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SEAONC Post Newsletter - Partner Organization

Published on 4/1/2022
Collaborations with EERI’s “Learning from Earthquakes” program

On January 25th,2022, the SEAONC Seismology invited Professor Eduardo Miranda to speak on his EERI’s “Learning from Earthquakes” (LFE) committee and discuss possible collaborations with SEAONC. The discussion started with noting the importance of earthquake reconnaissance, which Professor Miranda first experienced in Mexico City during his undergraduate studies. During this time, he interacted with many leading professors in earthquake engineering all around the world and found it surprising that these experts were taken back by the outcome of this earthquake. He incorrectly assumed that these experts, through years of studying and experimental tests, would be more knowledgeable about the outcome of an earthquake. After this reconnaissance, he realized how valuable the information gained after earthquake reconnaissance is and has been going on reconnaissance events ever since.

The LFE program, which Professor Miranda is leading, focuses on earthquake reconnaissance. The program, which was formally initiated in 1973, is one of EERI’s main program and its goal is to document damage after major earthquakes. In past years, it received funding from the National Science Foundation (NSF) to send a combination of experienced engineers and younger engineers out to recent earthquake sites to document the performance of structures. This was done in two ways. One was the production of specific reports on the reconnaissance event and the other was special issues of Earthquake Spectra. For some earthquake such as the 1985 Mexico City Earthquake, there were multi-volumes of Earthquake Spectra’s special issues created. The LFE program created many peer-reviewed paper which furthered our understanding of earthquake engineering. Unfortunately, NSF stopped funding this program recently and LFE is looking for alternative ways to continue the work they were doing.

While numerical studies and experimental test can provide insight into the performance of structures, their dynamic response during an earthquake is complex, and can only truly be understood through earthquake reconnaissance. Images of slender concrete walls from the 1985 Chilean Earthquake and 2011 New Zealand earthquake led to design changes in the US building code. During a reconnaissance event in Chile, Professor Miranda gained access to a video showing the failure of an elevator’s counterweight during their magnitude 8.8 earthquake. It would be highly unlikely to obtain this kind of information through numerical models or experimental tests. The photos Dr. Francisco Medina took after the Chilean Earthquake on buildings, bridges and refineries put pictures to the words in ACI 318. Professor Harry Bolton Seed, considered the father of geotechnical earthquake engineering, may never have witness liquefaction as captured in video during the 2011 Tohoku earthquake. Examples such as these were relayed back and forth by committee members.

The intent of this meeting was to discuss potential collaborations between EERI’s LFE and SEAONC. It is likely that a major impacting earthquake will take place in California in the future, and our organizations should be able to react quickly when this happens. The tagging of buildings started after the Loma Prieta earthquake. Although many buildings were tagged, it was not done in a systematic and organized way. The earthquakes which occurred after were not in large urban areas resulting in no development in the methodology of tagging. EERI is collaborating with committees such as GEER and STEER to prepare for this. GEER and STEER are more academic in nature, and teaming up an organization such as SEAONC, consisting of more practicing engineers, would be greatly beneficial. SEAONC already has plans in place to coordinate with Southern California after a major California earthquake, and this could compliment those efforts. Another project Professor Miranda and a few colleagues at Stanford have been launching concentrates on taking high resolution photos of buildings in San Francisco. This pre-earthquake data could help researchers understand damaged after an earthquake better and this program could use more volunteers. Seismology committee members suggested also collaborating with other disciplines which do similar reconnaissance events, such as the members from IEEE who went down to Chile after their major earthquake and took pictures of the substations. Lastly, engineers sent to earthquake disaster sites for company projects can document damage and provide those images to LFE.

The large earthquakes impacting densely populated areas in the last thirty years have accrued outside of California, and some of these areas have construction practices different from the US. Buckle restraint braces, for example, were introduced into the US fifteen years ago and are not commonly used in other countries. However, there is still information which could be gained from these earthquakes outside the US, such as the recorded ground motions. Additionally, California also has many structures which were built in a time before structures were designed for earthquakes. An example of this is the California Missions, which would have a similar earthquake response as the churches in South America. Some construction practices are not too far from the US. Many countries in South American follow ACI very closely and damage done to reinforced concrete buildings in Chile influenced US design of these buildings. Applicability of data collected from foreign reconnaissance events varies case by case. However, accessibility to data after an earthquake is much easier in other countries compared to the US because of its legal system. After the Loma Prieta Earthquake, the AT&T stadium was quickly wrapped in plastic so that pedestrians from the street could not see damage most likely due to an ongoing lawsuit. On the other hand, Professor Miranda along with Bill Homes freely walk around a military hospital taking pictures in Chile after its 8.8 earthquake. This type of accessibility would be highly unlikely in the US.

A challenge with earthquake reconnaissance is organizing the data collected. Historical, engineering firms, such as Degenkolb, would take two hundred photos after an earthquake. With the capabilities of modern smart phones, a single individual can take over one thousand photos. This overload of data can be a nightmare to organize. Furthermore, different organizations have been collecting data in their own database and a centralized database does not yet exist. A future vision of LFE is to gather all data from various organizations and attach keywords to each photo. The idea is derived from Google Images, where a user can locate an image by typing in a few relevant keywords. Professor Miranda helped Maryann Phipps on a related effort for nonstructural components. This document, FEMA E74, became so big that the authors realized it would never be published. A similar endeavor could be for other structures such as port facilitates. The information in these databases could have multiple purposes. For example, LFE collected a lot of images after the Puerto Rico earthquake, and these could be used by building officials for stricter enforcement for certain code provisions. Images of a damaged viaduct could be used by the engineers retrofitting similar structures. Another purpose could be a US building code committee using these images for introducing new code provisions.

With the advancements in technology, an idea for the next generation of earthquake reconnaissance would be equipping each participant with a go pro camera. While the participant is walking around and observing damage, there could be five other individuals assisting him or her from their desk. In case the on-site participant missed something, the remote individuals could alert the individual in real time. This would be especially beneficial if the on-site participant has only limited experience and requires help from someone more knowledgeable. Seismology committee member Neil Moore mentioned that he had suggested something similar for engineers red tagging and repairing buildings. The engineer on-site may not be fully equipped to provide detailed retrofits so this task could be outsourced to engineers back at the office. Another role technology could play in the next earthquake is gathering ground motions from smart phones. Current smart phones have built in accelerometers and, while they are not as good as a state-of-the-art kinematic accelerometer, they could provide motions not just at ground level but also along the height of a building. Shaking table tests have been used to understand the effectiveness of these instruments and there is current continuing research on this topic.

The meeting ended on potential collaborations between researchers and practitioners, and ways the Seismology committee can facilitate this. This was intended to be a continuation of a discussion which occurred at the 2022 SEAOC Convention. The convention discussion ended with three conclusions on how engineers could get more involved with research: (1) engineers should get involved in programs such as special project initiative (SPI) and University Research Program (URP), (2) companies could set up an internal research program and (3) some academic organizations, such as PEER, have an industry board with practicing engineers to advise the researchers. Professor Miranda noted that Stanford has interacted with practicing engineers in the past, and in general, they like to bring in consulting engineers on their larger projects. The reason for this is to make the research more practical. A large percentage of research never gets applied in practice due to the research being so utopian that it is not realistic in practice. Seismology committee member, Edward Gil, also suggested that the committee should interact with building jurisdictions, such as HCAI, and find out their research interests. Sometimes, engineers come up with innovative designs, and if there isn’t much documented research on these designs, the engineer is forced to create their own. The seismology committee intends to foster these ideas in future meetings.

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