• Title, Summary, Keyword: database-assisted design

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Tall Building Database-assisted Design: a Review of NIST Research

  • Yeo, DongHun;Potra, Florian A.;Simiu, Emil
    • International Journal of High-Rise Buildings
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    • v.8 no.4
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    • pp.265-273
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    • 2019
  • The purpose of this review paper is to briefly describe main the features of novel procedures developed by the National of Standards and Technology (NIST) for the design of tall buildings. Topics considered in the paper include: the division of tasks between wind and structural engineers; the determination of wind effects with specified mean recurrence intervals by accounting for wind directionality; the risk-consistent design of structures subjected to multiple wind hazards; iterative dynamic analyses and member sizing, including the use of modern optimization approaches; and commonalities of and differences between Database-assisted Design (DAD) and Equivalent Static Wind Loads procedures. An example of the application of the DAD procedure is presented for a reinforced concrete structure. Also included in the paper is an introduction to ongoing research on the estimation of wind load factors or of augmented design mean recurrence intervals commensurate with the uncertainties in the factors that determine the wind effects.

Practical estimation of veering effects on high-rise structures: a database-assisted design approach

  • Yeo, DongHun
    • Wind and Structures
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    • v.15 no.5
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    • pp.355-367
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    • 2012
  • Atmospheric boundary layer winds experience two types of effects due to friction at the ground surface. One effect is the increase of the wind speeds with height above the surface. The second effect, called the Ekman layer effect, entails veering - the change of the wind speed direction as a function of height above the surface. In this study a practical procedure is developed within a database-assisted design (DAD) framework that accounts approximately for veering effects on tall building design. The procedure was applied in a case study of a 60-story reinforced concrete building, which also considered the dependence of veering effects on the orientation of the building. Comparisons are presented between response estimates that do not account for veering, and account for veering conservatively. For the case studied in this paper veering effects were found to be small.

Wind-induced tall building response: a time-domain approach

  • Simiu, Emil;Gabbai, Rene D.;Fritz, William P.
    • Wind and Structures
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    • v.11 no.6
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    • pp.427-440
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    • 2008
  • Estimates of wind-induced wind effects on tall buildings are based largely on 1980s technology. Such estimates can vary significantly depending upon the wind engineering laboratory producing them. We describe an efficient database-assisted design (DAD) procedure allowing the realistic estimation of wind-induced internal forces with any mean recurrence interval in any individual member. The procedure makes use of (a) time series of directional aerodynamic pressures recorded simultaneously at typically hundreds of ports on the building surface, (b) directional wind climatological data, (c) micrometeorological modeling of ratios between wind speeds in open exposure and mean wind speeds at the top of the building, (d) a physically and probabilistically realistic aerodynamic/climatological interfacing model, and (e) modern computational resources for calculating internal forces and demand-to-capacity ratios for each member being designed. The procedure is applicable to tall buildings not susceptible to aeroelastic effects, and with sufficiently large dimensions to allow placement of the requisite pressure measurement tubes. The paper then addresses the issue of accounting explicitly for uncertainties in the factors that determine wind effects. Unlike for routine structures, for which simplifications inherent in standard provisions are acceptable, for tall buildings these uncertainties need to be considered with care, since over-simplified reliability estimates could defeat the purpose of ad-hoc wind tunnel tests.

Assessment of ASCE 7-10 for wind effects on low-rise wood frame buildings with database-assisted design methodology

  • He, Jing;Pan, Fang;Cai, C.S.
    • Wind and Structures
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    • v.27 no.3
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    • pp.163-173
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    • 2018
  • The design wind pressure for low-rise buildings in the ASCE 7-10 is defined by procedures that are categorized into the Main Wind Force-Resisting System (MWFRS) and the Components and Cladding (C&C). Some of these procedures were originally developed based on steel portal frames of industrial buildings, while the residential structures are a completely different structural system, most of which are designed as low-rise light-frame wood constructions. The purpose of this study is to discuss the rationality (or irrationality) of the extension of the wind loads calculated by the ASCE 7-10 to the light-frame wood residential buildings that represent the most vulnerable structures under extreme wind conditions. To serve this purpose, the same approach as used in the development of Chapter 28 of the ASCE 7-10 that envelops peak responses is adopted in the present study. Database-assisted design (DAD) methodology is used by applying the dynamic wind loads from Louisiana State University (LSU) database on a typical residential building model to assess the applicability of the standard by comparing the induced responses. Rather than the postulated critical member demands on the industrial building such as the bending moments at the knee, the maximum values at the critical points for wood frame buildings under wind loads are used as indicators for the comparison. Then, the critical members are identified through these indicators in terms of the displacement or the uplift force at connections and roof envelope. As a result, some situations for each of the ASCE 7 procedures yielding unconservative wind loads on the typical low-rise residential building are identified.

Towards cross-platform interoperability for machine-assisted text annotation

  • de Castilho, Richard Eckart;Ide, Nancy;Kim, Jin-Dong;Klie, Jan-Christoph;Suderman, Keith
    • Genomics & Informatics
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    • v.17 no.2
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    • pp.19.1-19.10
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    • 2019
  • In this paper, we investigate cross-platform interoperability for natural language processing (NLP) and, in particular, annotation of textual resources, with an eye toward identifying the design elements of annotation models and processes that are particularly problematic for, or amenable to, enabling seamless communication across different platforms. The study is conducted in the context of a specific annotation methodology, namely machine-assisted interactive annotation (also known as human-in-the-loop annotation). This methodology requires the ability to freely combine resources from different document repositories, access a wide array of NLP tools that automatically annotate corpora for various linguistic phenomena, and use a sophisticated annotation editor that enables interactive manual annotation coupled with on-the-fly machine learning. We consider three independently developed platforms, each of which utilizes a different model for representing annotations over text, and each of which performs a different role in the process.

Optimization of long span portal frames using spatially distributed surrogates

  • Zhang, Zhifang;Pan, Jingwen;Fu, Jiyang;Singh, Hemant Kumar;Pi, Yong-Lin;Wu, Jiurong;Rao, Rui
    • Steel and Composite Structures
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    • v.24 no.2
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    • pp.227-237
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    • 2017
  • This paper presents optimization of a long-span portal steel frame under dynamic wind loads using a surrogate-assisted evolutionary algorithm. Long-span portal steel frames are often used in low-rise industrial and commercial buildings. The structure needs be able to resist the wind loads, and at the same time it should be as light as possible in order to be cost-effective. In this work, numerical model of a portal steel frame is constructed using structural analysis program (SAP2000), with the web-heights at five locations of I-sections of the columns and rafters as the decision variables. In order to evaluate the performance of a given design under dynamic wind loading, the equivalent static wind load (ESWL) is obtained from a database of wind pressures measured in wind tunnel tests. A modified formulation of the problem compared to the one available in the literature is also presented, considering additional design constraints for practicality. Evolutionary algorithms (EA) are often used to solve such non-linear, black-box problems, but when each design evaluation is computationally expensive (e.g., in this case a SAP2000 simulation), the time taken for optimization using EAs becomes untenable. To overcome this challenge, we employ a surrogate-assisted evolutionary algorithm (SAEA) to expedite the convergence towards the optimum design. The presented SAEA uses multiple spatially distributed surrogate models to approximate the simulations more accurately in lieu of commonly used single global surrogate models. Through rigorous numerical experiments, improvements in results and time savings obtained using SAEA over EA are demonstrated.

Development of LCD-Oriented Impact Analysis System (LCD 모듈전용 충격해석시스템 개발)

  • Choi, Seong-Sik;Lee, Jeoung-Gwen
    • Proceedings of the KSME Conference
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    • pp.1419-1424
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    • 2003
  • Impact analysis of TFT-LCD module is very complicated because the structure is assisted with thin, small and non-uniform geometry. Especially, finite element modeling is more difficult and need time-consuming efforts. In this study, we developed LCD Impact Analysis System (LIAS) for the purpose of reducing the analysis time without accuracy reduction. This system contains pre-meshing data, material database, shock condition, auto-reporting etc. PATRAN and DYNA3D is used for meshing and solving. Previously, we performed impact test and reviewed the accuracy of analysis results. Simply we can control design parameters, the procedure such as meshing, running and reporting which are partially auto-prepared. By adopting proposed system, it is expected to achieve efficient impact analysis of LCD module.

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Design of Internet of Underwater Things Architecture and Protocol Stacks

  • Muppalla, Kalyani;Yun, Nam-Yeol;Park, Soo-Hyun;Kim, Changhwa
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.486-488
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    • 2013
  • In the earth more than half of the space filled with water. In that water most of the part is in the form of oceans. The ocean atmosphere determines climate on the land. Combining the Underwater Acoustic Sensor Network (UWASN) system with Internet Of Things (IoT) is called Internet of Underwater Things (IoUT). Using IoUT we can find the changes in the ocean environment. Underwater sensor nodes are used in UWASN. Underwater sensor nodes are constructive in offshore investigation, disaster anticipation, data gathering, assisted navigation, pollution checking and strategic inspection. By using IoT components such as Database, Server and Internet, ocean data can be broadcasted. This paper introduces IoUT architecture and and explains fish forming application scenario with this IoUT architecture.

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Evaluation of the limit ice thickness for the hull of various Finnish-Swedish ice class vessels navigating in the Russian Arctic

  • Kujala, Pentti;Korgesaar, Mihkel;Kamarainen, Jorma
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.3
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    • pp.376-384
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    • 2018
  • Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code.

An analysis of domestic research trends on elderly environment planing (국내 노인주거환경계획 분야 연구의 흐름 분석 연구)

  • Lee, Yeun Sook;Lee, So Young;Kim, Mi Sun;Lee, Jung Hwa;Kwak, Yoon Jung
    • KIEAE Journal
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    • v.7 no.2
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    • pp.77-85
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    • 2007
  • Korean society expects to be changing into aged society more rapidly than any other countries due to low birthrate and increase in life expectancy. Increasing number of elderly and social problems of aging society have provoked increase in research on elderly environment. Elderly housing facilities and living conditions are significantly related to the quality of life for older persons. The purpose of this study is to systematically analyze empirical studies on elderly physical environments in Korea, find out research streaming and understand social backgrounds and to suggest future research problems. For this study, contents analysis was conducted. Articles of four academic peer reviewed journals published from 1986 to 2005 were units of analysis. Using a keyword through library database systems, the articles were systematically selected. As results, trends of research according to 4 periods were defined. Among them as major trends, expansion of the quantity, expansion to interior design features for older persons, more facility types for dependent elderly(assisted living facilities, facilities for elderly with dementia, long term care facilities) have appeared. This result showed some directions and implications on elderly facility planning and development.