Thursday March 4th 2021,12.00 UK time
Professor Yukio Tamura, School of Civil Engineering, Chongqing University, China, Wind-related Disaster Risk Reduction: Current Status and Future Prospects
- Professor Forrest J. Masters, Ph.D., P.E. (FL), Professor and Associate Dean for Research and Facilities, Herbert Wertheim College of Engineering, University of Florida. Revisiting Hurricane Maria’s impact to Puerto Rico: Topographic wind speed up in complex terrains.*
- Professor Chris Baker, Emeritus Professor of Environmental Fluid Mechanics, School of Engineering, University of Birmingham. The resilience of transport and agricultural networks to strong winds.
* with contributions from Jorge X. Santiago-Hernandez, Graduate Research Assistant, Engineering School for Sustainable Infrastructure & Environment, University of Florida, Luis D. Aponte-Bermúdez, Ph.D., P.E. Professor, Department of Civil Engineering and Surveying, University of Puerto Rico at Mayagüez Edward C. Garcia, Graduate Research Assistant, Department of Civil Engineering and Surveying, University of Puerto Rico at Mayagüez
The Registration link can be found here.
Wind-related Disaster Risk Reduction: Current Status and Future Prospects. In the seminar, the current status of wind-related disaster risk reduction activities and future prospects are summarized. Wind engineers have been making great efforts to reduce wind-related disasters in the past few decades, but the number of devastating wind-related disasters and accompanying economic losses are still significantly increasing, and climate change due to global warming is hypothesized to exacerbate this trend in the future. The seminar aims to discuss what we should do now to cope with future unfavorable wind effects on our society. First, the various types of winds that cause serious disasters to our society are overviewed from extremely strong winds to moderate and light winds. Some typical examples of wind-induced damage to buildings and structures are introduced, and the importance of the performance of claddings and components is particularly demonstrated. Then, some problems with the wind-resistant-design principles are discussed, such as reassessment of the relation between design-load level and lifetime of individual buildings and elements including temporary buildings. In connection with this, a kind of paradigm shift in building design method focusing on a group of unspecified buildings rather than an individual specified building is recommended. Many other relevant issues are also discussed as follows: structures such as scaffoldings, cranes, movable roofs designed under the assumption that they will be controlled or maintained for strong wind cases based on a specified wind speed; design and construction principles of disaster prevention bases, evacuation facilities, high-risk facilities, high-priority facilities; engineering modeling of strong wind events; and so on. Some statistics of wind-related disasters are introduced, and future trends under climate change due to global warming are discussed. To stop the repetition of wind-related disasters, the necessity of accurate estimations of the performances of claddings and components are again emphasized, and it is recommended to devote more research attention to performance estimation. In conjunction with this, the necessity of full-scale storm simulators (FSSS) are finally demonstrated, with a motto of “Invest today, Save tomorrow”.
Revisiting Hurricane Maria’s impact to Puerto Rico: Topographic wind speed up in complex terrains. Complex topography can double the fluctuating surface velocity relative to flat terrain conditions, thus topography induced accelerations are regularly implicated in windstorm damage. The presentation will describe ongoing research on the use of machine learning, numerical weather prediction, and computational fluid dynamics (CFD) to predict wind ‘speedup’ in mountainous areas and other regions with steep slopes. It will review testing currently underway at the Terraformer boundary layer wind tunnel (BLWT) at the NSF Natural Hazards Engineering Research Infrastructure (NHERI) Experimental Facility at the University of Florida, which is using precision guided multi-port pitot tubes and particle image velocimetry (PIV) to collect high-resolution velocity field data over geometrically scaled models of sections of the main island of Puerto Rico and the municipal Islands of Vieques and Culebra. Comparison will be made between the lab measurements and predictions from shallow neural networks, RANS/LES CFD, and high-resolution Weather Research and Forecasting Model (ARW Core) modeling. The presentation will conclude with comments about the appropriate use of BLWTs for modeling wind-speed up and the prospects for using digital elevation data and machine learning to automate prediction.
The resilience of transport and agricultural networks to strong winds. The effects of high winds on individual buildings and structures has been given a great deal of attention over recent decades. Rather less attention has been given to the effects of high winds on geographically large-scale networks – such as transportation systems and large scale agricultural and forestry networks. This presentation will briefly discuss the nature of wind effects on such systems and the methods that can be used to both determine risk of different levels of system failure and to minimize the damaging effects of high winds as far as possible. It will be seen that the wind engineering information required to make such assessments is rather different from that required for the analysis of individual buildings and requires different non-standard statistical descriptions of the wind and also information on large scale temporal and spatial wind coherence. Statistical tools that can combine both deterministic aspects (such as transport timetables or specific agronomic interventions) with wind statistical information are required. The propagation of local failures with such systems will also be discussed.
Professor Yukio Tamura is a Professor of the School of Civil Engineering, Chongqing University, China, and the Honorary Director of the Wind Engineering Research Center, Tokyo Polytechnic University, Japan. He served as the President of the International Association for Wind Engineering for eight years from 2007 to 2015. He is currently serving as an Adjunct/Guest/Honorary Professor of 19 universities in China, Korea, Malaysia, Poland, and USA. Professor Yukio Tamura is a member of the Engineering Academy of Japan, a Foreign Fellow of the Indian National Academy of Engineering, and a Foreign Member of Chinese Academy of Engineering.
Dr. Forrest Masters is a Professor in the Engineering School of Sustainable Infrastructure & Environment and serves as Associate Dean for Research and Facilities in the Herbert Wertheim College of Engineering. He earned his PhD in civil (structural) engineering from the University of Florida in 2004. Dr. Masters has received support from more than 50 grants from state, federal and private sources, including the NSF CAREER and MRI Programs. He also leads one of seven Natural Hazards Engineering Research Infrastructure (NHERI) experimental facilities for the NSF to study the damaging effects of extreme wind events on civil infrastructure. Dr. Masters has published more than 100 papers in peer-reviewed journals and conference proceedings and given more than 100 invited presentations. He serves on the Board of the Federal Alliance for Safe Homes, and recently served on the NIST National Advisory Committee on Windstorm Impact Reduction. In 2014, Dr. Masters was awarded the junior International Association of Wind Engineering award, which is the highest award in his field that recognizes significant and original contributions to research by an individual under the age of 40. He was also honored with the Outstanding Achievement Award in Mitigation at the National Hurricane Conference.
Professor Chris Baker read Engineering at St Catharine’s College in Cambridge, graduating with a BA in 1975, and an MA and a PhD in 1978. Following a Research Fellowship at St Catharine’s College and the Department of Engineering, in the early 1980s he began work in the Aerodynamics Unit of British Rail Research in Derby, before moving to an academic position in the Department of Civil Engineering at the University of Nottingham. He remained there till 1998 as a lecturer, reader and professor with research interests in vehicle aerodynamics, wind engineering, environmental fluid mechanics and agricultural aerodynamics. In 1998 he moved to the University of Birmingham as Professor of Environmental Fluid Mechanics in the School of Civil Engineering. From 2003 to 2008 he was Head of Civil Engineering and was the Director of the Birmingham Centre for Railway Research and Education from 2005 to 2014. He retired at the end of 2017 and took up an Emeritus position. He continues to be involved in research in train aerodynamics, wind engineering and transport issues. In July 2020 he was awarded the Davenport Medal, the senior award of the International Association of Wind Engineering.
Questions and answers
Question from Yong Wang to Prof. Tamura. You emphasized the important combined effects of wind and water hazards, which can cause large scale loss. Could you suggest the most promising methodology for the study of wind and water effects? It seems to me that there may exist difficulties to simulate the effects of water even in the full-scale storm simulator.
Answer. Thanks for your good comment. It might also be possible to study water hazards in full-scale, but honestly speaking, the necessity for a full-scale facility for water is not clear to me. When we consider the combined effects of water and wind, I didn’t intend to test the combined effects of wind and water forces. In the case of water hazards, prediction of floods including storm surge and recommendations for evacuation timing are the most important issues. For those purposes, a full-scale facility is not necessary for water, but it is clearly necessary for wind.
Question from Asih to Prof. Tamura. You mentioned that its important for Wind Engineers to move from focusing from Load and Wind Action to Resistance and Structural Performance. What do you think of the recent Performance based Wind Code in the ASCE, is this the direction you are talking about?
Answer. Thanks for the good question. Performance-based design is actually a possible direction. In the case of wind-resistant design, “performance of cladding and components” is very important. Without knowing the real performance of cladding and component systems, we cannot realize performance-based wind-resistant design. For this, we need full-scale storm simulators. I think database assisted design or AI assisted design might be a possible direction, too.
Question from Ron Aquino to Prof. Tamura. Thank you for your lecture. “O hisashiburi!” While education and enforcement is important when it comes to building codes, do you think there is still any room for improvement in existing wind loading codes, both international/reference codes (ASCE, AIJ, AS/NZS, EN, etc) and national (e.g. codes that adopted ASCE, etc)? In what areas? Is moving to a performance-based approach rather than a code-based approach one of them?
Answer. Thanks, Ron, for your nice question. I think there are many issues to be improved, as I mentioned in my lecture. These include a design method for long-span roof structures, for which the traditional GLF method is not appropriate; a GLF for “ultimate limit state” design, which should be different from GLF for serviceability limit state” design; a design concept and definition of “temporary buildings” including construction work offices and scaffoldings; a current “Minimum LCC” design concept based only on the lifetime of an individual building. Yes, PBD is a possible direction, but for that, we need to know the real “Performance” of buildings, especially “Performance of Cladding and Components”. That’s why I emphasized the necessity for a full-scale storm simulator.
Question from Yufen Zhou to Prof. Masters.. Thank you for the interesting presentation. Could you talk about the role of machine learning in the PIV tests? How would machine learning help with the PIV data from wind tunnel test?
Answer.. The PIV data are being used to train the machine learning model, with the goal of using the model to predict speedup in all regions that have similar characteristics to the topography in the study region.
Question from Fred Haan to Prof. Masters. Did you have a chance to compare the velocity profiles from your topo tests with any full-scale data? Does any such full-scale data exist?
Answer. That is the long term plan, however it is not in the scope of the project we discussed. Once we train the model, we can apply it to study any weather station that is located in an area similar to Puerto Rico to test how well it works.