Ajrab, Pekca, and Mander 2004
In this work, the authors propose a rocking shear wall with a supplemental energy-dissipating system of various pre-stressed tendons in different configurations. Tendons are straight, draped, or not included in the model. The sensitivity of the structure to the level of pre-stressing and vertical tendon profile is analyzed. Nonlinear time-history analyses are performed on an analytical 6-story structure using ground motions from El Centro and Pacoima Dam.
System Concept
The system at hand involves a shear wall that is not rigidly connected to anything at its base, but is free to rock. This system lends itself to large deformation. The general strategy is to take advantage of these large deformations by using elements that can dissipate large amounts of energy from seismic events under large inelastic deformations forced upon them by the rocking of the shear wall. In this case, pre-stressed tendons are used to dissipate seismic energy.
Analytical Study, Results, and Discussion
An analytical study was performed on a 6-story structure with rocking shear walls. The pre-stressing level in the tendons was varied between 0%, 33%, and 67% of the tension yield strength. Tendons were also varied between straight, vertical, and draping.
It was observed that no damage to the structure was induced by the rocking of the system. It was also found that the level of pre-stressing did not have a significant impact on the response of the structure. This is likely because of the overwhelming size of the shear wall in comparison to the tendons. The tendons must still be pre-stressed, however, in order for them to yield and dissipate energy.
Reference
Ajrab, J. J., Pekcan, G., and Mander, J. B. (2004). "Rocking Wall–Frame Structures with Supplemental Tendon Systems," Journal of Structural Engineering, 130.6, pp. 895-903.