July 6th, 2019 | Categories: news
“Give me a fulcrum and I will lift the earth. -- Archimedes. Give you a standard, what can you hold up?”
Everyone knows the high loading capacity of standards in the system scaffolding. How big can it be? We speak with data.
1. Standard loading calculation
Rapid standard is divided into B type (standard type) and Z type (heavy-duty type), the material is no less than Q345. Section characteristics are shown in the table below.
According to "Technical specification for safety of ringlock steel tubular scaffold in construction" (JGJ231-2010) :
Calculation formula 1: l0=ηh
Calculation formula 2: l0=h '+2ka
η -- standard correction coefficient 1.2;
h -- the maximum stride distance of the middle layer of the scaffolding; (general item value is 1500)
h '-- the topmost step distance of the scaffolding should be reduced by one plate; (general item value is 1000)
k -- calculated length reduction coefficient of cantilever end, set as 0.7;
a -- the distance from scaffold standard to the center line of ledger on the top floor to the support point of adjustable base jack. (Max. 650mm)
The calculated length of scaffolding standard is of a large value, i.e., l0=1910mm
Aspect ratio: Type B λ=l0/i=119.3, Type Z λ=l0/i=94.6.
According to "JGJ231-2010" appendix D table D-2 Q345 steel pipe axis pressure component stability coefficient φ can be obtained: Type B φ =0.350, Z type, φ = 0.516.
Then the maximum allowable loading design value of a single scaffolding standard:
2. Standard loading test
Combined with the results of the standard calculation, Rapid Scaffolding (Engineering) Co., LTD. together with Southeast University, has done a series of scientific and systematic test of the loading capacity of ring lock scaffolding.
Ledger length 1500mm, step distance 1500mm, with full scaffolding diagonal braces.
Type B: ultimate bearing capacity F= 396.3kn (4 standard), equivalent to the weight of 28 family cars, a single standard 99.1kn, equivalent to the weight of 7 family cars.
Model Z: ultimate bearing capacity F= 546.0kn (4 standard), equivalent to the weight of 40 family cars with a single standard 136.5kn, equivalent to the weight of 10 family cars.