The micropile life time is introduced by reducing the area of the reinforcing tube using the reduction coefficient of the influence of corrosion of steel tube re and coefficient Fut taking into account connection of the micropile and the surrounding soil.
external diameter of reinforcing tube
wall thickness of reinforcing tube
coefficient taking into account connection of micropile and surrounding soil (0,5 -1,0)
BS EN 14199:2005 Execution of special geotechnical works. Micropiles British-Adopted European Standard / 30-Mar-2005 / 52 pages ISBN: 0580457249.