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NCREE and NLPI Organize Exhibition on Home Earthquake Safety

Taiwan is prone to earthquakes and typhoons, which in many cases bring about major disasters. Therefore, the National Science and Technology Council (NSTC) has devoted considerable resources to the research of disaster prevention technology as well as science exhibitions and activities to help the public learn the basics about disaster prevention. The National Center for Research on Earthquake Engineering (NRCEE) of NARLabs, in its implementation of NSTC policy, has collaborated with the National Library of Public Information (NLPI) to hold an earthquake-themed exhibition titled "Home Health Check - Protecting Lives" (宅健檢.護一生), which is now on display at NLPI in their Digital Art Center (2F) until June 30, 2023. The exhibition will enable the public to learn how to transform their homes to become more earthquake-safe.

On February 6, 2023, two powerful earthquakes of magnitude 7.8 and 7.5 hit southeastern Turkey and Syria. The number of victims was reported to have exceeded 30,000. Seeing such news, we in Taiwan felt deeply for those who suffered the calamity. The 1999 Jiji earthquake, the 2016 southern Taiwan earthquake, the 2018 Hualien earthquake, and the 2022 Taitung earthquake all exceeded 6 on the Richter scale. According to official statistics, 2,415 people were killed and more than 11,000 people were seriously injured in the Jiji earthquake, and 134 lives were lost and 846 were seriously injured in the 2016 and 2018 earthquakes, reminding us again and again of the horror earthquakes can cause. However, Taiwan and earthquakes are closely connected, for without earthquakes, this island would not have been formed. Co-existing with earthquakes is a task that all people living in Taiwan must face.

Hear the Experts on Home Earthquake Safety

Due to the large number of old buildings in Taiwan, coupled with the mixed residential and commercial lifestyle, improper construction (such as knocking over existing walls and columns, illegal roof additions, etc.) can easily create what is locally known as "soft-legged shrimp" or "back-less" buildings. Such buildings are weak and prone to damage or even collapse in an earthquake due to insufficient seismic capacity. At the "Home Health Check - Protecting Lives" exhibition, the public can learn more on how seismic assessment and retrofitting of old buildings is conducted, as well as what government incentives are available to do so.

The exhibition is divided into five sections, which guide visitors as they learn about what makes buildings earthquake-prone or earthquake-resistant, and how to apply that knowledge in their own homes. The first section illustrates the painful lessons learned from the 2016 southern Taiwan earthquake and the 2018 Hualien earthquake. In investigations conducted after these earthquakes, experts found that weak ground floors of buildings are one of the main reasons for the lack of seismic resistance.

But what does it mean to have a "weak ground floor?" In the following two sections, visitors learn what makes a ground floor considered weak, the common causes of weakness, and what kind of houses are more resistant to earthquakes. This area also features building blocks and a manual shake table which allow visitors to learn some basic know-how when it comes to seismic resistance. Visitors can use the building blocks to construct their own houses and put them on the shake table to test their earthquake resistance.

Assessment and Retrofitting Increase Safety

After a preliminary understanding of what makes a home prone to earthquake damage, visitors can then learn about what can be done to increase earthquake resistance, especially in old buildings. There are many tried-and-tested seismic retrofitting methods available on the market. In the fourth section of the exhibition, posters and models introduce common retrofitting methods, such as column expansion, shear wall reinforcement, wing wall reinforcement, diagonal bracing with steel frames, additional structure reinforcement, elevator wall reinforcement, etc. Each method has its own structural applicability and advantages and disadvantages, so we suggest the public seek the assistance of a professional to conduct seismic assessment of a building and select the retrofitting method that meets their needs.

At this point, many people remark that although they know the importance of increasing earthquake safety and want to strengthen their homes, they worry about the cost. In the final section, therefore, current retrofitting subsidy programs are introduced as well as real-life retrofitting projects that have been completed. To encourage the public to carry out seismic retrofitting, the Ministry of the Interior's Construction and Planning Agency has set up official guidelines for consultation on preliminary assessment of seismic capacity of buildings and for retrofitting subsidies. Subsidies are provided according to the size of the retrofitting area. NCREE has been commissioned by the Construction and Planning Agency to set up an office to provide technical support for the retrofitting program. For more information about the program, please see its official website (in Chinese): Subsidy types vary by case, and the maximum amount is NT$4.5 million, provided that the subsidy does not exceed 85% of the total retrofitting cost.

At present, many buildings in Taiwan have undergone retrofitting through the above subsidy program. For instance, the exhibition introduces a six-story reinforced concrete building (the ground floor being a parking lot, while floors 2 through 6 are residences) built in 1993 in Hualien City. Retrofitting of the weak ground floor was completed in just 50 days with a total cost of roughly NT$1.8 million (including design, inspection, and construction) under a Case A subsidy. In this case, shear wall reinforcement on the ground floor was chosen to significantly reduce the impact of construction on the daily lives of the occupants of the second to sixth floors.

Even after all this information, some still wonder how these reinforced buildings will perform in the face of an actual earthquake. To answer this question, NCREE installed sensors in four of its reinforced buildings (one in Taipei, two in Hualien, and one in Tainan) to conduct post-retrofitting structural monitoring. Structural monitoring data from six earthquakes with maximum magnitudes of 3 to 5- on the Central Weather Bureau seismic intensity scale that occurred between February and September 2022 showed that the maximum interstory drift ratio between the first and second floors was well below 0.5%, meeting the conditions for no small earthquake-induced damage.

Lastly, a paper model house DIY area in the exhibition allows both adults and children to build their own seismic-resistant houses to understand the importance of walls for safety during an earthquake. Through posters, videos, models, and hands-on activities, the exhibition aims to give all visitors a deeper understanding of home earthquake safety so that all can come together to improve the safety of their own homes.