Experimental investigation of behaviour of anchorage zones

This Paper is the first of three on the behaviour of anchorage zones for prestressed concrete. Details of an experimental investigation carried out to determine the behaviour of concrete prisms strip-loaded through rigid steel plates are presented. This loading arrangement represents the transfer of force from tendon to concrete at the anchorage of a prestressed concrete structure. The results of several tests have shown that present design methods of anchorage zones are generally very conservative, which leads to an excessive quantity of steel reinforcement in this highly stressed region, that can lead to poor-quality compaction. It has been found, however, that the spreading of such steel over depths greater than those presently used could perhaps relieve this congestion with little loss in strength of the anchorage. Out-of-plane failures during strip-loading tests were also encountered. Proof must therefore be obtained that such third-direction failure cannot occur in practice if planar failure of the anchorage has been assumed during analysis.