• Structural Engineering and Mechanics
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• v.77 no.2
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• pp.151-165
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• 2021

This paper aims to present a novelty damage detection method to identify damage locations by the simultaneous use of both the energy and displacement damage indices. Using this novelty method, the damaged location and even the damaged floor are accurately detected. As a first method, a combination of the instantaneous frequency energy index (EDI) and the structural acceleration responses are used. To evaluate the first method and also present a rapid assessment method, the Displacement Damage Index (DDI), which consists of the error reliability (β) and Normal Probability Density Function (NPDF) indices, are introduced. The innovation of this method is the simultaneous use of displacement-acceleration responses during one process, which is more effective in the rapid evaluation of damage patterns with velocity vectors. In order to evaluate the effectiveness of the proposed method, various damage scenarios of the ASCE benchmark problem, and the effects of measurement noise were studied numerically. Extensive analyses show that the rapid proposed method is capable of accurately detecting the location of sparse damages through the building. Finally, the proposed method was validated by experimental studies of a six-story steel building structure with single and multiple damage cases.

• Wind and Structures
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• v.2 no.3
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• pp.133-150
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• 1999

Significant costs to the public and private sectors due to recent extreme wind events have motivated the need for systematic post-hurricane damage data collection and analysis. Current post disaster data are collected by many different interested groups such as government agencies, voluntary disaster relief agencies, representatives of media companies, academicians and companies in the private sector. Each group has an interest in a particular type of data. However, members of each group collect data using different techniques. This disparity in data is not conducive to quantifying damage data and, therefore, inhibits the statistical and spatial description of damage and comparisons of damage among different extreme wind events. The data collection does not allow comparisons of data or results of analyses within a group and also prohibits comparison of damage data and information among different groups. Typically, analyses of data from a given event lead to different conclusion depending upon the definition of damage used by individual investigators and the type of data collected making it difficult for members of groups to compare the results of their analyses with a common language and basis. A formal method of data collection and analysis-within any single group-would allow comparisons to be made among different individuals, hazardous events and eventually among different groups, thus facilitating the management and reduction of damage due to future disaster. This research introduces a definition of damage to single family dwellings, and a common method of data collection and analysis suited for groups interested in regional characterization of damage. The current state-of-data is presented and a method for data collection is recommended based on these existing data collection methods. A fixed-scale damage index is proposed to consider the damage to a dwelling's feature. Finally, the damage index is applied to three dwellings damaged by Hurricane Iniki (1992). The damage index reflects the reduced functionality of a structure as a single family detached dwelling and provides a means to evaluate regional damage due to a single event or to compare damage due to events of different severity. Evaluation of the damage index and the data available support recommendation for future data collection efforts.

• Structural Engineering and Mechanics
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• v.72 no.1
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• pp.83-97
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• 2019

In this research, the vulnerability of some reinforced concrete frames with different stories are studied based on the Park-Ang Damage Index. The damages of the frames are investigated under various earthquakes with nonlinear dynamic analysis in IDARC software. By examining the most important characteristics of earthquake parameters, the damage index and vulnerability of these frames are investigated in this software. The intensity of Erias, velocity spectral intensity (VSI) and peak ground velocity (PGV) had the highest correlation, and root mean square of displacement ($D_{rms}$) had the lowest correlation coefficient among the parameters. Then, the particle swarm optimization (PSO) algorithm was used, and the sinusoidal waves were equivalent to the used earthquakes according to the most influential parameters above. The damage index equivalent to these waves is estimated using nonlinear dynamics analysis. The comparison between the damages caused by earthquakes and equivalent sinusoidal waves is done too. The generations of sinusoidal waves equivalent to different earthquakes are generalized in some reinforced concrete frames. The equivalent sinusoidal wave method was exact enough because the greatest difference between the results of the main and artificial accelerator damage index was about 5 percent. Also sinusoidal waves were more consistent with the damage indices of the structures compared to the earthquake parameters.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.3
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• pp.149-155
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• 2007

Damage assessment and Damage index for RC members failed in flexure was investigated by using the nonlinear finite element analysis, included with nonlocal constitutive law, which is analyzed for the localization of the failure on the post-peak region. In the nonlcal constitutive law, The local strains obtained at gauss points were averaged over a particular length, i.e. characteristic length and it was used to evaluate the damage of RC column member. As the analysis results, The value of nonlocal strain shows less mesh sensibility. In the damage assessment, It was confirmed that evaluations of damage of RC member were able to use nonlocal compressive strain on a cover concrete and a core concrete of the member. Moreover it was confirmed that damage process for the statically indeterminate structure was able to evaluate the damage context of the component members of the structure.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.331-346
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• 2004

A new sensor system is proposed for measuring damage indexes. The damage index is a physical value that is well correlated to a critical damage in a device or a structure. The mechanism proposed here utilizes elastic buckling of a thin wire and does not require any external power supply for memorizing the index. The mechanisms to detect peak strain, peak displacement, peak acceleration and cumulative deformation as examples of damage indexes are presented. Furthermore, passive and active wireless data retrieval mechanisms using electromagnetic induction are proposed. The passive wireless system is achieved by forming a closed LC circuit to oscillate at its natural frequency. The active wireless sensor can transmit the data much further than the passive system at the sacrifice of slightly complicated electric circuit for the sensor. For wireless data retrieval, no wire is needed for the sensor to supply electrical power. For the active system, electrical power is supplied to the sensor by radio waves emitted from the retrieval system. Thus, external power supply is only needed for the retrieval system when the retrieval becomes necessary. Theoretical and experimental studies to show excellent performance of the proposed sensor are presented. Finally, a prototype damage index sensor installed into a 7 storey base-isolated building is explained.

• Computers and Concrete
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• v.8 no.3
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• pp.311-325
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• 2011

Nowadays, many engineers believe that hybrid structures with reinforced concrete central core walls and perimeter steel frames offer an economical method to develop the strength and stiffness required for seismic design. As a result, a variety of such structures have recently been applied in actual construction. However, the performance-based seismic design of such structures has not been investigated systematically. In the performance-based seismic design, quantifying the seismic damage of complete structures by damage indices is one of the fundamental issues. Four damage states and the final softening index at each state for high-rise hybrid structures are suggested firstly in this paper. Based on nonlinear dynamic analysis, the relation of the maximum inter-story drift, the main structural characteristics, and the final softening index is obtained. At the same time, the relation between the maximum inter-story drift and the maximum roof displacement over the height is also acquired. A double-variable index accounting for maximum deformation and cumulative energy is put forward based on the pushover analysis. Finally, a case study is conducted on a high-rise hybrid structure model tested on shaking table before to verify the suggested quantities of damage indices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.127-135
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• 2018

With the nation showing increasing concern for earthquakes, there have been several methods for the analysis of earthquakes and evaluation of damage. Nevertheless, there is no clear standard to assess the seismic damage to structures quantitatively. Accordingly, this study conducted seismic analysis of several forms of seismic waves and actual seismic load, targeting the cable stayed bridge, which is supported by a cable and proposes a method for evaluating the damage based on the results. The damage index was calculated based on the tilting of the pylon of the cable-stayed bridge and the characteristics of physical seismic damage was suggested with 4 levels, such as A, B, C, and D. In addition, it is not proper to simply judge that the seismic damage index is obtained as large or small at all times depending on the seismic analysis method. Although this study focused on the proposal seismic damage index and an evaluation of the damage targeting the cable stayed bridge, the result was applied to a structure with a similar maximum displacement response.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.101-107
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• 2014

Damage location and extent of structure could be detected by the inverse analysis on dynamic response properties such as frequencies and mode shapes. The dynamic response of building structures has many noise and affected by nonstructural members and, above all, the behavior of building structure is more complex than civil structure and this makes the damage detection difficult. In recent researches the damage is detected by the indirect index such as sensitivity or assumed values. However, for the more reasonable damage detection, it needs to use the damage index directly induced from dynamic equation. The purpose of this study is to provide the damage detection method on shear building structures by the damage index directly induced from dynamic equation. The provided damage index could be estimated from measured mode shape of undamaged structure and frequency difference between undamaged and damaged structure. The damage detection method is applied to numerical analysis model such as MATLAB and MIDAS GENw for the verification. The damage index at damaged story represents (-) sign and 15 times than other undamaged sories.

• Journal of Navigation and Port Research
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• v.36 no.3
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• pp.163-168
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• 2012

Recently, people's desire for the waterfront space has been increasing, and more people want to spend their leisure time close to the water. This paper proposes a damage detection technique using the static strain for the floating structure. An existing damage index, in which the modal strain energy was utilized to identify possible location of damage, is expanded to apply the static strain. The new damage index is expressed in terms of the static strains of undamaged and damaged structures. After calculating damage index, the possible damage locations in the structure are determined by the pattern recognition technique. The accuracy and feasibility of the proposed method is demonstrated by using experimental strain data from a scale model of floating structure.

• Advances in concrete construction
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• v.5 no.4
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• pp.407-422
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• 2017

Evaluating seismic performance of urban structures for future earthquakes is one of the key prerequisites of rehabilitation programs. Irregular structures, as a specific case, are more susceptible to sustain earthquake damage than regular structures. The study here is to identify damage states of vertically irregular structures using the well-recognized Park-Ang damage index. For doing this, a regular 3-story reinforced concrete (RC) structure is first designed based on ACI-318 code, and a peak ground acceleration (PGA) of 0.3 g. Some known vertical irregularities such as setback, short column and soft story are then applied to the regular structure. All the four structures are subjected to seven different earthquakes accelerations and different amplitudes which are then analyzed using nonlinear dynamic procedure. The damage indices of the structures are then accounted for using the pointed out damage index. The results show that the structure with soft story irregularity sustains more damage in all the earthquake records than the other structures. The least damage belongs the regular structure showing that different earthquake with different accelerations and amplitudes have no significant effect on the regular structures.