• Title/Summary/Keyword: long-term settlements

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Shear-lag effect in twin-girder composite decks

  • Dezi, Luigino;Gara, Fabrizio;Leoni, Graziano
    • Steel and Composite Structures
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    • v.3 no.2
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    • pp.111-122
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    • 2003
  • The paper presents a model for analysing the shear-lag effect on the slab of twin-girder composite decks subjected to static actions, support settlements and concrete shrinkage, which are the main actions of interest in composite bridge design. The proposed model includes concrete creep behaviour and shear connection flexibility. The shear-lag in the slab is accounted for by means of a new warping function. The considered actions are then applied to a realistic bridge deck and their effects are discussed. The proposed method is utilised to determine the slab effective widths for three different width-length ratios of the deck. Finally, a comparison between the results obtained with the Eurocode EC4-2 and those obtained with the proposed model is performed.

Effects of Municipal LFG Characteristics on Settlement (도시폐기물 매립지의 LFG 특성이 침하에 미치는 영향)

  • Ahn, Tae-Bong;Jin, Han-Kyu;Park, Dae-Hyo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.461-468
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    • 2004
  • The amount of $CO_2$ and $CH_4$ that were produced during biodegradation with were measured as function of time. Also, the settlements of landfill lysimeters were measured at the same time, and the relation with LFF(landfill gas) production was investigated. The effects of leachate recycle on the acceleration of settlement were studied by comparing two lysimeters. The gas production rate constant, $^{\kappa}_{LFG}$ is obtained to predict future gas production and settlement. These will be key role factors to predict gas production patterns and residual long-term settlement.

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Crest Settlement Prediction of Concrete Faced Rock-Fill Dam After Initial Impounding (CFRD의 담수 후 정부침하량 예측)

  • Kim, Yong-Seong;Park, Han-Gyu;Lim, Heui-Dae
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.349-354
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    • 2005
  • In this study, settlement characteristics of 23 CFRD was investigated from monitoring data and the method to estimate the crest settlements considering internal settlement during constructions was proposed. Moreover, crest settlement smaller than 20cm and deflection of face slab smaller than 20cm are not considered to be critical to the stability of large dam whose height is over 40m. Therefore, we assigned the region as safe zone that can be used as a guideline of maintenance of dam. These estimated data can be used in the design, construction and long-term maintenance in domestic CFRD hereafter.

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A study on effects of the prevention of rush work of construction sites on human accidents (건설 현장 강행공사 방지가 인적사고에 미치는 영향에 관한 연구)

  • Lee, Sung-Il;Kang, Kyung-Sik
    • Journal of the Korea Safety Management & Science
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    • v.19 no.1
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    • pp.27-37
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    • 2017
  • In the construction sites, rush (speedy construction) work have recently been overused because of budget reductions by reducing the construction duration after the long-term economic recession and construction business stagnation with institutional change including the instruction of the duration shortening bidding system and the introduction of the post-construction sales system by the Korea Research Institute for Human Settlements. Due to this, negligent accidents have frequently occurred by forcing manpower, equipment, finance, and material procurement and pressing ahead with impractical construction wok at night according to the reduction of construction schedules. Therefore, this paper has the necessity of this study to seek for alternatives to prevent negligent accidents by finding factors related to rush work in the reality that the importance for preventing negligent accidents is more emphasized while they have not been reduced in construction sites.

Experimental estimate of Nγ values and corresponding settlements for square footings on finite layer of sand

  • Dixit, Manish S.;Patil, Kailas A.
    • Geomechanics and Engineering
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    • v.5 no.4
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    • pp.363-377
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    • 2013
  • Any structure constructed on the earth is supported by the underlying soil. Foundation is an interfacing element between superstructure and the underlying soil that transmits the loads supported by the foundation including its self weight. Foundation design requires evaluation of safe bearing capacity along with both immediate and long term settlements. Weak and compressible soils are subjected to problems related to bearing capacity and settlement. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. A number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footings. The reliability of any theory can be demonstrated by comparing it with the experimental results. Results from laboratory model tests on square footings resting on sand are presented in this paper. The variation of bearing capacity of sand below a model plate footing of square shape with variation in size, depth and the effect of permissible settlement are evaluated. A steel tank of size $900mm{\times}1200mm{\times}1000mm$ is used for conducting model tests. Bearing capacity factor $N_{\gamma}$ is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesic's $N_{\gamma}$ values. From the experimental investigations it is found that, as the depth of sand cushion below the footing ($D_{sc}$) increases, ultimate bearing capacity and settlement values show an increasing trend up to a certain depth of sand cushion.

Sequential Analysis of Adjacent Ground Behaviors Caused by Deep Excavations (굴착 공정별 주변지반 거동 분석)

  • Seo Min-Woo;Seok Jeong-Woo;Yang Ku-Seung;Kim Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.22 no.2
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    • pp.19-28
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    • 2006
  • Long-term field observations were performed in three excavation sites in order to investigate the displacement behavior of adjacent ground during overall excavation procedure, where the depths of deep excavations were 15 m$\∼$29 m. In this study, ground settlements and lateral displacements of braced wall measured during installation of retaining wall and removal of bracing were specially focused to evaluate the behavior quantitatively according to three-stage-divided procedure, i.e. pre-excavation, main excavation, and removal of bracing. Through field measurements on three excavation sites, lateral displacements induced during removal of bracing are approximate to 40$\%$ of the amount found during main excavation stage and additional adjacent ground deformation during post-excavation procedure ranges from 18$\%$ to 33$\%$ of that found during main excavation stage, based on the settlement volume. In conclusion, it was quantitatively identified in this study that the deformations of adjacent ground during pre- and post-excavation stage were not negligible.

Caregiver Burden of Patients with Dementia and Day Care Center of Small Size Model within a Zone of Life (치매환자 부양자부담과 생활권 내 소규모 주·야간 돌봄 서비스 모델)

  • Na, Seung-kwon;Park, Eun-Ju
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.4
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    • pp.428-438
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    • 2016
  • The aim of this study, in order to reduce the support burden of dementia primary caregiver, within the framework of long-term care insurance system to present its founding model for the development of new services. Previous research as analytical materials and based on the CARE study between 2012 to 2013. Primary caregiver burden of patient are both physical, psychological and economic aspects as well as difficulties in many aspects and had influence on many factors such as age, care burden, economic, health, and social support. It also came high-risk primary caregiver suffer from depression. This primary caregiver to take advantage of the elderly long-term care insurance system implemented at the time of the institutional support necessary for since 2008, presented additional services in this study. Of increasing the small sizes day care center (tentative name) to open an as established in the settlements at a scale of less than nine, within 5 minutes from the residence, limited dementia by expertise in the disease home care services scale model of the current system service It was to improve the quality of existing shares, small group sizes for day care centers and community life apart.

A Study on Methods for the Domestic Diffusion of Intelligent Security Project : With a Focus on the Case of Smart City Integrated Platform (지능형 방범 사업의 국내 확산 방안 연구 : 스마트시티 통합플랫폼을 대상으로)

  • Shin, Young-Seob;Han, Sun-Hee;Lee, Jae-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.7
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    • pp.474-484
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    • 2019
  • In this age, where the social environment is changing rapidly and unpredictably, interest in safety from crime is increasing in Korean society. As the desire to live a life free from the fear of crime increases, interest in the construction of safe cities is also rising nationwide. To meet the national demand, the Korean government is promoting a project to link public disaster safety systems by involving municipalities, 112, 119, and other emergency services and institutions through the Smart City Integrated Platform in order to construct a smart safety net. This study investigates the linking of theSmart City Integrated Platform and theIntelligent Security Project. The results are as follows. 1. The linkage's objective is clear. 2. The system sector can provide information to accident-related organizations. 3. The scenario area can be expanded to a crime-prevention sector, and a long-term urban information integration infrastructure can be created. 4. Product testing is enabled by a smart city road map and through continuous consultation with relevant organizations. 5. Project diffusion to other local governments can be promoted with the continued addition of commercial products.

EVALUATION OF MINIMUM REVENUE GUARANTEE(MRG) IN BOT PROJECT FINANCE WITH OPTION PRICING THEORY

  • Jae Bum Jun
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.800-807
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    • 2009
  • The limited public funds available for infrastructure projects have led governments to consider private entities' participation in long-term contracts for finance, construction, and operation of these projects to share risks and rewards between the public and the private. Because these projects have complicated risk evolutions, diverse contractual forms for each project member to hedge risks involved in a project are necessary. In light of this, Build-Operate-Transfer(BOT) model is considered as effective to accomplish Public Private Partnerships(PPPs) with a characteristic of an ownership-reversion. In BOT projects, the government has used such an incentive system as minimum revenue guarantee(MRG) agreement to attract the private's participation. Although this agreement turns out critical in success of BOT project, there still exist problematic issues in a financial feasibility analysis since the traditional capital budgeting theory, Net Present Value(NPV) analysis, has failed to evaluate the contingent characteristic of MRG agreement. The purpose of this research is to develop real option model based on option pricing theory so as to provide a theoretical framework in valuing MRG agreement in BOT projects. To understand the applicability of the model, the model is applied to the example of the BOT toll road project and the results are compared with that by NPV analysis. Finally, we found that the impact of the MRG agreement is significant on the project value. Hence, the real option model can help the government establish better BOT policies and the developer make appropriate bidding strategies.

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Promoting Regional Innovation Projects and Cluster Formation in Korea (지역혁신사업 추진지역의 산업 클러스터 형성여건과 정책적 함의)

  • Kwon, Young-Sub
    • Journal of the Korean Academic Society of Industrial Cluster
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    • v.1 no.1
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    • pp.29-46
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    • 2007
  • The purpose of this paper is to analyses current status and issues of cluster formation and extract policy implications. To this end, the questionnaire which surveyed the level of cluster formation were executed targeting the actors of regional innovation projects(RIPs). The results show that the situations and development stage of the cluster formation between capital region and non-capital region, large cities and small and medium sized cites are different. The level of clustering is also satisfactory, which is a requirement for cluster formation at its early stage. However, the capacity for phase II of cluster growth is not sufficient yet in terns of relationships between ventures and large corporations, institutions supporting management, finance and marketing, researchers from each individual sector of strategic industries and spin-off fines. Therefore, RIPs should be promoted with different policy tools for various regions that are devised according to the varying development stage of each region. The location of RIPs should be determined considering efficiency rather than equity, clustering rather than decentralization, and specialization rather than multiple development. In the long term, developed regions should pursue balanced regional development, with underdeveloped regions targeting specialization.

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