• Structural Engineering and Mechanics
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• 제18권6호
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• pp.709-729
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• 2004

This paper presents numerical and experimental investigations on damage detection of mono-coupled multistory buildings using natural frequency as only diagnostic parameter. Frequency equation of a mono-coupled multistory building is first derived using the transfer matrix method. Closed-form sensitivity equation is established to relate the relative change in the stiffness of each story to the relative changes in the natural frequencies of the building. Damage detection is then performed using the sensitivity equation with its special features and minimizing the norm of an objective function with an inequality constraint. Numerical and experimental investigations are finally conducted on a mono-coupled 3-story building model as an application of the proposed algorithm, in which the influence of modeling error on the degree of accuracy of damage detection is discussed. A mono-coupled 10-story building is further used to examine the capability of the proposed algorithm against measurement noise and incomplete measured natural frequencies. The results obtained demonstrate that changes in story stiffness can be satisfactorily detected, located, and quantified if all sensitive natural frequencies to damaged stories are available. The proposed damage detection algorithm is not sensitive to measurement noise and modeling error.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.577-582
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• 2001

Identification of damage of structures has recently received considerable attention in the light of maintenance and safety assessment under service loads. In buildings, the current techniques of safety assessment largely depend on partial experiments such as visual inspection, destructive and nondestructive tests which lead to overconsumption of time and cost as well as higher labor intensity. Therefore, a new trial for safety assessment is urgently needed today. In this respect, the vibration characteristics of buildings have been applied steadily to obtain a damage index of the whole building, but it cannot be established as a practical method until now. This study is aimed at investigating the application of damage identification methods using vibration characteristics of building. Numerical tests are performed on a apartment building. From the test results, it is observed that severity and location of damage can be estimated with a relatively small error by using natural frequency and mode shape data.

• 한국구조물진단유지관리공학회 논문집
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• 제2권3호
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• pp.161-167
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• 1998

A problem of frequency in the field of low-frequencies such as high-rise apartment building or construction vibration are often found. In this study, damage reason of a 25 stories apartment building was searched on the basis of actual damage. To find the damage reason, structural design procedure were reviewed and low-frequency vibration test was conducted. The results indicate that the main damage reason is not by the low-frequency vibration but the asymmetrical plan of that building.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.253-254
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• 2015

Currently, according to the climate change, the damages due to the hurricane is more increased than before. In this respect, several countries have been conducted the studies regarding the damage prediction model of buildings to minimize the damages from natural disaster. As hurricane is the complex disaster including a strong wind and heavy rain, to predict the damage of hurricane, various factors has to be considered. However, mostly research has been conducted to consider only hurricane properties. Therefore, the objective of this study is to develop the regression model for predicting damages of buildings considering geography, socio-economy, construction environment and hurricane information. In the future, this study can be utilized to developing damage prediction model for building from hurricane in South Korea.

• 한국지진공학회논문집
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• 제17권5호
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• pp.237-243
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• 2013

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.

• 한국지반공학회논문집
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• 제19권6호
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• pp.351-361
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• 2003

흙막이 지반굴착시 인접 구조물의 손상메카니즘을 규명하기 위하여 1.844m(길이)$\times$0.6m(높이)인 모형조적벽체를 실제의 1/10의 스케일로 모형화하였다. Peck(1969) 및 O'Rourke등(1976)이 제안한 지반침하량이 6단계에 걸쳐 모형실험에 적용되었다. Peck(1969)과 O'Rourke등(1976)의 방법을 적용한 모형실험결과, O'Rourke등(1976)에 의한 조적벽체의 각변위는 Peck(1969)의 각변위에 비해 21% 크게 나타났으며, 수평변위 또한 Peck(1969)에 의한 값보다 24% 크게 나타났다. O'Rourke등(1976)의 침하량이 적용된 경우의 건물손상 정도를 손상도표(Boscardin & Cording,1989)에 적용한 결과 Peck(1969) 방법에 의해 얻은 손상수준에 비해 보다 심각한 손상수준의 결과가 나타났다. 또한, 구조물의 강성 및 구조물과 지반의 interface 가 구조물 손상평가시 중요한 인자로써 고려되어야 함을 확인할 수 있었다.

• Earthquakes and Structures
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• 제22권2호
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• pp.185-201
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• 2022

Structural Health Monitoring (SHM) is used to provide reliable information about the structure's integrity in near realtime following extreme incidents such as earthquakes, considering the inevitable aging and degradation that occurs in operating environments. This paper experimentally investigates an integrated wireless sensor network (Wi-SN) based monitoring technique for damage detection in concrete structures. An effective SHM technique can be used to detect potential structural damage based on post-earthquake data. Two novel methods are proposed for damage detection in reinforced concrete (RC) building structures including: (i) Jerk Energy Method (JEM), which is based on time-domain analysis, and (ii) Modal Contributing Parameter (MCP), which is based on frequency-domain analysis. Wireless accelerometer sensors are installed at each story level to monitor the dynamic responses from the building structure. Prior knowledge of the initial state (immediately after construction) of the structure is not required in these methods. Proposed methods only use responses recorded during ambient vibration state (i.e., operational state) to estimate the damage index. Herein, the experimental studies serve as an illustration of the procedures. In particular, (i) a 3-story shear-type steel frame model is analyzed for several damage scenarios and (ii) 2-story RC scaled down (at 1/6th) building models, simulated and verified under experimental tests on a shaking table. As a result, in addition to the usual benefits like system adaptability, and cost-effectiveness, the proposed sensing system does not require a cluster of sensors. The spatial information in the real-time recorded data is used in global damage identification stage of SHM. Whereas in next stage of SHM, the damage is detected at the story level. Experimental results also show the efficiency and superior performance of the proposed measuring techniques.

• Earthquakes and Structures
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• 제23권1호
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• pp.1-11
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• 2022

This study implements a hybrid Genetic Algorithm to detect, locate, and quantify structural damage for multistory shear buildings using partial modal data. Measuring modal responses at multiple locations on a structure is both challenging and expensive in practice. The proposed method's objective function is based on the building's dynamic properties and can also be employed with partial modal information. This method includes initial residuals between the numerical and experimental model and a damage penalization term to avoid false damages. To test the proposed method, a numerical example of a ten-story shear building with noisy and partial modal information was explored. The obtained results were in agreement with the previously published research. The proposed method's performance was also verified using experimental modal data of an 8-DOF spring-mass system and a five-story shear building. The predicted results for numerical and experimental examples indicated that the proposed method is reliable in identifying the damage for multistory shear buildings.

• 건축역사연구
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• 제32권2호
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• pp.37-48
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• 2023

A literature study was conducted on the management of the pavilion of the royal tomb in the late Joseon Dynasty, focusing on "Gakneung Suri Deungnok(Records relating to the repair of royal tombs)". This study analyzed the royal tomb management system, organized the types of damage identified in the building, and examined how the damage status was recorded by type. In the above, the records related to the 1675~1713 repair of three JeongJaGak(Geonwonneung, Sungneung, and Mokneung), which are registered as state-designated cultural properties, are summarized in three aspects: management system, damage status, and expression words. The results of the study are as follows. First, the royal tomb pavilion was regularly inspected by Observator(觀察使) in spring and autumn, and Surunggwan(守陵官) every 5th, and Servant(守僕) regularly inspected every day and night, and also inspected and reported emergency cases of natural disasters or unexpected damage. Second, the damage status of each building was continuously observed and reported for the continuous maintenance of the buildings in the royal tomb. A total of 75 records of damage to the three royal tombs' pavilion were found to have been most frequently inspected, including 19 cases (25.3%), 14 cases (18.7%), 23 cases (30.7%) of the roof, and 19 cases (25.3%) of the roof. Third, the expression of the damage status is confirmed in various ways, such as separation, separation, burst, damage, excitation, moisture, leakage, and exfoliation. Among them, the main damage records were confirmed due to the separation of the base from the peeling, the furniture, cracks, leaks, leaks in the roof, and the collapse of the roof was able to check the damage records.

• Structural Engineering and Mechanics
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• 제30권4호
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• pp.445-466
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• 2008

This paper presents a novel structural damage detection method with a new damage index based on the statistical moments of dynamic responses of a structure under a random excitation. After a brief introduction to statistical moment theory, the principle of the new method is put forward in terms of a single-degree-of-freedom (SDOF) system. The sensitivity of statistical moment to structural damage is discussed for various types of structural responses and different orders of statistical moment. The formulae for statistical moment-based damage detection are derived. The effect of measurement noise on damage detection is ascertained. The new damage index and the proposed statistical moment-based damage detection method are then extended to multi-degree-of-freedom (MDOF) systems with resort to the leastsquares method. As numerical studies, the proposed method is applied to both single and multi-story shear buildings. Numerical results show that the fourth-order statistical moment of story drifts is a more sensitive indicator to structural stiffness reduction than the natural frequencies, the second order moment of story drift, and the fourth-order moments of velocity and acceleration responses of the shear building. The fourth-order statistical moment of story drifts can be used to accurately identify both location and severity of structural stiffness reduction of the shear building. Furthermore, a significant advantage of the proposed damage detection method lies in that it is insensitive to measurement noise.