Documents disponibles écrits par cet auteur

Active shear planes of bolted connections failing in block shear / Drew D. A. Clements in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013)

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 320–327 Titre : Active shear planes of bolted connections failing in block shear Type de document : texte imprimé Auteurs : Drew D. A. Clements, Auteur ; Teh, Lip H., Auteur Année de publication : 2013 Article en page(s) : pp. 320–327 Note générale : structural engineering Langues : Anglais (eng) Mots-clés : bolted  connections;  cold-formed  steel;  shear  failures;  steel  plates;  tensile  strength Résumé : In the steel design codes worldwide, the shear area for calculating the block shear capacity of a bolted connection is either the gross or the net shear area. The authors have previously noted independent experimental evidence indicating the shear failure planes to lie midway between the gross and the net shear planes, termed the active shear planes. This paper presents the nonlinear contact finite brick element analysis results that confirm the location of the active shear planes, indicated by regions of maximum shear stresses. The finite-element analysis also found that shear stresses approach zero toward the free downstream end of the connection block. The veracity of the active shear area is further demonstrated in terms of the ability of the resulting block shear equation to predict the governing failure modes of test specimens consistently, in comparison with the equations assuming the gross and the net shear areas. [article] Active shear planes of bolted connections failing in block shear [texte imprimé] / Drew D. A. Clements, Auteur ; Teh, Lip H., Auteur . - 2013 . - pp. 320–327. structural engineering Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 320–327 Mots-clés : bolted  connections;  cold-formed  steel;  shear  failures;  steel  plates;  tensile  strength Résumé : In the steel design codes worldwide, the shear area for calculating the block shear capacity of a bolted connection is either the gross or the net shear area. The authors have previously noted independent experimental evidence indicating the shear failure planes to lie midway between the gross and the net shear planes, termed the active shear planes. This paper presents the nonlinear contact finite brick element analysis results that confirm the location of the active shear planes, indicated by regions of maximum shear stresses. The finite-element analysis also found that shear stresses approach zero toward the free downstream end of the connection block. The veracity of the active shear area is further demonstrated in terms of the ability of the resulting block shear equation to predict the governing failure modes of test specimens consistently, in comparison with the equations assuming the gross and the net shear areas.

Block shear capacity of bolted connections in cold-reduced steel sheets / Teh, Lip H. in Journal of structural engineering, Vol. 138 N° 4 (Avril 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 4 (Avril 2012) . - pp. 459–467 Titre : Block shear capacity of bolted connections in cold-reduced steel sheets Type de document : texte imprimé Auteurs : Teh, Lip H., Auteur ; Drew D. A. Clements, Auteur Année de publication : 2012 Article en page(s) : pp. 459–467 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bolted  connections  Cold-formed  steel  Shear  failures  Steel  plates  Tensile  strength Résumé : This paper examines the mechanisms for block shear failures of bolted connections in steel plates postulated in the design equations specified in the North American, European, and Australian steel structures codes. It explains that there is only one feasible mechanism for the limit state of conventional block shear failure, that which involves tensile rupture and shear yielding, regardless of the steel material ductility. It describes the fundamental shortcomings of various code equations for determining the block shear capacity of a bolted connection. Based on the tensile rupture and shear yielding mechanism, an in-plane shear lag factor, and the active shear resistance planes identified in the present work, this paper proposes a rational equation that is demonstrated to provide more accurate results than all the code equations in predicting the block shear capacities of bolted connections in G450 steel sheets subjected to concentric loading. The resistance factor of 0.8 for the proposed equation is computed with respect to the LRFD approach given in the North American specification for the design of cold-formed steel structures. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000478 [article] Block shear capacity of bolted connections in cold-reduced steel sheets [texte imprimé] / Teh, Lip H., Auteur ; Drew D. A. Clements, Auteur . - 2012 . - pp. 459–467. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 4 (Avril 2012) . - pp. 459–467 Mots-clés : Bolted  connections  Cold-formed  steel  Shear  failures  Steel  plates  Tensile  strength Résumé : This paper examines the mechanisms for block shear failures of bolted connections in steel plates postulated in the design equations specified in the North American, European, and Australian steel structures codes. It explains that there is only one feasible mechanism for the limit state of conventional block shear failure, that which involves tensile rupture and shear yielding, regardless of the steel material ductility. It describes the fundamental shortcomings of various code equations for determining the block shear capacity of a bolted connection. Based on the tensile rupture and shear yielding mechanism, an in-plane shear lag factor, and the active shear resistance planes identified in the present work, this paper proposes a rational equation that is demonstrated to provide more accurate results than all the code equations in predicting the block shear capacities of bolted connections in G450 steel sheets subjected to concentric loading. The resistance factor of 0.8 for the proposed equation is computed with respect to the LRFD approach given in the North American specification for the design of cold-formed steel structures. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000478

Heuristic approach for optimum cost and layout design of 3D reinforced concrete frames / P. Sharafi in Journal of structural engineering, Vol. 138 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 7 (Juillet 2012) . - pp. 853–863 Titre : Heuristic approach for optimum cost and layout design of 3D reinforced concrete frames Type de document : texte imprimé Auteurs : P. Sharafi, Auteur ; Muhammad N. S. Hadi, Auteur ; Teh, Lip H., Auteur Année de publication : 2012 Article en page(s) : pp. 853–863 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Optimization  models  Costs  Frames  Three-dimensional  models  Algorithms Résumé : This paper presents a new methodology for cost optimization of the preliminary layout design of three-dimensional (3D) reinforced concrete (RC) frames. This approach is capable of being easily employed for the optimal layout design of a realistic large RC structure that accounts for constraints imposed by design standards. The new approach considers modeling, structural analysis, concrete member design, and discrete optimization together with data on the cost of systems and materials. The methodology is comprised of two parts. First, using the cross-sectional action effects as design variables, a heuristic cost function is presented as an alternative to traditional cost functions for layout optimization of RC structures. Using the presented cost function, a structural optimization problem is formulated for column layout design of 3D RC frames. Then, an ant system algorithm, a discrete method, is proposed to solve the cost optimization problem. Two comparative design examples are included to demonstrate the performance of the new methodology and the excellent convergence of the ant colony optimization algorithm. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000508 [article] Heuristic approach for optimum cost and layout design of 3D reinforced concrete frames [texte imprimé] / P. Sharafi, Auteur ; Muhammad N. S. Hadi, Auteur ; Teh, Lip H., Auteur . - 2012 . - pp. 853–863. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 7 (Juillet 2012) . - pp. 853–863 Mots-clés : Optimization  models  Costs  Frames  Three-dimensional  models  Algorithms Résumé : This paper presents a new methodology for cost optimization of the preliminary layout design of three-dimensional (3D) reinforced concrete (RC) frames. This approach is capable of being easily employed for the optimal layout design of a realistic large RC structure that accounts for constraints imposed by design standards. The new approach considers modeling, structural analysis, concrete member design, and discrete optimization together with data on the cost of systems and materials. The methodology is comprised of two parts. First, using the cross-sectional action effects as design variables, a heuristic cost function is presented as an alternative to traditional cost functions for layout optimization of RC structures. Using the presented cost function, a structural optimization problem is formulated for column layout design of 3D RC frames. Then, an ant system algorithm, a discrete method, is proposed to solve the cost optimization problem. Two comparative design examples are included to demonstrate the performance of the new methodology and the excellent convergence of the ant colony optimization algorithm. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000508

Net section tension capacity of bolted connections in cold-reduced steel sheets / Teh, Lip H. in Journal of structural engineering, Vol. 138 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 337-344 Titre : Net section tension capacity of bolted connections in cold-reduced steel sheets Type de document : texte imprimé Auteurs : Teh, Lip H., Auteur ; Benoit P. Gilbert, Auteur Année de publication : 2012 Article en page(s) : pp. 337-344 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bolted  connections  Cold-formed  steel  Net  section  tension  capacity  Steel  plates  Tensile  strength Résumé : This paper examines the accuracy of design equations specified in the North American, European and Australasian codes for cold-formed steel structures in determining the net section tension capacity of bolted connections in flat steel sheets. It points out that the shear lag factors embedded in the code equations either yield “anomalous” results or become irrelevant when they exceed unity. The “anomaly” was demonstrated through laboratory tests and is explained by using simple calculus. The configurations of specimens tested in the laboratory include single shear- and double-shear connections, with single or double bolts in a line parallel or perpendicular to the force. A proper mathematical expression for the in-plane shear lag factor, which does not suffer from the anomaly of the code equations and never implies shear lag factors greater than unity for any configuration, is presented and shown to yield improved results compared to the current specifications. The resistance factor of 0.8 for the proposed equation is computed with respect to the load and resistance factor design (LRFD) approach specified in the North American specification for the design of cold-formed steel structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p337_s1?isAuthorized=no [article] Net section tension capacity of bolted connections in cold-reduced steel sheets [texte imprimé] / Teh, Lip H., Auteur ; Benoit P. Gilbert, Auteur . - 2012 . - pp. 337-344. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 337-344 Mots-clés : Bolted  connections  Cold-formed  steel  Net  section  tension  capacity  Steel  plates  Tensile  strength Résumé : This paper examines the accuracy of design equations specified in the North American, European and Australasian codes for cold-formed steel structures in determining the net section tension capacity of bolted connections in flat steel sheets. It points out that the shear lag factors embedded in the code equations either yield “anomalous” results or become irrelevant when they exceed unity. The “anomaly” was demonstrated through laboratory tests and is explained by using simple calculus. The configurations of specimens tested in the laboratory include single shear- and double-shear connections, with single or double bolts in a line parallel or perpendicular to the force. A proper mathematical expression for the in-plane shear lag factor, which does not suffer from the anomaly of the code equations and never implies shear lag factors greater than unity for any configuration, is presented and shown to yield improved results compared to the current specifications. The resistance factor of 0.8 for the proposed equation is computed with respect to the load and resistance factor design (LRFD) approach specified in the North American specification for the design of cold-formed steel structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p337_s1?isAuthorized=no

Net section tension capacity of cold-reduced sheet steel angle braces bolted at one leg / Teh, Lip H. in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 328–337 Titre : Net section tension capacity of cold-reduced sheet steel angle braces bolted at one leg Type de document : texte imprimé Auteurs : Teh, Lip H., Auteur ; Benoit P. Gilbert, Auteur Année de publication : 2013 Article en page(s) : pp. 328–337 Note générale : structural engineering Langues : Anglais (eng) Mots-clés : bolted  connections;  cold-formed  steel;  shear  lag;  tensile  strength;  thin  wall  sections;  bracing Résumé : This paper examines the accuracy of equations specified by the North American and Australasian steel structures codes for determining the net section tension capacity of a cold-formed steel angle brace bolted at one leg. The configurations tested in the laboratory include single equal angle, single unequal angle bolted at the wider leg, single unequal angle bolted at the narrow leg, double angles, and alternate angles. The steel materials used in the experiment are among those with the lowest ductility for which nominal tensile strength is permitted by cold-formed steel design codes to be fully utilized in structural design calculations. Based on a modification to the equation derived for channel braces bolted at the web, a design equation is proposed for determining the net section tension capacity of a cold-formed steel angle brace bolted at one leg. The proposed equation is demonstrated, through laboratory tests on 61 specimens composed of G450 sheet steel, to be more accurate than the code equations and those existing in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000675 [article] Net section tension capacity of cold-reduced sheet steel angle braces bolted at one leg [texte imprimé] / Teh, Lip H., Auteur ; Benoit P. Gilbert, Auteur . - 2013 . - pp. 328–337. structural engineering Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 328–337 Mots-clés : bolted  connections;  cold-formed  steel;  shear  lag;  tensile  strength;  thin  wall  sections;  bracing Résumé : This paper examines the accuracy of equations specified by the North American and Australasian steel structures codes for determining the net section tension capacity of a cold-formed steel angle brace bolted at one leg. The configurations tested in the laboratory include single equal angle, single unequal angle bolted at the wider leg, single unequal angle bolted at the narrow leg, double angles, and alternate angles. The steel materials used in the experiment are among those with the lowest ductility for which nominal tensile strength is permitted by cold-formed steel design codes to be fully utilized in structural design calculations. Based on a modification to the equation derived for channel braces bolted at the web, a design equation is proposed for determining the net section tension capacity of a cold-formed steel angle brace bolted at one leg. The proposed equation is demonstrated, through laboratory tests on 61 specimens composed of G450 sheet steel, to be more accurate than the code equations and those existing in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000675

Spatial Rotation Kinematics and Flexural-Torsional Buckling / Teh, Lip H. in Journal of engineering mechanics, Vol.131, N°6 (Juin 2005)

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Tension capacity of staggered bolted connections in cold-reduced steel sheets / Teh, Lip H. in Journal of structural engineering, Vol. 138 N° 6 (Juin 2012) 

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