Residual Drifts of Self-Centering Systems Including Effects of Ambient Building Resistance

Abstract

There has been widespread interest in the development and use of self-centering (SC) lateral resisting systems that eliminate residual drifts after large earthquakes. SC systems often include a restoring force component and a component that dissipates seismic energy. Typically, it is assumed that the criterion for self-centering is satisfied if the restoring force is proportioned to be greater than the force required to yield the energy dissipating component. A parametric SDOF study was conducted using time-history analyses on several prototype buildings to quantify the effect of varying system parameters on structural response including residual drifts. The ambient resistance of the rest of the building was considered, as well as proportioning the system with less restoring force than the yield capacity of the dissipative component. In addition, the probabilistic mechanism that creates a propensity for reducing residual drifts in systems with little or no restoring force is explored and quantified. It was found that a restoring force that is at least one-half of the force required to yield the dissipative component will still reliably eliminate residual drifts in a non-softening system.

Experimental and Analytical Study on Hollow Precast Piers With Unbonded Conventional Reinforcement to Control Seismic and in-Service Response of Rocking Bridges

“…Makris and Vassiliou [7] and DeJong and Dimitrakopoulos [8] revisited the seismic response of the freestanding rocking frames. Various systems, not limited to prefabricated piers, that combine the use of recentering, such as prestress steel tendons and energy dissipation devices with rocking response have been proposed for both buildings [9] and bridges [10]- [13].…”

Self-Centering Seismic Lateral Force Resisting Systems: High Performance Structures for the City of Tomorrow

“…This type of partial self-centering has been referred to as dynamic stability [46] or probabilistic self-centering [30] and occurs as a result of an increased probability of yielding of the system toward plumb rather than away. Figure 6a shows a schematic diagram of the hysteretic response and potentially large residual drifts for a system without full self-centering.…”

“…However, if the system is at point B in Figure 6a, and there is equal probability of further positive or negative inertial force from ground shaking, then the hysteretic behavior of the system implies that there is a higher probability of reaching the smaller magnitude yield force in the direction of zero displacement than reaching the larger magnitude yield force away from the direction of zero displacement. Many response history analyses [30,47,48] and several shake table tests [32] have demonstrated that the majority of displacement cycles are concentrated in a narrow band as shown in Figure 6a. Systems in which the restoring force was half of the yield force associated with the energy dissipation element were found to exhibit residual drifts less than the out-of-plumb tolerance for new steel buildings for 98% of the response history analyses subjected to severe ground motion (2% probability of exceedance in 50 years) [30,47].…”

“…Computational studies on single degree of freedom structures suggest that there is a minimum amount of energy dissipation required for bilinear elastic (self-centering) systems to produce peak drifts similar to those of conventional bilinear elastic-plastic systems [28][29][30]. To produce sufficient energy dissipation, an energy dissipating element is incorporated into self-centering systems.…”

Enhancing Resilience of Steel Frame Buildings Using Superelastic Viscous Dampers

“…Shape memory alloys (SMAs) have attracted a great deal of attention as smart materials to be used in seismic protection systems for energy dissipating and re-centering purposes (Eatherton and Hajjar, 2011;Qian et al, 2009). SMAs behave similarly to linear-elastic materials for small-magnitude events, but for moderate and more severe strain levels, SMAs display superelastic behavior from which they can fully recover their original elastic shape upon unloading.…”