Cross correlations of modal responses of tall buildings in wind-induced lateral-torsional motion / Huang, M. F. in Journal of engineering mechanics, Vol. 135 N° 8 (Août 2009)  

Public ISBD [article]  inJournal of engineering mechanics > Vol. 135 N° 8 (Août 2009) . - pp. 802-812 Titre : Cross correlations of modal responses of tall buildings in wind-induced lateral-torsional motion Type de document : texte imprimé Auteurs : Huang, M. F., Auteur ; Chan, C. M., Auteur ; Kwok, K. C. S., Auteur Article en page(s) : pp. 802-812 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Dynamic analysis Motion Modal Correlation Wind loads Buildings high-rise Concrete construction Steel construction. Résumé : Recent trends towards developing increasingly taller and irregularly-shaped buildings imply that these complex structures are potentially more responsive to wind excitation. Making accurate predictions of wind loads and their effects on such structures is therefore a necessary step in the design synthesis process. This paper presents a framework for dynamic analysis of the wind-induced lateral-torsional response of tall buildings with three-dimensional (3D) mode shapes. The cross correlation reflecting the statistical coupling among modal responses under spatiotemporally varying dynamic wind excitations has been investigated in detail. The effects of intermodal correlations on the lateral-torsional response of tall buildings with 3D mode shapes and closely spaced natural frequencies are elucidated and a more accurate method for quantifying intermodal cross correlations is analytically developed. Utilizing the wind tunnel derived synchronous multipressure measurements, a full-scale 60-story asymmetric building of mixed steel and concrete construction is used to illustrate the proposed framework for the coupled dynamic analysis and highlight the intermodal correlation of modal responses on the accurate prediction of coupled building acceleration. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...] [article] Cross correlations of modal responses of tall buildings in wind-induced lateral-torsional motion [texte imprimé] / Huang, M. F., Auteur ; Chan, C. M., Auteur ; Kwok, K. C. S., Auteur . - pp. 802-812. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 8 (Août 2009) . - pp. 802-812 Mots-clés : Dynamic analysis Motion Modal Correlation Wind loads Buildings high-rise Concrete construction Steel construction. Résumé : Recent trends towards developing increasingly taller and irregularly-shaped buildings imply that these complex structures are potentially more responsive to wind excitation. Making accurate predictions of wind loads and their effects on such structures is therefore a necessary step in the design synthesis process. This paper presents a framework for dynamic analysis of the wind-induced lateral-torsional response of tall buildings with three-dimensional (3D) mode shapes. The cross correlation reflecting the statistical coupling among modal responses under spatiotemporally varying dynamic wind excitations has been investigated in detail. The effects of intermodal correlations on the lateral-torsional response of tall buildings with 3D mode shapes and closely spaced natural frequencies are elucidated and a more accurate method for quantifying intermodal cross correlations is analytically developed. Utilizing the wind tunnel derived synchronous multipressure measurements, a full-scale 60-story asymmetric building of mixed steel and concrete construction is used to illustrate the proposed framework for the coupled dynamic analysis and highlight the intermodal correlation of modal responses on the accurate prediction of coupled building acceleration. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...]

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Optimization of pile groups using hybrid genetic algorithms / Chan, C. M. in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 4 (Avril 2009)  

Public ISBD [article]  inJournal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 497–505 Titre : Optimization of pile groups using hybrid genetic algorithms Type de document : texte imprimé Auteurs : Chan, C. M., Auteur ; J.-M. Zhang, Auteur ; Jenny T. Ng, Auteur Année de publication : 2009 Article en page(s) : pp. 497–505 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Pile foundations caps groups Algorithms Optimization Limit states Résumé : This paper presents an automated optimal design method using a hybrid genetic algorithm for pile group foundation design. The design process is a sizing and topology optimization for pile foundations. The objective is to minimize the material volume of the foundation taking the configuration, number, and cross-sectional dimensions of the piles as well as the thickness of the pile cap as design variables. A local search operator by the fully stressed design (FSD) approach is incorporated into a genetic algorithm (GA) to tackle two major shortcomings of a GA, namely, large computation effort in searching the optimum design and poor local search capability. The effectiveness and capability of the proposed algorithm are first illustrated by a five by five pile group subjected to different loading conditions. The proposed optimization algorithm is then applied to a large-scale foundation project to demonstrate the practicality of the algorithm. The proposed hybrid genetic algorithm successfully minimizes the volume of material consumption and the result matches the engineering expectation. The FSD operator has great improvement on both design quality and convergence rate. Challenges encountered in the application of optimization techniques to design of pile groups consisting of hundreds of piles are discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2849 [...] [article] Optimization of pile groups using hybrid genetic algorithms [texte imprimé] / Chan, C. M., Auteur ; J.-M. Zhang, Auteur ; Jenny T. Ng, Auteur . - 2009 . - pp. 497–505. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 497–505 Mots-clés : Pile foundations caps groups Algorithms Optimization Limit states Résumé : This paper presents an automated optimal design method using a hybrid genetic algorithm for pile group foundation design. The design process is a sizing and topology optimization for pile foundations. The objective is to minimize the material volume of the foundation taking the configuration, number, and cross-sectional dimensions of the piles as well as the thickness of the pile cap as design variables. A local search operator by the fully stressed design (FSD) approach is incorporated into a genetic algorithm (GA) to tackle two major shortcomings of a GA, namely, large computation effort in searching the optimum design and poor local search capability. The effectiveness and capability of the proposed algorithm are first illustrated by a five by five pile group subjected to different loading conditions. The proposed optimization algorithm is then applied to a large-scale foundation project to demonstrate the practicality of the algorithm. The proposed hybrid genetic algorithm successfully minimizes the volume of material consumption and the result matches the engineering expectation. The FSD operator has great improvement on both design quality and convergence rate. Challenges encountered in the application of optimization techniques to design of pile groups consisting of hundreds of piles are discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2849 [...]

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