Functional Recovery of Buildings and Lifelines

Summary

This project advances key areas of engineering knowledge and practice that are necessary for the development of a robust framework for functional recovery design. Functional recovery performance aims for buildings and infrastructure systems to quickly return to function or service following an earthquake event. The ultimate goal of functional recovery design objectives are to reduce potential downtimes of critical infrastructure assets and services on which communities rely, thus improving community resilience to future hazards. Functional Recovery is a long-standing need identified across engineering, resilience, and risk mitigation fields, and is also recognized as a national priority in the NIST-FEMA report to Congress (FEMA P-2090 / NIST SP1254), by the National Earthquake Hazards Reduction Program (NEHRP) Advisory Committee, and in the forthcoming NEHRP Strategic Plan. NIST SP1254 outlines seven core recommended options to achieve functional recovery goals. The first four recommendations focus on the physical built environment via the creation of a national framework for performance objectives, design of new buildings, retrofit of existing buildings, and management of lifeline infrastructure systems for functional recovery. The report also highlights that the engineering-focused activities require correlated efforts across social systems, including pre-disaster recovery planning, education and outreach, as well as access to financial resources. Thus, program researchers continue research tasks on buildings, infrastructure systems, economic evaluation, and social science and communications. The tasks have been strategically chosen for their promising contributions towards development of functional recovery framework and codes and standards, and because they are areas where NIST is best able to positively shape the future of built environment post-hazard performance.

Description

Objective:

The Functional Recovery project is designed to improve the time for recovery of key social functions via strengthening of the built environment to withstand earthquake impacts. Our efforts will advance measurement science for the assessment and design of buildings and lifelines, contribute in key areas necessary for the improvement of economic and social considerations for performance enhancement,  and provide a framework usable for designing beyond current codes and standards by FY2026.

What is the Technical Idea?

Engineering advances to reduce risk from earthquakes have been primarily focused on maintaining the structural integrity of buildings or reliable performance of lifeline systems, rather than on ensuring that a building may be usable or a lifeline system can provide its service after an earthquake. In earlier times, the ability to save lives and prevent injury was the primary goal. Today, however, we have both the ability and also a societal preference to limit downtime, interruption, and repair costs. As a result, there is a need for a paradigm shift from safety-based to recovery-based objectives in design of the built environment. The Functional Recovery performance objective will enable quicker reoccupancy and resumption of functions and services that assets of the built environment provide, the key questions we are grappling with is how much, for whom, and by when? These questions require detailed technical assessment and planning for asset performance and also weighing significant social science topics such as cost and financing, supporting actions, and clear communications regarding the potential benefits of the new performance objective.

What is the Research Plan?

In addition, with regards to the extension of the EEG research on buried utilities, we will begin our effort by conducting a literature review that distills key information regarding the seismic design, performance, network modeling and resilience or mitigation strategies for buried utilities subject to geohazards. The literature review will seek to capture both state-of-practice and state-of-the-art resources. The next step will be to develop potential research avenues and project topics based on key findings from the literature review, and to identify topics requiring a more in-depth literature review.

RT1: Buildings

Nonstructural systems play an important role in recovery of buildings after an earthquake. As a first step, this project will identify key design parameters for several non-structural building systems (such as HVAC or electrical). This information will be used to design multiple alternative nonstructural systems for a set of archetype buildings. The archetype buildings, representative of modern code-compliant reinforced concrete moment frame buildings, will be designed in parallel.

To support this work and improve the understanding of the seismic performance of nonstructural components, this project will investigate the performance of several key nonstructural components, considering both component fragility and damage consequences as they relate to building downtime and loss of service. Given the extensive inventory of nonstructural components, systems, tenant contents, and component configurations that exist in modern building infrastructure, this study will focus on identifying several critical nonstructural components and systems that have been shown, either analytically or in previous earthquakes, to greatly impact the continuity of building occupancy and function. Nonstructural component performance will be quantified using advanced component-level analytical models and validated against ongoing full scale shake table tests. 

Next, a study will be conducted to explore correlations between asset-level functional recovery performance targets and community-level resilience goals, considering the regional distributions of essential assets and special variability in ground shaking. Outcomes from this study will be used to define “acceptable” recovery times for individual building that will support community resilience.

And finally, a framework will be developed to link structural and nonstructural design parameters with functional recovery performance objectives. At this stage, the impact of each of the structural and nonstructural design parameters on the recovery of the archetype buildings will be evaluated. The results will be used to identify the structural and nonstructural performance requirements that deliver an “acceptable” recovery time. In the last step, the proposed framework will be used to assess a set of archetype buildings to identify prescriptive requirements that can be used to achieve functional recovery.

RT2: Lifelines

RT2-1: Tool for Enhancing Recovery of Transportation Infrastructure Lifelines:

The NIST team submitted a contract package to AMD in FY21. The project was awarded in FY21 and launched in FY22. The NIST team is working closely  with the Contractor on the execution of the project. The in-house activities include: 1) oversee the activities conducted by the contractor; 2) collect fragility curves for bridges across the U.S. to be used in the tool. NIST will collaborate closely with the contractor to 3) incorporate the Edge$ capabilities within the new tool.

EEG is also planning to host a small workshop to discuss functional recovery and resilience of transportation systems, to share knowledge and interact with subject matter experts (SMEs). This effort will serve as a pilot test for the small workshop format and subsequent events may be hosted for other distributed system types (e.g., drinking water, storm/sewer water, electrical, gas, telecommunications). The ideas and information collected in this workshop may also be applicable to other distributed system types. Planning is underway with Conference Services, with the event scheduled for the end of FY22 or early FY23. A meeting summary will be made available following the event using one of the NIST publication formats.

RT2-2: Framework for Enhancing Resilience of Urban Rail Transit Networks:

The first step involves developing a framework to enhance the resilience of critical infrastructure networks, with the focus on railroad systems, through a set of computational steps. This includes collecting and processing data and developing algorithms to detect the vulnerable areas in the network. Next step is developing recommendations to protect vulnerable components of the network and improve the robustness of critical infrastructure networks, which are the basis for speedy recovery in the midst of disruption.

The recovery time will be minimized by optimizing the recovery process and considering the impact of multiple factors including recovery cost, demographic, and practicality. The final step involves providing suggestions for standards and guidelines to shift from safety-based objectives to recovery-based objectives for design of critical lifeline systems.

RT2-3: Framework to Apply Target Recovery Timeframes for Water, Wastewater, and Electric Power Systems:

Our contract with ATC on target recovery timeframes for water, wastewater, and electric power continues with an end date of October 2023. The Project Technical Committee is meeting regularly to develop the project’s framework and final report. Interactive virtual meetings ensure that concepts and objectives for the effort are shared across the group which represents input from engineers, emergency managers, and architecture fields. NIST personnel will work closely with ATC and the Project Technical Committee to ensure cohesive efforts consistent with a final report that is a NIST publication. This effort to involve external personnel with expertise in the operation, management, assessment, and recovery of lifelines infrastructure systems are imperative to ensure realistic recovery target time frame development, as well as a framework that can be broadly applicable across the nation.

RT3: Economic Evaluation

The research plan consists of two key activities: (1) the economic evaluation of recovery-based design; and (2) economic decision support for earthquake resilience.

The first activity builds on an EL-funded FY21 exploratory project, which establishes a framework for evaluating the benefits and costs of recovery-based design (FR-BCA). Beginning with FY23, the goal is to generalize application of FR-BCA from single building design to community level action (e.g., targeting building clusters), as well as to expand the scope of FR-BCA from new buildings to cover critical lifelines. For new buildings, the focus will be on methods for aggregating single-building FR-BCA to a portfolio of buildings at the community level. For existing buildings, the main challenge will be estimating cost. On the other hand, evaluating post-earthquake performance is possible with current software tools. The goal is to consider how modern retrofit solutions might achieve re-occupancy and recovery, and to categorize the potential benefits and costs of each retrofit solution. Expanding the FR-BCA framework to consider critical lifelines is a more challenging problem than buildings, but integral to the restoration of their functionality. The first step involves contributing to the development of a tool to conduct cost-benefit analysis and provide an optimal retrofit plan for bridges at the regional scale. This includes consideration of retrofit costs and return on investment and will directly link to the NIST Edge$ tool. In subsequent years, it will be important to continue expanding the scope of FR-BCA while also exploring the quantification of less tangible, more difficult to quantify benefits, including the avoided losses from mitigating impeding factors and the value of being able to reoccupy a building within a specific time frame. Moreover, for improved design standards there are potentially additional benefits from sustaining improved performance through multiple events. In principle, quantifying such benefits would apply for both new and existing buildings. Finally, there is a need to consider using economic evaluation to inform implementation of recovery-based design.

The second primary activity entails development of data and tools to facilitate decision making for earthquake risk reduction. This activity includes a “last mile” effort to disseminate previous NIST research on estimating seismic retrofit costs for existing buildings. The focus will be on developing a tool for economic decision support of seismic risk mitigation. The near-term goal is to bundle NIST’s previous work into a software package that contains historic retrofit cost data and models to estimate retrofit costs, which will generate estimates to be used in benefit-cost analysis tools such as FEMA’s BCA and NIST’s EDGe$. A longer-term goal is to develop protocols for collecting data for earthquake risk reduction decision support, including data that can be used in NIST-developed tools.

RT4: Social Science & Communications

RT4-1: External Communications

The distillation of key messages, preparation of associated communication tools to represent initial functional recovery messaging, and training of EEG personnel will require collaboration outside of the Division. The project will solicit significant input and assistance from both the Public Affairs Office and Office of Congressional and Legislative Affairs to ensure that functional recovery messaging can reach both technical and non-technical audiences.

Continuing efforts to support the development and utility of Functional Recovery communication, EEG has plans to utilize draft efforts from FY22 to finalize an infographic to communicate the FR concept in FY23. It is important that NIST continue to participate in and integrate information from a diversity of professional activities that are ongoing, in order to ensure that our efforts are responsive to the development of this new field. We must also continue to develop and communicate NIST’s efforts, in order to ensure that NIST is viewed accurately as a key player within the development of a Functional Recovery performance objective. A first effort in this direction is to create a brochure describing EEG focus areas, efforts, and strengths.

RT4-2: Stakeholder Research 

As the process for developing functional recovery frameworks proceeds, NIST researchers will need additional information regarding the anticipated timelines and appropriate mechanisms to apply the recovery time frame targets. This work builds upon the stakeholder workshops that were held as a part of the NIST-FEMA report (NIST SP 1254) writing process that provided information regarding preferred target timeframes for recovery from across a small sample of earthquake-oriented professionals (NIST SP 1269). Social scientists partnering with EEG engineers can help to collect and analyze additional information, to ensure that data gathered appropriately represents the population under consideration, including the public. In FY23, NIST will initiate a contract for the development and conduct of a workshop and data collection activity to inform the Functional Recovery framework development.

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References:

Exec. Order No. 13717: Establishing a Federal Earthquake Risk Management Standard, 81 Fed. Reg. 6405 (February 6, 2016).

Helgeson, J., P. Lavappa, and D. Webb. (2020), EDGe$ (Economic Decision Guide Software) Online Tool, Version 1.0, National Institute of Standards and Technology, https://doi.org/10.18434/M32185 

NIST-FEMA (2021), Recommended Options for Improving the Built Environment for Post-Earthquake Reoccupancy and Functional Recovery Time, Special Publication (FEMA P 2090 / NIST SP-1254), Federal Emergency Management Agency, Washington DC, National Institute of Standards and Technology, Gaithersburg, MD, https://doi.org/10.6028/NIST.SP.1254 (Accessed June 2, 2021)

NIST 2021, NIST-FEMA Post-earthquake Functional Recovery Workshop Report, NIST SP-1269, National Institute of Standards and Technology, Gaithersburg, MD.

NIST, 2014, Earthquake-Resilient Lifelines: NEHRP Research, Development and Implementation Roadmap, GCR 14-917-33,  National Institute of Standards and Technology, Gaithersburg, MD, https://www.nehrp.gov/pdf/nistgcr14-917-33.pdf\.

NIST, 2016, Critical Assessment of Lifeline System Performance: Understanding Societal Needs in Disaster Recovery, NIST GCR 16-917-39, National Institute of Standards and Technology, Gaithersburg, MD, https://nvlpubs.nist.gov/nistpubs/gcr/2016/NIST.GCR.16-917-39.pdf

NIST-FEMA, 2021, Recommended Options for Improving the Built Environment for Post-Earthquake Reoccupancy and Functional Recovery Time, FEMA P-2090, NIST SP 1254, Federal Emergency Management Agency, Washington D.C.,  National Institute of Standards and Technology, Gaithersburg, MD, https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.1254.pdf

Rojahn, et. Al, 2017, Community Resilience of Lifeline Systems: Societal Needs and Performance Assessment, 16^th World Conference on Earthquake Engineering, Santiago, Chile,  https://www.wcee.nicee.org/wcee/article/16WCEE/WCEE2017-2686.pdf