ABSTRACT
There are several cases in structural engineering where concentrated loads act on a concrete surface. Wellknown examples are bridge bearings and anchors for post-tensioning. Other examples are modern fixing devices (undercut anchors), but also the impact of hard ob-jects against concrete structures. It is common to all these loadings that the force acts only on an extremely small bearing area and that passive confinement is activated which causes a triaxial state of compressive stresses. This will increase the loading capa-city of concrete far beyond the uniaxial compressive strength.
