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National Building Code of Canada (NBC) specifies 45 Seismic Force Resisting Systems to ensure the safety of building structures. Conventional construction concrete moment-resisting frame (CC-CMF) is one of these systems whose seismic response has not been systematically studied in Canada. This paper is an attempt to study the seismic performance of this system using the FEMA P695 methodology. In this regard, different archetype configurations were developed and analyzed through nonlinear static and dynamic analyses. Performance assessment results show that the CSA and NBC requirements for CC-CMF system represent the lower bound of values for seismic force modification factors, and conservatively meet life safety objectives presented in the NBC. Furthermore, different scenarios were considered for identifying ductility-related seismic force modification factor from pushover curves. The effect of height and gravity load levels on seismic force modification factors and collapse margin ratios are also presented by comparing archetypes having different configurations. Keywords: conventional construction concrete moment-resisting frames, seismic performance assessment, seismic force modification factors, seismic design requirements, collapse margin ratio Le Code national du batiment du Canada (CNB) precise 45 systemes de resistance sismique pour assurer la securite des charpentes de batiment. Les ossatures resistant au moment de construction classique (<< CC-CMF >>) constituent l'un de ces systemes dont la reponse sismique n'a pas ete systematiquement etudiee au Canada. Dans le cadre de cet article, on tente d'etudier les performances sismiques de ce systeme en utilisant la methodologie FEMA P695. A cet egard, differentes configurations d'archetype ont ete elaborees et examinees au moyen d'analyses statiques et dynamiques non lineaires. Les resultats de l'evaluation de la performance montrent que les exigences de la CSA et du CNB pour le systeme CC-CMF representent la limite inferieure des valeurs pour les facteurs de modification des forces sismiques, et respectent de facon prudente les objectifs de securite des personnes presentes dans le CNB. En outre, differents scenarios ont ete envisages pour determiner le facteur de modification de la force sismique lie a la ductilite a partir des courbes de poussee (<< pushover curves >>). L'effet de la hauteur et des niveaux de charge de gravite sur les facteurs de modification des forces sismiques et les rapports de marge d'affaissement est egalement presente en comparant des archetypes ayant des configurations differentes. [Traduit par la Redaction] Mots-cles : ossatures resistant au moment de construction classique, evaluation de la performance sismique, facteurs de modification de la force sismique, exigences de conception sismique, rapport de marge d'affaissement, 1. Introduction The National Building Code of Canada (NBC 2015a) includes 45 different seismic force resisting systems (SFRSs) applicable to a wide range of seismicity levels and building configurations. Concrete [...]

A performance-based unified (PBU) procedure has recently been proposed by the National Research Council Canada to systematically evaluate seismic design requirements available in the National Building Code of Canada (NBC). Conventional construction reinforced concrete moment-resisting frame (CC-CMF) and ductile reinforced concrete moment-resisting frame (D-CMF) systems were used in this paper to first assess the proposed PBU procedure and second determine the adequacy of the basis for seismic design requirements in NBC and see its performance margin against different structural performance levels. Results indicate that the detailed screening in the PBU procedure efficiently reduces the number of incremental dynamic analysis by more than 60% for CC-CMF while providing remarkable accuracy. It was also found that the CC-CMF system designed for the Normal importance category can provide an adequate margin against life safety performance level objectives, while the D-CMF system designed for the same importance category passes the collapse prevention performance level criteria. [ABSTRACT FROM AUTHOR]

Research on seismic behaviour of shear walls with high-strength steel is limited. A combined experimental and analytical investigation was conducted to assess seismic behaviour of flexure-dominant shear walls. A large-scale concrete shear wall with Grade 690 MPa (ASTM A1035) reinforcement and 84 MPa concrete was tested under simulated seismic loading. The wall represented a 6-story building shear wall with 4.53 m height and 1.45 m length. It sustained a lateral drift of 1.8% prior to developing failure due to the rupturing of longitudinal reinforcement. This is 35% less than the drift capacity of a companion wall reinforced with 400 MPa reinforcement tested earlier. VecTor2 software was used to conduct an analytical parametric study to expand the experimental findings. The results indicate that the reinforcement grade has a significant impact on strength, ductility, and hysteretic behaviour of shear walls. Key words: high-strength steel, seismic-resistant shear walls, reversed cyclic loading, inelastic deformability, ASTM A1035. La recherche sur le comportement sismique des murs de cisaillement en acier a haute resistance est restreinte. Une etude a la fois experimentale et analytique a ete menee pour evaluer le comportement sismique de murs de cisaillement dominants en flexion. Un mur de cisaillement en beton a grande echelle avec armature de nuance 690 MPa (ASTM A1035) et en beton de 84 MPa a ete mis a l'essai sous une charge sismique simulee. Le mur representait un mur de cisaillement de six etages d'une hauteur de 4,53 m et d'une longueur de 1,45 m. Il a subi une derive laterale de 1,8 % avant de se deteriorer en raison de la rupture de l'armature longitudinale. C'est 35% de moins que la capacite de derive d'un mur compagnon avec armature de 400 MPa mis a l'essai plus tot. Le logiciel VecTor2 a ete utilise pour mener une etude parametrique analytique afin d'elargir les resultats experimentaux. Les resultats indiquent que la nuance de l'armature a un impact significatif sur la resistance, la ductilite et le comportement d'hysterese des murs de cisaillement. [Traduit par la Redaction] Mots-cles : acier a haute resistance, murs de cisaillement resistants aux seismes, charges cycliques inversees, deformabilite inelastique, ASTM A1035., Introduction Structural walls, more commonly known as shear walls, are widely used as part of seismic force resisting systems (SFRS) in concrete buildings. Such walls are ordinarily reinforced with conventional [...]

Fragility analysis was conducted for reinforced concrete frame buildings in Canada designed based on the 1965 National Building Code of Canada as representative of pre-1975 era of seismic design practice. Two-, five-, and ten-storey buildings were designed for Vancouver and Ottawa, representing buildings in high and medium seismic regions. They were modelled for inelastic response time history analysis, with respective inelastic hysteretic models for flexure and shear. Software PERFORM-3D was used to conduct incremental dynamic analysis under incrementally increasing earthquake intensity. Probabilistic analysis of the results of incremental dynamic analysis led to the development of fragility functions, which can be used as seismic vulnerability assessment tools. The results are compared with those generated for frame buildings designed on the basis of the 2010 NBCC. The comparison indicates that the probabilities of exceeding performance levels are significantly higher for older buildings relative to recently built fully ductile and moderately ductile buildings, respectively. Key words: conventional concrete buildings, ductile concrete buildings, moderately ductile concrete buildings, NBCC, reinforced concrete frame buildings, seismic design, seismic fragility curves, seismic performance, seismic vulnerability assessment. Une analyse de fragilite a ete effectuee pour des batiments a ossature en beton arme au Canada concus selon le Code national du batiment du Canada (CNB) de 1965, ceux-ci etant representatifs de l'epoque de pratique de conception sismique des annees anterieures a 1975. Des batiments de deux, de cinq et de 10 etages ont ete concus pour Vancouver et Ottawa, representant des batiments situes dans des regions hautement et moyennement sismiques, respectivement. Ils ont ete modelises aux fins d'analyse de l'histoire temporelle de la reponse inelastique, avec des modeles d'hysterese inelastiques respectifs pour la flexion et le cisaillement. Le logiciel PERFPORM-3D a ete utilise afin de realiser une analyse dynamique progressive sous une intensite de seisme augmentant progressivement. L'analyse probabiliste des resultats d'analyse dynamique progressive a permis de developper des fonctions de fragilite, qui peuvent etre utilisees comme outils d'evaluation de vulnerabilite sismique. Les resultats sont compares avec ceux produits pour des batiments a ossature concus en fonction du CNB de 2010. La comparaison indique que les probabilites d'exceder les niveaux de performance sont sensiblement plus elevees dans le cas de plus vieux batiments par rapport aux batiments entierement ductiles et moderement ductiles recemment construits, respectivement. Mots-cles : batiment traditionnel en beton, batiment ductile en beton, batiment moderement ductile en beton, Code national du batiment du Canada (CNB), batiment a ossature en beton arme, conception parasismique, courbes de fragilite sismique, performance en cas de seisme, evaluation de la vulnerabilite aux seismes., Introduction Seismic design requirements in the National Building Code of Canada (NBCC) have evolved over the years. The procedure for determining seismic shear forces improved since its inception in 1941. [...]

Performance of reinforced concrete frame buildings depends on seismic hazard of the region and vulnerability of the structure. Performance-based evaluation of buildings may be conducted through fragility curves developed for different levels of performance. Reinforced concrete frame buildings with 2, 5, and 10-stories, designed as moderately ductile buildings for Ottawa in Eastern Canada and fully ductile buildings for Vancouver in Western Canada were used to generate seismic fragility curves. The buildings were analyzed using PERFORM-3D software to assess seismic vulnerabilities. Incremental dynamic analysis was employed to generate fragility curves. Two sets of earthquake records compatible with uniform hazard spectra of 2010 NBCC were selected, where each set contained 20 records for each city. The fragility curves depict probabilities of exceedances for different damage states, and can be used for seismic vulnerability assessment of reinforced concrete frame buildings in Canada designed and built after 1985. Key words: fragility analysis, incremental dynamic analysis, performance-based evaluation, reinforced concrete frame buildings, seismic assessment, seismic damage estimation, vulnerability analysis. Le rendement d'immeubles a ossature de beton arme depend de l'alea sismique de la region et de la vulnerabilite de la structure. On peut mener une evaluation d'immeubles fondee sur le rendement au moyen de courbes de fragilite elaborees pour differents niveaux de rendement. Des immeubles a ossature de beton arme a deux, a cinq et a dix etages, concus comme immeubles moderement ductiles pour Ottawa a l'est du Canada et immeubles entierement ductiles pour Vancouver a l'ouest du Canada ont servi pour produire des courbes de fragilite sismique. On a analyse les immeubles en utilisant le logiciel PERFORM-3D afin d'evaluer les vulnerabilites aux seismes. On a employe l'analyse dynamique progressive pour produire des courbes de fragilite. Deux ensembles d'enregistrements de seisme compatibles avec les spectres de risque uniforme du CNBC de 2010 ont ete choisis, dont chaque ensemble comportait 20 enregistrements pour chaque ville. Les courbes de fragilite depeignent les probabilites de depassement au niveau de differents etats d'endommagement et peuvent servir a l'evaluation de vulnerabilite sismique des immeubles a ossature de beton arme au Canada concus et construits apres 1985. [Traduit par la Redaction] Mots-cles : analyse de fragilite, analyse dynamique progressive, evaluation fondee sur le rendement, immeubles a ossature de beton arme, evaluation sismique, evaluation des dommages causes par un seisme, analyse de vulnerabilite., Introduction Earthquakes occur frequently in Canada with historic damage. The seismic hazard in Canada can be characterized by the seismicity of two distinct regions; eastern Canada and western Canada; with [...]

With the advent of advanced materials and technology, construction materials are becoming superior in terms of not only strength but also durability. In recent years, the importance and necessity of [...]

This paper presents a summary of experimental research on the performance of blast-resistant window anchors and the development of a design procedure for the anchors. The experimental results, obtained from forty-six window tests conducted under simulated blast loading using a shock tube are reported. Two analysis procedures that were developed for anchor design are described. The first procedure involves a two-degree-of-freedom dynamic analysis. The second procedure involves a single degree of freedom analysis that can be implemented manually. The development of both methods is presented for the anchorage design of windows subjected to blast loads. [ABSTRACT FROM AUTHOR]

The influence of high strain-rate loading on the flexural response of typical light-frame wood construction has been investigated. A total of 30 stud grade 38 mm x 140 mm x 2440 mm (2' x6' x8') spruce-pine-fir (S-P-F) lumber specimens were tested within a range of low and high strain-rates between 6 x [10.sup.-6] [s.sup.-1] and 0.4 [s.sup.-1]. A single- degree-of-freedom iterative solution procedure was used to compute the high strain-rate modulus of rupture (MOR) and modulus of elasticity (MOE). The MOR was statistically enhanced by high strain-rates, while the MOE and strain at rupture were not. Since equilibrium of the dynamic stress-strain relationship requires that one or both of the MOE and strain at rupture must be sensitive to strain-rate effects, the lack of observed rate enhancement on these material properties was attributed to large scatter within a small sample set. Based on the results, material dynamic increase factors and a stress-strain relationship suitable for blast resistant design of timber structures were also proposed. Key words: blast, high strain-rate, dynamic increase factor, modulus of rupture, modulus of elasticity, S-P-F, timber, wood, lumber, shock tube. L'influence d'un chargement tres rapide sur la reponse en flexion d'une construction typique a ossature de bois a ete etudiee. Un total de 30 echantillons de categorie colombage de 38 mm x 140 mm x 2440 mm (2' x 6' x 8') en epinette - pin - sapin (E-P-S) a ete mis a l'epreuve sous diverses vitesses, basses et elevees, situees entre 6 x [10.sup.-6] [s.sup.-1] a 0,4 [s.sup.-1]. Le MOR (moment de resistance) et le MOE (module d'elasticite) sous une vitesse de chargement elevee ont ete calcules selon une procedure iterative a un seul degre de liberte. Le MOR a ete statistiquement accru par les vitesses de chargement elevees alors que le MOE et la contrainte a la rupture ne l'ont pas ete. Puisque l'equilibre de la relation tension-contrainte dynamique exige que le MOE et-ou la contrainte a la rupture soient sensibles aux effets de la vitesse de chargement, le manque d'observation d'un accroissement de la vitesse sur ces proprietes de materiaux a ete attribue a une grande dispersion dans un petit ensemble d'echantillons. En se basant sur les resultats, des facteurs d'augmentation du rapport resistance dynamique/resistance statique et une relation tension-deformation adequate pour la conception resistante aux vitesses de chargement rapides pour les structures a ossature de bois sont proposes. [Traduit par la Redaction] Mots-cles: explosion, vitesse de deformation elevee, facteur d'augmentation du rapport resistance dynamique/resistance statique, module de rupture, module d'elasticite, E-P-S, bois d'ceuvre, bois, montant, tube a chocs., Introduction Blast-resistant structures are designed to have sufficient strength to resist blast loads and are detailed to ensure ductility and continuity during response. Furthermore, these hardened facilities have higher structural [...]

The paper presents observed damage in reinforced concrete buildings during the 27 February 2010 Maule earthquake in Chile. Performance of concrete frame and shear wall buildings are discussed with emphasis on seismic deficiencies in design and construction practices. It is shown that the majority of structural damage in multistorey and high-rise buildings can be attributed to poor performance of slender shear walls, without confined boundary elements, suffering from crushing of concrete and buckling of vertical wall reinforcement. Use of irregular buildings, lack of seismic detailing, and the interference of nonstructural elements were commonly observed seismic deficiencies. A comparison is made between Chilean and Canadian design practices with references made to the applicable code clauses. Lessons are drawn from the observed structural performance. Key words: buildings, boundary elements, building code, concrete buildings, detailing, earthquakes, reinforced concrete, seismicity, seismic damage, seismic design, shear walls, structural damage. Cet article traite des dommages observes aux batiments en beton arme subis lors du seisme a Maule, Chili, le 27 fevrier 2010. Le comportement des batiments a ossature de beton et a murs de contreventement est aborde en faisant ressortir les manques sismiques dans la conception et les pratiques de construction. Il est montre que la majorite des dommages structuraux dans les immeubles a plusieurs etages et de grande hauteur peut etre attribuee au pietre rendement des murs de contreventement elances, sans elements de contour frettes, qui souffre de l'ecrasement du beton et du flambement de l'armature verticale des murs. L'utilisation de batiments non standards, le manque de details sismiques et l'interference d'elements non structuraux ont ete les manques sismiques les plus souvent observees. Les pratiques de conception chiliennes et canadiennes sont comparees avec des references aux normes des codes applicables. Des lemons sont tirees du comportement structural observe. [Traduit par la Redaction] Mots-cles: batiments, elements de contour, code du batiment, batiments en beton, details de construction, seismes, beton arme, seismicite, dommage sismique, conception sismique, murs de contreventement, dommages structuraux., Introduction A magnitude 8.8 earthquake occurred on 27 February 2010, off the coast of central Chile, causing widespread devastation in the Maule Region. The earthquake took place along the subduction [...]

This paper provides a summary of the damage to bridges in the Mw 8.8 Chile earthquake of 27 February 2010. Lessons from the different types of structural damage observed on concrete and steel bridges are discussed. The important roles played by soil liquefaction, settlement and embankment failures are highlighted. Aspects such as shear failure of steel piles, shear failure of concrete substructure elements, failures and severe buckling of steel braces, failures of shear keys and restrainers at supports, and damage to girders due to lack of diaphragms are described. Many examples of loss of superstructure support are presented. Skew supports and multi-span simply supported bridges were particularly susceptible to loss of support. Several aspects of the Chilean bridge design code are discussed and compared with North American codes (CSA S6 and AASHTO). Key words: bridges, seismic design, bridge codes, seismicity, soil amplification, skew bridges, loss of support, detailing. Cet article presente un sommaire des dommages subis par les structures de ponts durant le seisme de magnitude Mw 8,8 survenu au Chili le 27 fevrier 2010. On discute des legons tirees des differents types de dommages observes sur les ponts en beton arme et en acier. On souligne le role important joue par la liquefaction des sols, les tassements et la rupture des remblais. On decrit des aspects comme la rupture en cisaillement de pieux en acier, la rupture en cisaillement d'elements porteurs en beton arme, la rupture et le flambement de diagonales de contreventement en acier, la rupture de cles de cisaillement et systemes de retenue horizontale aux appuis et les dommages subis aux poutres decoulant de l'absence de diaphragmes. L'article presente aussi plusieurs exemples de perte d'appuis aux superstructures. On a note que les ponts comprenant un biais ou plusieurs travees simplement appuyees etaient particulierement vulnerables a une perte de support aux appuis. Certains aspects du code de conception des ponts du Chili sont presentes et compares aux codes en vigueur en Amerique du Nord (CSA S6 and AASHTO). Mots-cles: ponts, conception parasismique, normes de conception, alea sismique, effets de site, pont avec biais, perte d'appui, details relatifs a la conception., Introduction The 27 February 2010, Mw 8.8 subduction earthquake occurred at 0334 local time with the main shock located just off the coast about 100 km north of the major [...]

Damage to structures and infrastructure due to the Chile tsunami of 27 February 2010, is presented. Robust, modern engineered structures performed well during this tsunami and, generally, damage only to non-structural components was evident. The majority of damage was sustained by non-engineered residential homes located within the inundation zone. These dwellings consisted of either light timber frame construction or concrete frame construction with brick masonry infill walls. Many of the dwellings incorporated sheet metal as exterior cladding or roofing. The hydrodynamic (drag) forces, impulsive loading, hydrostatic forces, buoyant forces, and debris impact loading were probable sources during the tsunami causing the observed damage. Failures included punching of brick masonry infill walls, partial and complete collapse of load bearing elements such as columns, and sliding and unseating failures of second storey levels and roofs. A discussion of the state of the art in tsunami design practice is also provided. Key words: 2010 Chile tsunami, earthquakes, hydrodynamic forces, debris impact, damage. Les dommages causes aux structures et aux infrastructures par le tsunami au Chili le 27 fevrier 2010 sont presentes. Les structures techniques modernes et robustes ont bien resiste durant ce tsunami et, regle generale, des dommages n'etaient apparents que sur les composantes non structurales. Les residences non techniques situees dans la zone d'inondation ont subi la plus grande part des dommages. Ces residences etaient composees soit d'une charpente de bois legere ou de murs de beton avec remplissage en ma^onnerie de briques. Plusieurs de ces residences avaient des revetements exterieurs ou des toits en feuilles de metal. Les forces hydrodynamiques (resistance), les charges impulsives, les forces hydrostatiques, les forces de poussee et les charges d'impact des debris etaient les sources probables des dommages pendant le tsunami. Les defaillances comprenaient la perforation des murs avec remplissage en ma^onnerie de briques, l'effondrement partiel ou total des elements porteurs tels que les colonnes, et le glissement et les defaillances par deplacement des seconds etages et des toitures. Une discussion de la technologie d'avant-garde dans la pratique de conception contre les tsunamis est egalement presentee. [Traduit par la Redaction] Mots-cles: tsunami de 2010 au Chili, seismes, forces hydrodynamiques, impacts de debris, dommages., Introduction On 27 February 2010, at 3:34 a.m. local time, an [M.sub.w] 8.8 earthquake occurred offshore the Bio-Bio region of central Chile. The earthquake was generated along the subduction zone [...]

This paper presents performance of steel buildings and nonstructural elements during the 27 February 2010 Maule Earthquake in Chile. Structural steel buildings are not common in Chile, due to the relatively high cost of material. The majority of damage to steel structures was observed in industrial facilities. In general, the structural steel buildings performed well. Limited damage was observed in some of the older buildings. Extensive damage was sustained by nonstructural elements, including masonry infill walls, suspended ceilings, partition walls, and architectural features. Brick masonry partition walls, commonly used in Chilean buildings, suffered damage when used in frame buildings with little drift control. The paper presents a summary of observed damage and a comparison of Chilean and Canadian design practices for steel buildings, with lessons drawn from observed structural performance. Key words: bricks, buildings, building code, earthquakes, masonry, nonstructural elements, seismicity, seismic damage, seismic design, steel buildings, structural damage. Cet article traite du comportement des batiments a ossature d'acier et des elements non structuraux lors du seisme a Maule, Chili, le 27 fevrier 2010. Les batiments a ossature d'acier ne sont pas habituels au Chili en raison du cout relativement eleve des materiaux. La plus grande partie des dommages aux structures d'acier a ete remarquee dans les installations industrielles. Les batiments a ossature d'acier ont, en general, bien reagit. Des dommages limites ont ete remarques sur certains batiments plus ages. Les elements non structuraux ont subi une deterioration importante, dont les murs de maconnerie remplis, les plafonds suspendus, les murs de separation et les elements architecturaux. Les murs de separation en maconnerie de brique, frequemment utilises dans les batiments chiliens, ont subi des dommages lorsque presents dans les infrastructures de batiments avec peu de controle du mouvement. Cet article presente un resume des dommages observes et une comparaison des pratiques de conception chiliennes et canadiennes pour les batiments a ossature d'acier; des lemons sont tirees du comportement observe des structures. [Traduit par la Redaction] Mots-cles: briques, batiments, code du batiment, seismes, maconnerie, elements non structuraux, seismicite, dommage sismique, conception sismique, batiments a ossature d'acier, dommages structuraux., Introduction A team of structural engineers and a seismologist from Canada conducted reconnaissance in Chile after the magnitude 8.8 Maule Earthquake of 27 February 2010. The team visited Santiago, Curico, [...]

The selection of seismic motions is one of the most important issues for the time-history analysis of buildings. This paper discusses four different methods for obtaining spectrum-compatible acceleration time histories (i.e., accelerograms) of seismic motions. Based on these methods, four sets of accelerograms compatible with the design spectrum for Vancouver were selected for this study. These included (i) scaled real accelerograms, (ii) modified real accelerograms, (iii) simulated accelerograms, and (iv) artificial accelerograms. The selected sets were used as excitation motions in the nonlinear analysis of three reinforced concrete frame buildings designed for Vancouver. The buildings included a 4-storey, a 10-storey, and a 16-storey building, which can be considered representative of low- rise, medium-rise, and high-rise buildings, respectively. The storey shears, interstorey drifts, and curvature ductilities for beams and columns obtained from the analysis were used for the evaluation of the effects of the selected sets on the responses of the buildings. Based on the results from the analysis, scaled real accelerograms are recommended for use in time-history analysis of reinforced concrete frame buildings. Key words: seismic response, accelerogram, spectrum, reinforced concrete, building, analysis, drift, curvature ductility. Le choix des mouvements sismiques est l'une des questions les plus importantes de l'analyse de l'historique temporel des batiments. Cet article aborde quatre methodes differentes pour obtenir des historiques temporels d'acceleration des mouvements sismiques (c.-a-d. accelerogrammes) selon le spectre. En se basant sur ces methodes, quatre ensembles d'accelerogrammes compatibles avec le spectre de reponse pour Vancouver ont ete choisis pour cette etude. Ils comprenaient (i) des accelerogrammes reels proportionnes, (ii) des accelerogrammes reels modifies, (iii) des accelerogrammes simules et (iv) des accelerogrammes artificiels. Ces ensembles selectionnes ont ete utilises comme mouvements d'excitation dans l'analyse non lineaire de trois immeubles a ossature de beton arme concus pour Vancouver. Les immeubles comprenaient un immeuble de quatre etages, un de 10 etages et un de 16 etages, ce qui peut etre considere comme respectivement representatif d'immeubles de faible hauteur, de moyenne hauteur et de grande hauteur. Les efforts tranchants aux etages, les mouvements inter-etages et la reponse ductile de la courbure pour les poutres et les colonnes tires de l'analyse ont ete utilises pour evaluer les effets des ensembles choisis sur les reponses des immeubles. En se basant sur les resultats de l'analyse, il est recommande d'utiliser les accelerogrammes reels proportionnes lors de l'analyse de l'historique temporel des immeubles a ossature de beton arme. Mots-cles : reponse sismique, accelerogramme, spectre, beton arme, immeuble, analyse, mouvement, reponse ductile de la courbure. [Traduit par la Redaction], Introduction The nonlinear time-history analysis is the most reliable method for the assessment of the behaviour of buildings subjected to seismic loads. It has been widely used in research on [...]

Computer software was developed for inelastic analysis of structural members subjected to blast-induced shock waves. The software can predict the dynamic response of structural elements, provided the load-deformation characteristics are defined. The software has built-in capabilities to generate the load-deformation characteristics of common structural and non-structural members. Currently this capability includes reinforced concrete columns, one-way walls, beams, and one- way slabs. The input consists of member geometry, boundary conditions, dynamic material properties, explosive threat parameters, and desired performance levels. The results are presented in graphical format in terms of structural load-deformation characteristics, single degree of freedom displacement--time histories and iso-displacement pressure-impulse diagrams. The program was verified extensively using experimental data generated from simulated explosive loading of reinforced concrete members at the University of Ottawa shock tube testing facility. The shock tube has been shown to generate a wide range of pressure-impulse combinations, accurately simulating free-field detonation of high explosives of various mass and standoff distances. Key words: blast, blast response, computer analysis, computer software, concrete structures, dynamic analysis, pressure-impulse diagrams, reinforced concrete, structural analysis. Un logiciel d'analyse inelastique a ete developpe pour les elements de structure soumis a des ondes de chocs generees par une explosion. Le logiciel peut predire la reaction dynamique des elements de structure en autant que les caracteristiques contrainte-deformation soient definies. Le logiciel possede des capacites intrinseques pour generer les caracteristiques contrainte-deformation des elements structuraux et non structuraux communs. Cette capacite comprend actuellement les colonnes en beton arme, les murs, les poutres et les dalles unidirectionnels. Les donnees d'entree comprennent la geometrie de l' element, les conditions aux limites, les proprietes dynamiques du materiel, les parametres de danger d' explosion et les niveaux de rendement desires. Les resultats sont presentes sous forme de graphiques des caracteristiques contrainte-deformation structurale, des historiques temporels des deplacements a un seul degre de liberte et des diagrammes de pression due au choc a deplacement uniforme. Le programme a ete verifie en detail en utilisant des donnees experimentales generees a partir d'une charge explosive simulee sur des elements en beton arme aux installations d'essais avec tubes a choc de l'Universite d'Ottawa. Le tube a chocs peut generer une grande variete de combinaisons pression-impulsion simulant de maniere precise une detonation en champ libre d'explosifs de grande puissance de differentes masses et distances entre la charge et la structure. Mots-cles : explosion, reaction a l'explosion, analyse informatique, logiciel, structures en beton, analyse dynamique, diagrammes de pression due au choc, beton arme, analyse structurale. [Traduit par la Redaction], Introduction Reinforced concrete structural elements are typically idealized as having perfectly elastoplastic member resistance, and step-wise equivalent single degree of freedom (SDOF) transformation factors based on assumed elastic and plastic [...]

This is the second of two companion papers on improved intensity measures of strong seismic ground motions for use in probabilistic seismic demand analysis of reinforced concrete frame buildings. The first paper discusses the development of improved intensity measures. This paper describes the application of the developed intensity measures in probabilistic seismic demand analysis. The application is illustrated on the three reinforced concrete frame buildings (4, 10, and 16-storey high) that were used in the first paper. This involved computations of the seismic responses of the structures and the seismic hazard using the improved intensity measures. The response and the hazard results were then combined by means of probabilistic seismic demand analysis to determine the mean annual frequencies of exceeding specified response levels due to future earthquakes (i.e., the probabilistic seismic demands). For the purpose of comparison, probabilistic seismic demand analyses were also conducted by employing the spectral acceleration at the fundamental structural periods (Sa^)) as an intensity measure, which is currently the most used in practice. It was found that the use of the improved intensity measures results in significantly lower seismic demands relative to those corresponding to the intensity measure represented by Sa(ri), especially for long period structures. Key words: probabilistic seismic demand, analysis, intensity measure, collapse, interstorey drift, attenuation relation, period, building, frames. Cet article est le deuxieme sur les mesures de l'intensite ameliorees de grands mouvements sismiques du sol qui seront utilisees dans l'analyse probabiliste de la demande sismique des batiments a charpente en beton armee. Le premier article traite du developpement des mesures de l'intensite; ameliorees. Le present article decrit l'application des mesures de l'intensite; developpees par une analyse probabiliste de la demande sismique. L'application est illustree par trios batiments a charpente en beeton arme (4, 10 et 16 etages de haut) utilises dans le premier article. On y traitait du calcul des reponses sismiques des structures et des dangers sismiques en utilisant les mesures de l'intensite ameelioreees. Les resultats de la reponse et des dangers ont ete combines au moyen de l'analyse probabiliste de la demande sismique afin de determiner les frequences moyennes annuelles des niveaux exceedant la reeponse speecifieee en raison de prochains seismes (c.a-d. les demandes sismiques probabilistes). Aux fins de comparaison, les analyses probabilistes de la demande sismique ont eete reealiseees en utilisant l'acce;leeration spectrale a la periode de batiment fondamentale (Sa[T.sub.1])) en tant que mesure de l'intensite;, qui est actuellement la mesure de l'intensite la plus utilisee dans la pratique. Il s'est aveere que l'utilisation des mesures de l'intensite ameelioreees engendre des demandes sismiques considerablement plus faibles que celles correspondant a la mesure de l'intensitee representee par Sa([T.sub.1]), plus particulierement pour les structures a longue periode. Mots-cles: demande sismique probabiliste, analyse, mesure de l'intensite;, effondrement, mouvement inter-etages, relation de l'attenuation, periode, batiment, charpentes. [Traduit par la Redaction], Introduction Probabilistic seismic demand analysis (PSDA) is used to compute the mean annual frequencies of exceeding specified response levels of a given structure due to future seismic motions. It combines [...]

This is the first of two companion papers on improved intensity measures of strong seismic ground motions for use in probabilistic seismic demand analysis. It describes the formulation and the development of new intensity measures. The second paper illustrates the application of the developed intensity measures in probabilistic seismic demand analysis. The development of the intensity measures was based on investigations of the seismic responses of three reinforced concrete frame buildings (4, 10, and 16-storey high) designed for Vancouver. The buildings were subjected to a selected set of seismic motions scaled to different intensity levels. Maximum interstorey drifts obtained from nonlinear dynamic analyses were used as response parameters. Based on the results from the analyses, two intensity measures are proposed: one for short- and intermediate-period buildings, and another one for long-period buildings. The proposed intensity measures are superior compared to that represented by the spectral acceleration at the fundamental building period (Sa([T.sub.1])), which is currently the most widely used intensity measure in probabilistic seismic demand analysis. Key words: seismic, intensity measure, interstorey drift, period, building, frames, design, reinforced concrete, standard deviation. Cet article est le premier de deux articles connexes concernant l'amelioration des mesures d'intensite de grands mouvements sismiques du sol qui seront utiliseees dans l'analyse probabiliste de la demande sismique. Il decrit la formulation et le developpement de nouvelles mesures de l'intensite. Le deuxieme article illustre l'application des mesures de l'intensite developpeees par l'analyse probabiliste de la demande sismique. Le developpement de ces mesures de l'intensite; a ete base sur les etudes des reponses sismiques de trois batiments a charpente en beton arme (4, 10 et 16 etages de haut) concus pour Vancouver. Les batiments ont ete soumis a un ensemble de mouvements sismiques mis a l'echelle pour diffeerents niveaux d'intensite. Les mouvements inter-etages maximums, obtenus par analyse dynamique non lineiaires, ont ete utilises comme parametres de reponse. En se basant sur les resultats des analyses, nous proposons deux mesures de l'intensite: :une pour les batiments de periode courte et intermediate, et l'autre pour les batiments de longue peeriode. Les measures de l'intensite proposees etaient superieures a celles representees par l'acceeleeration spectrale a la peeriode de batiment fondamentale (Sa([T.sub.1])), laquelle est actuellement la mesure de l'intensite; la plus utiliseie dans l'analyse probabiliste de la demande sismique. Mots-cles: sismique, mesure de l'intensite, mouvement inter-etages, periode, batiment, charpentes, conception, beeton arme;,de;viation standard. [Traduit par la Redaction], Introduction Probabilistic seismic demand analysis (PSDA) is an important phase of the new approach for seismic assessment of existing structures and design of new structures, known as performance-based earthquake engineering [...]

The purpose of this paper is to provide a summary of the evolution of seismic design in Canada. This paper presents the significant changes to the approach taken in determining seismic hazards and seismic hazard maps, and describes the evolution of the seismic design provisions of the National building code of Canada. The introduction of important parameters in determining the seismic base shear such as the period of vibration of the structure, the influence of type of soil, and the concepts of ductility and energy dissipation capacity of elements and structures are presented. The levels of seismic design base shears, determined from different versions of the National Building Code of Canada, are compared for reinforced concrete frame and wall structures to illustrate the changes. Key words: National building code of Canada, seismic design, base shear, seismicity maps, natural period, foundation factors, torsional effects, structural systems, ductility. L'objectif de cet article est de presenter un sommaire de l'evolution de la conception parasismique au Canada en se refeerant aux modifications des efforts sismiques prescrits par le Code National du Batiment du Canada. Les changements majeurs concernant l'alea sismique et les cartes sismiques correspondantes qui ont ete creeeees sont presentes. On presente egalement les parametres importants, qui influencent le calcul sismique de l'effort tranchant a la base, tels que la periode de la structure, l'influence du type de sols, les concepts de ductilite et de dissipation d'eenergie. La variabilite du niveau des charges sismiques, pour les diffeerentes versions du Code National du Batiment du Canada, est presentee pour les cadres en beeton et les refends, afin d'illustrer ces changements. Mots-cles: Code National de Batiment du Canada, conception parasismique, effort tranchant a la base, cartes sismiques, periode naturelle, coefficient de fondation, effet de torsion, systemes structuraux, ductilite;. [Traduit par la Redaction], Introduction This paper forms part of a major effort by the Canadian Seismic Research Network to develop guidelines for seismic evaluation and retrofit of existing buildings. The evolution of Canadian [...]

This paper describes results from a study on the dynamic behaviour of the Confederation Bridge due to seismic loads. For the purpose of the seismic analysis of the bridge, a finite element model was developed using three-dimensional (3D) beam elements. The model was calibrated using measured data of the bridge vibrations during a dynamic load test. Dynamic analyses were conducted by subjecting the model to selected seismic ground motions representative of the expected motions at the bridge location. The bending moments and displacements obtained from the analyses were used for the seismic evaluation of the bridge. It was found that the seismic effects considered in the design are appropriate for the required safety during the service life of the bridge. Key words: bridge, dynamic analysis, seismic hazard, design spectrum, response, accelerogram. Cet article deecrit les resultats d'une etude sur le comportement dynamique du Pont de la Confederation lors de charges sismiques. Un modele par elements finis utilisant des poutres tridimensionnelles a ete deeveloppee aux fins de l'analyse sismique du pont. Le modele a ete; eetalonnee en utilisant les donnees mesurees des vibrations du pont durant un test de charge sismique. Des analyses dynamiques ont ete realisees en soumettant le modele a des mouvements sismiques du sol choisis representant les mouvements prevus a l'emplacement du pont. Les moments de flexion et les deplacements obtenus des analyses ont ete utilises pout revaluation sismique du pont. Il a ete conclu que les effets sismiques utilises dans la conception sont appropriees pour le niveau de securite requis durant la vie du pont. Mots-cles: pont, analyse dynamique, risque sismique, plage de conception, reponse, acceele;rogramme., Introduction The 12.9 km long Confederation Bridge, which was opened to traffic in June 1997, is one of the longest reinforced concrete bridges in the world (Fig. 1). The bridge [...]

Recent bomb attacks on buildings have raised awareness about the vulnerability of structures to blast effects. The resiliency of structures against blast-induced impulsive loads is affected by structural characteristics that are also important for seismic resistance. Deformability and continuity of structural elements, strength, stiffness, and stability of the structural framing system and resistance to progressive collapse are factors that play important roles on the survivability of buildings under both blast and seismic loads. The significance of these structural parameters on blast resistance of reinforced concrete buildings is assessed through structural analysis. Both local element performance and global structural response are considered while also assessing the progressive collapse potential. The buildings under investigation include 10-storey moment resisting frames with or without shear walls. The blast loads selected consist of different charge-weight and standoff distance combinations. The results are presented in terms of ductility and drift demands. They indicate improved performance of seismic-resistant buildings when subjected to blast loads, in terms of local column performance, overall structural response, and progressive collapse potential. Key words: blast, blast resistant design, charge, drift ratio, ductility, earthquake resistant design, explosives, inelastic structural response, progressive collapse. Les recentes attaques a la bombe sur des batiments ont souligne la vulnerabilite des structures aux effets d'une explosion. Les caracteristiques structurales, egalement importantes pour determiner la resistance sismique, affectent la resilience des structures aux charges impulsives generees par les explosions. La deformabilite et la continuite des elements structuraux de meme que la resistance, la rigidite et la stabilite des systemes de charpentes et la resistance a l'effondrement progressif sont tous des facteurs jouant des roles importants dans la survivance des batiments sous des charges d'explosion et sismiques. L'importance de ces parametres structuraux sur la resistance aux explosions des batiments en beton arme est evaluee par analyse structurale. Le rendement local des elements et la reponse globale de la structure sont consideres tout en evaluant aussi le potentiel d'ecroulement progressif. Les batiments etudies comprennent des structures de 10 etages resistant au moment avec ou sans murs de contreventement. Les charges d'explosion choisies comportaient differentes combinaisons charge-poids et distance d'explosion. Les resultats sont presentes en termes des demandes en ductilite et en derive. Ils indiquent un rendement accru des batiments resistants aux seismes lorsqu'ils sont exposes a des charges d'explosion en termes de rendement local des colonnes, de la reponse globale de la structure et du potentiel d'effondrement progressif. Mots-cles : explosion, conception resistant aux explosions, charge, rapport de derive, ductilite, conception resistant aux seismes, explosifs, reponse structurale non elastique, effondrement progressif. [Traduit par la Redaction], Introduction Embassy buildings, commercial centres, government buildings, industrial facilities, and residential buildings were attacked in recent years with explosives. These attacks, in the form of explosive devices loaded on nearby [...]

Abstract: The distributed Brillouin sensor (DBS) was used to monitor the structural changes in a steel pipe and a composite column subjected to heavy loads. The column was made of [...]

The use of high-strength concrete (HSC) in seismically active regions poses a major concern because of the brittle nature of the material. The confinement requirements for HSC columns may be prohibitively stringent since they require proportionately greater confinement than columns of normal-strength concrete. An alternative to conventional confinement reinforcement is the use of fiber reinforced polymer (FRP) casings, in the form of a stay-in-place formwork. This paper investigates the use of stay-in-place FRP formwork as concrete confinement reinforcement for HSC columns with square cross sections. Large scale HSC building columns, encased in FRP casings, were tested under simulated seismic loading. The columns had 270 mm square sections and concrete strengths up to 90 MPa. The casings were manufactured from carbon FRP and epoxy resin. The unique aspects of the test program were the introduction of the corner radius as a test parameter, and the presence of internally placed FRP crossties, integrally built with column casings, to improve the effectiveness of concrete confinement. Results indicate that the deformation capacity of HSC columns can be improved significantly by using FRP casings. The results further indicate that the confinement effectiveness of columns is significantly affected by the corner radius of casings. Additionally, the confinement efficiency can be improved with the use of FRP crossties. The columns developed inelastic drift capacities of up to 11%, demonstrating the usefulness of FRP stay-in-place formwork in improving deformability of HSC columns. DOI: 10.1061/(ASCE)0733-9445(2007)133:1(44) CE Database subject headings: Concrete columns; Earthquakes; High strength concretes; Fiber reinforced polimers; Confinement; Ductility.

Abstract: Spectrum-compatible seismic excitations are required when dynamic time-history analysis is used for determining the response of a structure. This paper presents results from a study on the effects of [...]