Search

Copyright of Revista Praxis & Saber is the property of Universidad Pedagogica y Tecnologica de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The correlation between intensity and damage measure for generic moment-resisting steel frames (MRSF) that are subjected to earthquake shaking was analysed using optimised nonlinear single degree of freedom (SDOF) models. The parameters for these SDOF models are based on nonlinear quasi-static pushover analyses of the multi-degree of freedom (MDOF) building systems. This intensity-damage relationship was then compared with those obtained from incremental dynamic analysis (IDA), that is a MDOF approach. Results show that the general trend line of intensity-damage measures for nonlinear SDOF model was qualitatively similar to the MDOF model that in this case represents a full nonlinear finite element analysis of the MRSF. While the SDOF model is not a precise match to the MDOF model, results suggests that it can be used in the vital role of ground motion record selection because of its computational efficiency. Furthermore, it is shown that the accuracy of intensity-damage estimates from the SDOF models can be improved if optimal damping, pseudo-yield, and ultimate loads are chosen. The efficacy of various intensity measures on damage are compared and contrasted. [ABSTRACT FROM AUTHOR]

This paper presents a detailed characterization of the monotonic, cyclic, and post-cyclic behavior of two strata within a recent Holocene alluvial deposit of silty sand, sandy silt, silt, and clay. Stratum A is composed predominantly of very soft clay and very loose silt with plasticity indices ranging from 5 to 27, whereas stratum B is composed predominantly of very loose silty sand and sandy silt with plasticity indices ranging from 0 to 10. Characterization included in situ testing, undisturbed soil sampling and laboratory testing, and a field surcharge test section. Consolidation tests and monotonic, cyclic, and post-cyclic direct simple shear tests were used to evaluate the effects of varying the consolidation stress, consolidation stress history, and initial static shear stress ratio. The field and laboratory test data show distinct differences in behavior between the two soil strata, which can be related to their different index test characteristics. These results are compared with their respective behaviors predicted using common engineering correlations. The field and laboratory test data summarized herein contribute to the database and understanding of the monotonic, cyclic, and post-cyclic behaviors of low-plasticity fine-grained soils. [ABSTRACT FROM AUTHOR]

The conventional Mononobe-Okabe method is widely used in practice, but is only applicable for calculating total seismic earth pressure of cohesionless soil, not for solving earth pressure distribution. Based on limit equilibrium theory, the backfill is considered to be an ideal elastic-plastic material that obeys the Mohr-Coulomb yield criterion, and a family of slip-lines in the plastic zone is assumed to be a group of straight lines, i.e., planar slip surfaces. Influencing factors including inclination of wall, slope angle of backfill, cohesion and friction angle of soil, adhesion and friction angle between wall and soil, uniform surcharge, and horizontal and vertical seismic coefficients are considered. A more reasonable plastic soil wedge analysis model is established to solve the seismic passive earth pressure on retaining walls, the soil reaction on slip surfaces, and their distributions by using the limit equilibrium method. The geometric and mechanical similarity principle is first proposed by dimensionless analysis. The results show that the total seismic passive earth pressure increases with the algebraic value of the horizontal seismic coefficient, and that it decreases as the algebraic value of the vertical seismic coefficient increases. The present analytical solution is identical to the results in existing literature, and the Mononobe-Okabe method is a special case of this solution. [ABSTRACT FROM AUTHOR]

During strong earthquakes, significant excess pore pressures can develop in saturated soils. After shaking ceases, the dissipation of these pressures can cause significant soil settlement, creating downward-acting frictional loads on piled foundations. Additionally, if the piles do not support the full axial load at the end of shaking, then the proportion of the superstructure's vertical loading carried by the piles may change as a result of the soil settlement, further altering the axial load distribution on piles as the soil consolidates. In this paper, the effect of hydraulic conductivity and initial post-shaking pile head loading is investigated in terms of the changing axial load distribution and settlement responses. The investigation is carried out by considering the results from four dynamic centrifuge experiments in which a 2 × 2 pile group was embedded in a two-layer profile and subjected to strong shaking. It is found that large contrasts in hydraulic conductivity between the two layers of the soil model affected both the pile group settlements and axial load distribution. Both these results stem from the differences in excess pore pressure dissipation, part of which took place very rapidly when the underlying soil layer had a large hydraulic conductivity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seismic screening software is developed for existing buildings in Canada on the basis of the requirements of 2010 National Building Code of Canada. The software is based on the 'Manual for Screening of Buildings for Seismic Investigation,' published by the National Research Council of Canada in 1992. The new software incorporates updated seismicity and soil classifications used in the National Building Code of Canada (NBCC) since 2005, as well as the new ductility and over-strength factors specified in the 2010 NBCC. The uniform hazard spectrum values of the current Canadian seismicity, defined for each municipality in Canada with a 2500 year earthquake return period, are used as reference hazard values. Seismic risk associated with the use of older seismic hazard values specified in older editions of the NBCC is identified relative to the current reference seismicity. The new site classifications are incorporated, while establishing relative soil amplification values between the new acceleration-based and velocity-based soil amplification factors and the foundation factors used in older codes. The new ductility and over-strength factors used in recent editions of the code are introduced in identifying different structural types with different toughness and energy dissipation capacities. The software can be used to conduct seismic screening of buildings located in different municipalities in Canada relative to the seismic requirements of NBCC-2010. It can also be used to generate tables for different locations in the country for manual screening of buildings. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To facilitate the design of seismic remediation for Tuttle Creek Dam in east central Kansas, a seismic finite difference analysis of the dam was performed using the software FLAC and the UBCSAND and UBCTOT soil constitutive models. The FLAC software has a key advantage because it can use calibrated site-specific constitutive models. Earlier deformation analyses using a hyperbolic constitutive model for the foundation fine-grained materials did not properly represent the modulus and strength reduction and predicted extremely large permanent deformations. Cyclic triaxial laboratory tests using high-quality samples and in situ vane shear tests were used to calibrate the FLAC constitutive model herein. The resulting FLAC analysis of the unremediated dam predicted an upstream slope toe deformation of about 0.6 m, a crest settlement of about 0.6 m, and a downstream slope toe deformation of about 1.5 m using the design ground motion. Based on the estimated permanent deformations and other factors, it was decided that the anticipated upstream slope and crest deformations were tolerable and only the downstream slope had to be remediated to protect the downstream seepage control system. [ABSTRACT FROM AUTHOR]

The Robertson and Wride method is the most widely used cone penetration test (CPT)-based method for soil liquefaction evaluation. This method is a deterministic model, which expresses liquefaction potential in terms of factor of safety. On many occasions, there is a need to express the liquefaction potential in terms of liquefaction probability. Although several probabilistic models are available in the literature, there is an advantage having a probabilistic version of the Robertson and Wride method so that the engineer who prefers to use this method can obtain additional information of liquefaction probability with minimal extra effort. In this paper, a simple model is developed, which links the factor of safety determined by the Robertson and Wride method to the liquefaction probability. The model, referred to as the probabilistic RW model, is developed, and verified, in a mathematically rigorous manner. Simplified equations for assessing the variation of liquefaction probability caused by the uncertainty in input parameters are also developed. Example applications are presented to demonstrate the developed models. [ABSTRACT FROM AUTHOR]

Farmers in the Mexicali Valley permanently face problems in the management of water from the Colorado River. The salinity of this river, the sediment swept along in its current from the United States, and the competition from subterranean streams seeping out of the All-American Canal represent management challenges for irrigators. The situation is even more complex than this because the irrigation area is located in a highly seismic zone. This study explores the management capacities of farm users to deal with these limitations on regional development, and the social and economic wellbeing of the inhabitants. It deals with cross-border issues that have a local impact on the efficiency, equity and sustainability of water use. An institutional analysis is carried out that makes it possible to characterize areas of conflict arising from the common use of a hydraulic resource. [ABSTRACT FROM AUTHOR]

Copyright of Revista Crítica de Ciências Sociais is the property of Centro de Estudos Sociais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In a flat plate structure, slab-column connections must possess sufficient drift capacity to survive the lateral deformation resulting from wind or earthquake. Partial debonding of the flexural reinforcement may be a means of increasing drift capacity of a slab-column structure. This article summarizes cyclic loading tests conducted on two full-scale interior slab-column connections, one with and one without partially debonded reinforcement. Each test specimen consisted of a 4.2 m square slab with a 355 mm square column protruding 1.5 m above and below the slab. The slab thickness was 152 mm. The specimen with partially debonded reinforcement exhibited more lateral drift capacity (4.5%) than did the specimen with fully bonded reinforcement (3.5%). The lateral load capacity of the debonded specimen was approximately 20% greater than that of the bonded control specimen. With partial debonding of the flexural reinforcement, cyclic load appeared to produce less damage to the connection in the vicinity of the slab-column joint. [ABSTRACT FROM AUTHOR]

Abstract: This work deals with the seismic activity felt in Algiers in the 18th century through a review of the French archives. These sources contain additional information on the different earthquakes that occurred during the Ottoman period, and on other events not reported before. We estimate that 64% out of the 50 earthquakes listed in this study, including aftershocks, are newly catalogued. Some destructive events occurred within a radius of less than 100km. They strongly shook the capital. Among them, the famous earthquake of 3 February 1716 near Algiers, a series of earthquakes that occurred in 1722 causing the destruction of the town of Miliana (90km southwest of Algiers). In 1760, a large part of the town of Blida (40km south) was destroyed. The city of Medea (60km south) was also affected in October 1790 by an earthquake that was hidden by the historic Oran earthquake that had occurred 15 days before. [Copyright &y& Elsevier]

Representative dynamic properties of municipal solid waste (MSW) are required to perform reliable seismic analyses of MSW landfills. A comprehensive large-scale cyclic triaxial laboratory testing program was performed on MSW retrieved from a landfill in the San Francisco Bay area to evaluate the small-strain shear modulus, and strain-dependent normalized shear modulus reduction and material damping ratio relationships of MSW. The effects of waste composition, confining stress, unit weight, time under confinement, and loading frequency on these dynamic properties were evaluated. The small-strain shear modulus depends primarily on waste composition, confining stress, unit weight, and time under confinement. The normalized shear modulus reduction and material damping curves for MSW depend on waste composition and confining stress. Based on the results of this study and a review of literature, strain-dependent shear modulus reduction and material damping relationships are recommended for use in landfill design. [ABSTRACT FROM AUTHOR]

This note describes a study on the seismic active earth pressure behind a nonvertical cantilever retaining wall using pseudo-dynamic analysis. A planar failure surface has been considered behind the retaining wall. The effects of soil friction angle, wall inclination, wall friction angle, amplification of vibration, and horizontal and vertical earthquake acceleration on the active earth pressure have been explored in this study. Unlike the Mononobe–Okabe method, which incorporates pseudo-static analysis, the present analysis predicts a nonlinear variation of active earth pressure along the wall. The results have been compared with the existing values in the literature. [ABSTRACT FROM AUTHOR]

The fundamentals of the energy concept to assess the liquefaction potential of cohesionless soils have been formulated in recent years. To examine the validity of this procedure, a series of centrifuge liquefaction tests were carried out using the same soils that were tested previously as part of extensive research conducted on the subject at Case Western Reserve University. A total of 30 liquefaction tests at accelerations of 50g and 60g were conducted on scaled pore fluid saturated models, prepared in a laminar box, representing a prototype soil deposit. The influence of relative density and effective confining pressure, as well as the effect of different grain size distribution on the energy per unit volume required for liquefaction, is studied. Generalized relationships were obtained by performing regression analyses between the energy per unit volume at the onset of liquefaction and liquefaction affecting parameters. These equations are compared with similar ones that were developed previously using torsional shear tests. A rational procedure to determine site response to earthquake loading and liquefaction susceptibility of a soil deposit is verified. [ABSTRACT FROM AUTHOR]

Given sufficient anchorage to the diaphragms, out-of-plane walls in unreinforced masonry (URM) buildings have been shown to crack above midheight and then rock as two rigid bodies. This study investigates the sensitivity of the rocking response to the type of ground motion and the quality of the wall construction. Shake table tests were conducted on four full-scale multi-wythe walls, all with a height to thickness (h/t) ratio of 12 but of varying construction quality and subjected to three different ground motions. All walls experienced cracking at less than one half of the 2005 National Building Code of Canada (NBCC) level for Vancouver, but exhibited a stable rocking behaviour without collapse beyond a ground motion 1.5 times the 2005 NBCC level. [ABSTRACT FROM AUTHOR]

Cartago city is vulnerable to seismic events, river floods, and many landslides. This work intends to evaluate those risks. [ABSTRACT FROM AUTHOR]

Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure during earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects the failure surface, the shear or axial strength of the column begins to degrade. This paper introduces a uniaxial material model that incorporates the failure surfaces and the subsequent strength degradation. When used in series with a beam-column element, the uniaxial material model can adequately capture the response of reinforced concrete columns during shear and axial load failure. The performance of the analytical model is compared with results from shake table tests. [ABSTRACT FROM AUTHOR]

Copyright of Building Research & Information is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the seismic (shake table) tests conducted on bookcase – partition wall systems. These nonstructural building components can be considered acceleration sensitive (or motion sensitive) rather than drift sensitive. The shake table floor motions used for the seismic testing are described in a companion paper. One bookcase fully loaded with books and two different cantilevered partition wall systems were considered in the shake table tests. Nine different configurations of these free-standing nonstructural building components were tested. For each configuration, three different seismic hazard levels were considered for the motions at the second floor level of a six-storey building designed for two different densely populated Canadian cities (Montréal and Vancouver). A total of 485 shake table tests were conducted in this experimental investigation. The experimental results indicated that pounding between unanchored bookcases and partition walls is very beneficial to the dynamic response of the bookcases, as it prevents resonance from occurring. Also, the seismic performance of bookcases improved dramatically by the proper installation of seismic restraint systems. Experimental fragility curves for overturning of tall bookcases are presented. [ABSTRACT FROM AUTHOR]

The problem of finding the horizontal pullout capacity of vertical anchors embedded in sands with the inclusion of pseudostatic horizontal earthquake body forces, was tackled in this note. The analysis was carried out using an upper bound limit analysis, with the consideration of two different collapse mechanisms: bilinear and composite logarithmic spiral rupture surfaces. The results are presented in nondimensional form to find the pullout resistance with changes in earthquake acceleration for different combinations of embedment ratio of the anchor (λ), friction angle of the soil (φ;), and the anchor-soil interface wall friction angle (δ). The pullout resistance decreases quite substantially with increases in the magnitude of the earthquake acceleration. For values of δ up to about 0.25–0.5φ, the bilinear and composite logarithmic spiral rupture surfaces gave almost identical answers, whereas for higher values of δ, the choice of the logarithmic spiral provides significantly smaller pullout resistance. The results compare favorably with the existing theoretical data.Key words: anchors, earthquakes, failure, limit analysis, sands.Dans la présente note, on aborde le problème de détermination de la capacité d'arrachement des ancrages verticaux enfouis dans le sable, en incluant les forces de masse horizontales sismiques pseudo-statiques. L'étude a été réalisée au moyen de l'analyse pour les limites supérieures, et en considérant deux mécanismes différents d'effondrement comprenant des surfaces de rupture bilinéaires et composites de spirale logarithmique. Les résultats sont présentés dans une forme non dimensionnelle pour trouver la résistance à l'arrachement avec des changements dans l'accélération du séisme pour différentes combinaisons du rapport d'enfouissement (λ) de l'ancrage, de l'angle de frottement (φ) du sol, et de l'angle de frottement (δ) de l'interface ancrage-sol du mur. La résistance à l'arrachement diminue de façon très substantielle avec les augmentations de la magnitude de l'accélération sismique. Pour des valeurs de δ jusqu'à environ 0,25–0,5φ, les surfaces de rupture bilinéaires et composites de spirale logarithmique ont donné des réponses presque identiques, alors que pour des valeurs plus élevées de δ, le choix de la spirale logarithmique fournit une résistance à l'arrachement significativement plus faible. Les résultats se comparent favorablement avec les donnée théoriques existantes.Mots clés : ancrage, séismes, rupture, analyse limite, sables.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The method of characteristics was used to generate passive earth pressure coefficients for an inclined wall retaining cohesionless backfill material in the presence of pseudostatic horizontal earthquake body forces. The variation of the passive earth pressure coefficients K[sub pq] and K[sub pγ] with changes in horizontal earthquake acceleration coefficient due to the components of soil unit weight and surcharge pressure, respectively, has been obtained; a closed-form solution for K[sub pq] is also provided. The passive earth resistance has been found to decrease sharply with an increase in the magnitude of horizontal earthquake acceleration. The computed passive earth pressure coefficients were found to be the lowest when compared to all of the previous solutions available in the literature.Key words: earth pressures, earthquakes, method of characteristics, retaining walls, sands.La méthode des caractéristiques a été utilisée pour générer les coefficients de butée pour un mur incliné soutenant un matériau de remblai pulvérulent en présence de forces horizontales pseudo-statiques simulant l'effet de séisme et proportionnelles au poids du matériau. On a obtenu la variation des coefficients de butée K[sub pq] et K[sub pγ] , due aux composantes du poids volumique du sol et de la pression de la surcharge respectivement, en fonction des changements dans le coefficient d'accélération horizontale du séisme; une solution exacte pour K[sub pq] est aussi fournie. On a trouvé que la résistance en butée diminue de façon abrupte avec l'accroissement de l'amplitude de l'accélération horizontale séismique. On trouve que les coefficients de butée sont plus faibles que toutes les solutions disponibles dans la littérature. Mots clés : pressions des terres, séismes, méthode des caractéristiques, murs de soutènement, sables.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This paper describes the seismic behaviour of chevron steel braced frames for 2-, 4-, 8-, and 12-storey steel building structures. Two different design approaches were considered: one that corresponds to current CSA-S16.1 seismic provisions for braced frames with nominal ductility with an R factor of 2.0, and one in which the beams are sized to develop a fraction of the yield tension capacity of the bracing members. In this second approach, an R factor of 3.0 was used for determining the seismic loads and chevron bracing with stronger beams capable of developing 100%, 80%, and 60% of the brace yield load were examined. The results show that current S16.1 provisions for chevron braced frames may lead to systems that are prone to dynamic instability for 4-storey and taller structures. Chevron bracing with stronger beams exhibits a more stable inelastic response and can be used for structures up to 8 storeys in height. For 2- and 4-storey buildings, chevron braced frames with beams designed to develop only 60% of the brace yield resistance can be used. The analyses also show that the force demand in brace connections, beams, and columns as determined from capacity design provisions agree well with that anticipated under strong ground motions.Key words: earthquakes, seismic design, steel, structures, braced frames, bracing members, beams, columns, connections.Cet article décrit le comportement sismique de contreventements en treillis avec diagonales en chevron utilisés dans la charpente d'acier de bâtiments de 2, 4, 8 et 12 étages. Deux approches de conception ont été considérées : l'une qui suit les dispositions actuelles de la norme CSA S16.1 pour les contreventements à ductilité nominale et l'autre où les poutres sont conçues pour résister aux efforts engendrés lorsque l'effort dans la diagonale tendue atteint une fraction de sa limite élastique. Pour la seconde méthode, on a considéré un coefficient R égal à 3,0 pour le calcul des charges sismiques et on a étudié des contreventements dont les poutres pouvaient reprendre des efforts correspondant à un effort dans les diagonales tendues égal à 100%, 80% et 60% de leur limite élastique. Les résultats montrent que les contreventements de 4 étages et plus peuvent subir de grandes déformations latérales et être sujets à une instabilité dynamique lorsque conçus selon la norme S16.1 actuelle. Les contreventements avec poutres pouvant soutenir la plastification des diagonales tendues ont un comportement plus stable et peuvent être utilisés dans des structures jusqu'à 8 étages. Pour des bâtiments de 2 et 4 étages, on peut utiliser des poutres conçues pour un effort dans les diagonales tendues égal à 60% de leur résistance plastique. Les analyses dynamiques démontrent également que les efforts dans les assemblages des diagonales, dans les poutres et dans les poteaux tels, qu'obtenus d'un calcul par capacité, correspondent bien aux efforts que l'on peut anticiper lors d'un séisme important.Mots clés : séismes, conception parasismique, acier, structures, contreventements en treillis, diagonales, poutres, poteaux, assemblages. [ABSTRACT FROM AUTHOR]