Timber shear walls with large openings: experimental and numerical prediction of the structural behaviour

Abstract

A numerical model based on the finite element method is presented for prediction of the cyclic response of wood frame structures. The model predicts the cyclic response of shear walls. Nonlinear phenomena are assumed to be concentrated in the connections that are modelled through elements linking the structural elements including the posts, beams, and sheathing panels. Identification of model parameters relies on tests on individual connections. Connection tests on different nail lengths were conducted under monotonic and cyclic lateral loads. Based on the results from past studies that indicate the pull-through failure is an important failure mode in common nail connections with lumber and oriented strand board (OSB), washers were considered as a means to reinforce the connection. The influence of reinforced nailing on the static and dynamic performance of full-size wood frame shear walls with large openings, sheathed with OSB panels, was evaluated experimentally. Combinations of parameters were studied, such as the number of holddowns, the panel shapes, the nail distribution, and the bracing systems. Comparisons of the dissipated energy per cycle revealed a higher capacity for walls using nails with washer reinforcement than without. Results from numerical simulations of the monotonic and cyclic tests performed on the walls are presented.Résumé : Une approche fondée sur la méthode des éléments finis est proposée pour la prédiction de la résistance de structures bois sous chargement monotone et cyclique. Les phénomènes de dégradation sont supposés concentrés dans les assemblages reliant les éléments structuraux. L'identification des paramètres de la méthode repose sur des essais de connections. L'étude de connections par clous lisses entre des poutres et des panneaux d'OSB permit de mettre en évi-dence un mode de rupture par perforation des plaques. L'ajout de rondelles permet de limiter ce phénomène. Des connections par pointes lisses, renforcées ou non par des rondelles, connectant un panneau d'OSB avec une poutre en bois furent testées en cisaillement sous chargement monotone et cyclique. L'influence des connections renforcées sur les performances statiques et dynamiques de murs contreventés par des panneaux d'OSB et incluant une très grande ouverture est évaluée expérimentalement. Les combinaisons des paramètres tels que le nombre de tirants d'ancrage, la forme des panneaux, la distribution des clous ainsi que le rajout d'une poutre diagonale furent étudiées. La comparaison de l'énergie dissipée par cycle révéla une meilleure capacité pour les murs renforcés. Les simulations numériques des tests effectués sur les murs sont présentées (essais monotones et cycliques).Mots clés : éléments finis, ossature bois, contreventement, connexions, énergie dissipée. Richard et al. 724

Analytical Model for Sheathing-to-Framing Connections in Wood Shear Walls and Diaphragms

“…A number of specialized structural analysis programs for wood shear walls have been developed based on the understanding that the overall lateral behavior is dominated by the individual behavior of sheathing-to-framing connections (Tuomi and McCutcheon 1978;Kuo 1985, 1987;Filiatrault 1990;Dinehart and Shenton 2000;Folz and Filiatrault 2000;Richard et al 2002). In these structural analysis programs, sheathing-to-framing connections are represented using a single nonlinear spring or a pair of orthogonal nonlinear springs.…”

Numerical analysis on seismic resistance of a two-story timber-framed structure with stone and earth infill

“…Both of them have been tested by Vieux-Champagne et al (2014b) in an experimental setup consisting only of one horizontal beam and one post connected by the steel strip. Such a modeling approach is classical for timber-framed structures (Andreasson, Yasumura, and Daudeville 2002, Yasumura et al 2006, Richard et al 2002, Xu and Dolan 2009. Both the nonlinearity in the diagonals and in the steel strip are described by a non linear constitutive law (Humbert et al 2014).…”

Parametric Evaluation of Racking Performance of Platform Timber Framed Walls

“…In the PD 6693-1 document, in order to limit the racking deflection of a wall, a stiffness criterion has been introduced and to suit the format used in this paper it has been re-arranged and is given in Eq. (9). In accordance with the functions used in PD 6693-1, this empirical relationship can be expressed in terms of the design racking load, P U LS , of the wall at the Ultimate Limit State (ULS), where:…”

“…In particular, dynamic [3,4,5,6] and cyclic load [7,8,9,10,11] testing: aimed at providing a better understanding and characterisation of the wall behaviour under the effect of seismic actions. Quasi-static monotonic testing, has been used to assess the influence of various parameters, such as the presence and size of openings [8,9,12], the type of fixing being used for the panel-to-frame connections (i.e. nails or staples [13]) and the use of reinforcements [14,15].…”