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What Is the Best Earthquake Resistance Technique? 2022 IDEERS Competition

NARLabs' National Center for Research on Earthquake Engineering (NCREE), under the National Science and Technology Council (NSTC), is committed to promoting research and education on disaster prevention and its related technology. In line with NSTC policy, NCREE assists with domestic research on earthquake prevention and mitigation technology, as well as organizes the Introducing and Demonstrating Earthquake Engineering Research in Schools (IDEERS) competition for young students to gain knowledge about proper earthquake prevention. The competition aims to attract more young people to engage in research on earthquake prevention and mitigation and create earthquake resistant homes.

IDEERS, which tests earthquake resistance in models built by students, was held on Sept. 17, 2022. First place in the general and vocational high school division was won by Yang-Tze High School, first place in the college-level institution and university division was won by National Taiwan University, and first place in the graduate division was won by National Central University. The Seismic Isolation and Damping Innovation Award was presented to National Cheng Kung University.

Coexisting with Earthquakes: IDEERS Promotes Disaster Prevention Education

It has now been more than 20 years since the 1999 Jiji earthquake, and although earthquake engineering technology is constantly being innovated, it is still impossible to effectively predict earthquakes with our current technology. Therefore, it is important to educate people about earthquake preparedness and disaster prevention. The IDEERS earthquake resistance competition has been held annually since 2001 (with the exception of 2020 and 2021), with a cumulative total of over 8,000 student participants from Taiwan and abroad. Countries and regions that have participated in the past include the United Kingdom, the United States, Japan, Korea, Singapore, Indonesia, India, Hong Kong, Malaysia, Vietnam, New Zealand, Australia, Belize, the Philippines, and Guatemala. Due to the COVID-19 pandemic, the 2020 and 2021 IDEERS competitions were suspended. Although an improvement in the pandemic situation allowed the event to be held again this year, the entry of international participants into Taiwan was still affected by COVID prevention measures. Therefore, this year's event was restricted to Taiwanese schools only, and the rules were adjusted to meet COVID prevention regulations. This year, the competition attracted 225 participants from 45 teams representing general and vocational high schools, college-level institutions and universities, and graduate schools.

The event was held over two days, kicking off on Sept. 16 with model making. Teams worked remotely, having to complete their models within 5.5 hours on camera. Then, they were tasked with recording a video to introduce their model's design features and concepts as well as the methods they used to improve stabilization, seismic isolation, and shock absorption, all of which the organizers evaluated. The next day, on Sept. 17, the teams were divided by division, and the models were submitted to the judges for review and for load capacity testing, followed by overall testing of the model. For the high school and college/university divisions, iron blocks of at least 7.5 kg were added to the model according to the area of its levels. For the graduate division, 10-kg iron blocks were added to each floor for a total of 40 kg.

Capability-Price Ratio Determines Victor

The challenge presented to the high school and college/university divisions was to make a tower-shaped structure with a single load platform (such as an observation tower, a water tower, a bridge pier, etc.) out of long, thin wooden strips, hot glue, rubber bands, and thin cotton rope. Then, the structure must be tested under various kinds of earthquakes of different magnitudes, with the magnitude increasing gradually until the maximum earthquake strength specified in the competition is reached or until all models collapse. Graduate students were given the freedom to design various seismic isolation and shock absorption devices so that their models would collapse under a required seismic force (1050 gal). Sinotech Engineering Consultants Inc. sponsored the Seismic Isolation and Damping Innovation Award for graduate student participants. Three to six finalists were selected by a panel of judges from among the participating teams, and sensors were installed on their models to measure the acceleration of the top floor of the models to better understand their seismic isolation and damping effects. The team with the best results was awarded NT$100,000 in prize money.

Before the models are placed on the shake table, the mass of each model is recorded (heavier mass means excessive material was used, thus lowering the score). During the test, the seismic intensity that causes damage to the model is recorded. These values are used to calculate the capability-price ratio of each model. After the shake test, the three models with the highest capability-price ratios were selected from each group and awarded prize money and trophies. In addition, the jury also conferred a "Best Design" award, presenting prize money and a certificate to encourage the young students.

The top three winners in the general and vocational high school division were Yang-Tze High School, Chung Hwa Commercial Vocational Senior High School, and National Yeong-Jing Industrial Vocational High School, respectively. The college-level institution and university division winners were National Taiwan University, Chung Yuan Christian University, and China University of Technology. In the graduate division, the top awards were won by National Central University, National Yang Ming Chiao Tung University, and National Cheng Kung University. The most prestigious award in the graduate division, the Seismic Isolation and Damping Innovation Award, was presented to National Cheng Kung University.

The Yang-Tze High School team, winners of the general and vocational high school division, built a model with a simple but robust structure with only one platform on the top floor. It was a typical tower structure with no superfluous components, and the platform bore the most mass blocks, meaning that its efficiency was quite high. In addition, although there were only four columns, their anchor-type foundation raised the stability of the column base, and inclined support provided lateral bracing and an energy dissipation mechanism. Cotton rope also provided restoring force, so the tough structure remained standing without swaying even when acceleration reached 900 gal.

The National Taiwan University team who won first in the college-level institution and university division faced this year's challenge by using computer analysis before the competition and adopting a "softness over strength" design for their model. They focused on the selection of materials for the columns and optimization of the layering of the flooring. They also took into consideration the stiff center of the structure and the center of gravity of the weight blocks, so that the two were as close as possible in the design, successfully tackling the problem of earthquake-induced structural torsion.

In the graduate student division, National Central University took home the top prize. Their model employed an active seismic isolation system formed by slide rail isolation and active control. When an earthquake occurs, the acceleration gauges installed on the ground measure the vibration signals on the earth's surface. These signals get fed back to an internal computer, and then the required control force is calculated by the seismic isolation control system designed by the team. The control force is applied by a motor, precisely controlling the displacement of the seismic isolation structure so that the shaking will hardly affect the upper structure. The team's advanced active control technology combined cross-disciplinary knowledge of civil engineering, electromechanical control, and signal measurement, resulting in their model's excellent performance.

The Seismic Isolation and Damping Innovation Award was won by a team from National Cheng Kung University. Their concept was based on the common practice of seismic isolation and tuned mass dampers, which were integrated into a single model to enhance structural safety. Furthermore, the tuned mass dampers were advantageous for seismic isolation precisely within the ground acceleration amplitude set by the competition. The design of the upper structure, with its traditional symmetry and facade, significantly reduced possible torsion, and the combined strengths of the seismic isolation system and the upper structure made it a worthy winner of the top award.