• Title, Summary, Keyword: seismic behavior

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Seismic Analysis of Tunnel Response by Response Displacement Method (응답변위법에 의한 터널의 내진해석)

  • Yun, Se-Ung;Shin, Jong-Ho;Park, Du-Hee
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.457-462
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    • 2009
  • In this study, seismic analysis is performed using simplified method, analytical solution and numerical analysis based on one-dimensional seismic site response analysis. The results show that analytical solution of tunnel response is predicted more conservative than numerical solution. And simplified method is not appropriate for seismic analysis of tunnel response. In addition, it is reasonable to determine shear-modulus reduction ratio performing seismic site response analysis to consider ground nonlinear-behavior.

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Capacity Design of RC Bridge Columns for Seismic Loading

  • Lee Jae Hoon;Ko Seong Hyun;Choi Jin Ho;Shin Sung Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.591-594
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    • 2004
  • Recently, a tendency for development of seismic approach of foreign countries is capacity design development. Capacity design is rational seismic design concept of capacity protection considering not only earthquake magnitude, but also behavior of structure. For that reason, the most bridge seismic design specifications contain capacity protection provisions explicitly or implicitly. The capacity protection is normally related with slenderness effect of the columns, force transfer in connections between columns and adjacent elements, and shear design of columns. It intends to prevent brittle failure of the structural components of bridges, so that the whole bridge system may show ductile behavior and failure during earthquake events. The objectives of this paper are to deduce needed provisions for the moderate seismicity regions such as Korea after studying current seismic design codes and to establish rational criteria provisions of seismic design for future revision of seismic design specifications.

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An Analysis of Seismic Response of High - Rise Building with Mid-Story Isolation System According to Change of Characteristics of the Seismic Isolation Device (중간층 면진시스템이 적용된 고층건물의 면진장치 특성변화에 따른 지진응답분석)

  • Kang, Joo-Won
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.8
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    • pp.149-156
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    • 2019
  • In this study, dynamic responses of high - rise buildings were analyzed through the change of horizontal stiffness and yield strength among characteristics of seismic isolation system by applying middle - layer seismic isolation system to high - rise buildings of 120m height. As a result in order to prevent the displacement of the isolation layer and to control the maximum torsion angle, it is possible to appropriately control by increasing or decreasing the horizontal stiffness and the yield strength. However, depending on the maximum torsional angle and the hysteretic behavior of the seismic isolation system, excessive yield strength and horizontal stiffness increase may induce the elastic behavior of the structure and amplify the response. Therefore, it is considered that it is necessary to select the property value of the appropriate isolation device.

Seismic behavior of a new type of seismic energy dissipation shear wall system

  • Lu, Xilin;Wu, Xiaohan;Meng, Liang
    • Structural Engineering and Mechanics
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    • v.5 no.2
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    • pp.167-175
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    • 1997
  • A new seismic energy dissipation shear wall structure is proposed in this paper. The new shear wall is one with purposely built-in vertical slits within the wall panel, and various seismic energy dissipation devices are installed in the vertical slits so that the dynamic characteristics of the structure (for instance, lateral stiffness, ductility and fundamental period) can be controlled. In order to verify this concept, shaking table tests of two 10-story shear wall models were carried out, and the seismic behavior of the two models are studied by analyzing the test data and computing the nonlinear seismic response of the models.

The Establishment Plan of Strong-Motion Instrumentation of Dams for Monitoring of Seismic Behavior and Taking An Urgent Countermeasure (댐의 지진관측 및 내진대책 수립을 위한 지진계측시스템 구축 방안에 관한 연구)

  • Oh, Byung-Hyun;Lee, Jong-Wook
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1588-1595
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    • 2005
  • In this study, the installation location of accelerometer and accelerograph for dam are investigated in the field to establish of emergency action against dam failure when earthquake occur and to guarantee the results of seismic stability of dams which are analysed with dynamic analysis method during 1999 to 2003 by KOWACO. By a comparative study concerning of domestic and foreign guidelines of seismic strong motion instrumentation for dams, "Guidelines of Seismic Strong-Motion Instrumentation Installation, Operation and Maintenance for Dams" is established to set up the standard of seismic strong-motion instrumentation for dam, are supervised by KOWACO There is some problems in taking a measure of stability of dams when earthquake event occur because the existing seismic strong motion instruments are operated independently. This make difficult to confirm the occurrence of seismic event. For that reason, in this study the plan of unified operation and maintenance system for strong-motion instrument for dams is designed. It will make possible real-time seismic monitoring, data transmission and receiving, giving warning for earthquake, and exchanging data with national seismic network.

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Assessment of seismic fragility curves for existing RC buildings in Algiers after the 2003 Boumerdes earthquake

  • Mehani, Youcef;Bechtoula, Hakim;Kibboua, Abderrahmane;Naili, Mounir
    • Structural Engineering and Mechanics
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    • v.46 no.6
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    • pp.791-808
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    • 2013
  • The main purpose of this paper is to develop seismic fragility curves for existing reinforced concrete, RC, buildings based on the post earthquake field survey and the seismic performance using capacity design. Existing RC buildings constitute approximately 65% of the total stock in Algiers. This type of buildings, RC, was widely used in the past and chosen as the structural type for the future construction program of more than 2 millions apartments all over Algeria. These buildings, suffered moderate to extensive damage after the 2003 Boumerdes earthquake, on May 21st. The determination of analytical seismic fragility curves for low-rise and mid-rise existing RC buildings was carried out based on the consistent and complete post earthquake survey after that event. The information on the damaged existing RC buildings was investigated and evaluated by experts. Thirty four (34) communes (districts) of fifty seven (57), the most populated and affected by earthquake damage were considered in this study. Utilizing the field observed damage data and the Japanese Seismic Index Methodology, based on the capacity design method. Seismic fragility curves were developed for those buildings with a large number data in order to get a statistically significant sample size. According to the construction period and the code design, four types of existing RC buildings were considered. Buildings designed with pre-code (very poor structural behavior before 1955), Buildings designed with low code (poor structural behavior, between 1955-1981), buildings designed with medium code (moderate structural behavior, between 1981-1999) and buildings designed with high code (good structural behavior, after 1999).

Nonlinear Seismic Behavior Analysis of Skewed Bridges Considering Pounding Between Deck and Abutment (상판과 교대의 충돌을 고려한 사교의 비선형 지진거동 해석)

  • Kang, Seung Woo;Choi, Kwang Kyu;Song, Si Young;Son, Min Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.5
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    • pp.301-310
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    • 2016
  • There are differences in seismic behavior between non-skewed bridges and skewed bridges due to in-plane rotations caused by pounding between the skewed deck and its abutments during strong earthquake. Many advances have been made in developing design codes and guidelines for dynamic analyses of non-skewed bridges. However, there remain significant uncertainties with regard to the structural response of skewed bridges caused by unusual seismic response characteristics. The purpose of this study is performing non-linear time history analysis of the bridges using abutment-soil interaction model considering pounding between the skewed deck and its abutments, and analyzing global seismic behavior characteristics of the skewed bridges to assess the possibility of unseating. Refined bridge model with abutment back fill, shear key and elastomeric bearing was developed using non-linear spring element. In order to evaluate the amplification of longitudinal and transverse displacement response, non-linear time history analysis was performed for single span bridges. Far-fault and near-fault ground motions were used as input ground motions. According to each parameter, seismic behavior of skewed bridges was evaluated.

Seismic response simulations of bridges considering shear-flexural interaction of columns

  • Zhang, Jian;Xu, Shi-Yu
    • Structural Engineering and Mechanics
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    • v.31 no.5
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    • pp.545-566
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    • 2009
  • Bridge columns are subjected to combined actions of axial force, shear force and bending moment during earthquakes, caused by spatially-complex earthquake motions, features of structural configurations and the interaction between input and response characteristics. Combined actions can have significant effects on the force and deformation capacity of RC columns, resulting in unexpected large deformations and extensive damage that in turn influences the performance of bridges as vital components of transportation systems. This paper evaluates the seismic response of three prototype reinforced concrete bridges using comprehensive numerical models that are capable of simulating the complex soil-structural interaction effects and nonlinear behavior of columns. An analytical approach that can capture the shear-flexural interacting behavior is developed to model the realistic nonlinear behavior of RC columns, including the pinching behavior, strength deterioration and stiffness softening due to combined actions of shear force, axial force and bending moment. Seismic response analyses were conducted on the prototype bridges under suites of ground motions. Response quantities of bridges (e.g., drift, acceleration, section force and section moment etc.) are compared and evaluated to identify the effects of vertical motion, structural characteristics and the shear-flexural interaction on seismic demand of bridges.

The role of slenderness on the seismic behavior of ground-supported cylindrical silos

  • Demir, Aysegul Durmus;Livaoglu, Ramazan
    • Advances in concrete construction
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    • v.7 no.2
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    • pp.65-74
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    • 2019
  • This paper reports on the results of a parametric study, which examines the effects of varying aspect ratios on the dynamic response of cylindrical silos directly supported on the ground under earthquake loading. Previous research has shown that numerical models can provide considerably realistic simulations when it comes to the behavior of silos by using correct boundary conditions, appropriate element types and material models. To this end, a three dimensional numerical model, taking into account the bulk material-silo wall interaction, was produced by the ANSYS commercial program, which is in turn based on the finite element method. The results obtained from the numerical analysis are discussed comparatively in terms of dynamic material pressure, horizontal displacement, equivalent base shear force and equivalent bending moment responses for considered aspect ratios. The effects experienced because of the slenderness of the silo in regards to the seismic response were evaluated along with the effectiveness of the classification system proposed by Eurocode in evaluating the loads on the vertical walls. Results clearly show that slenderness directly affects the seismic response of such structures especially in terms of behavior and the magnitude of the responses. Furthermore the aspect ratio value of 2.0, given as a behavioral changing limit in the technical literature, can be used as a valid limit for seismic behavior.

Seismic responses of base-isolated nuclear power plant structures considering spatially varying ground motions

  • Sayed, Mohamed A.;Go, Sunghyuk;Cho, Sung Gook;Kim, Dookie
    • Structural Engineering and Mechanics
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    • v.54 no.1
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    • pp.169-188
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    • 2015
  • This study presents the effects of the spatial variation of ground motions in a hard rock site on the seismic responses of a base-isolated nuclear power plant (BI-NPP). Three structural models were studied for the BI-NPP supported by different number of lead rubber bearing (LRB) base isolators with different base mat dimensions. The seismic responses of the BI-NPP were analyzed and investigated under the uniform and spatial varying excitation of El Centro ground motion. In addition, the rotational degrees of freedom (DOFs) of the base mat nodes were taken to consider the flexural behavior of the base mat on the seismic responses under both uniform and spatial varying excitation. Finally, the seismic response results for all the analysis cases of the BI-NPP were investigated in terms of the vibration periods and mode shapes, lateral displacements, and base shear forces. The analysis results indicate that: (1) considering the flexural behavior of the base mat has a negligible effect on the lateral displacements of base isolators regardless of the number of the isolators or the type of excitation used; (2) considering the spatial variation of ground motions has a substantial influence on the lateral displacements of base isolators and the NPP stick model; (3) the ground motion spatial variation effect is more prominent on lateral displacements than base shear forces, particularly with increasing numbers of base isolators and neglecting flexural behavior of the base mat.