The Gyeongju and Pohang earthquakes caused damages to many cultural properties; particularly, stone pagoda structures were significantly damaged among masonry cultural properties. To preserve these structures, it is necessary to understand their dynamic behavior characteristics under earthquakes. Analyses on such areas as deformation, frequency, maximum acceleration, permanent displacement, sliding, and rocking have to be performed. Although many analytical studies have already been conducted, dynamic behavior studies based on experiments are insufficient. Therefore, this study analyzed dynamic behavior characteristics by performing a shaking table experiment on a three-story stone pagoda structure at the Cheollongsa temple site damaged by the Gyeongju earthquake. As a result of the experiment, the displacements of stylobates did not occur significantly, but the tower body parts rotated. In particular, the rotation of the 1F main body stone was relatively larger than that of the other chief body stones because the 1F main body stone is relatively more slender than the other parts. In addition, the decorative top was identified as the component most vulnerable to sliding. This study found that the 1F main body stone is vulnerable to rocking, and the parts located on the upper part are more vulnerable to sliding.

Current seismic fragility functions for buildings were developed by defining damage state threshold based on story drift concerning foreign references and using the capacity spectrum method based on spectral displacement. In this study, insufficient details and dependence on the core location of piloti-type buildings were not reflected in the fragility function because it was developed before the Pohang earthquake. In order to develop an improved one for piloti-type buildings, several types of core were selected, damage state threshold was determined based on the capacity of structural members, and three-dimensional analyses were utilized. As a result, seismic fragility functions based on spectral acceleration were developed for various core locations and different shear strengths of the column stirrup. The fragility of piloti-type buildings significantly varied according to core location, an additional single wall, and whether the contribution of column stirrup was included or not. To estimate fragility more reasonably, it is necessary to prepare the parameters to reflect actual state well.

In 2017 Pohang Earthquake, a number of residential buildings with pilotis at their first level were severely damaged. In this study, the results of an analytical investigation on the seismic performance and structural damage of two bearing wall buildings with pilotis are presented. The vibration mode and lateral force-resisting mechanism of the buildings with vertical and plan irregularity were investigated through elastic analysis. Then, based on the investigations, methods of nonlinear modeling for walls and columns at the piloti level were proposed. By performing nonlinear static and dynamic analyses, structural damages of the walls and columns at the piloti level under 2017 Pohang Earthquake were predicted. The results show that the area and arrangement of walls in the piloti level significantly affected the seismic safety of the buildings. Initially, the lateral resistance of the piloti story was dominated mainly by the walls resisting in-plane shear. After shear cracking and yielding of the walls, the columns showing double-curvature flexural behavior contributed significantly to the residual strength and ductility.

The paper presents the damage estimation of bridge structures in Daegu city based on the scenario-based earthquakes. Since the fragility curves for domestic bridge strucures are limited, the Hazus methodology is employed to derive the fragility curves and estimate the damage. A total of four earthuquake scenarios near Daegu city are assumed and structure damage is investigated for 81 bridge structures. The seismic fragility function and damage level of each bridge had adopted from the analytical method in HAZUS and then, the damage probability using seismic fragility function for each bridge was evaluated. It was concluded that the seismic damage to bridges was higher when the magnitude of the earthquake was large or nearer to the epicenter.

Severe earthquakes can cause damage to society both socially and economically. An appropriate initial response can alleviate damage from severe earthquakes. In order to formulate an appropriate initial response, it is necessary to identify damage situations in societies; however, it is difficult to grasp this information immediately after an earthquake event. In this study, an earthquake damage assessment methodology for buildings is proposed for estimating damage situations immediately after severe earthquakes. A response spectrum database is constructed to provide response spectra at arbitrary locations from earthquake measurements immediately after the event. The fragility curves are used to estimate the damage of the buildings. Earthquake damage assessment is performed from the response spectrum database at the building scale to provide enhanced damage condition information. Earthquake damage assessment for Gyeongju city and Pohang city were conducted using the proposed methodology, when an earthquake occurred on September 12, 2016, and November 15, 2017. Results confirm that the proposed earthquake damage assessment effectively represented the earthquake damage situation in the city to decide on an appropriate initial response by providing detailed information at the building scale.

This study examines the seismic failure of RC low-rise building structures having irregularities at the ground story during the 15 November 2017 Pohang, Korea, earthquake, Mw = 5.4, which is the second strongest since the government began monitoring them in 1978 in South Korea. Some 2,000 private houses were damaged or destroyed in this earthquake. Particularly, serious damage to the piloti story of RC low-rise residential building structures of fewer than five stories was observed within 3 km of the epicenter with brittle shear failure of columns and walls due to severe torsional behavior. Buildings below six stories constructed before 2005 did not have to comply with seismic design requirements, so confinement detailing of columns and walls also led to inadequate performance. However, some buildings constructed after 2005 were damaged at the flexible side of the piloti story due to the high torsional irregularity. Based on these results, this study focuses on the problems of the seismic torsion design approach in current building codes.

This paper investigates seismic damage potential of recent September 12 M5.8 Gyeongju earthquake from diverse earthquake engineering perspectives using the accelerograms recorded at three stations near the epicenter. In time domain, strong motion durations are evaluated based on the accelerograms and compared with statistical averages of the ground motions with similar magnitude, epicentral distance and soil conditions, while Fourier analysis using FFT is performed to identify damaging frequency contents contained in the earthquake. Effective peak ground accelerations are evaluated from the calculated response spectra and compared with apparent peak ground accelerations and the design spectrum in KBC 2016. All these results are used to consistently explain the reason why most of seismic damage in the earthquake was concentrated on low-rise stiff buildings but not quite significant. In order to comparatively appraise the damage potential, the constant ductility spectrum constructed from the Gyeongju earthquake is compared with that of the well-known 1940 El Centro earthquake. Deconvolution analysis by using one accelerogram speculated to be recorded at a stiff soil site is also performed to estimate the soil profile conforming to the response spectrum characteristics. Finally, response history analysis for 39- and 61-story tall buildings is performed as a case study to explain significant building vibration felt on the upper floors of some tall buildings in Busan area during the Gyeongju earthquake. Seismic design and retrofit implications of M5.8 Gyeongju earthquake are summarized for further research efforts and improvements of relevant practice.

Damage potential has been investigated for a domestic metropolitan railway bridge subjected to 2016 Gyeongju earthquake which has been reported as the strongest earthquake in Korea. For this purpose, nonlinear static pushover analyses for the bridge piers have been carried out to evaluate ductility capacities. Then, the capacities have been compared with those suggested by Railway Design Standards of Korea. This comparison shows that all piers possess enough safety margins. Nonlinear dynamic time-history analysis has also been conducted to estimate both displacement and shear force demands for the bridge subjected to ground motions recorded at stations in near of Gyeongju. Maximum demands reveal that response under the ground motions remains essentially in elastic. In addition, for a further assessment of the bridge under the Gyeongju earthquake, fragility analyses have been performed using those ground motions. The fragility results indicate that the recorded earthquakes do not significantly affect the damage exceedance probability of the bridge piers.

In the Korean Building Code (KBC), the Design Eccentricity involves the torsional amplification factor (TAF), and the inherent and accidental eccentricities. When a structure of less than 6-stories and assigned to seismic design category C or D is designed using equivalent static analysis method, both KBC-2006 and KBC-2009 use the TAF but apply different calculation methods for the of design eccentricity. The design eccentricity in KBC-2006 is calculated by multiplying the sum of inherent eccentricity and accidental eccentricity at each level by a TAF but that in KBC-2009 is calculated by multiplying only the accidental eccentricity by a TAF. In this paper, the damage indices of a building with planar structural irregularity designed by different design eccentricities are compared and the relationship between the earthquake damage and design eccentricity of the building is evaluated. On the basis of this study, the increment of design eccentricity results in the decrement of final eccentricity and global damage index of structure. It is observed that design eccentricity in KBC-2006 reduces the vulnerability of torsional irregular building compared to design eccentricity in KBC-2009.

본 연구에서는 도로교의 지진피해평가체계를 구축하기 위해 필요한 정보항목들을 정의하고 우리나라 실정에 맞는 데이터 베이스 구축방법을 제시하였다. 도로교 지진피해평가를 위한 정보요소는 크게 구조물 관련 정보와 위치관련 정보로 구분하였다. 구조물 관련정보는 도로망에 위치한 교량의 지진피해를 예측하는데 필요한 도로교의 취약도 곡선 정보항목으로 구성하였다. 위치관련 정보항목인 도로망의 데이터구조는 상세한 교차로 모델링이 가능하도록 기존의 GIS 데이터구조를 보다 세분화하여 정의하였다. 고속도로망에 위치한 110개의 교량을 대상으로 시범 시스템을 개발하였으며, 제시된 데이터베이스 구축 방법은 도로망의 신속한 피해복구를 위한 의사결정 지원체계 구축에 효과적으로 활용이 가능함을 보였다.

본 논문은 지진으로 인한 라이프라인과 공공설비에 대한 위험 지역 묘사 및 물리적 손실추정에 중점을 두었으며, 또한, 지리정보시스템(GIS)과 지진영향의 공간적 특성 평가에 사용된 송수관망을 통한 GIS 적용이 강조되었다. 1994년도의 Northridge 지진에서 얻어진 물 공급 능력이 기록된 GIS 자료를 통하여 매장된 라이프라인 피해와 다양한 지진 매개변수들의 상호 관계가 검증되었으며, 통계학적으로 가장 뚜렷한 상호 관계를 갖는 지진 매개변수들이 발견되었다. Northridge지진으로부터 얻어진 GIS 자료를 이용하여 송수관의 손상률, 종류, 직경, 그리고 다양한 지진 매개변수들이 평가되었다.

본 연구는 해외각국의 RC건물의 내진화기술 가운데, 일본의 기존 RC건물에 대한 내진성능의 평가수법인 내진진단규준의 현황을 소개함과 동시에 그 적용사례 및 지진대책에의 활용가능성을 분석검토하여, 향후 한국실정에 맞는 RC건물의 내진화기술의 개발에 기초적인 자료로서 활용하고자 하는 것이 주목적이다. 이를 위해 본 연구에서는 일본의 동경도에서 최근 실시되어진 지진경험이 없는 RC건물의 내진성능을 내진진단규준에 의한 진단결과인 구조내 진지표(Is)치를 중심으로 통계학적으로 분석하여, 이미 조사되어진 타 지역의 내진성능과 비교검토하였고, 또한 확률론에 입각하여 대상지역의 Is치의 분포특성과 이미 지진 피해를 받은 지역 건물의 Is치 분포특성을 비교검토하여 지진피해율을 추정하였다. 본 연구의 결과는 지진에 대한 보강건물의 효율적인 선정 등, 지진대책에 기본적인 자료로서 활용이 가능하며, 또한 일본의 내진성능 평가방법, 통계학적인 분석방법, 확률론에 입각한 지진피해율 평가방법 등의 방법론은 향후 한국의 RC건물에 대한 내진화기술의 개발에 활용이 가능하다고 사료된다.

장주기 성분의 지진파는 주로 일반적인 구조성 지진과 화산대의 화산폭발로 인한 화산성 지진이 대표적이며, 국내의 경우 일본에서 발생한 대규모의 지진에 의한 부산 해운대의 피해와 최근 폭발 가능성이 제기되는 백두산 화산폭발로 인한 화산성 지진으로 인한 서울 및 인천 송도지역의 피해가 예측되며, 이 지역들은 고층건물의 밀집지역이라는 점에 대하여 장주기 성분 지진에 취약한 고층건물들의 방재대책이 시급한 실정이다. 실제로 최근에 Tohoku(M9.1 2011, Japan)지진으로 인하여 장주기 성분의 지진파가 발생하였으며, 진원지에서 약 400km 정도의 거리에 있는 고층건물들의 비구조재에 대한 피해가 보고되었으며, 이를 계기로 비구조재에 관한 내진설계에 대한 연구도 활발히 진행되고 있다. 따라서 우리나라의 경우에도 장주기 성분의 지진파에 의한 고층 건물의 피해를 고려하여 고층건물 내의 비구조재 손상을 평가하기 위하여 단주기 성분 지진파 및 장주기 성분 지진파를 적용하여 그에 따른 시험체의 층간변위 및 가속도에 인한 피해를 예측을 위한 실험을 실행하였으며, 그에 따른 고층건물 내의 비구조재의 손상을 분석하였다.

Many researches about damage prediction for earthquake have been managed separately in Korea so that it would be managed comprehensively and systematically. Also it is necessary to develop the algorithms of ground for earthquake disaster response system in NEMA. This is a study to improve the reliability for damage estimation. We compared foreign cases to find a development direction which can be applied to the earthquake disaster response system.

As the quantitative index of the post-earthquake safety evaluation for wooden frames, the residual story drift ratio was considered, and the its limit values for the five damage levels were presented by using test results of full-scale one-span wooden frames.

Many researches about damage prediction for earthquake have been managed separately in Korea so that it would be managed comprehensively and systematically. Also it is necessary to develop the algorithms of ground for earthquake disaster response system in NEMA. This is a study to improve the reliability for damage estimation. We compared foreign cases to find a development direction which can be applied to the earthquake disaster response system.

To evaluate the post-earthquake damage status of URM buildings in Korea, damage state level from the Earthquake Disaster Response System is classified and static test results of 20 URM walls, dynamic test results of 1 URM building are analyzed. From the analysis results, damage state, maximum story drift ratio and residual story drift ratio regarding to the each damage state level are suggested.

한반도는 지리적으로 주변국보다는 지진재해의 빈도가 비교적 적은 지역으로 인식되어 있지만, 지진 발생 빈도수가 점차 증가함에 따라 지진재난으로부터 국민의 생명과 재산을 보호하기 위한 방재대책이 필요한 시대적인 요구에 직면해 있다. 이를 대비한 시스템으로 현재 소방방재청에서는 지진재해대응시스템을 구축·운영 중이다. 이번 연구에서는 기존 지진재해대응시스템에 추가적으로 적용할 수 있는 지진재해로 인한 사회 경제적 피해예측 모델 적용을 위한 지진재해대응시스템의 방법론과 관련된 연구를 진행하고자 하였다. 피해예측 모델을 적용하기 위해서는 먼저 지진피해평가기법을 완성하여야 하는데, 이를 위해 지진기록 뿐만 아니라 지진피해에 대한 다양한 현장조사 기록 및 기초 자료들이 필요하다. 하지만 국내에는 이와 같은 기초자료서 활용가능 기본 데이터베이스의 구축이 자료의 양은 적지 않으나, 오래된 자료가 많고 이번 연구에 적용가능의 활용도가 떨어지는 경우가 많다. 지진재해대응시스템에 응용하기 위해 기초자료로서 사용되는 지진가속도자료 또는 토양층 정보, 전단파 속도자료 데이터베이스 정보 등을 선별하여, 최대지반가속도 또는 스펙트럴 가속도 등을 구하는 경험식에 적용하고자 하였다. 또한, 현재 소방방재청에서 진행 중인 지진가속도계측자료통합관리시스템의 산출물인 가속도 정보를 향후에 지진재해대응시스템의 기초자료로서 사용할 수 있는 방안을 설계단계에서 고려하는 연구를 진행 중이다. 이를 통해 해당분야의 적용연구에 대한 선행연구로 이용될 수 있을 것이다.

본 연구에서는 경복궁, 숙정문, 창경궁, 창덕궁 등의 중요한 건축문화재가 위치하고 있는 서울특별시 ○○산 일대를 연구지역으로 선정하여, 지진에 의한 변위량 해석에 이용되는 Newmark displacement model(뉴마크 변위 모델)을 통해 지진시 산사태 위험지 예측을 실시하였다. 또한 산사태 발생 시 토석류의 흐름 양상을 예측하고, 산사태가 산지 부근에 위치하고 있는 문화재에 미치는 영향을 분석하였다.