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5th International Conference on Structural engineering, Mechanics and Computation, SEMC 2013

作者： Landesmann, A. Camotim, D. Basaglia, C. Civil Engineering Program COPPE Federal University of Rio de Janeiro Brazil Civil Engineering Department Instituto Superior Técnico Technical University of Lisbon Portugal Structural Engineering Department São Carlos School of Engineering University of São Paulo Brazil

ISBN: (纸本)9781138000612

This paper reports the available results of an ongoing numerical research effort and whose final goal is to assess and mechanically interpret the influence of the cross-section geometry and end support conditions on the elastic distortional post-buckling behavior and strength of cold-formed steel columns. This work deals only with simply supported columns exhibiting lipped channel, hat and zed cross-sections, which share common critical distortional buckling loads. Taking advantage of the GBT modal decomposition features, the buckling analyses are used to mechanically characterize the various column critical bucking modes. The paper presents and discusses results concerning the elastic post-critical strength of the selected column triplets, obtained from Ansys shell finite element analysis. The post-critical strength data are used to attempt identifying key parameters, in the sense that they play a pivotal role in influencing the features exhibited by the column distortional post-buckling behavior and strength. © 2013 Taylor & Francis Group, London, UK.

关键词： Buckling

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Application of direct strength method design to distortional buckling resistance of thin-walled steel columns exposed to fire

Application of direct strength method design to distortional...

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11th International Conference on Computational Structures Technology, CST 2012

作者： Landesmann, A. Camotim, D. Civil Engineering Program COPPE Federal University of Rio de Janeiro Brazil Department of Civil Engineering and Architecture Instituto Superior Técnico Technical University of Lisbon Portugal

ISBN: (纸本)9781905088546

This paper presents a numerical (shell finite element) investigation aimed at assessing the performance of the current direct strength method (DSM) provisions against distortional failure to estimate the ultimate strength of fixed-ended coldformed steel lipped channel and rack-section columns (i) subjected to various uniform temperature distributions caused by fire conditions and (ii) exhibiting different room-temperature yield stresses, covering a wide distortional slenderness range. In particular, the work addresses how does the temperature-dependence of the steel material behaviour, which is felt through both the (reduced) Young's modulus and nominal yield stress values, influences the quality (accuracy and safety) of the column ultimate strength predictions provided by the DSM distortional strength curve. Five different temperature-dependent steel constitutive laws are considered, namely (i) two models prescribed in part 1.2 of Eurocode 3 (EC3), for cold-formed and hot-rolled steel, and (ii) three experimentally-based analytical expressions recently reported in the literature. The DSM column ultimate strength estimates are compared with the numerical failure loads obtained through geometrically and physically non-linear ANSYS shell finite element analyses incorporating criticalmode initial imperfections with small amplitudes. © civil-Comp Press, 2012.

关键词： Design

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DSM design of cold-formed steel columns failing distortionally exposed to fire: How relevant is the temperature dependence of the material behavior?

DSM design of cold-formed steel columns failing distortional...

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Structural Stability Research Council Annual Stability Conference 2012

作者： Landesmann, A. Camotim, D. Civil Engineering Program COPPE Federal University of Rio de Janeiro Brazil Civil Eng. Dept. Instituto Superior Técnico Technical University of Lisbon Portugal

ISBN: (纸本)9781622760756

This paper presents a numerical (shell finite element) investigation aimed at assessing the performance of the current Direct Strength Method (DSM) provisions against distortional failure to estimate the ultimate strength of fixed-ended cold-formed steel lipped channel and rack-section columns (i) subjected to various uniform temperature distributions caused by fire conditions and (ii) exhibiting different room-temperature yield stresses, covering a wide distortional slenderness range. In particular, the work addresses how does the temperature-dependence of the steel material behavior, which is felt through both the (reduced) Young's modulus and nominal yield stress values, influences the quality (accuracy and safety) of the column ultimate strength predictions provided by the DSM distortional strength curve. Three different temperature-dependent steel constitutive laws are considered, namely (i) a model prescribed in part 1.2 of Eurocode 3 (EC3) and (ii) two experimentally-based analytical expressions recently reported in the literature. The DSM column ultimate strength estimates are compared with numerical distortional failure loads obtained through geometrically and physically non-linear ANSYS shell finite element analyses that incorporate critical-mode initial imperfections with small amplitudes.

关键词： Temperature distribution

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Early stages hydration of high initial strength Portland cement: Part I. thermogravimetric analysis on calcined mass basis

Early stages hydration of high initial strength Portland cem...

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作者： Junior, Alex Neves Filho, Romildo Dias Toledo De Moraes Rego Fairbairn, Eduardo Dweck, Jo Civil Engineering Program COPPE Rio de Janeiro Federal University Rio de Janeiro Brazil School of Chemistry Rio de Janeiro Federal University Rio de Janeiro Brazil

Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to analyze the early stages of hydration of a high-initial strength and sulphate resistant Portland cement (HS SR PC) within the first 24 h of setting. The water/cement (W/C) mass ratios used to prepare the pastes were 0.35, 0.45, and 0.55. The hydration behavior of the pastes was analyzed through TG and DTG curves obtained after different hydration times on calcined cement mass basis to have a same composition basis to compare the data. The influence of the W/C ratio on the kinetics of the hydration process was done through the quantitative analysis of the combined water of the main hydration products formed in each case. TG and DTG curves data calculated on calcined mass basis of all the results were converted to initial cement mass basis to have an easier way to analyze the influence of the W/C ratio on the free and combined water of the different main hydrated phases. The gypsum content of the pastes was totally consumed in 8 h for all cases. A significant part of the hydration process occurs within the first 14 h of setting and at 24 h the highest hydration degree, indicated by the respective content of formed calcium hydroxide, occurs in the case of the highest initial water content of the paste. © Akadémiai Kiadó, Budapest, Hungary 2011.

关键词： Thermogravimetric analysis

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Community response to noise and environmental noise impact assessment according noise pollution legislations on neighborhoods of santos dumont airport in Rio de Janeiro, Brazil.

Community response to noise and environmental noise impact a...

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41st International Congress and Exposition on Noise Control engineering 2012, INTER-NOISE 2012

作者： De Cássia Cordeiro Nogueira, Rita Mansur, Webe João Sattler, Miguel Aloysio PEC/UFRJ/COPPE Civil Engineering Program Federal University of Rio de Janeiro Rio de Janeiro Brazil CEFET-RJ Federal Center for Technological Education from Rio de Janeiro Rio de Janeiro Brazil PPGEC/UFRGS Civil Engineering Program Federal University of Rio Grande do Sul Rio Grande do Sul Brazil

ISBN: (纸本)9781627485609

This paper describes the present stage and recent results related to research in process that started in 2008 including noise annoyance social survey on the neighborhoods of Santos Dumont Airport. 70 residences distributed on five distinct districts of Rio de Janeiro, in Brazil compose an intentional sample. The surveyed locations are identified in accord to each corresponding Land Use Zone, aiming at recognizing the attendance of the measured noise levels, to the limits indicated in the Municipal Noise Pollution Legislation and to establish criteria noise levels. The noise levels limits indicated by the federal Legislation, which define noise contours areas as Specific Noise Planning, in the are also confronted with the noise levels limits indicated by the Municipal Law. It allows comparing noise levels collected in field by acoustic measurements with both limits noise levels indicated by municipal and federal laws relating to the residences locations. Notes about background noise are taken keeping in mind the importance of others noise sources aiming to approach adequately the airport noise environmental impact. Finally some conclusions are presented intending to better understand the environmental noise impact related to the airport landings and takeoffs activities considering community noise perception and the different subjective and objective variables involved.

关键词： Noise pollution

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Local-distortional-global interaction in lipped channel columns: Experimental results, numerical simulations and design considerations

Local-distortional-global interaction in lipped channel colu...

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作者： Dinis, Pedro B. Batista, Eduardo M. Camotim, Dinar Dos Santos, Eliane S. Department of Civil Engineering and Architecture ICIST Technical University of Lisbon Av. Rovisco Pais 1049-001 Lisboa Portugal Civil Engineering Program COPPE Federal University of Rio de Janeiro C.P. 68506 CEP 21945-972 Rio de Janeiro RJ Brazil

This work aims at contributing towards understanding the structural response and predicting the ultimate strength of cold-formed steel lipped channel columns affected by local-distortional-global (LDG) interaction. Initially, the most relevant aspects concerning the buckling and elastic-plastic post-buckling behaviours of fixed-ended lipped channel columns with nearly coincident local, distortional and global (flexural-torsional) buckling loads are briefly addressed. Then, the paper (i) summarises the most important test results obtained in a recently reported experimental investigation carried out at the federal University of Rio de Janeiro, (ii) addresses their numerical simulation by means of Abaqus shell finite element analyses (SFEA) and (iii) presents the outcome of a fairly extensive numerical parametric study performed to obtain ultimate strength data concerning fixed-ended lipped channel columns experiencing LDG interaction. Finally, the ultimate strength data bank gathered, consisting of 12 experimental and 134 values, are used as the starting point to assess the performance (accuracy and safety) of design approaches, based on the currently available Direct Strength Method (DSM) strength curves and intended to estimate the failure loads of cold-formed steel lipped channel columns affected by the triple mode interaction under consideration. © 2012 Elsevier Ltd. All rights reserved.

关键词： Buckling

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The Use of Support Vector Machine and Genetic Algorithms to Predict Protein Function

The Use of Support Vector Machine and Genetic Algorithms to ...

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IEEE International Conference on Systems, Man, and Cybernetics

作者： Walkiria K. Resende Renato A. Nascimento Carolina R. Xavier Iara F. Lopes Cristianc N. Nobre Department of Computer Science Universidade Federal de Sao Joao del Rei - UFSJ Department of Computer Science Pontificia Universidade Catolica de Minas Gerais PUC/MG Civil Engineering Program COPPE - UFRJ

ISBN: (纸本)9781467317139

In Bio informatics, the prediction of protein function is considered a very important task but also difficult. Using a set of enzymes represented by Hydrolase, Isomerase, Ligase, Lyase, Transferase and Oxidoreductase classes, previously used by Dobson et ah, this paper proposes a self-learning process able to predict their classes, based on their primary and secondary structures, through a Support Vector Machine (SVM) classifier and genetic algorithm. An SVM can he characterized as a supervised machine learning algorithm capable of resolving linear and non-linear classification problems. During the learning process, both the training data and the corresponding output are presented to the SVM to allow its parameters to he adjusted. This study utilized genetic algorithms - optimization heuristics often used to estimate parameters - to adjust the main parameters of the classifier such as kernel function type and parameter C, which provides the relationship between the training error and the margin of separation between classes. In this specific prediction problem, the results indicate that the best function is an RBF where width is 6.1 and C is 6.9. Using these parameters, the classifier obtains an average accuracy of 79.74%.

关键词： Component: Proteins Prediction Support Vector Machine Genetic Algorithms protein structure function Support Vector Network Genetic Algorithm (GA) Classifiers Learning processes secondary structures

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DSM design of cold-formed steel columns against distortional failure: Numerical investigation on the influence of the cross-section geometry and support conditions

DSM design of cold-formed steel columns against distortional...

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2011 Annual Stability Conference, ASC

作者： Landesmann, A. Camotim, D. Civil Engineering Program COPPE Federal University of Rio de Janeiro Brazil Dept. of Civil Engineering and Architecture ICIST/IST Technical University of Lisbon Portugal

ISBN: (纸本)9781618391384

This work reports the results of a numerical investigation on the influence of the cross-section geometry and end support conditions on the post-buckling behavior and Direct Strength Method (DSM) design of cold-formed steel lipped channel and rack-section columns buckling and failing in distortional modes. The columns analyzed exhibit (i) four end support conditions, (ii) different cross-section dimensions and lengths, and (iii) several yield stresses. These characteristics were carefully selected in order to ensure, as much as possible, that all the columns (i) buckle and fail in "pure" distortional modes and (ii) cover a wide (distortional) slenderness range. The post-buckling equilibrium paths and ultimate loads presented and discussed in the paper were obtained through ANSYS elastic and elastic-plastic shell finite element analyses. Moreover, the ultimate strength data acquired are used to show that, regardless of the column geometry, the current DSM distortional design curve is not able to predict adequately (safely and accurately) the ultimate loads of columns with other than fixed end supports. The paper also includes a preliminary assessment/proposal of the modifications that must be incorporated into this DSM design curve in order to overcome the above limitation.

关键词： Geometry

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Social survey about noise perception on Santos Dumont Airport neighbourhoods in Rio de Janeiro, Brazil - Data collection and analysis methods

Social survey about noise perception on Santos Dumont Airpor...

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10th International Congress on Noise as a Public Health Problem 2011, ICBEN 2011

作者： De Cássia Cordeiro Nogueira, Rita Mansur, Webe João Sattler, Miguel Aloysio PEC/UFRJ/COPPE Civil Engineering Program Federal University from Rio de Janeiro Rio de Janeiro Brazil CEFET-RJ Federal Center for Technological Education from Rio de Janeiro Rio de Janeiro Brazil PPGEC/UFRGS Civil Engineering Program Federal University from Rio Grande Do sul Rio Grande do Sul Brazil

ISBN: (纸本)9781618390790

This work is concerned with the use of social survey about noise affected communities' perception as a parameter to improve airport noise environmental impact studies. Among July 2009 and December 2009 this author began this research applying a noise annoyance social research on Santos Dumont Airport neighborhoods'. Interviews were conducted in about 70 different addresses distributed on five distinct districts as a purposeful sample of residents indicated and priority contacted through residents associations. The interviews were conducted by this first author coordinating undergraduate students trained throughout 40 hours lessons course for developing field research skills. The scope of the questionnaire carefully elaborated to be applied during interviews and the data collecting and tabulation methods are presented in this work. This work yet in course aims contribute to better understand community response to airport noise considering the residents profiles and their perception about many other types of noise investigated throughout this survey. The survey plan is according to ISO15666 (2003) and its data analysis and tabulation are performed using surveys and statistics specialized software. The next steps involve applying new small questionnaire to check out changes on interviewed individuals' perceptions from 2009 to 2011 and also continuing tabulation data and performing sound measures in field.

关键词： Airports

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Classification Method fo Urban Solid Waste Disposal Sites

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Journal of Environmental Protection 2011年第4期2卷 473-481页

作者： Adriana Soares de Schueler Claudio Fernando Mahler Department of Architecture and Urbanism Technology Institute Federal Rural University of Rio e Janeiro Program of Civil Engineering COPPE Federal University of Rio e Janeiro

One of the environmental liabilities left by abandoned urban waste disposal sites, closed without the correct procedures, is the risk of exposure to their effluents, whose emissions may occur for many years. The purpose of the proposed methodology, referred to as SISTAVAFE, an assessment system of a closed landfill, is to contribute in the risk assess- ment of exposure to leachate as well as to suggest procedures for site monitoring, according to different levels of care and urgency. The method is based on four matrices that help make an initial evaluation of the risk source, potential target and the surface and underground environmental paths. This paper only addresses the contamination caused by liquid effluents.

关键词： Environmental Impact Solid Waste Landfill Later Occupation Risk of Exposure Leachate Classification Tool Multi-Criteria Analysis

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