This thesis presents an experimental and numerical research programme which investigates the influence of embedded flanged anchor units on the anchorage zone of post-tensioned concrete members. a typical embedded anchor is made from castiron and consists of a conical barrel with one surface flange and one embedded flange. the object of this work is to clarify the relative contributions of the anchor components to the load transfer mechanism, their load-carrying capacity, and their influence on stress distributions in the anchorage zone. the study aims at developing improved rules to assess the effective magnitude of the bursting forces when using embedded flanged anchors. the experimental part of the investigation consisted of tests carried out on square reinforced concrete end-biocks of constant dimensions loaded by a single concentric monotonic force in increments through an es ccl standard embedded anchor. the action of the load transfer component of the anchor was isolated by machining off unwanted components or by wrapping elements in a plastazoate sheet. the results demonstrate the advantages and disadvantages of different aspects of anchor geometry. a theoretical study was also carried out in which the anchor was modelled with shell elements and the surrounding reinforced concrete by lateral support on the shell elements. the initial linear elastic response was extended to nonlinear response by modifying the circumferential stiffness of the concrete once cracking has occured. an alternative idealisation was developed by modelling the anchor block and embedded anchor as an axisymmetric finite element problem. from these studies, the relevance of the present design rules when dealing with new embedded anchor geometries is clear and the need for improvement of these rules demonstrated. recommendations are also made for new shapes of anchor which could smooth the peak of the bursting stresses, minimise the reinforcement and reduce the congestion of the bursting reinforcement in the end-block.