Assessment and quantification of hurricane induced damage to houses

Chiu, Gregory L.F.,Wadia-Fascetti, Sara Jean Techno-Press 1999 Wind and Structures, An International Journal (WAS Vol.2 No.3

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.

Global seismic damage assessment of high-rise hybrid structures

Xilin Lu,Zhihua Huang,Ying Zhou 사단법인 한국계산역학회 2011 Computers and Concrete, An International Journal Vol.8 No.3

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.

전국 홍수위험도 평가의 국토도시계획적 함의

최충익,김원 대한국토·도시계획학회 2006 國土計劃 Vol.41 No.4

This study aims to find the implications in urban and regional planning of nationwide flood risk assessment. Also, we try to develop the standard indicators on flood damage to assess urban and regional risk state. The process of this research passes through three stages. Constructing the flood damage index using time-series data on flood damage is a first-stage. Developing the flood risk indicators through clustering analysis of flood damage indices is a second-stage. Based on 1-2 stages, a third-stage is to make suggestions on urban and regional planning. In this research, the indicators such as casualty index, damage index and inundation index enable non-experts to understand the situation of flood damages with time series. Relevant and measurable indicators would be an important tool in reducing and managing flood risk. The indicators on flood management planning could be helpful to decision makers against disasters.

Physiologic Evaluation of Microvascular Damage in Culprit Vessel After Successful Primary Percutaneous Coronary Intervention for ST-elevation Myocardial Infarction Patients

박일,이주명 한국지질동맥경화학회 2017 지질·동맥경화학회지 Vol.6 No.1

We investigated the importance of comprehensive physiologic assessment about culprit vessel in STEMI in estimating long-term clinical outcomes after complete revascularization. Comprehensive physiologic assessment provides additional information about microvascular function in coronary artery disease. This assessment includes three indices, fractional flow reserve (FFR), index of microcirculatory resistance (IMR) and coronary flow reserve (CFR). We have performed the comprehensive physiologic assessment in culprit vessels after successful primary PCI in STEMI patients. Both cases were thrombotic total occlusion in mid right coronary artery with inferior wall STEMI, successfully revascularized with stent implantation after thrombus suction. However, in post PCI physiologic assessment, one case showed overt microvascular damage. CFR was 1.1, and IMR was 75U, which was defined as a combined criterion of low CFR (<2.0) and high IMR (≥25U) in culprit vessel, but the other case showed 2.2 in CFR and 24U in IMR, which suggested no overt microvascular damage. Moreover, we can validate these findings by cardiac MR after primary PCI. Previous studies presented that the presence of overt microvascular damage was significantly associated with worse clinical outcome in patients with coronary artery disease. We suggest that comprehensive physiologic evaluation provides important information about the degree of microvascular damage and long-term clinical outcomes after complete revascularization in culprit vessel in STEMI.

사장교의 내진 손상지수의 제안 및 손상도 평가

김응록(Eung-Rok Kim) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.1

최근 국내에서의 잦은 지진 발생으로 지진에 대한 관심이 증가함에 따라 이에 대한 해석법 및 손상도를 평가하는 여러 가지 방법이 제시되고 있다. 그러나 해석 및 손상도를 평가함에 있어 각각의 부재에 대한 변위와 부재력 뿐 아니라 실제 발생하는 지지에 대하여 구조물의 손상고를 정량적으로 평가하기에는 기준 및 방법이 미비한 실정이다. 따라서 본 논문에서는 케이블지지 교량인 사장교를 대상으로 실제지진하중 및 여러 가지 형태의 지진파에 대하여 지진해석을 수행하고 그 결과를 바탕으로 손상도 평가방법을 제시하였다. 손상지수는 사장교의 주탑 기울기를 기반으로 산정하였으며 물리적 내진손상 특성은 각각 A, B, C, D 레벨의 4단계로 제안하였다. 또한 지진해석방법에 따라 내진 손상지수가 항상 크거나 또는 작게 나온다고 단순하게 판단 할 수는 없었으며 본 연구는 사장교를 대상으로 하여 내진 손상지수의 제안 및 손상도 평가를 수행한 것이나 지진하중 하에서 비슷한 최대 변위응답 특성을 보이는 구조물에도 확장하여 적용할 수 있으리라 생각된다. 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.

지수평가기법을 적용한 태풍 산바의 낙동강 유역에 미친 피해특성 분석

이재혁,이은구,박재록,신현석 한국방재학회 2016 한국방재학회논문집 Vol.16 No.2

The uncertainty of major floods caused by torrential downpours and frequency of typhoon occurrence has been dramatically increased. Especially the frequency and the damage of localized rainfall are becoming unpredictable because of meteorological change and other factors, but most of the measures are the type of recover after-the-fact. This reveals the limitation to seek and designate the potential damage area and to concentrate budget and resources so the active measures are needed to execute in practice. For those reasons the definitions of flood damage factors from analysis of hydro-hydraulic-mophic characteristics could be used practically as the basis for decision-making in flood damage management. In this study, the characteristics of flood-damaged areas caused by typhoon “SANBA”are analysed using the investigation report of the past flood damage records, and the usability is proposed as a pre-process for local and specific assessment. Also the flowchart which consists of damage report-hydrologic modelling-hydraulic modelling-characteristics analysis-definition of risk area and the need to establishment of system are proposed. 최근 집중 호우 및 태풍 등의 대규모 호우사상에 대한 불확실성이 증가하는 추세이며, 기후변화와 같은 기상학적 요인 외에도 예측하기 힘든 국부적 호우로 인해 대규모 홍수의 발생빈도와 사회적 손실이 높아지고 있지만 현재까지의 홍수관리방안은 사후복구 형태의 피해관리방안이 대부분이다. 이러한 대응방안은 잠재위험지역 색출 및 자원과 예산 집중을 위한 합리적 대처에 한계점을 나타내고 있으며, 사전예방적 홍수관리방안을 통한 능동적 대처가 필요하다. 이에 수문수리지형학적 특성분석을 통한 홍수위험요인의 파악은 관리방안 수립시 의사결정을 지원할 수 있는 기초자료로써 활용될 수 있다. 본 연구에서는 실제 태풍 “산바”로 인한 피해조사 결과를 바탕으로 피해지점과 관련한 인자들의 특성을 분석하고 이를 바탕으로 국부적 상세피해원인 규명을 위한 전 단계로써의 지수평가기법의 활용성을 제시하였다. 또한 향후 사전대응적 홍수관리대책 수립시 의사결정 지원을 위해 피해지점조사-수문모형구축-수리모형구축-특성분석-위험지점 선정으로 이어지는 연구흐름을 제안하여 시스템 구축의 필요성 및 기초자료를 제시하고자 하였다.

Condition assessment of bridge pier using constrained minimum variance unbiased estimator

Tamuly, Pranjal,Chakraborty, Arunasis,Das, Sandip Techno-Press 2020 Structural monitoring and maintenance Vol.7 No.4

Inverse analysis of non-linear reinforced concrete bridge pier using recursive Gaussian filtering for in-situ condition assessment is the main theme of this work. For this purpose, minimum variance unbiased estimation using unscented sigma points is adopted here. The uniqueness of this inverse analysis lies in its approach for strain based updating of engineering demand parameters, where appropriate bound and constrained conditions are introduced to ensure numerical stability and convergence. In this analysis, seismic input is also identified, which is an added advantage for the structures having no dedicated sensors for earthquake measurement. First, the proposed strategy is tested with a simulated example whose hysteretic properties are obtained from the slow-cyclic test of a frame to investigate its efficiency and accuracy. Finally, the experimental test data of a full-scale bridge pier is used to study its in-situ condition in terms of Park & Ang damage index. Overall the study shows the ability of the augmented minimum variance unbiased estimation based recursive time-marching algorithm for non-linear system identification with the aim to estimate the engineering damage parameters that are the fundamental information necessary for any future decision making for retrofitting/rehabilitation.

Application of Lagrangian approach to generate P-I diagrams for RC columns exposed to extreme dynamic loading

Zhang, Chunwei,Abedini, Masoud Techno-Press 2022 Advances in concrete construction Vol.14 No.3

The interaction between blast load and structures, as well as the interaction among structural members may well affect the structural response and damages. Therefore, it is necessary to analyse more realistic reinforced concrete structures in order to gain an extensive knowledge on the possible structural response under blast load effect. Among all the civilian structures, columns are considered to be the most vulnerable to terrorist threat and hence detailed investigation in the dynamic response of these structures is essential. Therefore, current research examines the effect of blast loads on the reinforced concrete columns via development of Pressure- Impulse (P-I) diagrams. In the finite element analysis, the level of damage on each of the aforementioned RC column will be assessed and the response of the RC columns when subjected to explosive loads will also be identified. Numerical models carried out using LS-DYNA were compared with experimental results. It was shown that the model yields a reliable prediction of damage on all RC columns. Validation study is conducted based on the experimental test to investigate the accuracy of finite element models to represent the behaviour of the models. The blast load application in the current research is determined based on the Lagrangian approach. To develop the designated P-I curves, damage assessment criteria are used based on the residual capacity of column. Intensive investigations are implemented to assess the effect of column dimension, concrete and steel properties and reinforcement ratio on the P-I diagram of RC columns. The produced P-I models can be applied by designers to predict the damage of new columns and to assess existing columns subjected to different blast load conditions.

한국형 피해산정형 전과정 영향평가 지표 개발

박필주(Pil Ju Park),김만영(Mann Young Kim) 大韓環境工學會 2010 대한환경공학회지 Vol.32 No.5

이 연구에서는 피해산정형 모델에 기초하여 제품 환경성 관련 정보를 국내 지리적, 환경적, 사회적 특성을 최대한 반영하여 ‘화폐가치`로 나타낼 수 있는 전과정 영향평가 지표를 제시하였다. 먼저 평가단계를 ‘특성화`, ‘피해평가`, `통합화의` 3단계로 구분하였으며, 자원소비, 지구온난화, 오존층영향, 산성화, 부영양화 및 광화학산화물 생성의 6대 영향범주를 고려하였다. 아울러 6대 영향범주와 관련된 16개 범주별 종말점과 4대 보호대상에 대한 피해함수 및 피해계수를 도출하였다. 최종적으로 도출된 영향범주별 기준물질의 통합화 지수는 21.8원/kg Sb, 6.19원/kg CO₂, 53,000원/kg CFC-11, 13,100원/kg SO₂, 2,310원/kg PO₄ 3-, 3,030원/kg C₂H₄로 나타났다. 이 연구결과를 활용하여 제품 전과정에 걸쳐 발생하는 환경부하가 보호대상에 미치는 영향을 화폐가치로 단일 지수화할 수 있으므로 도출되는 전과정 영향평가 결과의 이해도와 활용도를 높일 수 있다. This study proposed a life cycle impact assessment index that can indicate the environment-related information of the product in monetary value such that the national geographical, environmental, and social features are fully reflected based on a damage-oriented model. First, the estimation process was classified into characterization, damage assessment, and integration stages considering the six biggest impact categories: resource depletion, global warming, ozone depletion, acidification, eutrophication, and photochemical oxidant creation. Moreover, this study came up with the 16 category endpoints related to the 6 impact categories, and the damage function, to the 4 largest safeguard subjects. The integration indices of finally identified impact categories were KRW 21.8/kg Sb, KRW 6.19/kgCO₂, KRW 53,000/kg CFC-11, KRW 13,100/kg SO₂, KRW 2,310/kg PO₄ 3-, and KRW 3,030/kg C₂H₄. Using the results of this research, environmental impacts based on the environmental load generated throughout the entire life cycle of a product can serve as a single index in monetary value; thus enhancing understanding and utilization of the results of life cycle impact assessments.

Damage Assessment of Square RC Bridge Columns Subjected to Torsion Combined with Axial Compression, Flexure, and Shear

Qian Li,Abdeldjelil Belarbi 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.3

Reinforced Concrete (RC) bridge columns can be subjected to combined flexure, shear, axial and torsional loadings under multidirectional earthquake motions and significant vertical motions, specifically in skewed and curved bridges, bridges with specific structural restraints, and bridges with unequal spans or column heights. This paper presents experimental and analytical studies to assess the damage progression of square RC bridge columns under combined loadings including torsion. The main variable in this study is the ratio of Torsional-to-bending Moments (T/M). The effects of combined loadings on the torsional and flexural hysteretic responses, strength, plastic hinge distribution, and progression of damage states are highlighted in this paper. A unified equivalent damage index model is proposed to couple the flexural and torsional actions for combined loadings. Quantified damage indices value under combined loadings can be correlated to the categorized damage states from a performance-based point of view. Based on the experimental and analytical results, the progression of damage was found to be amplified by the torsion effect, and the rotational ductility was decreased due to the effect of combined loadings.