Dynamic overturning capacity of rocking precast thin wall structures

Abstract

Most of the damages in precast wall panels occur within the plastic hinge zone (PHZ) which located at one-third bottom height of the wall. Fixed-base monolithic walls panels are commonly used in the construction of low, medium and high-rise buildings where the connection between wall and foundation beam is vulnerable to damage during earthquake. Damage Avoidance Design (DAD) is proposed in this paper in order to reduce the damage significantly and remain functional after earthquake. To validate and prove the level of damage, a specimen is designed, constructed, tested and analysed in this research. A slender wall panel with size of 3000x800x50mm is tested on shaking table under a few earthquake input such as white noise excitation, impulse excitation and Taft ground motion scaled to 0.2g PGA. Data collection and some visual observation are made during testing where the wall experienced minor damage because the bottom part of wall is steel-armoured and the wall is rocking steel-on-steel bed. A pair of unbonded post-tensioned tendons was used to provide self-centring and avoid any residual displacement during rocking mechanism. The amount of energy dissipated is also calculated and compare between experimental and theoretical values so that some correlation can be determined. In this experiment, the rocking damping is 0.12% and upper bound of hysteretic damping is 5%. Thus, it is recommended to use 12% for effective damping in designing precast thin wall panel which proved to have minimal damage through experimental results obtained.