Erkmen and Schultz 2009
The authors perform an analytical study on the impact of unbounded posttensioning on the self-centering ability of concrete shear walls under cyclic loading. The results are then compared to previous experimental studies.
System Concept
Tendons are initially pre-stressed vertically in concrete shear walls. When a lateral force is applied and the wall deforms, the pre-stressed tendons apply a restoring force to self-center the structure. The self-weight of the wall and other vertical loads applied also act to return the wall to its original position. Frictional resistance to sliding also assists the wall in re-centering.
Analytical Study, Results, and Discussion
An analytical study was perform on concrete shear walls with varying numbers of tendons and rocking allowed at the base of the wall. It was found that the initial posttensioning force did not have a significant impact on the self-centering capability of the wall, nor does the placement location of the tendons. This indicates that the effect of other loads on the structure can be enough to self-center the walls. Wall panels remained undamaged during the test, and this possibly contributed to the ability to self-center.
Reference
Erkmen, B. and Schultz A.E. (2009). "Self-Centering Behavior of Unbonded, Post-Tensioned Precast Concrete Shear Walls," Journal of Earthquake Engineering, 13.7, pp. 1047-1064.