Experimental behaviour of anchor bolts under pullout and relaxation tests

The anchoring between a metallic component and a concrete block is an essential point in stability and durability of the structure. This joint has to transfer the deadweight of the structure and tensile, compressive and shearing loads created by the structure in service. This study focuses on the joint constituted of long anchor bolts cast-in-place. The anchor rods are prestressed in order to minimize the effects of fatigue stress. To design these anchors the long-term behaviour of concrete is not taken into account whereas the concrete creep and shrinkage involves a decrease in the initial prestress level. This paper presents experimental results of pull-out tests and mass-spring modelling of the joint is proposed. In this model the long-term behaviour of the joint is taken into account using the creep and shrinkage laws given in Eurocode 2. The modelling of the evolution in time of the rod prestress shows good agreement with the measurements obtained in relaxation tests.