Collapse risk and residual drift performance of steel buildings using post-tensioned MRFs and viscous dampers in near-fault regions

Abstract

Abstract:The potential of post-tensioned self-centering moment-resisting frames (SCMRFs) and viscous dampers to reduce the collapse risk and improve the residual drift performance of steel buildings in near-fault regions is evaluated. For this purpose, a prototype steel building is designed using different seismic-resistant frames, i.e.: moment-resisting frames (MRFs); MRFs with viscous dampers; SC-MRFs; and SC-MRFs with viscous dampers. The frames are modeled in OpenSees where material and geometrical nonlinearities are taken into account as well as stiffness and strength deterioration. A database of 91 nearfault, pulse-like ground motions with varying pulse periods is used to conduct incremental dynamic analysis (IDA), in which each ground motion is scaled until collapse occurs. The probability of collapse and the probability of exceeding different residual story drift threshold values are calculated as a function of the ground motion intensity and the period of the velocity pulse. The results of IDA are then combined with probabilistic seismic hazard analysis models that account for near-fault directivity to assess and compare the collapse risk and the residual drift performance of the different seismic-resistant frames. The paper highlights the benefit of combining the post-tensioning and supplemental viscous damping technologies in the near-source. In particular, the SC-MRF with viscous dampers is found to achieve significant reductions in collapse risk and probability of exceedance of residual story drift threshold values compared to the MRF.

A probabilistic framework for estimating the residual drift of idealized SDOF systems of non‐degrading conventional and damped structures

“…1,2 As a result, the losses associated with the demolition and replacement of these structures may be very significant even if the structure is not severely damaged. While well-designed conventional or damped List of important symbols: μ, Displacement ductility; p, Post-yield stiffness ratio; ξ, Viscous damping ratio; μ r , Trilinear system yield displacement ratio; R s , Residual ratio (residual over peak disp.…”

“…2,[5][6][7] Using realistic models of entire structures captures the residual drift trends for different structural systems, including the influence of MDOF effects. The first approach relies on numerical analysis of representative multi-story buildings to draw statistical inferences on the residual drift.…”

“…structures are generally very effective at controlling the peak displacement to prevent severe structural damage, degradation of the system, and collapse, they can still sustain large residual deformations. 1,2 As a result, the losses associated with the demolition and replacement of these structures may be very significant even if the structure is not severely damaged. 3,4 Unfortunately, only a handful of studies examined the residual drift response in relation to different system properties in the past, and there is no reliable general prediction method that can be used to evaluate the difference in the residual drift performance of non-degrading structures with different structural properties, or with supplemental damping systems.…”

“…This approach has been used to examine the residual drift performance of specific, conventional, or high-performance structures. 2,[5][6][7] Using realistic models of entire structures captures the residual drift trends for different structural systems, including the influence of MDOF effects. However, the statistical models developed in these studies are usually very case specific and/or require an independent calibration when applied to a system that differs even slightly from the one used in the study.…”

Finite Element Analyses on Free From Damage Seismic Resisting Beam-to-Column Joints

“…Therefore, worldwide research effort is currently devoted to improve the traditional structural systems as well as to develop cost effective alternatives to eliminate or limit and localize the damage, such as buckling restrained braces (BRBs) [14][15][16][17], shear metal panels [18,19], viscous dampers [20][21][22], replaceable shear links in eccentrically braced frames (EBFs) [23,26] and dissipative joints [27][28][29][30][31][32].…”