the longitudinal sweeping pole with right angle fastener
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The horizontal sweeping pole shall be fixed on the vertical pole close to the bottom of the longitudinal sweeping pole with right angle fastener
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2.5 the end of the scaffold is open without reinforcement measures
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6.6.5 the two ends of the open type double row scaffold must be provided with transverse diagonal braces
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Note: 6.6.5 both ends of open scaffold are weak links
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Setting horizontal diagonal braces at both ends and strengthening the connection with the main structure can provide strong overall stiffness for this kind of scaffold
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The static simulation test shows that: for the I-shaped scaffold, when there are transverse diagonal braces (zigzag) at both ends and cross braces at the outside, the bearing capacity of the scaffold can be increased by about 20% compared with that of the scaffold without cross braces.
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