Rocking wall-frame structures with supplemental tendon systems

This paper introduces the implementation of proposed rocking shear walls-as opposed to conventional fixed-based walls-in frame structures following the principles of the damage avoidance design philosophy. For improved seismic response, rocking walls are coupled with a separate nonload bearing nonlinear supplemental damping system. In view of the typical response of rocking systems, it is proposed that an energy dissipation system is configured and devices are strategically placed to exploit the expected large displacements. A performance-based design methodology is introduced and used to design a six-story rocking wall-frame building with various supplemental system configurations which include prestressed tendons and energy dissipation devices. Seismic performance and response evaluation, using nonlinear time-history analyses, suggests that desired performance levels (minor to no damage) can be achieved with added equivalent viscous damping (similar to20%) resulting in reduced floor accelerations interstory drifts. Finally, a sensitivity study on the effect of various system parameters on the performance of the structure showed that the seismic response was not sensitive to the prestress level in tendons and to wall base width. Whereas a draped tendon profile results in a lower and more even distribution of interstory drifts in comparison to those in fixed-based structures.