Diskussionsbeitrag zur axialen Traglast von Wänden im Grenzzustand des Versinkens

Contribution for discussion concerning axial bearing capacity of walls

Due to the increasing load from container cranes the axial bearing capacity of walls is becoming more important especially in harbor constructions. A complex bearing behavior exists. This behavior consists of a wall bending due to lateral loading occurring from earth and water pressure as well as of axial loading. Conventionally, lateral and axial bearing behavior are considered in separate limit states. The stresses from earth and water pressure from the service limit state are applied during the limit state sinking of the wall. It needs to be noted that the wall friction angle is dependent on the relative displacement between the wall and the soil and is independent of the wall friction angle applied laterally. To prove this statement the coupled lateral and axial bearing behavior of the wall is investigated exemplarily for a simple system using the finite element method. The results show that the mobilized wall friction angle during the limit state sinking of the wall caused by an axial load should not be applied as a loading (as suggested in Recommendations on Excavations (EAB) (2012) and Recommendations of the Committee for Waterfront Structures Harbours and Waterways (EAU 2012)) but rather as a resistance. This only holds true if the axial displacement of the wall compared to the subsoil is big enough and if the displacement can be tolerated.