PRESTRESS LOSS OF POST-TENSiONED CLAY DIAPHRAGM AND FIN BRICKWORK

Abstract

Unlike calcium silicate and concrete block masonry which undergo shrinkage with time, clay brickwork has been known to expand instead. Expansion of brick units in prestressed masonry will cause an increase in the prestressing force instead of prestress loss. However, not all clay brickwork expand with time; higher strength clay units tend to undergo shrinkage with time. The main objective of this paper is to present experimental data obtained for prestress loss in post-tensioned high strength clay diaphragm and fin brickwork. The main objective of this paper is to present experimental data obtained for prestress loss in posttensioned high strength clay diaphragm and fin brickwork. The brickwork were built from clmis B clay engineering brick with compressive strength of 103 MPa with designation (ii) mortar. The tests which involve monitoring prestress loss, creep and shrinkage of clay sections were carried out over a period of 120 days. Usiog the 120-day experimental data, the predicted long-term prestress loss is 20%