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The site amplification factors in the 2015 edition of the National Building Code of Canada (NBCC 2015) for South Western British Columbia (SWBC) were developed using only the single site term associated with the ground motion prediction equation (GMPE) for crustal sources. The seismic hazard in SWBC is derived from three source types; crustal, subduction intraplate, and subduction interface sources. Therefore site factors based only on a crustal site term are approximate. This study was conducted to assess the degree of approximation. Alternative site amplification factors for Vancouver and Victoria, British Columbia were calculated using site specific look-up tables incorporating all the GMPEs associated with each seismic source type and their associated site terms. The alternative site factors are significantly greater than those given in NBCC 2015 for periods 0.3 s, 0.5 s, and 1.0 s. These results suggest that the process for calculating site amplification factors should be reassessed by the committee currently reviewing seismic hazard for NBCC 2020. Key words: uniform hazard spectrum, ground motion prediction equation, 2015 national building code of Canada, site effects, site amplification factor. Les facteurs d'amplification de site dans l'edition du Code national du batiment du Canada de 2015 (NBCC 2015) pour le sud-ouest de la Colombie-Britannique ont ete developpes en utilisant seulement le terme de site unique associe a l'equation previsionnelle des mouvements de sol (GMPE) en fonction des sources crustales. L'alea sismique au sud-ouest de la ColombieBritannique provient de trois types de sources, dont les sources crustales, de subduction intraplaque et de subduction d'interface. Par consequent, les facteurs de site etablis seulement en fonction d'un terme de site crustal sont approximatifs. On a mene cette etude afin d'evaluer le degre d'approximation. D'autres facteurs d'amplification de site pour Vancouver et Victoria en Colombie-Britannique ont ete calcules en utilisant des tables de recherche propres au site prenant en compte toutes les GMPE associees a chaque type de source sismique et leurs termes de site connexes. Les facteurs de site de rechange calcules sont considerablement plus eleves que ceux fournis dans le NBCC 2015 pour des periodes de 0,3 s, 0,5 s et 1,0 s. Les resultats laissent entendre que le processus de calcul des facteurs d'amplification de site devrait etre reexamine par le comite actuellement charge de faire le point sur l'alea sismique en vue du Code national du batiment du Canada de 2020. [Traduit par la Redaction] Mots-cles: spectre de danger uniforme, equation previsionnelle des mouvements de sol, Code national du batiment du Canada de 2015, effet de site, facteur d'amplification de site., Introduction and context The National Building Code of Canada released updated seismic hazard maps in 2015 (NBCC 2015) based on an updated seismic catalogue, revised seismic sources, and new ground [...]

The most commonly used program for the analysis of piles under static lateral loading is LPILE. The program uses the nonlinear Winkler springs recommended by the American Petroleum Institute (API) to model soil-pile interaction. The p-y (load-displacement) curves were developed from field tests, with pile diameters in the range 0.324-0.67 m. When these p-y curves are used to analyze load tests on piles with larger diameters, the computed load-deflection curves underestimate the stiffnesses of the test piles. This effect is referred to as the pile diameter effect. In this technical note, a very different approach is presented to evaluate the pile diameter effect. Both LPILE and a continuum-based finite element program VERSAT-P3D were calibrated to closely simulate the results of two lateral load tests on small-diameter piles at two different sites. VERSAT-P3D modelled the volume of the pile and LPILE did not. Each program was used to develop p-y curves for increasingly larger pile diameters up to 2.0 m. An important finding for practice is that there was no pile diameter effect for displacements up to 60 mm. LPILE can be used with confidence in practice in this displacement range. Thereafter, the load-deflection curves from LPILE became softer and the pile diameter effect became evident. Key words: soil-pile interaction, pile diameter effect, calibrating load-displacement (p-y) curves, continuum modelling of piles, coping with pile diameter effect. Le programme le plus frequemment utilise pour analyser le comportement de pieux soumis a un chargement statique lateral est appele LPILE. Ce programme utilise les ressorts non lineaires de Winkler, comme le recommande l'American Petroleum Institute (API), pour modeliser les interactions sol-pieux. Les courbes p-y (chargement-deplacement) ont ete tracees a l'aide de donnees obtenues lors d'essais realises sur le terrain sur des pieux de diametre compris entre 0,324 et 0,67 m. Lorsque ces courbes p-y sont utilisees pour analyser les essais de chargement realises sur des pieux de plus grand diametre, on constate que les courbes chargement-deflexion calculees sous-estiment la rigidite des pieux experimentaux. Cet effet est appele <>. Dans le present article, une methode tres differente est presentee, qui permet d'evaluer cet effet. Le programme LPILE et un programme base sur la methode des elements finis en milieu continu, VERSAT-P3D, ont ete calibres pour pouvoir simuler avec precision les resultats de deux essais de chargement lateral effectues sur des pieux de petit diametre installes sur deux sites differents. Contrairement au programme LPILE, le programme VERSAT-P3D a permis de modeliser le volume des pieux. Chaque programme a servi a tracer des courbes p-y pour des pieux de diametre de plus en plus important, pouvant atteindre 2.0 m. On a constate l'absence d'effet de diametre de pieu dans le cas de deplacements inferieurs ou egal a 60 mm, une decouverte interessante sur un plan pratique. On peut donc sans hesiter mettre en pratique LPILE pour de tels deplacements. Par la suite, les courbes chargement-deflexion tracees a l'aide de LPILE se sont lissees et l'effet de diametre de pieu est devenu evident. [Traduit par la Redaction] Mots-cles: interaction sol-pieu, effet de diametre de pieu, calibrage des courbes chargement-deplacement (p-y), modelisation de pieux en milieu continu, prise en compte de l'effet de diametre de pieu., Introduction The most commonly used program for the analysis of piles under static lateral loading is LPILE (Ensoft Inc. 2012). The program uses nonlinear Winkler springs to model soil-pile interaction: [...]

The lateral response of piles embedded in soil is typically analyzed using the beam on nonlinear Winkler springs approach, in which soil-pile interaction is modeled by nonlinear p-y curves (where p is soil resistance and y is horizontal displacement). In this approach, one of the most common methods of accounting for interaction effects in pile groups is to modify the single pile p-y curves using a p-multiplier for each row of piles in the group, with higher values for leading row and lower values for trailing rows. The leading and trailing rows interchange during seismic loading; therefore, sometimes an average p-multiplier is used for all piles in the group. This average p-multiplier is called the group reduction factor. Group reduction factors have been established from experimental data from static loading tests on small pile groups, mostly 3 x 3 groups with free pile head conditions and center-to-center pile spacings of about 3 pile diameters. In this paper, continuum simulations are used to study the group reduction factors in 3x3 to 6x6 square pile groups subjected to static loading. The study includes the effects of various parameters, including pile spacing, pile head condition, and the friction angle of soil, on the group reduction factors. Calculated group reduction factors from this study compare well with available group test data, that is, typically small pile groups. However, the study shows that design guidelines such as the American Association of State Highway and Transportation Officials (AASHTO) and Federal Emergency Management Agency (FEMA) P-751 overestimate the group reduction factors, hence the lateral resistance, in larger pile groups and larger spacings, especially for fixed pile head conditions. Key words: pile group, p-y method, group reduction factor, soil-pile interaction, continuum model. La reponse laterale de pieux enfouis dans un sol est generalement analysee a l'aide de l'approche non lineaire d'une poutre sur des ressorts de Winkler, dans laquelle l'interaction pieu-sol est modelisee par des courbes p-y non lineaires. Dans cette approche, une des methodes les plus courantes pour considerer les effets d'interaction dans les groupes de pieux est de modifier les courbes p-y pour un pieu unique avec un multiplicateur-p pour chaque rangee de pieux dans le groupe, en assignant des valeurs plus elevees pour la rangee principale et des valeurs plus faibles pour les rangees suivantes. La rangee principale et les autres rangees s'echangent durant des sollicitations sismiques; alors parfois un multiplicateur-p moyen est utilise pour tous les pieux dans un meme groupe. Ce multiplicateur-p moyen est appele le facteur de reduction du groupe. Des facteurs de reduction du groupe ont ete etabli a partir de donnees experimentales provenant d'essais en chargement statique sur des petits groupes de pieux, principalement des groupes 3x3 dont la tete des pieux est libre et l'espacement du centre au centre des pieux est d'environ 3 fois le diametre des pieux. Dans cet article, des simulations continues sont utilisees pour etudier les facteurs de reduction du groupe dans des groupes 3x3 a 6x6 soumis a des sollicitations statiques. L'etude inclut les effets de plusieurs parametres, incluant l'espace entre les pieux, la condition de la tete du pieu, et l'angle de friction du sol, sur les facteurs de reduction du groupe. Les facteurs de reduction du groupe calcules dans cette etude se comparent bien avec les donnees disponibles sur les essais de groupe, generalement realises sur des petits groupes de pieux. Cependant, l'etude demontre que les criteres de conception comme American Association of State Highway and Transportation Officials (AASHTO) et Federal Emergency Management Agency (FEMA) P-751 surestiment les facteurs de reduction du groupe, et consequemment la resistance laterale, dans les grands groupes de pieux et dont l'espacement est grand, particulierement dans des conditions ou la tete des pieux est fixe. [Traduit par la Redaction] Mots-cles: groupe de pieux, methode p-y, facteur de reduction du groupe, interaction sol-pieu, modele continu., Introduction The lateral response of piles is typically analyzed using the beam on nonlinear Winkler springs model. The nonlinear springs are based on the p-y curves (where p is soil [...]

Abstract: This paper presents a comparison of the two main regional damage estimation methodologies currently in use, namely the modified Mercalli intensity (MMI) based approach and the spectral parameter based [...]

The 1996 Duvall earthquake in Washington State triggered ground motion stations in the Fraser Delta, British Columbia, located on varying depths of Holocene and Pleistocene soils to a maximum depth of 800 m and one station on bedrock. Recorded ground motions were used to examine the applicability of 1-D and 2-D site response analyses for amplification studies in the Delta. 1-D response analysis gave a good indication of the period of peak response. Response spectra computed by 1-D analysis did not compare well with recorded spectra except at very deep sites. The use of 2-D analyses to include buried topography generally improved the predictions of site response spectra at the shallow sites. However, for the shallow earth sites, the recorded motions showed a strong spectral response at short periods in the range of 0.1–0.25 s. Neither 1-D nor 2-D analysis predicted this response. [Copyright &y& Elsevier]

Presents a study that examined foundation factors in seismic codes to capture the amplification effects of local soil conditions on ground motions. Review of developments in categorizing site conditions for seismic codes; Analysis of approaches to foundation factors; Implications of the results for the proposed 2005 edition of the National Building Code of Canada.

The state of the art for evaluating the potential for the occurrence of liquefaction in saturated sands and silts under earthquake shaking is presented for level ground conditions which is the most common situation in engineering practice. The latest liquefaction assessment charts based on data from various penetration tests and on in situ shear wave velocity are presented. All these standard charts are for level ground, earthquake moment magnitude MW=7.5 and effective confining stress of 100 kPa. The latest correction factors required to make the findings from the charts applicable for other magnitudes and confining pressures are presented and critically reviewed. [Copyright &y& Elsevier]