Modeling techniques for post-tensioned cross-laminated timber rocking walls

Seismic loss analysis of buildings with post-tensioned cross-laminated timber walls

“…where m is the number of nonstructural components considered, E [ L i | NC , SA = sa ] is the expected repair cost of the i th component for SA magnitude sa under NC condition, and P ( NC | SA = sa ) is the conditional probability of NC given SA magnitude sa . Wall strength degradation does not occur under the typical level of earthquake demand (see Wilson et al, 2019), such that collapse conditions were not considered in this study. Therefore, P ( NC | SA = sa ) was taken as 1.0 in Equation 6.…”

“…Drift limits were taken as 2% at DE and 4% at MCE R based on ASCE 7–16 Chapter 16 (2016). The PT tendons were not expected to yield at these drift limits, based on a parametric study conducted by Wilson et al (2019) that showed a lack of PT tendon yielding up to 5% drift. The gravity system was not expected to sustain damage under the lateral demands.…”

“…The UFPs were represented as an inelastic shear link with a kinematic hardening relationship and a backbone curve defined by Baird et al (2014), consistent with the approach used by Wilson et al (2019). The mid-height rocking layer of the mid-rise building was modeled as shown in Figure 2.…”

“…Specifically, the PT rods provide self-centering to minimize residual drift, while inelastic deformation was limited to the corners (or toes) of the CLT panels and the structural steel U-shaped coupling devices that connect adjacent walls. While experimental testing and computational analysis has been conducted on PT CLT rocking walls (Ganey et al, 2017; Jin et al, 2019; Kovacs and Wiebe, 2017; Pei et al, 2019; Wilson et al, 2019), earthquake risk analysis following the FEMA P-58 guidelines has not been conducted for model buildings with PT CLT rocking walls.…”

“…Numerical models for PT CLT rocking walls were developed by Ganey (2015) and Kovacs and Wiebe (2017) using OpenSees (McKenna et al, 2010). Wilson et al (2019) formulated finite element models using SAP2000 (Computers and Structures, Inc. (CSI), 2016) that enabled determination of the horizontal spread of plasticity along the base of the wall in addition to the vertical spread of plasticity up the height of the wall. To address the lack of computational efficiency in using the finite element model for nonlinear time-history (NLTH) analysis, Wilson et al (2019) provided a procedure to formulate a lumped plasticity model for a PT CLT wall based on results from a pushover analysis of a finite element model.…”