Time-of-flight modeling of transversal ultrasonic scan of wood

Time-of-flight is a time for an ultrasonic pulse to cross a sample. It contains valuable information about the mechanical properties of a material. For the ultrasonic pulse propagating in wood perpendicular to the grain the relation between the time-of-flight and the elastic constants is rather complex due to the strong anisotropicity of wood....

Influence of material deterioration on strength properties of hydraulic timber structures

Hydraulic timber structures such as mooring poles, fenders, lock gates and jetties are widely-used in inner and sea harbours all over the world. In general these structures give satisfactory performance with regard to the technical requirements. Because of the harsh exposure conditions such as brackish and contaminated water, drying-out,...

Applicability of various wood species in glued laminated timber: Parameter study on delamination resistance and shear strength

In a current research project the gluability of four European timber species and their applicability in glued laminated timber is investigated. The influence of different processing parameters on the adhesive bonding is assessed with regard to shear strength and delamination resistance. Furthermore, microscopy-based investigations revealed...

Lateral behavior of post-tensioned cross laminated timber walls using finite element analysis

Cross laminated timber (CLT) has been rapidly developed and utilized for multi-rise constructions in recent years, even high-rise CLT buildings with 40 stories have been proposed and designed. A use of unbonded post-tensioning (PT) steel bars through over CLT walls of the high-rise CLT buildings to take up the tensile forces produced by wind...

Load carrying capacity of large mortise and tenon joints in wooden mitre gates

Wooden mitre gates are used for centuries in waterways and canals. For newly built as well as the renewal of such gates, a number of wood species is used, ranging from oak to dense tropical hardwoods. As mitre gates have high loads to withstand, their strength verification has become more and more important. As strength verification rules for...

Safety of timber: An analysis of quality control options

The quality assurance of timber properties is important for the safety of timber structures. In the current study, the quality control options of timber are analysed under the prism of the different growth regions. Therefore, these options - machine and output control - are simulated in accordance with EN 14081, and the performance is assessed...

Strength grading of timber in Europe with regard to different grading methods

Structural timber in Europe is either graded visually or by machine. Both grading methods are applied to limit the variation in engineering properties of sawn timber. The obtained grading results are largely dependent on the method chosen. In addition, parameters such as species, source, and cross-section of the timber, as well as the applied...

The importance of characterisation and sampling of tropical wood species with regard to strength and durability classification

Strength class assignments and durability class assignments of wood species to be used in structures are necessary to make it possible for the engineer to design safe and durable timber structures. As a result of sustainable managed forests, more tropical wood species with relative small batch size, are coming on the market. In Europe, strength...

Comparison of design rules for glued-in rods and design rule proposal for implementation in European standards

Material model for wood

Wood is highly anisotropic and shows ductile behaviour in compression and brittle behaviour in tension and shear where both failure modes can occur simultaneously. A 3D material model for wood based on the concepts of continuum damage mechanics was developed. A material subroutine containing the developed model was implemented into a standard FE...

Comparison of theoretical and experimental determination of deformations of timber façade elements against wind load

The current practice is that the deformations of timber façade elements are determined by testing, or they are limited by prescribing dimensions in a very conservative way. To use generic calculation models, suitable for almost all types of windows, approximations deviating from the actual behaviour have to be done. This paper investigates if a...

Pre-grading of Douglas-fir logs for glulam lamella production

Development of a high-capacity engineered wood product-LVL made of European beech (fagus sylvatica l.)

Brittleheart as a critical feature for visual strength grading of tropical hardwood: Approach of detection

Constitutive model for wood based on continuum damage mechanics

Classification and sampling of tropical wood species for strength and durability assignments

End-of-life wood quality of mooring poles