Investigations of the bond stress of driven piles with grouted skin

The paper focuses on the bond stress in the joint between pile shaft and grouting mortar of driven piles with grouted skin and driven grouted piles. The prestandard E DIN 18538 specifies design values for this joint, which are lower than the experiences of the construction site. This results in uncertainties in the execution phase. The load bearing behaviour of the joint was investigated by experimental, numerical and statistical methods. The results show that the magnitude of the bond stress depends on the profile geometry, use of an expanding agent and the thickness of the grouting mortar. A restraint effect occurs between opposite sides of the profile (i. e. between the inner flange). Concluding new design values are proposed which depends on profile geometry and the use of an expanding agent.