Def

ser.fin (EC5, equation (2.12)) (2.40) where the functions are as previously defined and f 2 is the factor for the quasipermanent value of the action causing the largest stress in relation to the strength. If this is a permanent action, a value of 1 should be used. If the determination of f 2 is assessed to be a complicated or difficult exercise, a safe result will be obtained by adopting a value of 1 for the factor (see Table 2.2 for the value of f 2). (c) When undertaking a second-order...

Design Of Glued Composite Sections

Because these sections are designed to function as solid units, the strain is taken to vary linearly over their depth. However, as the value of the modulus of elasticity, E, of each material in the section will normally be different, the theory of bending cannot be directly applied. To analyse these sections the equivalent section approach (sometimes referred to as the modular ratio approach) can be is adopted and has been incorporated into the design procedure used in this chapter. In this...

Design Of Members Subjected To Axial Actions

5.3.1 Members subjected to axial compression These are members that are subjected to a compressive action acting parallel to the grain and along the centroidal x-x axis of the member, as shown in Figure 5.2. Such members function as columns, posts, stud members in walls or struts in pin jointed trusses. When a member is subjected to axial compression its failure strength is dependent on several factors strength stiffness - compressive strength and modulus of elasticity of the timber geometry of...

Design Of Stud Walls

In timber frame construction, the main functions of walls are to provide vertical support for floor and roof structures and strength and stability against the effects of lateral loading, generally caused by wind actions. The design of walls subjected to vertical loading and out of plane lateral actions, and where the sheathing is not designed to function compositely with the wall studs, is addressed in this chapter. The strength of stud walling in which the sheathing and the studs are designed...

Info

Note For strength-related calculations, take Gg,05 E0,g,05 16. Mean density is taken to be the average of the mean density of the inner and outer laminates, based on BS EN 338. * Based on the properties given in BS EN 1194 1999. Note For strength-related calculations, take Gg,05 E0,g,05 16. Mean density is taken to be the average of the mean density of the inner and outer laminates, based on BS EN 338. * Based on the properties given in BS EN 1194 1999. In BS EN 1194 examples are given of beam...

Info Tse

Equation (5.23) is valid for the condition where lateral torsional buckling will not occur, i.e. A.rel,m < 0.75, at which crit 1. For this situation the boundary condition for equation (5.23), based on the use of solid timber, LVL (or glulam) rectangular sections, will be as defined by the solid line in Figure 5.13. Where the relative slenderness ratio for bending exceeds 0.75, the EC5 strength criteria will be as given in 5.4.2. 5.4.2 Lateral torsional instability under the effect of bending...

Moment Behaviour In Timber Connections Rigid Model Behaviour

Validation of the strength of a connection required to transfer a moment in a structure is undertaken in two stages. There is the analysis of the structure to determine the stress resultants the connection will be subjected to and this is followed by the design procedure to demonstrate that the connection is strong enough to resist these forces. Unless a structure is statically determinate, depending on whether connections behave in a rigid or a semi-rigid manner, the force distribution in a...

Plywood

Plywood is a flat panel made by bonding together, and under pressure, a number of thin layers of veneer, often referred to as plies (or laminates). Plywood was the first type of EWP to be invented. Logs are debarked and steamed or heated in hot water for about 24 hours. They are then rotary-peeled into veneers of 2-4 mm in thickness and clipped into sheets of some 2 m wide. After kiln-drying and gluing, the veneers are laid up with the grain perpendicular to one another and bonded under...

Suspended Timber Flooring

A suspended flooring system generally comprises a series of joists closely spaced, being either simply supported at their ends or continuous over load-bearing partition walls. The floor boarding or decking is applied on the top of the joists and underneath ceiling linings are fixed. A typical suspended floor arrangement is shown in Figure 1.18a. The distance between the centres of the joists is normally governed by the size of the decking and ceiling boards, which are normally available in...

The Effective Number Of Fasteners In A Row In A Moment Connection

When a connection is subjected to a moment the direction of the force in each fastener in the connection will vary and where the fastener configuration is such that (a) no row exists where a force component from two or more fasteners in the row is parallel to the grain in any of the connected members, (b) or there are rows where the above situation will arise but the spacing between the fasteners parallel to the member grain complies with the criteria given in Table 12.2, the full number of...

Strength behaviour

Ring and shear-plate connectors are circular in shape and manufactured from aluminium alloy, hot rolled or temper rolled steel strip, hot rolled steel alloy strip, grey cast iron or cast metal, in accordance with the requirements of BS EN 912. They fit into preformed grooves in the timber members that accurately profile the connector and are capable of taking much greater loads than are achievable with toothed-plate connectors. The strength equations for these types of connectors are given in...

Structural Timber Design Examples

As stated in 4.3, Chapter 4, in order to verify the ultimate and serviceability limit states, each design effect has to be checked and for each effect the largest value caused by the relevant combination of actions must be used. However, to ensure attention is primarily focussed on the EC5 design rules for the timber or wood product being used, only the design load case producing the largest design effect has generally been given or evaluated in the following examples. Example 6.7.1 A series of...

Axial Loading Of Metal Dowel Connection Systems

Perpendicular Grain

The strength equations given in the following sub-sections assume that the tensile strength of fasteners will always exceed their withdrawal capacity from the connection. If, however, there is a need to evaluate the tensile strength of the fastener, it should be carried out in accordance with the requirements of EN 1993-1-1. The withdrawal capacity of nails loaded axially is dependent on the type of nail being used. Smooth round wire nails give the poorest result and with threaded nails the...

Fhk

In deriving these equations, friction forces between the members of the connection are ignored as well as the withdrawal resistance of the fasteners. In EC5 the Johansen yield equations form the basis of the strength equations, however for those failure modes that involve yielding of the fastener, the equations have been modified to include for friction and withdrawal effects. There are two types of friction effects that can arise in a connection. One will develop if the members are in contact...

N I

Medium duration variable loading acting downwards on the beam, Qk.1 Instantaneous duration variable loading acting upwards on the beam, Qk.2 Table 2.2, f values UKNA to EN 1990 2002 TableNA.Al.1 Factor for the combination value of medium duration f01 0.7 Factor for the combination value of wind action Qk 2, f0 2 f0 2 0.5 a Partial factors for equilibrium ULS Table 2.8, equation EQU a UKNA to EN 1990 2002 TableNA.A1.2 A For permanent favourable actions, yG.e yG.e 0.9 For variable unfavourable...

Timber Tension Member Design

As stated in 4.3, in order to verify the ultimate and serviceability limit states, each design effect has to be checked and for each effect the largest value caused by the relevant combination of actions must be used. However, to ensure attention is primarily focussed on the EC5 design rules for the timber or wood product being used, only the design load case producing the largest design effect has generally been given or evaluated in the following examples. Example 10.13.1 A timber-to-timber...

The Inplane Racking Resistance Of Timber Walls Under Horizontal And Vertical Loading

The stud walls associated with timber-framed buildings are usually sheathed on one or both faces with the sheathing securely fixed to the studs, enabling the wall to act as a rigid diaphragm. The fixings e.g. nails provide the bulk of the racking resistance through timber bearing and nail deformation when the lateral external force is applied as shown in Figure 9.8b. Horizontal sliding of the wall is resisted by anchorages such as nails or bolts along the sole plate sufficient to resist the...