Resilient Cities and Structures最新文献

Tools that quantify community disaster resilience are essential for informed decision-making on community disaster resilience improvement measures. One of the major research gaps in quantifying community disaster resilience are community disaster recovery simulations. Such simulations enable an insight into factors that enable a rapid and efficient community disaster recovery and vice versa. The iRe-CoDeS framework presented in this paper, simulates community disaster recovery as a time-stepping loop, where at each time step the interplay of demand and supply of community components for various resources and services dictates components’ ability to operate and recover. Disaster resilience of a community is then quantified using a multi-dimensional metric, where each dimension represents the unmet demand of a community regarding a certain resource or a service, labelled Lack of Resilience (LoR). This paper presents how such a demand/supply approach can be applied to account for resource and service constraints, impeding factors, that prolong component recovery and thus decrease community disaster resilience. Housing resilience of North–East San Francisco exposed to a Mw7.2 earthquake on the San Andreas Fault is quantified to illustrate the proposed approach. rWhale application framework recently developed at the NHERI SimCenter is used for this purpose, presenting how such a regional simulation on the effect of natural disasters on communities can be extended using the iRe-CoDeS framework to simulate community disaster recovery and quantify community disaster resilience. It is shown that housing resilience quantification results obtained in the case study focused on a part of San Francisco are in accordance with the existing estimates of housing resilience. The evolution of the post-disaster community-level supply and demand for recovery resources and services is obtained, identifying how and when the unmet demand for these resources and services impedes community recovery. Lastly, the effect of community’s ability to mobilize resources and services needed for its recovery on its disaster resilience is investigated.

Balloon type cross laminated timber (CLT) rocking shear walls are a novel seismic force resisting system. In this paper, the seismic performance of four 12-story balloon type CLT rocking shear walls, designed by a structural engineering firm located in Vancouver (Canada) using the performance-based design procedure outlined in the technical guideline published by the Canadian Construction Materials center (CCMC)/National Research Council Canada (NRC), is assessed. The seismic performance of the prototype CLT rocking shear walls was investigated using nonlinear time history analyses. Robust nonlinear finite element models were developed using OpenSees and the nonlinear behavior of the displacement-controlled components was calibrated using available experimental data. A detailed site-specific hazard analysis was conducted and sets of ground motions suitable for the prototype buildings were selected. The ground motions were used in a series of incremental dynamic analyses (IDAs) to quantify the adjustable collapse margin ratio (ACMR) of the prototype balloon type CLT rocking shear walls. The results show that the prototype balloon type CLT rocking shear walls designed using the performance-based design procedure outlined in the CCMC/NRC technical guideline have sufficient ACMR when compared to the acceptable limits recommended by FEMA P695.

This paper presents the development and testing of a novel internal dissipation connection for the use of post-tensioned rocking columns. The solution is one of the many referring to the dissipative controlled rocking (DCR) bridge design philosophy. The internal dissipaters are carefully designed to be cost-effective and reduce the overall construction cost. The dissipaters are fully threaded, Grade 300 bars connected to the permanent column and foundation longitudinal reinforcement with threaded couplers. In this research, a DCR column is subjected to subsequent earthquake events, and the dissipaters' strain design limits are chosen such that there is no need for replacing after a significant seismic event. The result is a recommended design strain limit of 1.5% for the dissipaters that guarantees the structural integrity of the DCR column after a seismic event. Additionally, a cumulated strain of 5% is recommended for the dissipaters before replacement is suggested. The proposed connection detailing with replaceable internal dissipaters, combined with post-tensioned high strength bars and well-confined concrete, provided self-centring capabilities (no residual displacement), dissipation capacity and significantly less damage in the bridge column than a traditional reinforced concrete solution.

Self-centering systems exhibit superior performance during earthquake shaking with lower damage and less residual deformations. Although the equivalent static force design procedure is the commonly used one for most structural systems for seismic applications, the cumulative damage and the effective duration of earthquakes cannot be explicitly considered, which has significantly affected the behaviors and post-earthquake performance of self-centering systems. Energy-based design theory (EBDT), which introduces the energy demand as the critical parameter to establish relations with structural damage, has gained attention around the world in recent decades. The EBDT can provide comprehensive considerations for structural responses and damage in design procedures, especially for self-centering systems. However, few researches and actual energy design projects focus on the use of EBDT for self-centering systems. This paper intends to present thorough review of several critical issues in EBDT. Meanwhile, pivotal gaps that need to be further investigated towards the application of EBDT to self-centering systems are identified and discussed in the paper.