Seismic Performance of Ancient Masonry Structures in Korea Rediscovered in 2016 M 5.8 Gyeongju Earthquake

Abstract

The Gyeongju Historic Areas, which include the millennium-old capital of the Silla Kingdom, are located in the region most frequently affected by seismic events in the Korean peninsula. Despite the numerous earthquakes documented, most of the stone architectural heritage has retained their original forms. This study systematically reviews and categorises studies dealing with the seismic risk assessment of the architectural heritage of the historic areas. It applies research methodologies, such as the evaluation of the engineering characteristics of subsoil in architectural heritage sites, site-specific analysis of the ground motions in response to earthquake scenarios, geographic information system (GIS)-based seismic microzonation according to the geotechnical engineering parameters, reliability assessment of dynamic centrifuge model testing for stone masonry structures and evaluation of seismic behaviour of architectural heritage. The M 5.8 earthquake that hit Gyeongju on 12 September 2016 is analysed from an engineering point of view and the resulting damage to the stone architectural heritage is reported. The study focuses on Cheomseongdae, an astronomical observatory in Gyeongju, whose structural engineering received considerable attention since its seismic resistance was reported after the last earthquake. Dynamic centrifuge model tests applying the Gyeongju Earthquake motions are performed to prove that it is not a coincidence that Cheomseongdae, a masonry structure composed of nearly 400 stone members, survived numerous seismic events for over 1300 years. The structural characteristics of Cheomseongdae, such as the well-compacted filler materials in its lower part, rough inside wall in contrast to the smooth exterior, intersecting stone beams and interlocking headstones are proven to contribute to its overall seismic performance, demonstrating outstanding seismic design technology.

Experimental Investigation of Traditional Clay Brick and Lime Mortar Intended for Restoration of Cultural Heritage Sites

“…Due to its durability and economy, masonry has been used not only in buildings but also in many other structures such as stone towers, castles, arch bridges and dome structures, from ancient times (Mesopotamian civilization) to the present [1][2][3]. It is estimated that brick and mortar were first used in the period of the Three States Kingdom of ancient Korea (57 BCE-668 CE) as high-class materials to construct royal facilities such as palaces, tombs and shrines rather than ordinary structures [4][5][6]. Many ancient and modern masonry structures, e.g., the Royal Tombs, Brick Pagodas, Suwon Hwaseong Fortress (listed as a UNESCO cultural heritage site in 1997), Namhansanseong Fortress (listed as a UNESCO cultural heritage site in 2014) were designed and constructed with the evolving civilization of the country.…”

Development of a Probabilistic Seismic Performance Assessment Model of Slope Using Machine Learning Methods

“…However, since the start of monitoring and measuring earthquake motions in 1978, earthquakes in Korea with a moment magnitude of 2.0 or higher have occurred 20 times per year until 1998, but this frequency has increased to an average of 48 times per year during the period between 1998 and 2015 [3]. Furthermore, Korea has experienced two strong earthquakes, one in Gyeongju in 2016 and the other in Pohang in 2017, raising concerns over safety during earthquakes near major facilities [1,[4][5][6].…”