Fachvereinigung Kaltwalzwerke e.V. |
Examination of the stability of steel strip coils having a horizontal centre line,
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su=s0=50mm |
sl=sr=50mm |
sl=sr=1/18,93 Da h=1/123,05 Da φ=3° |
A surveyor measured a measuring square of 2 x 2 m² of the different floors in 3 enterprises; the existing slopes were determined by carrying out a graduated regression analysis. This surveying covered a total of 73 % of the floors mentioned in the catalogue of questions, the percentage of which is shown in the following illustration.
These surveyings and evaluations revealed that the slope does not exceed 2° (incl. surface slope for fluid drainage). However, it is necessary to remedy smaller damages/defective parts immediately. For the impact load test, also the impact of a moving worker (m = 85 kg [2] and v = 6 km/h) was taken into account in addition to the previously defined static tilting force of 0,5 kN. In accordance with the new standard generation (Eurocode), a partial safety factor of 1,5 was applied to these effects. Due to their favourable effect, the resistance side is multiplied by a partial safety factor of 1,0. When determining the balance of the static or dynamic effect and the mass impedance by taking into accout the lever arms, the maximum admissible deformations of the steel strip coils, the lifting of the steel strip coils from zero level and the surface slope, the following dimensioning diagram results (inner diameter = 500 mm; psteel = 78,5 kN/m³). |
The examinations carried out in this study show that it is only partially possible to reach the goal to extend the dimensioning range laid down by the Bundesanstalt für Arbeitsschutz. From the dimensioning proposal shown in figure 3, the range results in which a single steel strip coil having a horizontal centre line is to be considered stable. In order to be able to apply this dimensioning proposal, the following conditions apply:
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This dimensioning proposal does not cover dynamic impact forces due to crane or forklift truck operation.
Where these conditions are not fulfilled, the steel strip coils shall be stored in a stable way in cradles or similar.
As a matter of principle, steel strip coils having a width of < 275mm shall be stored in a stable way in cradles or similar, or they shall be tied together until a stable storing acc. to figure 3 is possible.
Due to the new dimensioning proposal, it becomes possible to make optimum use of the space available for the storing of steel strip coils having a horizontal centre line whilst preserving the necessary and prescribed occupational safety at the workplace.
[1] | Storing of coils and steel strip coils Bundesanstalt für Arbeitsschutz, H.-H. Kamps, Dortmund 1985 |
[2] | Statistisches Bundesamt Deutschland Mikrozensus-Ergebnisse, April 2002 |
[3] | Draft DIN 4149: Buildings in German earthquake zones, September 2003 |
© Fachvereinigung Kaltwalzwerke e.V. 2005 |