• Title/Summary/Keyword: earthquake safety

Search Result 883, Processing Time 0.031 seconds

A Study on the Construction Methods of Sealer of Injection Type for Leakage Maintenance for Water Leakage and Cracks in Concrete (콘크리트 누수균열의 유지관리를 위한 누수보수용 주입형 실링재 시공방법 연구)

  • Kwon Shi-Won;Oh Mi-Hyun;Kwak Kyu-Sung;Oh Sang-Keun
    • Journal of the Korea Institute of Building Construction
    • /
    • v.6 no.1 s.19
    • /
    • pp.87-91
    • /
    • 2006
  • Since water leakage and cracks are not the source of serious problems such as long-term lowering of performance and durability of a stricture, including damages to operating facilities of a structure, damages to internal finishing materials, exhibition, and goods, and pollution of residential environment, they might have led to development of positive coping skills; however, an instant loss of lives or property due to earthquake, explosion, typhoon, or a fire was indeed neglected. In these days, repair materials for leakage cannot help but being taken in temporary way without any noticeable countermeasure. This kind of repair is socially criticized many times that is defective construction even if this costs a lot. It was not arrange the standard for construction methods of sealer of injection type for leakage maintenance, even it has been used various type of construction methods for leakage part. In conclusion, we suggest that the construction methods of sealer of injection type for leakage maintenance for leakage to establish the leakage repairing technology as increase of structure demand. Therefore, it would be possible to provide a stage-by-stage solution by developing systematic research activities among the industry, schools, and research institutes to spread maintenance management techniques globally through technical solution to water leakage and cracks, acquisition of structural safety with prolonged durability for life cycle, reduction of water leakage repair expense s, and so on.

The Evaluation of Seismic Performance and the Design of Initial Member Sections for Architectural Steel Structures (건축 강구조물의 초기 부재단면 설계 및 내진성능에 관한 연구)

  • Lee, Sang-Ju;Lee, Dong-Woo;Han, Sang-Eul
    • Journal of Korean Association for Spatial Structures
    • /
    • v.6 no.1 s.19
    • /
    • pp.101-109
    • /
    • 2006
  • An initial member sections of steel structures is selected by experience of expert building structural designers. And appropriate member section is designed by repeat calculation through structural analysis. Therefore an initial assumption of member section is necessary for saving the time for structural design and is important to acquire safety of building structures. Also brace damper are generally used to prevent or decrease stuctural damage by its hysteretic behavior in building structures subjected to strong earthquake. Based on plastic design, the initial section of members for architectural steel structures with hysteretic damper braces is presented and seismic effect of structural behavior by the ratio of damper stiffness to structural story stiffness is estimated in this paper.

  • PDF

Geostatistical Integration of MT and Borehole Data for RMR Evaluation (암반등급 평가를 위한 MT와 시추공 자료의 지구통계학적 복합해석)

  • Oh, Seok-Hoon;Chung, Ho-Joon;Lee, Duk-Kee
    • Geophysics and Geophysical Exploration
    • /
    • v.7 no.2
    • /
    • pp.121-129
    • /
    • 2004
  • The geostatistical approach was applied to integrate MT (Magneto-telluric) resistivity data and borehole information for the spatial RMR (Rock Mass Rating) evaluation. Generally, resistivity of the subsurface is believed to be positively related to the RMR, thus the resistivity and borehole RMR information was combined in a geostatistical approach. To relate the two different sets of data, we take the MT resistivity data as secondary information and estimate the RMR mean values at unsampled points by identification of the resistivity to the borehole data. Two types of approach are performed for the estimation of RMR mean values. Then the residuals of the RMR values around the borehole sites are geostatistically modeled to infer the spatial structure of difference between real RMR values and estimated mean values. Finally, this geostatistical estimation is added to the previous means. The result applied to a real situation shows prominent improvements to reflect the subsurface structure and spatial resolution of RMR information.

The Study for Establishing the Criteria of Measurement Items in the Monitoring System for the Steel-Box Girder Bridge by FEM Analysis (구조해석에 의한 강상자형교 상시계측시스템 계측항목별 관리기준치 설정 연구)

  • Joo, Bong-Chul;Park, Ki-Tae;You, Young-Jun;Lee, Chin-Hyung;Hwang, Yoon-Koog
    • Journal of Korean Society of societal Security
    • /
    • v.2 no.4
    • /
    • pp.35-41
    • /
    • 2009
  • If any bridge has the monitoring system, the bridge manager can check the history of bridge behavior and the progress of the damage more exactly. When the unexpected event (ex: earthquake and flood) happens, the manager can check the safety condition of the bridge and make the pertinent action for bridge management which is reduction of vehicle speed or traffic control through the system. Additionary the manager can make the well-timed repair or reinforcement through the system, so he can save the management cost or the life cycle cost. This study presents the method of setting the criteria by FEM analysis in bridge monitoring system, and the standard progress for setting the criteria about measurement items of monitoring system for the steel box type bridge.

  • PDF

Static and Dynamic Analysis for the Optimal Relation of Rise-Span-Girder Depth in Langer Arch Bridge (랭거아치교의 라이즈-경간-형고의 최적관계를 위한 정적 및 동적해석)

  • Hur, Eun Mi;Choi, Jee Hoon;Cho, Byoung Chil;Lee, Young Jae
    • Journal of Korean Society of Steel Construction
    • /
    • v.14 no.2
    • /
    • pp.319-327
    • /
    • 2002
  • Development of high-strength and light-weight structural steel as well as advancement in steel structure analysis enable construction of long span steel arch bridge. In an economic viewpoint, however, the design values of long span steel arch bridge needs to be optimized to reduce construction cost and achieve proper levels of structural safety. This study investigated the girder depth and the rise-span ratio for optimum design values, as well as the spectral analysis for protection against earthquake. The relationship between rise-span ratio and girder depth was derived based on the parametric studies of the basic span lengths of 60, 70, 80, 90, and 100m using a commercial Cis SAP2000. The equation relating the two variables was derived using linear regression.

Magneto-rheological and passive damper combinations for seismic mitigation of building structures

  • Karunaratne, Nivithigala P.K.V.;Thambiratnam, David P.;Perera, Nimal J.
    • Earthquakes and Structures
    • /
    • v.11 no.6
    • /
    • pp.1001-1025
    • /
    • 2016
  • Building structures generally have inherent low damping capability and hence are vulnerable to seismic excitations. Control devices therefore play a useful role in providing safety to building structures subject to seismic events. In recent years semi-active dampers have gained considerable attention as structural control devices in the building construction industry. Magneto-rheological (MR) damper, a type of semi-active damper has proven to be effective in seismic mitigation of building structures. MR dampers contain a controllable MR fluid whose rheological properties vary rapidly with the applied magnetic field. Although some research has been carried out on the use of MR dampers in building structures, optimal design of MR damper and combined use of MR and passive dampers for real scale buildings has hardly been investigated. This paper investigates the use of MR dampers and incorporating MR-passive damper combinations in building structures in order to achieve acceptable levels of seismic performance. In order to do so, it first develops the MR damper model by integrating control algorithms commonly used in MR damper modelling. The developed MR damper is then integrated in to the seismically excited structure as a time domain function. Linear and nonlinear structure models are evaluated in real time scenarios. Analyses are conducted to investigate the influence of location and number of devices on the seismic performance of the building structure. The findings of this paper provide information towards the design and construction of earthquake safe buildings with optimally employed MR dampers and MR-passive damper combinations.

3-Dimentional numerical study on dynamic behavior of connection between vertical shaft and tunnel under earthquake loading (3차원 수치해석을 이용한 지진 시 수직구-터널 접속부 동적 거동 분석)

  • Kim, Jung-Tae;Cho, Gye-Chun;Kang, Seok-Jun;Kim, Ki Jung;Hong, Eun-Soo
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.20 no.5
    • /
    • pp.887-897
    • /
    • 2018
  • 3D time history analysis was performed on vertical shaft-tunnel connection to provide insight into the dynamic stress-strain behavior of the connection considering the effects of soil layers, periodic characteristics and wave direction of earthquakes. MIDAS GTS NX based on FEM (Finite Element Method) was used for this study. From this study, it is revealed that the maximum displacement occurred at the upper part of the connection when the long period seismic waves propagate through the tunnel direction in soft ground. Also, stress concentration occurs due to different behaviors of vertical shaft and tunnel, and the stress concentration could be influence for safety on the connection. The results of this study could be useful for the seismic performance design of vertical shaft-tunnel connection.

Analytical Study for Seismic Capacity Enhancement for Non-structural Elements in Power Plants (발전플랜트 시설 내부 비구조요소의 내진 안전성 향상을 위한 해석적 연구)

  • Bang, Jin Soo;Kwon, Yangsu;Yim, Hong Jae
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.24 no.2
    • /
    • pp.1-8
    • /
    • 2020
  • In the case of power plant facilities, seismic stability of non-structural elements is important. In particular, Cabinet structures to which electrical equipment is attached, should have functional safety against earthquakes. Therefore, in this study the dynamic characteristics of non-structural elements inside existing power plant buildings were identified and the response level generated during dynamic behavior was analyzed. In addition, The steel plate dampers were adopted and adjusted to suit the size of the target equipment. In order to derive the optimal seismic reinforcement, the variables according to the attachment location were set and the responses were analyzed by the seismic movement input before and after reinforcement.

An Experimental Study on the Reinforcement of Low-Rise RC Structure for Seismic Performance (저층 RC 건물의 내진성능 보강에 관한 실험적 연구)

  • Kim, Dongbaek;Lee, Byeonghoon;Kwon, Soondong;Lee, Induk
    • Journal of the Society of Disaster Information
    • /
    • v.12 no.2
    • /
    • pp.144-149
    • /
    • 2016
  • Nowaday, most of the low-rise concrete structures which have less than five stories were built before the intensified seismic code was established 2005. According to the fact that our country is not a safety zone ay more, studies are need to reinforce the seismic performance of that structures. The basic frame of low-rise structure are consist of beams and columns with partition walls, therefore that are very weak about secondary wave of earthquake because of the high stiffness. The partition wall are consist of open channel for sunlight or ventilation and intermediate wall. The intermediate walls will enhance the stiffness of columns, but will cause shear failure with short column effects because of the reduced effective depth. But we don't have studies and adequate design code for partition wall effects, therefore some more studies are need for these facts.

A Study of the Vibration Safety Criterion on the Dynamic Behavior of Buried Pipeline with the Free Ends (양단자유 경계조건을 가진 매설관의 동적거동에서 진동안전 기준에 관한 연구)

  • 이병길;정진호;장봉현;안명석
    • Explosives and Blasting
    • /
    • v.22 no.3
    • /
    • pp.13-26
    • /
    • 2004
  • This work reports results of our study on the dynamic response of buried pipelines depending on their boundary conditions. We have studied behavior of the buried pipelines both along the axial and the transverse direction with a boundary condition of free ends. The buried pipelines are modeled as beams on elastic foundation while the seismic wave as a ground displacement in the form of a sinusoidal wave. The natural frequency, its mode, and the effect of parameters have been interpreted in terms of the free vibration. In order to investigate the response on the earthquake, the resulting frequency and the mode shape obtained from the free vibration have been utilized to derive the mathematical formula for the farced vibration. We have also completed the computer program to simulate the time-displacement graphs of the pipe lines with free ends for both cases of vibrations.