• Title/Summary/Keyword: Structural alternative

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Additive 2D and 3D performance ratio analysis for steel outrigger alternative design

  • Lee, Dongkyu
    • Steel and Composite Structures
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    • v.20 no.5
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    • pp.1133-1153
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    • 2016
  • In this article, an additive performance ratio method using structural analysis of both 2D and 3D is introduced to mitigate the complexity of work evaluating structural performances of numerous steel outrigger alternatives in multi-story buildings, especially high-rise buildings. The combined structural analysis process enables to be the design of economic, safe, and as constructional demanding structures by exploiting the advantages of steel, namely: excellent energy dissipation and ductility. First the approach decides the alternative of numerous steel outriggers by a simple 2D analysis module and then the alternative is evaluated by 3D analysis module. Initial structural analyses of outrigger types are carried out through MIDAS Gen 2D modeling, approximately, and then the results appeal structural performance and lead to decide some alternative of outrigger types. ETABS 3D modeling is used with respect to realization and evaluation of exact structural behaviors. The approach reduces computational burden in compared to existing concepts such as full 3D analysis methods. The combined 2D and 3D tools are verified by cycle and displacement tests including comprehensive nonlinear dynamic simulations. The advantages and limitations of the Additive Performance Ratio Approach are highlighted in a case study on a high rise steel-composite building, which targets at designing the optimized alternative to the existing original outrigger for lateral load resisting system.

On the Design of the Brackets without Flange in Ships' Structure (플랜지가 없는 선체 브라켓의 설계에 관한 연구)

  • Lee, Joo-Sung;Lee, Dong-Bu;Han, Doo-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.2 s.146
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    • pp.197-205
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    • 2006
  • In general, brackets found at tank boundary are design according to the Classification Society Rule. Since much man power is needed in manufacturing the brackets stiffened by flange, it is necessary to suggest alternative designs, of which flanges are removed, through the rigorous structural analysis. In this paper non-linear structural analysis for brackets with and/or without flange have been carried out to examine their structural behavior and ultimate strengths. Alternative designs for brackets are suggested based on the results of ultimate strength analysis so that the alternative brackets have the similar level of strength and stiffness to the original brackets. It has been seen that the structural safety of alternative brackets proposed in this paper are beyond the appropriate level. The primary benefit of replacing the original brackets by the alternatives is the reduction of man power in manufacturing brackets and 10 to 15% weight saving can be expected in additional. This paper ends with some comments about the extension of the present study.

A Method for Selecting a Structural Optimal Flood Mitigation Plan Using Analytic Hierarchy Process (계층화분석기법을 통한 구조물적 홍수방어 최적대안 선정 방안 연구)

  • Lee, Jeong-Ho;Jun, Young-Joon;Ahn, Jae-Hyun;Kim, Tae-Woong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.3
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    • pp.117-126
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    • 2009
  • Various dimensions of watershed structural/non-structural planning can be applied in comprehensive flood mitigation plan in a river basin. Especially structural counterplans have very broad and diverse nature as flood control facilities. It is not easy to find the optimum alternative to maximize the ability of a basin to reduce flood risk using a combination of structural counterplans. In addition, there is no standard for evaluating the performance of structural counterplans and for selecting optimal combination of them. This study focused on how to select the best alternative of a comprehensive watershed structural plan from various flood defense alternative candidates. By introducing an analytic hierarchy process, we would like to show how we decide the best alternative using standard worksheets developed in this study for economics and policy evaluation, and Expert Choice 11.5, which calculates weights for evaluation items. Based on the results from this study, we would like to suggest the best practice of a standardized watershed plan for flood protection.

A Study on the Alternative Evaluation of the High-rise Building Structural System (고층건물 구조시스템의 대안평가 방안 연구)

  • Kim, Yeong-Min;Kim, Chee-Kyeon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.425-434
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    • 2010
  • This study presents the alternative evaluation technique for the high-rise building structural system. The alternative evaluation of the structural system is performed in three steps, that is, preliminary evaluation, main evaluation and detailed evaluation. The evaluation categories are composed of structural performance, economic feasibility and term of work. Each categories are composed of detailed items to evaluate of its own. In preliminary evaluation, qualitative evaluation based on experimental knowledge is performed. In main and detailed evaluations, quantitative evaluations based on numeric data are performed. The weighted-sum method is applied to integrate the evaluated results of each items and its importance. The applicability of the proposed method was verified by applying it to the practical buildings and simulate the procedures.

Seismic performance of a fiber-reinforced plastic cable-stayed bridge

  • Hodhod, Osama A.;Khalifa, Magdi A.
    • Structural Engineering and Mechanics
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    • v.5 no.4
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    • pp.399-414
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    • 1997
  • This paper presents an investigation into the seismic response characteristics of a proposed ligh-weight pedestrian cable-stayed bridge made entirely from Glass Fiber Reinforced Plastics(GFRP). The study employs three dimensional finite element models to study and compare the dynamic characteristics and the seismic response of the GFRP bridge to a conventional Steel-Concrete (SC) cable-stayed bridge alternative. The two bridges were subjected to three synthetic earthquakes that differ in the frequency content characteristics. The performance of the GFRP bridge was compared to that of the SC bridge by normalizing the live load and the seismic internal forces with respect to the dead load internal forces. The normalized seismically induced internal forces were compared to the normalized live load internal forces for each design alternative. The study shows that the design alternatives have different dynamic characteristics. The light GFRP alternative has more flexible deck motion in the lateral direction than the heavier SC alternative. While the SC alternative has more vertical deck modes than the GFRP alternative, it has less lateral deck modes than the GFRP alternative in the studied frequency range. The GFRP towers are more flexible in the lateral direction than the SC towers. The GFRP bridge tower attracted less normalized base shear force than the SC bridge towers. However, earthquakes, with peak acceleration of only 0.1 g, and with a variety of frequency content could induce high enough seismic internal forces at the tower bases of the GFRP cable-stayed bridge to govern the structural design of such bridge. Careful seismic analysis, design, and detailing of the tower connections are required to achieve satisfactory seismic performance of GFRP long span bridges.

Thinking Modernity Historically: Is "Alternative Modernity" the Answer?

  • Dirlik, Arif
    • Asian review of World Histories
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    • v.1 no.1
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    • pp.5-44
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    • 2013
  • This essay offers a historically based critique of the idea of "alternative modernities" that has acquired popularity in scholarly discussions over the last two decades. While significant in challenging Euro/American-centered conceptualizations of modernity, the idea of "alternative modernities" (or its twin, "multiple modernities") is open to criticism in the sense in which it has acquired currency in academic and political circles. The historical experience of Asian societies suggests that the search for "alternatives" long has been a feature of responses to the challenges of Euromodernity. But whereas "alternative" was conceived earlier in systemic terms, in its most recent version since the 1980s cultural difference has become its most important marker. Adding the adjective "alternative" to modernity has important counter-hegemonic cultural implications, calling for a new understanding of modernity. It also obscures in its fetishization of difference the entrapment of most of the "alternatives" claimed--products of the reconfigurations of global power--within the hegemonic spatial, temporal and developmentalist limits of the modernity they aspire to transcend. Culturally conceived notions of alternatives ignore the common structural context of a globalized capitalism which generates but also sets limits to difference. The seeming obsession with cultural difference, a defining feature of contemporary global modernity, distracts attention from urgent structural questions of social inequality and political injustice that have been globalized with the globalization of the regime of neoliberal capitalism. Interestingly, "the cultural turn" in the problematic of modernity since the 1980s has accompanied this turn in the global political economy during the same period. To be convincing in their claims to "alterity", arguments for "alternative modernities" need to re-articulate issues of cultural difference to their structural context of global capitalism. The goal of the discussion is to work out the implications of these political issues for "revisioning" the history and historiography of modernity.

Evaluation of RPV according to alternative fracture toughness requirements

  • Lee, Sin-Ae;Lee, Sang-Hwan;Chang, Yoon-Suk
    • Structural Engineering and Mechanics
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    • v.53 no.6
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    • pp.1271-1286
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    • 2015
  • Recently, US NRC revised fracture toughness requirements as 10CFR50.61a to reduce the conservatism of 10CFR50.61. However, unlike previous studies relating to the initial regulation, structural integrity evaluations based on the alternative regulation are not sufficient. In the present study, PTS and P-T limit curve evaluations were carried out by using both regulations and resulting data were compared. With regard to the PTS evaluation, the results obtained from the alternative requirements were satisfied with the criterion whereas those obtained from the initial requirements did not meet the criterion. Also, with regard to the P-T limit curve evaluation, operating margin by 10CFR50.61a was greater than that by 10CFR50.61.

Generation and Evaluation of Structural Design Alternatives Using Multicriteria Optimization (다목적 최적화 방법을 이용한 구조설계 대안의 생성과 평가)

  • 양영순;유원선;김기화
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.199-209
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    • 1998
  • Since most engineering problems have had open-ended and ill-defined characteristics, design process is in advance attended with determination of alternatives based on realistic constraints after definition of appropriate problem. And it is completed with selection of best alternative through their comparison and investigation, and with performance of selected-alternative's detail design. As the process of structural design compared with that of general design, this paper presents a paradigm which can generate structural design alternatives, select optimum structure among them and simultaneously set its optimum design variables in reference of several objective as a result in more extended design region. For this purpose, specialized genetic algorithms which can handle design alternatives and multicriteria problems is used.

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COMPARISON OF VARIABLE SELECTION AND STRUCTURAL SPECIFICATION BETWEEN REGRESSION AND NEURAL NETWORK MODELS FOR HOUSEHOLD VEHICULAR TRIP FORECASTING

  • Yi, Jun-Sub
    • Journal of applied mathematics & informatics
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    • v.6 no.2
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    • pp.599-609
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    • 1999
  • Neural networks are explored as an alternative to a regres-sion model for prediction of the number of daily household vehicular trips. This study focuses on contrasting a neural network model with a regression model in term of variable selection as well as the appli-cation of these models for prediction of extreme observations, The differences in the models regarding data transformation variable selec-tion and multicollinearity are considered. The results indicate that the neural network model is a viable alternative to the regression model for addressing both messy data problems and limitation in variable structure specification.