Behavior of ungrouted and unbonded post-tensioned masonry beams and slabs

The paper shows and discusses the results of an experimental program aimed at assessing the flexural behavior of ungrouted and unbonded post-tensioned masonry (UUPTM) elements such a beams or two-way slabs. In this structural system, the bed and head mortar joints are excluded and the concrete blocks are post-tensioned with unbonded tendons. A special tendon restraint block has been added to provide nonlinear displacement capacity of the specimens. The global performance is assessed in terms of cracking patterns, failure modes and load-deflection curves. Results from the experimental program indicate that the tendon restraints blocks improve the flexural behavior in terms of strength and nonlinear displacement capacity. Comparison between measured and predicted strength demonstrated that the equations of out-of-plane or in-plane flexural capacity of walls or solid masonry beams provided by building codes for masonry structures, may be used to estimate the maximum flexural capacity of the UUPTM beams having tendon restraint block.