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Concrete-filled coupled composite plate shear walls (also known as as SpeedCore walls) are gaining acceptance for construction in seismic region throughout North America. Design provisions for this lateral load-resisting system have already been added to ASCE 7-22 and to the American Institute of Steel Construction Seismic Design Provisions. Adequacy of the seismic design parameters used for this structural purpose has been validated in the USA using the FEMA P695 methodology. An interest was expressed by the practicing engineering community to use these walls in Canada, which requires demonstration of satisfactory seismic performance within the Canadian context. As such, new analyses are needed using Canadian-specific sets of ground motions to confirm the adequacy of the seismic design parameters proposed for implementation of these composite walls in the National Building Code of Canada. This paper presents the results of these analyses, showing that the proposed seismic performance factors are appropriate for this structural system in Canada. [ABSTRACT FROM AUTHOR]

A full-scale, two-tiered steel buckling-restrained braced frame (BRBF) was tested to evaluate experimentally the seismic behavior of steel multitiered BRBFs, namely, column stability response, column seismic demands, and tier deformations under a loading protocol representing earthquake ground motions. The test specimen consisted of diagonal braces oriented in opposing directions in the two adjacent tiers to create the most critical multitier response. The test frame was designed in accordance with the 2010 AISC Seismic Provisions as a lateral load-resisting system of a single-story building. The frame was subjected to a three-phase loading protocol consisting of lateral displacement time histories corresponding to a far-field ground motion record and a near-field ground motion record applied sequentially achieving total frame drifts in excess of 3.5%, followed by a final monotonic lateral displacement corresponding to 4.5% story drift. The test frame exhibited a stable response despite a non-uniform distribution of frame inelastic deformation between the tiers, which induced significant in-plane bending moments in the columns. Flexural bending, combined with a large axial compression force, led to partial yielding in the columns. Large deformation demands were also observed in the BRB yielding in tension and attracting the majority of frame lateral deformation. On the basis of test results, a displacement-based analysis approach was proposed to relate column in-plane bending and flexural stiffness to relative inelastic tier deformations. [ABSTRACT FROM AUTHOR]

This brief technical note compares the adjusted collapsed margin ratios for concrete-filled coupled composite plate steel walls, as obtained from the FEMA P695 methodology, separately considering only subduction zone earthquakes and only shallow earthquakes. For shallow earthquakes, collapse margin ratios were similar to those obtained in prior studies, but they were substantially smaller for the set of subduction earthquakes. While both sets of collapse margin ratios were considered to provide satisfactory seismic performance, this study provides insights into the impact of considering subduction earthquakes in FEMA P695 studies and, by inference, on expected collapse margin ratio for subduction earthquakes. [ABSTRACT FROM AUTHOR]

This article discusses the significance of effective communication skills for veterinarians who work with food animals. It emphasizes that communication is not only about educating clients, but also about facilitating change. The article suggests that understanding clients' general personality characteristics can help veterinarians present new ideas and suggestions in a manner that is more likely to be accepted and adopted. It also explores different communication styles based on personality types and provides tips for better communication with clients and colleagues. The article concludes by highlighting the potential for individuals to adapt their communication styles to better match the preferences of others. Additionally, the text discusses the benefits of implementing communication training in a clinic setting, particularly with clinic staff and colleagues. It emphasizes the importance of tailoring communication to match the style of clients, which can improve relationships and increase client uptake of recommendations. The author also shares their experience with small group meetings as a way to facilitate change in clients' management decisions, highlighting the power of information shared between farmers. The text provides tips for maximizing knowledge transfer in small group meetings, including asking open-ended questions and involving all participants in the discussion. It concludes by emphasizing the importance of using communication skills routinely and provides information on submitting photographs for the cover of The CVJ. [Extracted from the article]

This article explores the significance of training farmers and farm workers in euthanasia techniques for livestock. It acknowledges the complexity of euthanasia in veterinary practice, particularly in food animal systems where non-veterinarians often perform the procedure. The article emphasizes the need to consider animal well-being and economic health when making end-of-life decisions, while also recognizing the stress and discomfort experienced by care providers. It highlights the importance of proper training to ensure humane euthanasia and shares insights from veterinarians experienced in training animal care providers. The article specifically focuses on the importance of euthanasia training for individuals working with cattle and small ruminants, emphasizing the need for sensitivity, empathy, and understanding of the trainee's background knowledge, skill, and comfort level. It provides guidance on key points to cover during euthanasia training, including equipment familiarity, animal anatomy, proper restraint, and applying a secondary kill step. The article suggests that veterinarians can play a crucial role in providing leadership and training in on-farm euthanasia. [Extracted from the article]

This article provides an overview of the working life of veterinarians in aquaculture, specifically focusing on salmon farming in Canada. It explains the two phases of salmon farming, the challenges of providing veterinary care in aquaculture, and the importance of water quality and environmental monitoring. Vaccination and routine disease screening are crucial tools used to prevent diseases in farmed salmon. The article also discusses the use of antibacterial and antiparasitic drugs in aquaculture, the regulations surrounding their usage, and the challenges faced by aquaculture veterinarians. It acknowledges the controversies surrounding salmon net-pen farming and concludes by highlighting the importance of fish farming in sustainable food production and coastal communities in Canada. [Extracted from the article]

This paper presents the experimental investigation of two brace middle connections: 1) using a slotted tube knife‐plate connection (STKPC), and 2) a bolted sandwich plate connection (BSPC). The STKPC consists of a gusset plate slotted through the continuous brace and welded to discontinuous braces. The BSPC consists of two cover plates and four U‐shaped plates connecting the discontinuous braces using bolts. The two cover plates pass on either side of the continuous brace and are bolted to the U‐shaped plates. These connections are used to join the discontinuous braces in steel concentrically braced frames (CBFs) configured with X‐bracing. These connections were tested as part of a full‐scale CBF using quasi‐static testing. In both specimens, seismic energy dissipated through yielding and buckling of the braces. However, in the specimen with STKPC, axial deformation is concentrated in a single discontinuous brace, which led to local buckling at mid‐length and subsequent fracture. In contrast, the BSPC is able to better distribute axial deformation between the two discontinuous braces delaying local buckling. Moreover, the measured buckling capacity of braces when using the BSPC matches well the expected compressive resistance calculated using an effective length factor K = 0.45. [ABSTRACT FROM AUTHOR]

This paper presents finite element (FE) investigations of the seismic response of a bridge incorporating a base rocking steel pier. The pier consists of a circular steel tube, circular end plates, posttensioned (PT) tendon(s), and supplemental energy dissipation devices, and is configured to rock at its interface with the foundation. The main characteristic of such a pier is its ability to ensure small residual drifts after undergoing inelastic deformations during cyclic loading. The system has a tendency to close the gap due to the presence of superstructure dead load (DL) and tendon posttensioning force. Using experimental data, the calibration of the FE procedure is done at the material, component, and global system levels. The FE model of a prototype bridge is developed with the rocking pier modelled by continuum elements while superstructure, bearing units, abutment walls and backfill material modelled by discrete elements. The analysis procedure includes the application of one or two earthquake excitations, traffic loads, and braking force. The varied parameters are the diameter‐to‐thickness ratio of the column, presence of a PT tendon, addition of supplemental energy dissipaters (EDs), base plate dimensions, height of ED chairs, and ED strength. The results of dynamic FE studies demonstrate that a bridge utilizing such a pier has the potential to undergo consecutive earthquakes without sustaining significant damage and return to its original position without requiring abutment component stiffness and strength. [ABSTRACT FROM AUTHOR]

This article investigates the seismic design and response of steel multi-tiered concentrically braced frames (MT-BFs) in which braces meet at columns between diaphragms. The seismic design provisions of CSA S16-14 are described and illustrated for three-tiered Type MD (moderately ductile) and five-tiered Type LD (limited ductile) braced frames. Analysis methods are proposed to evaluate the in-plane flexural demand on columns. The seismic response of the frames is examined through nonlinear response history analysis. As assumed in design, inelastic deformations tend to concentrate in one tier over the frame height, causing non-uniform drift demands and in-plane bending moments in the columns. CSA S16 provisions predicted well the frame in-plane flexural response and result in acceptable ductility demands on the braces. An extended seismic analysis and design approach that accounts for vertical distribution of brace tension yielding along the frame height is proposed for frames that exceed the limits prescribed in CSA S16. Key words: multi-tiered concentrically braced frames, seismic response, nonlinear analysis. Resume : Cet article examine la conception et la reponse sismiques de charpentes contreventees concentriques a multiples segments en acier (<< MT-BFs >>) dans lesquelles les diagonales se rencontrent aux diaphragmes. Les dispositions de la conception sismique de la norme CSA S16-14 sont decrites et illustrees pour des charpentes contreventees fi trois segments de type << MD >> (ductilite moderee) et a cinq segments de type << LD >> (ductilite limitee). On propose des methodes d'analyse pour evaluer la demande de flexion en plan sur les colonnes. On examine la reponse sismique des charpentes au moyen d'analyses temporelles non lineaire. Selon l'hypothese en conception, les deformations inelastiques ont tendance fi se concentrer dans un des segments de la charpente, causant des deplacements horizontaux non uniformes et des moments flechissant en plan des colonnes. Les dispositions de la norme CSA S16 ont bien predit la reponse de la flexion en plan de la charpente et produisent des demandes en ductilite acceptables en ce qui a trait aux diagonales. On propose une analyse sismique et une approche conceptuelle qui prennent en compte la distribution verticale de la plastification des diagonales travaillant en traction le long de la hauteur de la charpente, et ce, pour des charpentes qui excedent les limites prescrites dans la norme CSA S16. [Traduit par la Redaction] Mots-cles : charpente contreventee concentrique a multiples segments, reponse sismique, analyse non lineaire., Introduction Steel multi-tiered braced frames (MT-BFs) are braced frames that comprise two or more bracing panels stacked on top of each other between horizontal diaphragms in a building. This geometry [...]

The design provisions for seismically isolated bridges in the CAN/CSA-S6 Canadian Highway Bridge Design Code and the AASHTO Guide Specifications for Seismic Isolation Design (AASHTO 2010, 2014) have been developed primarily based on ground motions recorded along the west coast of North America. Both codes include a simplified analysis procedure that relies on an equivalent effective linearization of the nonlinear isolated structure together with damping coefficients to account for the effect of energy dissipation on the response of the isolated system. The appropriateness and range of application of codespecified simplified methods were investigated through nonlinear time-history analyses to propose improvements to this procedure for the new edition of the CSA-S6-2014 code. Based on these analyses, new damping coefficients are proposed for Eastern North America (ENA) and new limits for the application of the simplified method are defined. For ENA, the method with newly proposed damping coefficients can give good bridge displacement estimates for equivalent damping ratios of up to 40%, which broadens the possible designs that can be achieved using the simplified method. This study also showed that applicability limits could be defined more accurately as a function of the system properties. Key words: seismic design, bridge structures, seismic isolation and damping. Les dispositions de conception des ponts isoles parasismiques du Code canadien sur le calcul des ponts routiers CAN/CSA-S6 et de l' << AASHTO Guide Specifications for Seismic Isolation Design >> (AASHTO 2010, 2014) ont ete developpees principalement en se basant sur les mouvements du sol enregistres le long de la cote ouest de l'Amerique du Nord. Les deux codes comprennent une procedure d'analyse simplifiee fondee sur une linearisation effective equivalente de la structure isolee non lineaire de pair avec des coefficients d'amortissement pour representer l'effet de la dissipation de l'energie sur la reponse du systeme isole. On a examine la pertinence et la gamme d'application des methodes simplifiees precisees par le code, et ce, par des analyses de l'historique temporel non lineaire afin de proposer des ameliorations fi la procedure en vue de la nouvelle edition du code CSA-S6-2014. On propose de nouveaux coefficients d'amortissement et on definit de nouvelles limites de l'application de la methode simplifiee. Cette etude a aussi montre que les limites d'applicabilite pourraient etre definies plus precisement comme une fonction des proprietes du systeme. [Traduit par la Redaction] Mots-cles : conception sismique, structures des ponts, isolation et amortissement sismique., Introduction In 2014, major changes were introduced to the seismic design provisions for bridge structures in the CAN/CSA-S6 Canadian Highway Bridge Design Code (CSA 2014). One of the main changes [...]

The first phase of experiments presented in Part I of this study is used to calibrate the 3D finite element (FE) modelling procedure of the tested fuse-type filler-injected buckling-restrained stainless steel energy dissipaters (EDs). The models are generated using a combined continuum-macro FE approach. A discussion is provided on the selection and calibration of material models. Sensitivity analyses are performed to investigate the effects of mesh sizes, imperfection shape and size, contact stiffness and friction coefficient on the cyclic response. After validating the FE analysis results against those obtained from the experiments, a parametric study is conducted with the objective of quantifying the required stiffness of the restraining system to avoid global-level buckling. At the end, an idealized elastic-perfectly plastic model with equivalent energy dissipation property is proposed for use in macro models. [ABSTRACT FROM AUTHOR]

The seismic performance of structures could be enhanced by the inclusion of supplemental components that dissipate the earthquake-induced energy. This is especially crucial for rocking structures that possess low energy dissipation properties due to their damage avoidance mechanism. Amongst variously developed yielding-type energy dissipaters (EDs), buckling-restrained energy dissipating carbon steel bars have received considerable attention as they make the most use of the inherent energy dissipation of steel and are easy to fabricate. However, maintenance, repair costs, and performance disruptions owing to corrosive environments have been mostly disregarded in past investigations. Employing stainless steel can be a viable solution to overcome such issues. The work described in this two-part study sheds light on various aspects of the buckling-restrained stainless steel EDs through experimental and finite element (FE) investigations. The mechanical properties of type 304L stainless steel including uniaxial monotonic response, strain sensitivity, and cyclic hardening are characterized. It is shown that the material possesses high ductility along with substantial hardening characteristics. In the first phase of testing, energy dissipating bars with different fuse diameters and lengths are designed. Load and strain capacities and bar-tube interactions of the buckling-restrained energy dissipation device are studied through quasi-static tests. In the second phase of testing, various EDs are designed, fabricated with stainless and mild steel, and tested under quasi-static loading to validate the findings of the FE investigations. The test results demonstrate a stable hysteresis response of the buckling-restrained stainless steel EDs with a cyclic average strain capacity of 10%. The FE modelling procedure, calibration, and parametric studies are presented in the companion paper as Part II. [ABSTRACT FROM AUTHOR]

The slotted-hidden-gap (SHG) connection eliminates the need to reinforce the slot region of hollow structural sections (HSS) braces of concentrically braced frames (CBFs). However, the existing design approach for SHG connections is rather empirical and limited by the range of the connection geometries and materials that had previously been tested. A general design approach based on the findings of a large-scale parametric study is presented in this paper, where the most critical parameters of the connection were varied. Different weld configurations were investigated to examine the effect of shear lag on the overall performance of the brace. The inelastic performance of SHG-connected braces designed using the proposed approach was validated by means of numerically simulating the resulting braces and connections and subjecting them to a reversed-cyclic loading protocol. The simulated braces were able to attain their yield tensile resistance and fracture away from the connection region while sustaining an axial deformation corresponding to an average story drift of 5.43%. The proposed design and detailing method was, as such, found to be effective in the design of square HSS SHG connection braces ranging in size and steel grade. [ABSTRACT FROM AUTHOR]

A parametric study was performed to examine the seismic behavior of moderately ductile (MD) reinforced concrete shear walls designed according to Canadian code provisions, including National Building Code of Canada (NBCC) 2010 and Canadian Standards Association (CSA) 23.3-04, when subjected to typical high-frequency eastern North America earthquakes. The numerical models were experimentally validated based on large specimens shaking table test results. The results obtained following the code response spectrum procedure were compared with the results from inelastic response historey analyses to investigate the effect of higher modes on seismic force demands. The results indicate that current code provisions for MD shear walls need to be modified. A new base shear factor and shear force design envelop are proposed to evaluate the seismic shear force demand more realistically. This study also recommends that the current CSA 23.3-04 requirements for ductile shear walls for bending moments could be applied to constrain the location of inelastic flexural deformations at the base of MD shear walls. Key words: shear walls, higher mode effects, high frequency content earthquakes, moderately ductile, seismic force demand, capacity design. Une etude parametrique a ete realisee pour examiner le comportement sismique de murs de contreventement en beton arme moderement ductile concus selon les dispositions des codes canadiens, dont le Code national du batiment du Canada(CNBC) et l'Association canadienne de normalisation (CSA) 23.3-04, lorsqu'ils sont soumis a des seismes a haute frequence, typiques de l'est de l'Amerique du Nord. Les modeles numeriques ont ete valides par experiences en se basant sur des resultats d'essais sur table a secousses avec de grands echantillons. Les resultats obtenus suite a la procedure du spectre de reponse des codes ont ete compares aux resultats d'analyses historiques de reponse inelastique afin d'etudier l'effet des modes superieurs sur les demandes des forces sismiques. Les resultats indiquent que les dispositions actuelles des codes pour les murs travaillant en cisaillement moderement ductiles doivent etre modifiees. Un nouveau facteur de cisaillement de base et une nouvelle enveloppe de conception de la resistance au cisaillement sont proposes pour evaluer la demande de force sismique de cisaillement de maniere plus realiste. La presente etude recommande egalement que les exigences actuelles de la CSA 23.3-04 concernant les moments de flexion puissent etre appliquees pour limiter l'emplacement des deformations en flexion inelastique a la base des murs de cisaillement moderement ductiles. [Traduit par la Redaction] Mots-cles : murs de cisaillement, effets des modes superieurs, seismes a hautes frequences, moderement ductile, demande de force sismique, capacite nominale., Introduction Most seismic design codes for shear walls, including the NBCC 2010 (NRCC 2010), New Zealand codes (NZS 2006), and Eurocode (EC) 8 (CEN 2004), are based on capacity design [...]

This paper presents the results of a finite-element (FE) study on posttensioned (PT) rocking steel bridge piers, each composed of a circular tubular column, welded end plates, PT strands, and axially yielding steel energy dissipators (EDs), and corresponding chairs. The pier is configured so that it rocks at its base. Previously conducted experiments on five scaled rocking steel columns are summarized. Three-dimensional (3D) continuum FE models of the tested specimens are generated with the objective of verifying the capability of the modeling approach in the simulation of the local and global responses. Strain-controlled cyclic coupon tests were performed to quantify the kinematic and isotropic hardening material parameters. A simplified method is proposed to model the cyclic loss of prestressing because of wedge seating in a typical industry monostrand anchorage system. The FE procedure is then calibrated against the experimental data at the material, component, and global pier levels. A parametric study is conducted to examine the effects of key factors such as material model, P-Delta, base plate dimensions, column diameter-to-thickness and initial axial force ratios, ED chairs, and ED location on the lateral cyclic response. It is demonstrated that, for a given target drift, local buckling and the resulting residual lateral deformations of a rocking steel pier are a function of the diameter-to-thickness and initial axial force ratios of the column and the ED chairs. By the proper selection of these variables, a stable and robust self-centering response can be obtained with minimal damage to the bridge pier. [ABSTRACT FROM AUTHOR]

This paper provides a summary of the damage to industrial facilities in the [M.sub.w] 8.8 Chile earthquake of 27 February 2010. The types of damage observed include failure of elevated tanks, collapse and cracking of concrete silos, buckling of steel silos, collapse of conveyor systems, failure of steel bins, and failure of anchor rods. Damage to industrial buildings included buckling of bracing members, failure of brace connections, shear failures of reinforced concrete columns, and shear failures of heavily loaded steel girders. Aspects of the current Chilean design code for industrial structures are reviewed and discussed. Recommendations are proposed for the development of Canadian seismic design provisions for industrial structures. Key words: buildings, tanks, anchor rods, bracing members, connections, girders, concrete columns, seismic design, detailing. Dans cet article, on decrit et commente les dommages que les batiments industriels ont subis lors du seisme de magnitude [M.sub.w] 8,8 survenu au Chili le 27 fevrier 2010. Les differents types de dommages observes incluent la rupture de reservoirs en hauteur, la fissuration et l'effondrement de silos en beton, le flambage de silos en acier, l'effondrement de convoyeurs, la rupture de reservoirs en acier et le bris de tiges d'ancrage. Des dommages ont egalement ete observes dans les batiments industriels tels que le flambement de contreventements et la rupture d'assemblages dans les contreventements en acier et la rupture par cisaillement de poteaux en beton arme et de poutres en acier. Certains aspects de la norme chilienne pour la conception des batiments industriels sont examines. Des recommandations sont proposees pour le developpement de regles de conception parasismique canadiennes pour les batiments industriels. Mots-cles: batiments, reservoirs, tiges d'ancrage, contreventements, assemblages, poutres, poteaux en beton, conception parasismique, details de fabrication., Introduction The M8.8 Offshore subduction earthquake of 27 February 2010 occurred at 3:34 a.m., with its epicentre located off the Pacific coast approximately 100 km North of Concepcion and 340 [...]

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 [...]

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 impact of applying different procedures for selecting and scaling seismic ground motion records and the influence of site conditions on ground motion amplification are examined by investigating the nonlinear seismic response of a building structure. Site class C is investigated for western Canada whereas class D and E sites are studied for eastern Canada. Ground motion records are selected and calibrated using several intensity-based procedures to match the NBCC 2005 design spectra. The focus is on simulated ground motion time histories. Nonlinear analysis of a four-storey concentrically braced steel frame showed that all scaling methods resulted in similar median inelastic brace deformations, in spite of differences between the characteristics of the historical and simulated records. Similar ground motion amplification at class D and E sites is also obtained for simulated and historical records. Simulated records are found adequate for the nonlinear seismic analysis of the structure studied. Key words: ground motion selection and scaling, nonlinear analysis, simulated motion, braced frame, seismic inelastic response of buildings. Cet article examine l'impact de l'application de diverses procedures pour selectionner et etalonner des enregistrements de tremblements de terre ainsi que l'influence des conditions du site sur l'amplification des signaux sismiques en analysant la reponse sismique non lineaire d'un batiment. Un site de classe C est examine dans l'Ouest du Canada, alors que des sites de classes D et E sont etudies dans l'Est du Canada. Les registres de mouvements du sol ont ete choisis et etalonnes en utilisant plusieurs procedures basees sur l' intensite afin de rencontrer les spectres theoriques de conception du CNB 2005. Les accelerogrammes ont ete choisis et etalonnes en utilisant plusieurs procedures basees sur l'intensite du spectre afin d'obtenir la compatibilite avec les spectres de calcul definis dans le CNB 2005. Une attention particuliere est portee a l'utilisation des accelerogrammes synthetiques. Les analyses non-lineaires d'un cadre en acier a contreventement concentrique de quatre etages ont demontre que les valeurs medianes de deformations inelastiques des diagonales etaient similaires peu importe la methode de selection et de l' etalonnage utilisee, et ceci malgre la difference entre les caracteristiques des accelerogrammes historiques et synthetiques. Une amplification comparable des signaux sismiques a ete aussi observee pour les accelerogrammes historiques et synthetiques. Les accelerogrammes synthetiques utilises dans cette etude se sont montres adequats pour investiguer la reponse sismique non-lineaire du batiment choisi. Mots-cles: selection et mise a l'echelle des mouvements du sol, analyse non lineaire, mouvement simule, armature contreventee, reponse sismique inelastique des immeubles. [Traduit par la Redaction], Introduction Nonlinear time history analysis is gaining popularity in engineering practice to study the behaviour of building structures under seismic ground motions. It is used to determine the seismic demand [...]

A percentage rule for the prediction of interacting seismic responses of bridge columns under multi-directional earthquake components is derived for eastern and western Canada seismic regions. A total of 14 regular bridges with different geometrical properties were examined for the two sites. The new rule was developed by comparing the column longitudinal steel ratio required from response spectrum analysis with combination rules to the ratio determined from the results of linear dynamic time history analysis of the bridge structures under bidirectional ground motions. The required steel ratios were found to vary with the weighted percentages used in the combination rules, the ground motion characteristics, and bridge properties. It was found that a 100%-20% combination rule is applicable for most bridges studied in eastern Canada. A 100%--10% rule is more appropriate for bridges located in western Canada. The results show that these rules need not be applied for regular straight bridges without skew but further investigation is needed before such a relaxation can be applied. Nonlinear dynamic time histories analysis of a two-span skewed bridge designed with the proposed percentage rule for eastern and western Canada showed that the columns would not experience excessive damage. Key words: combination rule, bridge column, multi-directional earthquake components, interacting seismic responses. Une regle de pourcentage servant a predire les reponses sismiques interactives des piliers de ponts sous l'effet des composantes sismiques multidirectionnelles est derivee pour les regions sismiques de l'Est et de l'Ouest canadien. Un total de 14 ponts reguliers possedant differentes proprietes geometriques a ete etudie pour les deux regions. La nouvelle regle a ete developpee en comparant le taux d'armature longitudinale de la colonne requis obtenu par analyse spectral et des regles de combinaison avec le taux d'armature determine a partir des resultats d'analyses dynamiques temporelles des structures des ponts sous des mouvements de sol bidirectionnels. Les taux d'armature requis variaient selon les pourcentages utilises dans la regle de combinaison, les caracteristiques du mouvement du sol et les proprietes des ponts. Les resultats montrent qu'une combinaison de 20 % est applicable a la plupart des ponts etudies dans l'Est du Canada. Une regle de 40 % est plus appropriee pour les ponts situes dans l'Ouest canadien. Les resultats montrent qu'il n'est pas necessaire d'appliquer ces regles aux ponts droits reguliers sans biais. Une etude plus poussee est cependant requise avant qu'un tel assouplissement de la regle ne puisse etre adopte. Les analyses dynamiques temporelles non lineaires d'un pont biais a deux travees, concu selon la regle de pourcentage proposee pour l'Est et l'Ouest du Canada, ont montre que les piliers ne subiraient pas de dommages excessifs. Mots-cles : regle de combinaison, pilier de pont, composantes de seismes multidirectionnelles, reponses sismiques interactives. [Traduit par la Redaction], Introduction The prediction of the seismic effects of structures under the simultaneous action of two horizontal ground motion components can be achieved using the response spectrum dynamic analysis method. A [...]