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Corrigendum to “Numerical and analytical assessment of the buckling behaviour of Blockhaus log-walls under in-plane compression” [Eng. Struct. 82 (2015) 134–150]

The paper investigates the seismic response of Blockhaus shear walls under in-plane lateral loads. As known, the typical Blockhaus systems consists in a series of timber structural elements stacked horizontally once upon each other and interacting by means of traditional timber joints based on the effectiveness of carvings and contacts of multiple surfaces. Native of forested areas, Blockhaus systems are widely used in daily practice for the construction of wooden houses also in earthquake-prone regions. However, the seismic characterization of this construction system currently requires further investigations and studies. In order to assess the vulnerability of the examined structural typology, Finite-Element numerical investigation on log-haus timber walls subjected to in-plane lateral loads are performed by means of a computationally effective FE-model derived from earlier research contributions. In it, non-linear hysteretic springs implemented in ABAQUS/Standard and validated to cyclic experiments of single joints are used to describe the joint behaviour. Parametric cyclic investigations are first presented, in order to highlight the effects of multiple geometrical and mechanical aspects on the in-plane cyclic response of single log-walls. Refined non-linear dynamic analyses are then proposed for a significant set of configurations characterized by different geometrical properties and applied vertical loads, and preliminary estimations for the q-behaviour factor are presented.

Blockhaus structural systems are obtained by assembling multiple timber logs able to interact with each other by means of simple mechanisms (e.g. contacts, tongues and grooves, and carpentry joints, also referred to as ‘corner’ joints). Although these systems have ancient origins, the structural behaviour of Blockhaus systems under well-defined loading and boundary conditions is still complex to predict. The paper focuses on the assessment of the typical buckling behaviour and resistance of in-plane compressed timber log-walls. The effects of various mechanical and geometrical aspects such as in-plane rigid inter-storey floors, load eccentricities, different types of lateral restraints, openings (e.g. doors or windows) or additional metal stiffeners, are investigated by means of full-scale buckling experiments. Results are then critically discussed and preliminarily assessed via analytical formulations taken from classical theory of plate buckling and column buckling. Although further advanced studies are required for the development of a generalized buckling design method, it is shown that several mechanical and geometrical aspects should be properly taken into account to correctly predict the structural capacity of Blockhaus systems under in-plane compression.

Blockhaus structural systems are commonly obtained by assembling multiple timber logs, by stacking them horizontally on the top of one another. Although based on simple mechanisms of ancient origins, the structural behaviour of Blockhaus systems under well-defined loading and boundary conditions is complex to predict. The paper focuses on the assessment of the typical buckling behaviour and resistance of vertically compressed timber log-walls. The effects of various mechanical and geometrical variables such as possible load eccentricities and initial curvatures, openings (e.g. doors or windows), fully flexible or in-plane rigid inter-storey floors are investigated by means of detailed finite-element (FE) numerical models. These FE models were first validated on test results of past buckling experiments performed on scaled log-wall specimens, as well as on recent buckling experiments carried out on full-scale timber log-walls, demonstrating the capability to appropriately describe the effective interaction between timber logs and to correctly predict the expected buckling failure mechanisms and ultimate resistance for the log-walls that were investigated. Comparisons with analytical solutions partly derived from classical theory of plate buckling and column buckling are also presented and critically discussed, in order to assess the applicability of these existing formulations – although specific for fully monolithic and isotropic plates and columns – to Blockhaus structural systems. A closed-form solution is finally proposed as a simplified design buckling method for timber log-walls under in-plane compression.

Blockhaus systems represent a traditional construction technology where structural resistance is attained by direct contact between multiple timber surfaces obtained via carvings, notches, and ancient carpentry joints. Although this technology is frequently used in practice for the construction of buildings (Fig.1), due to the complexity of various phenomena (loading perpendicular to the grain, effect of friction, influence of gaps in the joints, creep, etc.), their structural behavior under specific loading/boundary conditions is not completely known. The interaction between multiple logs, as well as the restraint effectiveness of carpentry timber joints and the anisotropy of timber, can strongly affect the load-carrying capacity of these structural systems [1][2][3][4]. The paper focuses on the assessment of the typical buckling behavior and resistance of vertically compressed timber-log walls. The effects of various mechanical and geometrical variables such as possible geometrical imperfections, openings (e.g. doors or windows), fully flexible or in-plane rigid inter-storey floors are investigated by means of advanced finite-element (FE) numerical models [5] validated on experimental results. Comparisons with analytical solutions are presented and critically discussed, in order to assess the applicability of existing formulations to Blockhaus structural systems. Finally, a simplified design approach suitable for implementation in the new Eurocode 5 is proposed for the stability check of timber log-walls under in-plane compressive loads.