Unfortunately, we don’t have to wait long anymore for another natural disaster to lead the news. Varying combinations of length of time, area covered, and intensity of storms, wildfires, earthquakes, and other weather extremes are growing, devastating lives, livelihoods, and infrastructure.
A new book from ASCE Press helps engineers design to anticipate the greater impacts of these worsening events. Effects of Climate Change on Life-Cycle Performance of Structures and Infrastructure Systems: Safety, Reliability, and Risk is the product of three Structural Engineering Institute working groups with more than 40 team members, part of a special project handled by the SEI/ASCE Technical Council on Life-Cycle Performance, Safety, Reliability and Risk of Structural Systems.
Fabio Biondini, Ph.D., P.E., F.SEI, F.ASCE, a structural engineering professor in the Department of Civil and Environmental Engineering at Politecnico di Milano in Milan, Italy, is the former chair of the SEI/ASCE Technical Council and one of three project coordinators and co-editors on the 360-page volume. He spoke with Civil Engineering Source about how it will help engineers enhance structural resilience in the face of climate change.
Civil Engineering Source: Beyond the increasing imperative to act amid worsening disasters that evidence suggests are driven by climate change, how did the book come into being? What was the initial impetus?
Biondini: Since its foundation in 2008 and for over 15 years, the SEI/ASCE Technical Council has provided a forum for reviewing, developing, and promoting the principles and methods of life-cycle performance, safety, reliability, and risk of structural systems in the analysis, design, assessment, inspection, maintenance, operation, monitoring, repair, rehabilitation, and optimal management of civil infrastructure systems under uncertainty. The technical council’s activities have focused primarily on evaluating the safety of structural systems under natural and human-made hazards using historical data. However, historical climate-related events may not accurately reflect future impacts and extremes due to global warming and uncertainties associated with estimating the effects of climate change on the long-term performance of structures and infrastructure facilities. These effects will increase climatic loads and alter environmental conditions, exacerbate the occurrence of extreme events, and accelerate aging and structural deterioration processes, requiring major adjustments to infrastructure maintenance schedules, climate adaptation options, management strategies, resource allocations, prioritization plans, and optimized decision-making processes.
It was therefore decided to establish a dedicated special project to review available information on climate change and identify methodologies and tools that would help structural engineers address the impacts of climate change on the life-cycle performance, safety, reliability, and risk of structures and infrastructure systems, including buildings, bridges, and other infrastructure facilities.
To achieve the project goals, three working groups were established under the umbrella of the technical council to address 1) climate projection models and data, 2) impacts of climate change on infrastructure performance, and 3) life-cycle risk-based decision making in a changing climate. The activities of the three working groups were complemented by a survey and an international workshop held at ASCE headquarters. The book is the result of this collaborative effort.
Source: What kinds of challenges did the working groups encounter? Did objectives or targets have to change, based on things like accessibility to sources and quality of data?
Biondini: While ASCE and other organizations were making efforts along similar lines, the unique feature of this special project is its multidisciplinary approach. It gathered a team of structural engineers and climate scientists to focus on methods for projecting future climatic loads and outlining procedures for the design and safety assessment of buildings, bridges, and other structures.
This feature, requiring a closer coordination between climate scientists, engineering experts in structural reliability methods and risk assessment, and code writers, also represented one of the main challenges we had to face in coordinating the working groups, mainly because of some inconsistencies between the climate projection data that climate science groups and agencies are developing, and those required for the design and the safety assessment of structures and infrastructure systems.
Climate projections should not only provide the overall general trends in the intensities and frequencies of climate events but also provide estimates of the maximum annual extreme events at a sufficiently high spatial resolution. This information must include changes in statistical parameters and the probability distributions of these events over time. It has been noted that changes in overall trends often do not reflect trends in the intensity of extreme events. For example, some regions may experience fewer rain or snowstorms, but the most extreme rain or snowstorms may become more intense than in the past.
While objectives and targets are firmly established and do not necessarily have to change, a strong effort is needed to adapt the theoretical and methodological frameworks to the type and quality of data developed by climate science groups and agencies, and accessibility to the engineering community for direct implementation in engineering practice. Much of the climate projection data needed for application in structural engineering is not readily available at this time. This issue has pre-empted the development of design codes and standards that engineers can easily apply during design processes, and it is a major issue to be addressed in delivering new generations of climate-responsive design codes. Relatedly, future code developments should also include approaches for accounting for the effect of climate change on accelerating structural deterioration, and how to gather information from existing structures and experimental tests for calibration and validation of standards.
Source: What will engineers be able to learn and apply immediately to their project work to enhance its life-cycle performance?
Biondini: Engineers will be able to identify issues related to the effects of climate change and extreme weather events on the life-cycle performance, safety, reliability and risk of structural systems; learn about ongoing major developments in climate projection models and future climatic trends, assessment of impacts of climate change on infrastructure performance, and life-cycle risk-based decision making in a changing climate; then gather the necessary background, information, and guidance to address the impacts of climate change and extreme weather events on structural design and assessment.
This is critically important to develop a deep awareness of the severity of climate-related problems and be prepared to implement the advances of upcoming climate-resilient design codes into design practice, which are expected to have a significant impact on the future vision and practice of the civil engineering profession.
Source: Which professionals will benefit most from the guidance?
Biondini: The book fulfills a need in structural engineering. It will serve as a reference for all those concerned with the life-cycle design, assessment, maintenance, and management of climate-resilient structures and infrastructure systems. This includes students, researchers, practitioners, consultants, contractors, decision-makers, code writers, and representatives of managing bodies and public authorities across civil and structural engineering.
Then again, it is also a reference for climate scientists who seek closer interdisciplinary coordination with engineering experts in structural reliability and risk assessment. It is hoped that this book will solidify SEI/ASCE’s leading role in promoting and advancing the application of quantitative life-cycle performance metrics to incorporate sustainability and climate-resilience issues in design practice, influencing the development of structural design codes and standards, and enhancing the state of the nation’s infrastructure to protect public safety, improve the quality of life and ensure resilient communities.
Source: If, after finishing the book an engineer would come away knowing just one new thing, what should that be?
Biondini: The key aspect in incorporating climate change effects into structural engineering is non-stationarity. As mentioned, historic climate-related events do not accurately reflect future impacts and extremes associated with climate change effects, implying that both demand and resistance change over time. Consequently, the assumption of stationarity underlying the concept of return period, which is used in current climate statistical modeling, is invalid because the annual extreme climate variables are not identically distributed.
Thus, characterizing the non-stationary nature of time-variant structural reliability becomes essential for guiding the determination of design targets and safety criteria that ensure adequate levels of structural safety and reliability throughout the structure’s life-cycle. This is a paradigm shift of paramount importance for civil and structural engineering.
Learn more about Effects of Climate Change on Life-Cycle Performance of Structures and Infrastructure Systems: Safety, Reliability, and Risk, edited by Fabio Biondini, Zoubir Lounis, and Michel Ghosn, and available in print and as an e-book in the ASCE Library.
