Collaborative Research: Converging Design Methodology: Multi-objective Optimization of Resilient Structural Spines

新西兰、智利和日本的震后重建工作正在推动新型、低破坏的横向力抵抗系统的发展，以最大限度地减少社会破坏和财产损失。这些努力，再加上美国城市面临的地震风险，促使美国各机构将重点放在提高城市抵御未来极端事件的能力上，方法是根据震后再占用和功能恢复指标确定绩效目标。与此同时，非营利组织正在推动使用更可持续的建筑材料和施工实践。该项目将在结构工程中创造一种新的设计范式，采用多目标优化来最大限度地提高震后功能恢复，同时将可持续建筑实践融入设计过程。新的设计范式将应用于弹性木结构系统的设计和施工。大量木结构建筑的新颖性和有限的可用性规范和标准使其成为创新结构系统和新设计范例的独特先锋，例如结合多目标优化。该项目开发的独特设计范式被称为“融合设计”，因为该方法能够更好地融合生命安全、震后功能恢复和环境可持续性目标。这项研究将辅以一项外展计划，其中包括培训下一代行业和学术领袖，并促进学术界、工业界、建筑规范官员和政府机构之间的伙伴关系。此外，该研究将通过机构研究和本科生推广经验项目以及与nsf资助的本科生研究经验网站的合作，为本科生提供STEM方面的一些经验。该项目将支持美国国家科学基金会（NSF）在国家减少地震灾害计划中的作用。该项目的目标是将基于功能的设计和多目标优化整合到一个单一的融合设计范式中，为抗侧向力系统提供弹性、可持续的地震解决方案。该项目将整合来自实验室和数值工作的现有和新数据，以(1)定义功能恢复和可持续性指标，包括不确定性的量化，用于设计采用大量木材脊柱解决方案的创新侧力抵抗系统；(2)创建并实施一种考虑弹性和可持续性目标的多目标优化融合抗震设计方法；(3)开发优化的抗地震侧向力系统，其性能在美国国家科学基金会支持的加州大学圣地亚哥分校（UCSD）自然灾害工程研究基础设施（NHERI）室外振动台的六层全尺寸建筑测试项目中得到验证。这座六层楼高的试件重复使用了现有的十层楼高的振动台试件，该试件将于2021/2022年在UCSD振动台上进行测试。一系列专家启发式访谈和参与性研讨会将支持弹性指标的定义，包括实现功能的时间和可持续性指标（例如，隐含碳），以实现研究目标。将创建面向工业和高等教育的教育模块。一个行业工作组将促进学术界、工业界和政府机构之间的合作和创新。该项目将带来新的抗震设计可能性，并基于数十年的抗震设计研究，在支持设计优化的高性能计算和功能恢复建模（包括可持续性目标）方面的进步，推进大规模木结构的功能和可持续性知识。项目数据将存档并在NHERI数据仓库（https://www.designsafe-ci.org）.This)中公开提供，该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，认为值得支持。

Post-earthquake reconstruction efforts in New Zealand, Chile, and Japan are motivating the development of novel, low damage lateral force resisting systems to minimize social disruptions and property damage. These efforts, combined with earthquake scenarios highlighting seismic risks to cities in the United States, have led U.S. agencies to focus on increasing urban resilience against future extreme events by defining performance goals in terms of post-earthquake re-occupancy and functional recovery metrics. In parallel, non-profit organizations are driving the use of more sustainable building materials and construction practices. This project will create a new design paradigm within structural engineering that employs multi-objective optimization to maximize post-earthquake functional recovery while integrating sustainable building practices into the design process. The new design paradigm will be applied to the design and construction of resilient mass timber structural systems. The novelty of mass timber construction and limited availability of codes and standards make it uniquely positioned to pioneer innovative structural systems and new design paradigms, such as incorporating multi-objective optimization. The unique design paradigm developed in this project is called "converging design," as the methodology will be better able to converge across competing life-safety, post-earthquake functional recovery, and environmental sustainability objectives. The research will be complemented by an outreach program that includes training of the next generation of industry and academic leaders and fosters increased partnerships among academia, industry, building code officials, and government agencies. In addition, the research will lead to several undergraduate student experiences in STEM through an institutional Research and Extension Experiences for Undergraduate Student program and collaborations with NSF-funded Research Experiences for Undergraduates sites. This project will support the National Science Foundation (NSF) role in the National Earthquake Hazards Reduction Program. The goal of this project is to integrate functionality-based design and multi-objective optimization into a single converging design paradigm that will support resilient, sustainable seismic solutions for lateral force resisting systems. The project will integrate existing and new data from laboratory and numerical work to (1) define functional recovery and sustainability metrics, including quantification of uncertainty, for the design of innovative lateral force resisting systems employing mass timber spine solutions; (2) create and implement a multi-objective optimization converging seismic design methodology that considers resiliency and sustainability goals; and (3) develop optimized seismic lateral force resisting systems, whose performance is validated through a six-story full-scale building test program at the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) outdoor shake table at the University of California, San Diego (UCSD). The six-story specimen re-uses an existing ten-story shake table specimen that will be tested on the UCSD shake table in 2021/2022. A series of expert elicitation interviews and participatory workshops will support the definition of resiliency metrics, including time to functionality and sustainability metrics (e.g., embodied carbon) to meet the goal of the research. Educational modules for industry and higher education will be created. An industry working group will promote increased collaboration and foster innovation among academia, industry, and government agencies. This project will lead to new seismic design possibilities and advance knowledge of the functionality and sustainability of mass timber structures based on decades of research in seismic design, advances in high-performance computing that support optimization in design, and functional-recovery modeling, including sustainability goals. Project data will be archived and made publicly available in the NHERI Data Depot (https://www.designsafe-ci.org).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.