by David Corke, director, DC ProjectSolutions and John Gannon, director, Byland Engineering. This paper was first published in GE’s February 2010 issue.
BR 470 Working platforms for tracked plant1 was published in 2004 and provides good practice guidance on the design, installation, maintenance and repair of ground supported working platforms constructed of granular material for the use of tracked plant.
Previously there was no published or widely used simple design method for these working platforms, and since 2004 the BR 470 design method has been used extensively. However, some users have reported that this design method leads to unnecessarily (and uneconomically) large platform thicknesses.
The calculations involved in the design method are particularly sensitive to the the angle of friction of the granular working platform material and the shear strength of the sub-grade. This paper demonstrates this sensitivity and recommends how testing can be used to provide safe but still economical design parameters, with case studies of examples of testing.