• Title/Summary/Keyword: local site effects

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Site-Specific Ground Motions based on Empirical Green`s Function modified for the Path Effects in Layered Media (층상구조에서 지진파 전파경로를 고려하여 수정된 경험 Green 함수를 이용한 지반운동 모사)

  • 조남대;박창업
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.09a
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    • pp.19-27
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    • 2001
  • Seismic parameters fur computation of ground motions in Southern Korea are obtained from recently recorded data, and site-independent regional and site-dependent local strong ground motions are predicted using efficient computational techniques. For the computation of ground motions, we devised an efficient procedure to compute site-independent $x_{q}$ and dependent $x_{s}$ values separately. The first step of this procedure is to use the coda normalization method far computation of site independent Q or corresponding $x_{q}$ value. The next step is the computation of $x_{s}$, values fur each site separately using the given $x_{q}$ value. For computation of ground motions the empirical Green's function (EGF) is modified to account fur the depth and distance variations of subevents on a finite fault plane using the theoritical Green's function. It is computed using wavenumber integration technique in layered media. The site dependent ground motions at seismic stations in southeastern local area were properly simulated using the modified empirical Green's function method in layered medium. The proposed method and procedures fur estimation of site dependent seismic parameters and ground motions could be efficiently used in the low and moderate seismicity regions.ons.s.ons.

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A site-specific CFD study of passing ship effects on multiple moored ships

  • Chen, Hamn-Ching;Chen, Chia-Rong;Huang, Erick T.
    • Ocean Systems Engineering
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    • v.9 no.1
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    • pp.43-77
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    • 2019
  • A local-analytic-based Navier-Stokes solver has been employed in conjunction with a compound ocean structure motion analysis program for time-domain simulation of passing ship effects induced by multiple post-Panamax class ships in the exact condition of a real waterway. The exact seabed bathymetry was reproduced to the utmost precision attainable using the NOAA geophysical database for Virginia Beach, NOAA nautical charts for Hampton Roads and Norfolk harbor, and echo sounding data for the navigation channel and waterfront facilities. A parametric study consists of 112 simulation cases with various combinations of ship lanes, ship speeds, ship heading (inbound or outbound), channel depths, drift angles, and passing ship coupling (in head-on or overtaking encounters) were carried out for two waterfront facilities at NAVSTA Norfolk and Craney Island Fuel Terminal. The present paper provides detailed parametric study results at both locations to investigate the site-specific passing ship effects on the motion responses of ships moored at nearby piers.

Soil-structure interaction vs Site effect for seismic design of tall buildings on soft soil

  • Fatahi, Behzad;Tabatabaiefar, S. Hamid Reza;Samali, Bijan
    • Geomechanics and Engineering
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    • v.6 no.3
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    • pp.293-320
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    • 2014
  • In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes $D_e$ and $E_e$ according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

Effects of EMLA Cream in Intradermal Skin Test of Ampicillin Sodium Antibiotics (EMLA 크림이 ampicillin sodium 항생제 피내반응검사에 미치는 효과)

  • Kim, Jin;Kang, Hee-Young
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.18 no.1
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    • pp.46-53
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    • 2011
  • Purpose: The purpose of this study was to identify the effects of EMLA cream (eutectic mixture of local anesthetics, lidocaine and prilocaine) on pain during ampicillin sodium intradermal (ID) skin test, and also to assess skin reaction after the skin test. Methods: Forty-three nurse-volunteers had skin tests with 0.01ml-0.05ml ampicillin sodium antibiotics. Skin tests were done on each forearm to compare the pain level of the skin test site after application of EMLA cream with the pain level when no EMLA cream was applied. EMLA cream was applied at the ID skin test site with an occlusive dressing for one hour. Pain was evaluated using a visual analogue scale and pain sensation using the short form McGill Pain Questionnaire. The transverse diameter of the wheal and redness was read right after and at 15 minutes after the skin test. The results were compared using independent t-tests. Results: Pain score and sensation with EMLA cream treatment were significantly lower than when EMLA cream was not applied. There was no difference in skin reactions; reading of the skin test was not affected by EMLA cream. Conclusions: EMLA cream was found to be an effective local anesthetic to relieve the pain of clients having ampicillin sodium antibiotics ID skin tests.

Seismic Zonation of Site Period at Daejeon within Spatial GIS tool (공간 GIS 기법을 활용한 대전 지역 부지 주기의 지진 구역화)

  • Sun, Chang-Guk;Shin, Jin-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.563-574
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    • 2008
  • Most of earthquake-induced geotechnical hazards have been caused by the site effects relating to the amplification of ground motion, which are strongly influenced by the local geologic conditions such as soil thickness or bedrock depth and soil stiffness. In this study, an integrated GIS-based information system for geotechnical data, called geotechnical information system (GTIS), was constructed to establish a regional counterplan against earthquake-induced hazards at an urban area, Daejeon, which is represented as a hub of research and development in Korea. To build the GTIS for the area of interesting, pre-existing geotechnical data collections were performed across the extended area including the study area and a walk-over site survey was additionally carried out to acquire surface geo-knowledge data. For practical application of the GTIS used to estimate the site effects at the area of interesting, seismic microzoning map of the characteristic site period was created and presented as regional synthetic strategy for earthquake-induced hazards prediction. In addition, seismic zonation for site classification according to the spatial distribution of the site period was also performed to determine the site amplification coefficients for seismic design and seismic performance evaluation at any site in the study area. Based on the case study on seismic zonations at Daejeon, it was verified that the GIS-based GTIS was very useful for the regional prediction of seismic hazards and also the decision support for seismic hazard mitigation.

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The effect of local topography on the seismic response of a coupled train-bridge system

  • Qiao, Hong;Du, Xianting;Xia, He;De Roeck, Guido;Lombaert, Geert;Long, Peiheng
    • Structural Engineering and Mechanics
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    • v.69 no.2
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    • pp.177-191
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    • 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.

Estimation of Site Response Characteristics at Town Fortress Areas Damaged by Historical Earthquakes (역사 지진 피해 발생 읍성 지역의 부지 응답 특성 평가)

  • Sun, Chang-Guk;Bang, Eun-Seok;Chung, Choong-Ki;Kim, Dong-Soo
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.125-132
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    • 2006
  • To estimate the local site effects at two town fortress areas where stone parapets were collapsed during historical earthquakes, site characteristics were evaluated using borehole drillings and seismic tests and equivalent-linear site response analyses were conducted based on the shear wave velocity (Vs) profiles determined from site investigations. The study sites are categorized as site classes C and B according to the mean Vs to 30 m ranging from 500 to 850 m/s, and their site periods are distributed in short period range of 0.06 to 0.16 sec. For site class C in the study areas, the short-period (0.1-0.5 sec) and mid-period (0.4-2.0 sec) site coefficients, $F_{\alpha}$ and $F_\nu$ specified in the Korean seismic design guide, underestimate the ground motion in short-period band and overestimate the ground motion in mid-period band, respectively, due to the characteristics showing high amplification in short period range, which can result in the collapse of stone parapets having the short natural period.

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Comparative Study on Street Landscape of Bugok Hot Spring and Kinosaki Hot Spring - Focused on Color Analysis - (부곡온천과 기노사끼온천 관광지 가로경관 비교분석 - 색채 분석을 중심으로 -)

  • Kim, Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.5 s.118
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    • pp.24-31
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    • 2006
  • The tourism sites and attractions of South Korea in many ways have little specialties in their image due to the local development plan's uniformed way of designing and improving landscape. The lack of specialties in tourist sites and attractions have caused displeasure from the local residents, as the sites don't characterize the locals as attractively and appealingly as is the potential. There have been no research or studies on the scenic effect on tourism or resort development thus producing an urgent call for local authorities to develop planned landscapes of local sites. This study compares Bugok Onchon (hot spring), whose image hardly differentiates itself from the others, with Kinosaki Onsen (hot spring). Bugok Hot Spring, which is the case study of this report, has recorded a steady decline of visitors due to a result of uniformed development planning. In the case of Kinosaki Hot Spring, scenery development, however, has made a breakthrough in tourist increase despite its no-so-easily-accessible location. The study assumes that scenery effects changes in promoting local tourism, thus analyzing and comparing the two hot springs to unearth critical factors in tourist site development, as well as viewing the present state of Bugok Hot Spring for further study. Furthermore, the study provides tourist site developers with a guideline of the two comparative Hot Spring cases. Investigations and analyses are mainly focused on colors, which are important factors in making underlying images of tourist sites, and the comparison of Bugok Hot Spring with Kinosaki Hot Suing. Bugok Hot Spring shows the influences of accent colors as well as a variety of color combinations and similarities of color tones. Kinosaki Hot Spring shows a combination of naturally-generated colors its own scenic beauty by trimming the landscape. Through the comparative study of the two hot springs, Bugok (boulevard) uncovers a typical case of Korean local landscape planning, even with the well-known tourist attraction 'Bugok-Hawaii', and calls upon a new, serious landscape-improvement plan to increase visitors.

Liquefaction hazard assessment in a GIS environment: A case study of Buğday Pazarı neighborhood in Çankırı province

  • Erenm Yurdakul;Sevkim Ozturk;Enderm Sarifakioglu
    • Geomechanics and Engineering
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    • v.36 no.5
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    • pp.455-464
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    • 2024
  • Seismic movements have varying effects on structures based on characteristics of local site. During an earthquake, weak soils are susceptible to damage due to amplified wave amplitudes. Soil-structure interaction issue has garnered increased attention in Türkiye, after devastating earthquakes in Kocaeli Gölcük (1999), Izmir (2020), Kahramanmaraş Pazarcık and Elbistan (2023). Consequently, liquefaction potential has been investigated in detail for different regions of Türkiye, mainly with available field test results. Çankırı, a city located close to North Anatolian Fault, is mainly built on alluvium, which is prone to liquefaction. However, no study on liquefaction hazard has been conducted thus far. In this study, groundwater level map, SPT map, and liquefaction risk map have been generated using Geographical Information System (GIS) for the Buğday Pazarı District of Çankırı province. Site investigations studies previously performed for 47 parcels (76 boreholes) were used within the scope of this study. The liquefaction assessment was conducted using Seed and Idriss's (1971) simplified method and the visualization of areas susceptible to liquefaction risk has been accomplished. The results of this study have been compared with the City Council's precautionary map which is currently in use. As a result of this study, it is recommended that minimum depth of boreholes in the region should be at least 30m and adequate number of laboratory tests particularly in liquefiable areas should be performed. Another important recommendation for the region is that detailed investigation should be performed by local authorities since findings of this study differ from currently used precautionary map.

Strong ground motion characteristics of the 2011 Van Earthquake of Turkey: Implications of seismological aspects on engineering parameters

  • Beyen, Kemal;Tanircan, Gulum
    • Earthquakes and Structures
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    • v.8 no.6
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    • pp.1363-1386
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    • 2015
  • The October 23 2011 Van Earthquake is studied from an earthquake engineering point of view. Strong ground motion processing was performed to investigate features of the earthquake source, forward directivity effects during the rupture process as well as local site effects. Strong motion characteristics were investigated in terms of peak ground motion and spectral acceleration values. Directiviy effects were discussed in detail via elastic response spectra and wide band spectograms to see the high frequency energy distributions. Source parameters and slip distribution results of the earthquake which had been proposed by different researchers were summarized. Influence of the source parameters on structural response were shown by comparing elastic response spectra of Muradiye synthetic records which were performed by broadband strong motion simulations of the earthquake. It has been emphasized that characteristics of the earthquake rupture dynamics and their effects on structural design might be investigated from a multidisciplinary point of view. Seismotectonic calculations (e.g., slip pattern, rupture velocity) may be extended relating different engineering parameters (e.g., interstorey drifts, spectral accelerations) across different disciplines while using code based seismic design approaches. Current state of the art building codes still far from fully reflecting earthquake source related parameters into design rules. Some of those deficiencies and recent efforts to overcome these problems were also mentioned. Next generation ground motion prediction equations (GMPEs) may be incorporated with certain site categories for site effects. Likewise in the 2011 Van Earthquake, Reverse/Oblique earthquakes indicate that GMPEs need to be feasible to a wider range of magnitudes and distances in engineering practice. Due to the reverse faulting with large slip and dip angles, vertical displacements along with directivity and fault normal effects might significantly affect the engineering structures. Main reason of excessive damage in the town of Erciş can be attributed to these factors. Such effects should be considered in advance through the establishment of vertical design spectra and effects might be incorporated in the available GMPEs.