Seismic performance of unbonded post-tensioned precast wall systems subjected to shake table testing

Abstract

Post-tensioned precast concrete rocking walls, as a seismic resilient system, dissipate energy imparted to them during an earthquake through the inherent viscous damping, radiation damping due to the wall impacting the foundation, and any available hysteretic damping. A shake table study on eight rocking wall units designed with different quantities of hysteretic damping ratio varying between 4 to 15%, generally demonstrated their satisfactory seismic performance during design-level and higher intensity earthquake motions. The test results confirmed lower participation of energy dissipation due to impacts as the hysteretic component increased. Larger hysteretic damping also led to greater reduction in the maximum drift of rocking walls as well as number of large drift cycles after the first peak of response. While larger displacement amplitude was achieved for the walls relying on lower hysteretic damping, it was shown that the duration of dynamic response of these walls was reduced by negative rate of input energy, which favorably removed a part of the seismic energy imparted to the system.

Computational modelling of a four storey post-tensioned concrete building subjected to shake table testing

“…[33]. Shake table tests conducted by Twigden [7] and Nazari [34] both confirmed recommended damping of 2% for accurate non-linear time history analysis of isolated rocking walls. Therefore, an increase in damping to 2.5% was considered reasonable for a computational model that considered the entire building where additional sources of damping were present.…”

مدل‌سازی رفتار لرزه یی و برآورد خسارت دیوارهای گهواره‌یی بتنی تحت بار زلزله

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