In order to evaluate the seismic safety of weir structure subjected to seismic ground motions, Non-linear elastic 2D plane strain Finite Model (FE) was developed in ABAQUS. Also, the 1994 Northridge earthquake as a ground motion uncertainty was selected. The numerical results show that the tensile stress was increased with increase the friction coefficient
This study is to solve the structural optimization problem by a quantum-inspired harmony search algorithm. For the optimization, we suggest the mathematical modeling of the plane truss which is possible to minimum weight design. In its model, the cost function is minimum weight and constraint function consists of the stress.
In this paper, we propose an image-based measurement method of structure dynamic characteristics to assess the damage of structure in a more cost-effective way than traditional structure health monitoring system.
The purpose of this study is to utilize the basic data and to propose the service life prediction method of RC structures. For this, we analyzed the existing programs used for service life prediction software in international such as U.S, Japan, Greece and Canada. The results of Analysis, the prediction of carbonation and chloride were common items in respectively programs.
Recently, assessment of vulnerability of existing dam structures is a rising key issue in aspects of entire life year from design, construction to maintenance even in Korea due to more frequent earthquakes and effects of climate change. This study aims to develop a vulnerability assessment method for existing dam structures by using fragility analysis method based on 2-D FEM analyses, which can take into consideration various uncertainty information to dam structure safety assessment, and which may be incorporated into an integrated safety management platform under development by K-water.
A filming technique using Side Scan SONAR should be varied upon condition in order to obtain high-resolution data. Because the theoretical measurement scope is different from the actual measurement scope. It is possible to obtain the accurate data only after adjusting the water depth, distance from a structure and emission angle. Via the multiple regression analysis of data accumulated through field experiments and relations of 3 variables, and equation was devised.
이 연구의 목표는 학교 건물과 같은 저층 보-기둥 철근콘크리트 구조 건물에서 프리캐스트 벽패널을 사용한 새로운 내진보강 방법을 개발하는 것이다. 1개의 무 보강 보-기둥 실험체와 U형 PC 벽패널로 보강한 2개의 보강 보-기둥 실험체에 대한 정적 이력 하중실험을 진행하였다.
앵커접합 PR1-UA 실험체와 철판접합 PR1-UP 실험체는 무 보강 실험체보다 평균 2.8배(평균 591.8 kN)의 강도 증가를 보여 주었다. 최대 변위비도 1.4%에서 2.7%사이 값을 보여주었다. RC 골조 우측 상단에서 좌측방향으로 가력 할 때 우측에 있는 RC 기둥과 보강 PC 패널의 수직 요소는 완전 합성상태로 가정하였고, 좌측에 있는 RC 기둥과 PC 패널은 완전 비 합성 거동하는 것으로 가정하여 해석한 결과 전체적인 휨 거동은 실험 결과와 대체적으로 부합하는 것으로 판단되었다.
본 연구에서는 하도 내 수제 형 수리구조물을 설치하였을 때, 만곡수로와 수충부에서의 흐름 양상 변화를 3차원 유속 측정을 통해 확인하였다. 연구를 위해 길이 24.4m, 폭 1.5m, 하상경사 2%의 만곡수로에서 실험을 수행하였다. 실험은 단일 수제의 설치 여부에 따라 크게 두 가지 경우로 나누어 수행하였다. 유속의 측정에는 3차원 초음파 유속계(Acoustic Doppler velocimeter, ADV)를 사용하였으며 각 단면 당 약60개의 측점을선정하여 일정한시간 동안측정하였다. 측정된 유속들은시간평균하였으며, 각단면에서의측정결과를연결하여만곡수로의수면유속을파악하였다. 그결과, 수제설치로 인해구조물하류에위치한만곡부외측에서의유속이현저하게감소하였고제방을향했던흐름의방향이내측으로변화하 였음을 확인할 수 있었다.
구조물 건전성 모니터링은 센서로부터 구조물의 응답을 수집하고 분석하여 구조물의 정확한 상태를 진단하는 기술이다. 최근 노후화된 구조물의 증가로 인하여, 지속가능한 사회 발전을 위해 더욱 발달된 구조물 건전성 모니터링 기술이 요구되고 있다. 최신 구조물 건전성 모니터링 기술 중 하나인 무선 스마트 센서와 센서 네트워크 기술은 기존의 유선 방식의 모니터링 시스템과 비교하여 더욱 효율적이며 경 제적인 모니터링 시스템의 구축을 가능하게 하는 기술이다. 최근까지도 관련 연구자들은 스마트 센서의 성능 및 확장성 향상을 위하여 연 구개발을 진행하고, 다양한 실내, 실외 실험을 통한 성능 테스트를 진행하였다. 본 논문에서는 최근 (2010년 이후를 중심으로)에 개발된 스마트 센서의 하드웨어, 소프트웨어, 그리고 응용 사례들을 정리함으로써, 구조물 건전성 모니터링을 위한 스마트 센서의 최신 연구동향에 대해 소개하고자 한다.
This study developed the Anti-Floating Method using PHC Pile adapting to the Underground Structures. This Method fixed the wedges on the P.C. strands of the PHC Pile to reinforce the adhesion strength in the concrete foundation. Pullout test result showed 2~3 times better than the present method, so the developed method can be used as the Anti-Floating Method of underground structures.
There are a lot of difficulty in present inspection that need many inspectors and much time. It is necessary to improve this inspection working environment. So, we developed an inspection system it can solve problems in current visual inspection and it systemize the inspection tasks scientifically. This is an optimized culvert inspection system which enable to measure a surface condition and sectional shape change. it is used various convergence technology such as 3D laser scanning, digital image processing and texture mapping.
After reviewing the technical consulting reports and field surveying the whole corrugated steel plate structures in the Expressway, factors causing the problems are analyzed suggestions for the improvement of the design and construction of the structures are given.
Chloride attack, one of the reasons for early deterioration of concrete, is a phenomenon where detrimental ions such as chlorine ion penetrate into concrete from outside to diffuse and corrode the steel rebar, greatly deteriorating the durability of RC members or structures. Sources of chloride attack can be divided into the direct / indirect influence caused by seawater or its splash in the maritime environment and the de-icing salts used for the purpose of thawing the ice on the wintry road. Most notably, the usage of de-icing salts is essential for the safety of drivers and smooth traffic flows in expressways. However, they also quicken the deterioration of concretes, necessitating the countermeasures for the problem.
This paper discusses the early deterioration and measurements of RC Structures under de-icing salts environments.
Concrete represents the mostly widespread structural material for construction of buildings due to its mechanical properties such as durability, variability and availability of resources. But, cement production is associated with large energy consumption and consequently with high CO2 emissions. This paper analyzed the amount of CO2 emissions in various concrete mix design on the viewpoint of service life periods using Korean LCI DB.
According to the results of case studies on leakage in large scale aquarium structures, the causes have been identified as construction failure of sealant for joint of sealant design failure in acryilic panel and concrete substrate joints. However, as there currently are no standardized design or specifications for such principles, this study proposes a design formulation of a width and depth of sealant when applied to acrylic panels in large scale aquarium structures.
The ultimate strength of existing offshore structure is calculated by Nonlinear Push-over analysis and the damage of structure is assessed through a reserve strength ratio(RSR). High-risk members are detected through the failure mechanism to analyze the plastic analysis results.
The monitoring technique using acoustic emission(AE) and microseismicity(MS) are recently used in domestic geotechnical structures. Since AE amd MS rapidly increase before the large-scale failure of geotechnical structures, they can be used as an indicator of failure symptoms. This study shows case studies, especially applied to the rock slope and tunnel.
This paper aims to develop a wireless multi-sensing system for structural health monitoring of civil structures. This system is designed to measure all kinds of data--static and dynamic response, etc--from a multi-sensing data logger, and to transmit the measured data by means of a wireless real-time RF module, and to analyze the transmitted data for a health monitoring of structure. To test its validity, a FE analysis of a model cable-stayed bridge has been conducted for system identification. And a modal test of the model bridge has been also performed by both the proposed system and a cable based commercial measurement system(IOTech) for comparison. Based on those results, the proposed system was found to have an excellent capability of measuring and transmitting data from actual structure, and thus to be applicable to health monitoring of civil structures.
The quality of injection sealer for water leakage maintenance be being managed by KS. However, the test result of response to the substrate movement performance have some errors by an experimenter. So, the revision standard of test method is proposed. Therefor, will verify that in this study.
The purpose of this study is able to prevent accidents as users will tell you in real time the long distance is to the safety inspection of various structures using a 3D scanner
therefore, it is possible to use civil engineering structures, such as building structures