• 대한건축학회논문집:구조계
• /
• 제34권11호
• /
• pp.27-35
• /
• 2018

The purpose of this study is to examine the effects of boundary RC frame(composed of one tie-beam and two tie-columns) on seismic performance of unreinforced masonry walls to suggest alternative way for seismic design of unreinforced masonry wall structures. Two test specimens are prepared, one is a typical unreinforced masonry wall and another is alternative unreinforced masonry wall with additional boundary RC frame. The structural experiments were carried out to evaluate the difference of seismic resistance performance between two test specimens with or without the boundary RC frames. From the test results, it was found that the failure mode of unreinforced masonry wall fundamentally changed from 'brittle' to 'ductile' by the installing of boundary RC frames. And, the maximum load and energy dissipation capacity of the test specimen with boundary RC frame was increased about 1.6~1.7 and 2~3 times respectively compared with a typical unreinforced masonry wall specimen.

• Structural Engineering and Mechanics
• /
• 제69권2호
• /
• pp.177-191
• /
• 2019

The local topography has a significant effect on the characteristics of seismic ground motion. This paper investigates the influence of topographic effects on the seismic response of a train-bridge system. A 3-D finite element model with local absorbing boundary conditions is established for the local site. The time histories of seismic ground motion are converted into equivalent loads on the artificial boundary, to obtain the seismic input at the bridge supports. The analysis of the train-bridge system subjected to multi-support seismic excitations is performed, by applying the displacement time histories of the seismic ground motion to the bridge supports. In a case study considering a bridge with a span of 466 m crossing a valley, the seismic response of the train-bridge system is analyzed. The results show that the local topography and the incident angle of seismic waves have a significant effect on the seismic response of the train-bridge system. Leaving these effects out of consideration may lead to unsafe analysis results.

• Nuclear Engineering and Technology
• /
• 제54권4호
• /
• pp.1382-1393
• /
• 2022

This paper investigates the seismic behavior of an electrical cabinet considering the influence of equipment-anchor-interaction (EAI) that is generally not taken into consideration in a decoupled analysis. The hysteresis behavior of an anchor bolt in concrete was thereby considered to highlight this interaction effect. To this end, the experimental behavior of an anchor bolt under reversed cyclic loading was taken from the recently developed literature, and a numerical model for the anchor hysteresis was developed using the component approach. The hysteresis properties were then used to calibrate the multi-linear link element that is implemented as a boundary condition for the cabinet incorporating the EAI. To highlight this EAI further, the nonlinear time history analysis was performed for a cabinet considering the hysteresis behavior comparative to a fixed boundary condition. Additionally, the influence on the seismic fragility was evaluated for the operational and structural condition of the cabinet. The numerical analysis considering the anchor hysteresis manifests that the in-cabinet response spectra (ICRS) are significantly amplified with the corresponding reduction in the seismic capacity of 25% and 15% for an operational and structural safety condition under the selected protocols. Considering the fixed boundary condition over a realistic hysteresis behavior of the anchor bolt is more likely to overestimate the seismic capacity of the cabinet in a seismic qualification procedure.

• 한국구조물진단유지관리공학회 논문집
• /
• 제24권5호
• /
• pp.77-85
• /
• 2020

본 연구에서는 2주탑 콘크리트 사장교를 대상으로 경계조건에 따른 지진 취약도 곡선을 작성하고, 경계조건이 교량의 지진 취약도에 미치는 영향을 평가하고자 한다. 대상교량에 대한 해석모델이 Midas Civil을 사용하여 구축되었고 Fiber요소와 콘크리트, 철근의 재료모델을 적용하여 비선형 시간이력해석을 수행하였다. 주탑과 보강형 사이의 경계조건을 강결, 비구속, 포트받침, 면진받침의 총 4가지로 구분하여 각각의 경계조건에 대해 지진 취약도 곡선을 작성하였다. 주탑의 소성힌지구간과 연결부, 케이블을 취약부재로 선정하고 이 부재들에 대해 지진 취약도 곡선을 작성하였다. 분석결과 주탑의 소성힌지구간과 연결부에서는 면진받침모델이 가장 낮은 손상확률을 나타내고, 케이블의 지진 취약도는 경계조건에 의한 영향이 다른 부재에 비해 크지 않은 것을 알 수 있다.

• Ocean and Polar Research
• /
• 제24권3호
• /
• pp.189-196
• /
• 2002

A multichannel seismic survey was conducted in the southern Ayu Trough which is the only spreading boundary between the Philippine Sea and Caroline plates. The seismic system used in this study comprises of 2.46-l sleeve gun and a 12-channel streamer with a group interval of 6.25m. Migration technique was used to analyze seismic velocity, and poststack depth migration was applied to the stacked data. The sediment thickness obtained from the depth section tends to increase with distance from the spreading axis. Sedimentation rates are poorly constrainted in the study area. The apparent half-spreading rates estimated from the sediment thickness and sedimentation rate from DSDP hole on the caroline plate are 4.7mm/yr and 7.9mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively, which are fester than Previously suggested. On the basis of new oblique spreading geometry, the recalculated spreading rates are 5.4mm/yr and 9.1mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively. Seismic sections show that the topography is asymmetric across the Ayu Trough and the acoustic basement is rough. These features are consistent with the earlier suggestion that the Ayu Trough is a slow-spreading divergent boundary. A detailed examination of seismic profiles away from the axis shows that sediments can be divided into two layers which implies a possible change in the spreading rate anuor sedimentation condition during the formation of the trough.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
• /
• pp.155-162
• /
• 1998

The influence of the dam-reservoir interaction on the seismic response of dams is studied. To represent the radiation of energy into the infinite region of the reservoir, a transmitting boundary is newly developed. The results obtained using the transmitting boundary is compared with abvailabel analytic solutions.

• 지질공학
• /
• 제32권4호
• /
• pp.535-545
• /
• 2022

내진설계에서 지반의 안정성을 향상시키기 위해서는 지진하중을 받는 지반의 동적거동을 이해하는 것이 필수적이다. 따라서 지반의 동적거동을 이해하는데 진동대 시험은 중요한 실험 중 하나이다. 이러한 진동대 시험에서 가장 중요한 인자 중 하나인 경계조건에 대한 영향성을 확인하고자 하였다. 본 연구의 목적은 지진하중에 의한 모형사면의 위치별 경계조건의 영향성을 확인하고자 한다. 연성토조(laminar shear box, LSB)안에 모형사면을 제작하여 위치에 따라 경계조건의 영향을 확인하였다. 토조 벽면으로부터 100, 50, 25 cm 지점에 각각의 모형사면을 조성하여 동일한 크기의 정현파 지진하중을 입력하였다. 그 결과, 모형사면에 대한 진동대 실험 시 25 cm 지점에 위치한 경우는 경계조건의 영향을 크게 받아 가속도가 증폭하는 모습을 확인할 수 있었으며 50~100 cm 지점에 위치한 경우 경계조건의 영향이 감소하여 적합한 위치로 판단되었다.

• 한국지진공학회논문집
• /
• 제3권1호
• /
• pp.123-132
• /
• 1999

댐-호소 계의 지진응답해석에 있어서의 어려운 문제 중 하나는 댐 상류방향으로의 에너지 방사를 적절하게 처리하는 것이다 본 논문에서는 깊이가 일정한 호소 원역으로의 에너지 방사를 잘 모델링할 수 있는 전달경계를 제시하였다 개발된 방법에서 수면파의 영향을 고려하였으며 호소-지반의 상호작용을 근사적으로 표현할수 있는 흡수경계조건도 도입하였다 댐과 호소의 경계면이 지표면에 수직하고 호소의 깊이가 일정할 경우에는 제안된 전달경계를 댐체의 모델에 직접 연결할 수 있다 댐체는 선형탄성거동을 가정하여 유한요소로 모델링 하였다 얻어진 댐-호소 계의 운동방정식을 이용하여 댐의 지진응답특성을 조사하였다

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
• /
• pp.180-187
• /
• 1998

One of the major difficulties in the seismic analysis of a dam-reservoir system is the treatment of the energy radiation in the upstream direction of the reservoir. In this paper a new transmitting boundary is presented that can model properly the radiation of energy in the far field direction of a semi-infinite reservoir with constant depth. In the newly developed method, effects of surface wave motion are taken into account and the reservoir-foundation interaction is approximately accounted for with an absorbing boundary condition. If a dam has vertical upstream face and the infinitely long reservoir maintains constant depth, then the proposed transmitting boundary can be directly coupled with the model of dam body. In present study, the dam body is assumed to behave elastically and modeled by finite element method. Seismic responses of a dam model are investigated using the newly developed transmitting boundary.

• Earthquakes and Structures
• /
• 제10권3호
• /
• pp.539-562
• /
• 2016

The seismic behavior of a ${\frac{1}{2}}$ scaled, three-story three-bay RC frame with masonry infill walls was studied experimentally and numerically. Pseudo-dynamic test results showed that despite following the column design provisions of modern seismic codes and neglecting the presence of infill walls, shear induced damage is unavoidable in the boundary columns. A finite element model was validated by using the results of available one-story one-bay frame tests in the literature. Simulations of the examined test frame demonstrated that boundary columns are subjected to shear demands in excess of their shear capacity. Seismic assessment of the test frame was conducted by using ASCE/SEI 41-06 (2006) guidelines and the obtained results were compared with the damage observed during experiment. ASCE/SEI 41-06 method for the assessment of boundary columns was found unsatisfactory in estimating the observed damage. Damage estimations were improved when the strain limits were used within the plastic hinge zone instead of column full height.