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Accurate growth and yield projection for plantations is critical for evaluating management decisions and anticipating future yields. Development of site index (SI) models is often costly and can be problematic when new, short-rotation species are introduced, for example, hybrid poplar plantations, which are increasingly common due to their very fast growth and high productivity. Airborne laser scanning (ALS) allows accurate measurement of tree and stand height and is increasingly being used to develop top height models. In this paper, we demonstrate an approach to develop SI models from ALS data across hybrid poplar plantations in Quebec, Canada. We exploit a single time step ALS acquisition to generate top height estimates at 10 m grid level. Using existing information on planting date and management practices, we developed top height models for unique classes of fertilization treatment and clone. The generic models for unfertilized and fertilized stands showed good fit statistics, with [R.sup.2] of 0.71 and 0.82, respectively. Clone-specific models showed similar goodness of fit, with the best model resulting in an [R.sup.2] of 0.89 and relative root mean square error (RMSE) of 16.6%. Analysis of variance (ANOVA) results showed that clone, fertilization status, and the interaction term between clone and fertilization were significant. Our results confirm the development of top height models from a chronosequence of ALS data was successful and offers a new approach to derive SI models in single-species plantation sites. Key words: hybrid poplar, Populus, forest productivity, lidar, site index, plantations, fertilization Une projection precise de la croissance et du rendement des plantations est essentielle si on veut evaluer les decisions de gestion et anticiper les rendements futurs. Le developpement de modeles d'indice de site (IS) est souvent couteux et peut poser des problemes lorsque de nouvelles especes a rotation courte sont introduites, par exemple les plantations de peupliers hybrides, qui sont de plus en plus courantes en raison de leur croissance tres rapide et de leur productivite elevee. Le balayage laser aeroporte (Airborne laser scanning ou ALS) permet de mesurer avec precision la hauteur des arbres et est de plus en plus utilise pour developper des modeles de hauteur de cime. Dans cet article, nous presentons une approche permettant de developper des modeles d'IS a partir de donnees ALS dans des plantations de peupliers hybrides au Quebec, Canada. Nous utilisons une acquisition ALS unique pour generer des estimations de la hauteur de la cime a un niveau de grille de 10 m. En utilisant les informations existantes sur la date de plantation et les pratiques de gestion, nous avons developpe des modeles de hauteur de cime pour des classes uniques de traitement de fertilisation et de clone. Les modeles generiques pour les peuplements non fertilises et fertilises ont montre de bonnes statistiques de correspondance, avec un [R.sup.2] de 0,71 et 0,82, respectivement. Les modeles specifiques aux clones ont montre une qualite comparable de correspondance, le meilleur modele ayant donne un [R.sup.2] de 0,89 et un RMSE relatif de 16,6%. Les resultats de l'analyse de la variance (ANOVA) ont montre que le clone, le statut de fertilisation et le terme d'interaction entre le clone et la fertilisation etaient significatifs. Nos resultats confirment que le developpement de modeles de hauteur de cime a partir d'une chronosequence de donnees ALS a ete couronne de succes et offre une nouvelle approche pour deriver des modeles IS dans des sites de plantation a espece unique. [Traduit par la Redaction] Mots-cles: peuplier hybride, Populus, productivite forestiere, lidar, indice de site, plantations, fertilisation, 1. Introduction Accurate information on forest attributes is crucial for sustainable forest management. Collected during forest inventories, this information is used to assess current as well as projected forest conditions [...]

Several major changes were introduced in the seismic design provisions of the 2005 edition of the National Building Code of Canada (NBCC). The lateral earthquake design force at the base and the lateral force distribution along the building height depend on the design spectra and on modification factors that, in most cases, require a large number of interpolations and calculations. This note presents a spreadsheet that facilitates determination of the 2005 NBCC seismic design forces from the equivalent static force procedure. Key words: 2005 National Building Code of Canada, seismic design, equivalent static force procedure, spreadsheet. Des changements majeurs ont ete introduits dans les clauses de calcul sismique du Code national du batiment Canada 2005 (CNB). L'estimation de la force de calcul sismique laterale agissant a la base du batiment et de la distribution des forces laterales depend d'un spectre de dimensionnement et de facteurs de modification qui necessitent dans la majorite des cas un grand nombre d' interpolations et de calculs. Cette note presente un tableur qui facilite la determination des efforts sismiques de dimensionnement selon la Methode Statique Equivalente du CNB 2005. Mots-cles : Code national du batiment du Canada 2005, conception parasismique, methode statique equivalente, tableur., Introduction Several major changes were introduced in the seismic design provisions of the 2005 edition of the National Building Code of Canada (NBCC 2005; NBCCC 2005). A summary of the [...]

ABSTRACT This article presents language for the analysis of structures (LAS). It is a development environment and a high-level language for learning matrix structural analysis, dynamics of structures, and the finite element method. LAS is a flexible learning environment in which users list pre-programmed commands in the right order to solve finite element static and dynamic problems. In addition to structural analysis commands, the language also includes powerful operators, conditional expressions, loop expressions, and several functions (matrix manipulations, linear algebra, direct stiffness assembly, modal analysis, time domain dynamic analysis, frequency domain dynamic analysis). The LAS environment includes an editor used to list the commands, a matrix manager, a graphics post-processor, and a Fourier-analysis tool. © 2015 Wiley Periodicals, Inc. Comput. Appl. Eng. Educ. 24:89-100, 2016; View this article online at ; DOI [ABSTRACT FROM AUTHOR]