The Technical File | Groundforce Groundforce Shorco | Technical File Issue 3.0 MP60 Mechanical Strut MP60 Mechanical Strut - Working Load Chart - see section ’i’ for definition of terms The lines on the chart below indicate the maximum working axial strut loading at various spans and includes an allowance for either 0kN, 10kN or 20kN accidental load applied at mid-span (see load effect diagram below). The area under the lines indicate the envelope for a safe solution. It is not considered necessary to account for thermal effects in MP60 struts when used in the UK and therefore this is not included in this chart. Please refer to section ’i’ for more information on load effects on struts. Explanation: The horizontal Green portion of the lines on the chart indicates the working axial capacity of the strut assembly as limited by the local capacity of the mechanical screw unit i.e. 570kN. The sloping lines indicate a load reduction from this value due to the potential for buckling of the steel tubular extension members. The sloping Green Line represents the working load after taking into account a 20kN mid -span accidental load. The Red Line represents the working load after taking into account a 10kN accidental load. The Blue Line represents the working load without allowing for any accidental loading effects. The blue line must be used with caution and after a full risk analysis. Notes on applied factors of safety: The lines on the graph below are expressed in terms of working load limit. These values represent the remaining structural capacity or resistance once allowances have been made for the bending effects induced by self weight, accidental loading, eccentricity and secondary moments (see diagram below and also notes in section ‘i’). All steelwork structural resistances have been calculated in accordance with BS5950: 2000. A global factor of 1.6 has been applied to ULS values to reduce them to working values. In addition the adjustable screw unit has been subjected to load tests. Its maximum working local capacity of 570kN represent a global safety factor in excess of 2. Notes: 1. Thermal effects are not included in the graph. 2. P-delta effects are taken into account and include a 10% strut diameter allowance for eccentricity of loading W. Working Load (kN) at Zero Accidental Load Working Load (kN) at 10kN Accidental Load Working Load (kN) at 20kN Accidental Load 4.2.3