Jph

Different types of rotational stiffness, k, in a timber connection. structures but to a lesser degree in timber structures, is to represent the rotational stiffness of each connection by a spring. Where the rotational stiffness varies, an iteration procedure has to be incorporated into the analysis to take account of the non-linear behaviour. However, where the rotational stiffness can be considered to be linear this procedure is not required. As stated in 10.10 and 11.8, in EC5 the...

Syk

The pack or gusset plates and their connections to the shafts must be designed for the effects of the shear force shown in Figure 8.7. The moment on the connection at the shaft is obtained by multiplying the shear force in the pack or gusset plate by the distance to the face of the shaft when packs are used or the distance to the centre line of the shaft when gusset plates are used. 8.4.5 Built-up sections - latticed columns A latticed column is a built-up column where there are two identical...

A

Where Iy is the second moment of area of the cross-section about the y-y. The term Iy z is referred to as the section modulus about the strong axis and is denoted by the symbol Wy. The value of Wy is dependent on the distance from the y-y axis and the values used in design for z are the distances to the extreme tension and compression fibre position on the section. Adopting the symbols defined in Chapter 2, the design bending stress, am,y,d, at the extreme fibre position in the rectangular...

Aa

Lateral torsional buckling of a beam subjected to uniform end moments M applied about the major axis (lateral buckled position shown solid). Km is the partial coefficient for material properties, given in Table 2.6. km is a modification factor that allows for an element of redistribution of stress (yield behaviour) in the stress block and also takes into account the effect of variation in material properties. Values for the factor are given in 6.1.6(2), EC5 - For solid timber and LVL...

Bb

Typical stud wall construction. The strength of the wall is primarily derived from the studs and all concentrated loading should be located directly over the studs and not in the span area of the header plate. For any loading over the span area, the plate must be checked to confirm whether it can function satisfactorily as a beam or alternatively additional studs can be inserted to carry the load. When several equally spaced similar members are laterally connected by a continuous...

Bending Stiffness Of Builtup Columns

In Chapter 5 it is shown that when dealing with solid section columns, for normal design situations the design strength will generally be determined by the buckling strength of the member. This is also the case for columns made from built-up sections. With built-up sections, however, the determination of the buckling strength is a more involved exercise, because of the following reasons Materials having different properties can be combined. There will be slip within the section when mechanical...

Brittle Failure Due To Connection Forces At An Angle To The Grain

This form of brittle failure can arise when connectors apply a force at an angle to the timber grain resulting in the possibility of splitting caused by the force component perpendicular to the grain, as shown in Figure 11.10. The failure can occur at a load less than the design capacity of the fasteners. This form of failure is discussed in 10.3.6.1 and the splitting strength of a connector in which a tension component can occur at right angles to the grain is obtained from equation (10.41d).

Combined Axial Loading And Moment

Whether a built-up column is formed by gluing or by mechanical fixings, the design procedure is only applicable where the column is subjected to axial loading acting through the centre of gravity of the built-up section and to the cases where there are only small moments (e.g. due to self-weight) in addition to the axial loading. Under such conditions, the design requirements for built-up columns are the same as those for solid sections detailed in 5.4.1(b). Because of the small moment...

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 Considerations

Composite sections will function as flexural elements, discussed in Chapter 4, and must comply with the relevant design rules and requirements of EC5 for such elements. The limit states associated with the main design effects are the same as those given in Table 4.1 and where used in residential floors their vibration behaviour must comply with the requirements covered in 4.6.2. The primary difference between the design process used for composite sections and that used for solid sections is...

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...

Design Strength Of A Laterally Loaded Metal Dowel Connection

The strength equations given in the following sub-sections assume that in the connection the design shear strength of the fasteners will always exceed the design capacity derived from the timber panel strength equations for the relevant fastener type. Where the shear strength of the fastener is required, it must be determined in accordance with the requirements of EN 1993-1-1, Eurocode 3, Design of Steel Structures, General Rules and Rules for Buildings. The design strength of a laterally...

Design Value Of The Effect Of Actions

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. In the case of the ultimate limit states, the largest values will be derived from the application of the fundamental combination of actions referred to in 2.2.24 and given in Table 2.8. Where accidental situations have to be designed for, the combination of actions given in Table 2.9 must also be used. For...

Bwz

(b) At the condition associated with the final mean value of stiffness (i) where the permanent action produces the design condition Aef,fin Af + (Epa- ) ( ) Aw (7.5) Emeanw ( 1 + kdef,f Ief,fin If + - M - Iw (7.6) (ii) where a variable action condition Qi produces the design condition Aef,fin Af + ( ) ( 1 ++ ldef,f ) Aw (7.7) ( -Emean X ( 1 + f 2,ikdef,f . (78) ef,fin if + - 77 --- I lw ( .8) V Emean,f 1 + f 2,i& def,v Here the symbols are as previously defined and Af is the total flange...

Engineered Wood Products Ewps

The readily available sawn sections of softwood are limited in size and quality. The largest section sizes available are 75 mm thick x 225 mm wide and at most 5 m in length. Any larger section sizes would suffer from both conversion and seasoning defects. EWPs are developed to overcome the limitations of sawn timber and are produced, in combination with adhesives, in a variety of forms dried thin planks of wood are glued together to form glued-laminated timber or glulam veneered, by peeling...

Eurocodes General Structure

Eurocodes form a set of documents that will enable building and civil engineering structures to be designed to common standards across the European Union using different structural materials. The documents are structured on a hierarchical basis, led by EN 1990, Eurocode - Basis of structural design, defining the basis of structural design, followed by EN 1991, Eurocode 1 Actions on structures, which comprises ten parts, defining the actions that have to be withstood. These documents are...

Examples

To be able to validate that the critical design effect of actions is being used, the design effects arising from all possible load combinations have to be investigated as part of the design process. Example 4.8.1 is given to show the load cases that have to be investigated in the case of a simply supported beam subjected to a permanent and a variable action. In the remaining examples, unless otherwise stated, only the load combination(s) giving the greatest design effects have been considered,...

Iri

Where F is the SLS load on the connection, and Kser is the slip modulus of the fastener per shear plane at the service condition. When a structure is subjected to a characteristic permanent action Gk, a dominant characteristic variable action Qk1 and accompanying unrelated characteristic variable actions Qk,i, the design load on a connection at the SLS, Fd, will be obtained by analysing the structure under the characteristic loading combination referred to in 2.2.25.2, i.e. (c) oin with two...

F Md fh ft

Fff,inst,t,d I - I 2,inst - II (7.15a) and at the final mean value condition it will be f Md f hf,A CTf,fin,t,d 0-t,2 I J- I y2,fin - II (7.15b) The EC5 design requirement is that the design stress be less than or equal to the design tensile strength, t,o,d, i.e. fff,inst,t,d and CTf,fin,t,d < t,0,d (7.16) k mod ksys kh ft,0,k . where the functions are as described previously and the rest of the factors are as follows t,0,d is the design compressive strength of the flange material parallel to...

Wxk

(a) Typical nailed screwed connection (b) Typical bolted connection Fmax is the maximum load taken by the connection ulnst is the instantaneous slip at the SLS. Fig. 10.22. Typical instantaneous load-slip behaviour of a metal dowel fastener connections. type being used, and typical load-slip curves for a nailed or screwed connection and for a bolted connection are shown in Figure 10.22. With bolts, because of the tolerance required to enable the bolt to be fitted and the bedding in process of...

Fh rfTNmm

Smooth round nails (EC5, equation (8.14)) Square nails (EC5, equation (8.14)) Smooth shank screws with a smooth shank diameter d < 6 mm Smooth shank screws with smooth shank diameter d > 6 mm d is the diameter of the nail, bolt, staple or dowel (in mm). For staples with rectangular sections, d is the square root of the product of the leg dimensions and for screws d is the effective diameter referred to in Table 10.3. fu is the tensile strength of the nail wire (or screw material) (in N...

Fig E

Member 3 Member 2 Shear plane (1) Shear plane (2) Thickness of members 2, t2 Thickness of member 3, t3 Member width (all members), h Tensile stress area of the bolt, Abt t1 50 mm t2 50 mm t3 70 mm h 150 mm h Table 1.3, strength class C18 (BS EN 338 2003(E), Table 1) Characteristic strength perpendicular to the grain, c.90.k Characteristic density of the timber, pk Characteristic strength of the bolt, u k 3. Partial safety factors and modification factor Table 1.6 (UKNA to BS EN 1995-1-1, Table...

Fig Ea

Thickness of each plywood gusset plate, tp Cross-sectional area of member 1, A1 Cross-sectional area of member 2, A2 A1 h1 tt A2 h2 tt d 3.0mm dh 2.25 d Minimum penetration of nail in inner member, ipoint.pen (10.3.5.1(1) (EC5, 8.3.1.2(1))) Minimum nail penetration criteria met Table 1.3, strength class C18 (BS EN 338 2003(E), Table 1) Characteristic density of the timber, pk pk 320 kg m3 Table 1.9, 12-mm-thick Finnish birch plywood Characteristic tensile strength at 90 to the face grain...

Fig Eb

Example 10.13.3 The five-member single-bolt (12 mm diameter) joint of a truss functioning in service class 2 conditions and supporting medium-term variable loading is shown in Figure E10.13.3. All members are 150 mm wide C18 timber to BS EN 338 2003 and the member thicknesses are as detailed below. The design forces in the members are a combination of permanent and medium-term variable actions. Check that the joint complies with the design requirements of EC5. (There is no requirement to check...

Fire Safety And Resistance

Fire safety involves prevention, detection, containment and evacuation requiring prevention of the ignition of combustible materials by controlling either the source of heat, reducing the combustibility of the materials or providing protective barriers. This involves proper design and detailing, insulation or construction and maintenance of the building and its components. Timber and wood-based materials comprise mainly cellulose and lignin, which are combustible and will burn if exposed to an...

General

In addition to the constraint on the type of loading that can be taken by these columns, the design rules in EC5 only apply to members in which the elements of the column are made from full length parts (i.e. there are no joints along the length of the members) and the built-up column is pin jointed and effectively held laterally in position at each end. (a) Glued spaced columns with glulam sections (b) Bolted spaced columns with solid sections Fig. 8.2. Typical built-up (spaced) columns. (a)...

General matters

In the Eurocodes, the procedure for displaying a decimal point is to use a comma, e.g. 4,5, in accordance with the requirements of the ISO. The United Kingdom, however, uses a full stop for the decimal point, i.e. 4.5, and the UK practice has been used in the book. The traditional practice in the United Kingdom is to show the z-z axis as the longitudinal axis of a member and the x-x and y-y axes to denote the respective major and minor axes of its cross-section. In the Eurocode suite the...

Iiiiihhhh

Layout of a typical wall (wall i) and its associated actions and reactions. Fig. 9.11. Layout of a typical wall (wall i) and its associated actions and reactions. The racking strength Fi VjRd of wall i is the lateral withstand capability of the wall and can be considered to be equivalent to the maximum resistance force the wall will be capable of sustaining at its top as shown in Figure 9.11. The risk of the wall sheets buckling under load can be ignored provided equation (9.33) in...

Info

T1 3he (EC5, equation (8.73)) (11.5) where t1 and t2 are as defined in Figure 11.2 and he is the tooth penetration depth (in mm). The strength of the connection will reduce to 75 of its full value if the minimum permitted values of t1 and t2 are used. Also, when t1 and t2 exceed 3he and 5he respectively, there will be no increase in joint strength due to this factor. k2 is the modification factor for the loaded end distance, a3jt, and, for a member with a sloping end, based on the requirements...

Info Ges

F r figure (c) Shear plane (y) for Fig. 10.18. Multiple shear plane connection procedure. joint (say the left side) and setting up a series of three-member symmetrical connections such that the central member of each connection is the actual joint member and the outer members are its adjacent members. Where the adjacent members have different properties (i.e. material, cross-sectional or directional) the member on the right side of the connection is replaced by the left-side member to form the...

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...

K

Bnet bw d dc de h,i,k ax,k c,0,d c,w,d c,f,d m,k m.y.d m,z,d in, a,d p,osb,c Design racking capacity of a wall diaphragm Design value of a material strength property Characteristic value of a material strength property Spacing, parallel to the grain, of fasteners within one row Spacing, perpendicular to the grain, between rows of Distance between fasteners at an unloaded end Distance between fasteners at a loaded end Distance between fasteners at an unloaded edge Distance between fasteners at a...

Loaded at an angle to the grain

When connectors are laterally loaded at an angle to the grain, the force components parallel and perpendicular to the grain have to be derived, and (i) the component of the design force acting parallel to the grain must not exceed the load-carrying capacity of the connection determined as defined in 11.8.1, and (ii) the component of the design force acting perpendicular to the grain must not exceed the lesser of load-carrying capacity of the connection determined as defined of the load-carrying...

Loaded parallel to the grain

The design strength of a laterally loaded single connector, Fv Rd, is obtained from the characteristic load-carrying capacity of the laterally loaded connector as follows kmod is the modification factor referred to in 2.2.20, and where the connection comprises two timber elements, kmod,1 and kmod,2, the value used in the equation will be kmod k mod, 1 kmod ,2, as required by EC5, equation (2.6). km is the partial factor for connections given in Table 2.6. Except when determining the plate...

Multiple Shear Plane Connections

Where a connection involves multiple shear planes and the connected members are at varying angles to each other, it is not possible to directly apply the joint strength equations given in Tables 10.2 and 10.3. For such situations, the guidance in EC5, 8.1.3(1), is that the resistance of each shear plane is derived on the assumption that the shear plane in the connection forms part of a series of three-member connections and the connection strength is derived by combining the strength values of...

N N

Stiffness of each elastic supports C span a t m, where m is the number of supported elements along the member length span a t m, where m is the number of supported elements along the member length Fig. 9.3. Plan view on the lateral buckling modes of an elastically supported member. Fig. 9.3. Plan view on the lateral buckling modes of an elastically supported member. 9.3.2 Bracing of single members (subjected to direct compression) by local support The method detailed in 9.2.5.2 of EC5 is...

O

These relationships are given in equations (6.21) and (6.22) of 6.3.2 in EC5. When the member is short and stocky, buckling will not occur and failure will be due to the timber failing under stress and in EC5 this applies when both Xrei y and AreljZ are < 0.3. Inserting the characteristic values for c 0,kand E0.05 given in BS EN 338 2003 3 for softwood species into equation (5.3), when Xrel 0.3, the maximum slenderness ratio of the member will be between 16.2 and 18.1, the range being...

P p p MyRk p

(2 My.Rk h.1.k d) Fv.Rk.ff 973.91 N The characteristic lateral resistance per shear plane per nail, Fv Rk, will be Fy.Rk min(Fy.Rk.a, Fv.Rk.b, Fv.Rk.c, Fv.Rk.d, Fv.Rk.e, Fv.Rk.f, Fv.Rk.ee, Fv.Rk.ff) Fv.Rk 812.12 N i.e. failure mode (e) The design resistance per nail per shear Fv Rd plane, Fv.Rd mconnretion

Pa p p

The characteristic lateral resistance per shear plane per nail will be Fv.Rk min(Fv.Rk.a, Fv.Rk.b, Fv.Rk.c, Fv.Rk.d, Fv.Rk.e, Fv.Rk.f, Fv.Rk.dd) Fv.Rk 764 N The design resistance per nail per Fv Rd shear plane, Fv Rd Number of nails for member 1 connection per shear plane Number of nails required per Mnaiis side, Mnails For a symmetrical nailing pattern N1nails ceil(N1nails) adopt 2 nails per side Number of nails for member 2 connection per shear plane Number of nails required per side, N2naUs...

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...

References

Structural Wood Design. West Publishing Company, St Paul, MN, 1990. 2 Illston, J.M. Construction Materials - Their Nature and Behaviour. E& FN Spon, London, 1994. 3 BS 5359. Nomenclature of Commercial Timbers Including Sources of Supply. British Standards Institution, London, 1991. 4 Johansson, C.J. Grading of timber with respect to mechanical properties. In Thelandersson, S., Larsen, H.J. (eds), Timber Engineering. Wiley, London, 2003. 5 Hoffmeyer, P. Wood as a Building...

Related British Standards for Timber Engineering in Buildings

The following list of Eurocodes and their associated United Kingdom National Annex BS EN 1990 Eurocode - Basis of structural design BS EN 1991-1-1 Densities, self-weight and imposed loads for buildings BS EN 1991-1-2 Actions on structures exposed to fire BS EN 1991-1-6 Actions during execution Eurocode 5 Design of timber structures BS EN 1995-1-1 General - Common rules and rules for buildings BS EN 1995-1-2 General rules - Structural fire design BS EN 1995-2 Bridges BS EN 300 Oriented strand...

Sls

Joints made with dowels are easy to fabricate. They are inserted into pre-drilled holes having a diameter not greater than the dowel diameter. With a bolted connection, the diameter of the pre-drilled hole in the timber must not be more than 1 mm greater than the bolt diameter. Where steel plates are used in the connection the tolerance on the hole diameter in the steel plate (i.e. the difference between the pre-drilled hole size in the plate and the bolt diameter) will influence the...

Stiffness Behaviour Of Toothedplate Ring And Shearplate Connectors

The lateral stiffness of toothed-plate, split-ring and shear-plate connectors is determined in the same way as discussed in 10.10 for metal dowel type fasteners. The content of 10.10 is applicable to connections formed using these types of connector and although some matters of detail have been repeated in the following paragraphs for clarity, generally the content relates to areas where differences arise. The slip modulus Kser per shear plane per connector at the serviceability limit state is...

Strength Grading Of Timber

The strength capability of timber is difficult to assess as often there is no control over its quality and growth. The strength of timber is a function of several parameters including the species type, density, size and form of members, moisture content, duration of the applied load and presence of various strength reducing characteristics such as slope of grain, knots, fissures and wane. To overcome this difficulty, the strength grading method of strength classification has been devised....

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...

T

Bracing member stabilising force system Bracing member stabilising force system Reaction force of bracing system due to combination of bracing member and external loading ' Bracing system with a Nd Nb Nd+Nb flexural stiffness EI Fig. 9.5. Bracing system for a series of compression or bending members. where qd is the maximum value of the equivalent lateral load per unit length on the system. Under the effect of q the additional lateral deflection of the bracing system, zq, will be and the...

The Analysis Of Structures With Semirigid Connections

If the connections in a statically indeterminate structure exhibit semi-rigid rather than fully fixed rotational behaviour, there will be a reduction in the stiffness of the structure leading to smaller moments at connections, an increase in member span moments and an increase in those displacements that are affected by the moment distribution in the structure. By taking the effect of semi-rigidity into account, in the analysis process a more realistic assessment of the moment distribution and...

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...

The Structure Of Timber

Structural timber is sawn (milled) from the trunk of the tree, which provides rigidity, mechanical strength and height to maintain the crown. Trunk resists loads due to gravity and wind acting on the tree and also provides for the transport of water and minerals from the tree roots to the crown. Roots, by spreading through the soil and acting as a foundation, absorb moisture-containing minerals from the soil and transfer them via the trunk to the crown. Crown, comprising branches and twigs to...

What Is Mathcad

Mathcad (developed by MathSoft Engineering and Education Inc.) 1 is an electronic notepad (live worksheet) that allows mathematical calculations to be performed on a computer screen in a format similar to the way it would be carried out for hand calculations. While Mathcad employs the usual mathematical symbols (i.e. +, -, , ), for algebraic operations it also uses the conventional symbols of calculus for differentiation and integration to perform these operations. It preserves the conventional...

Y I

Forces in a row of fasteners in a connection subjected to combined moment and lateral loading. Fig. 12.10. Forces in a row of fasteners in a connection subjected to combined moment and lateral loading. The capacity of each fastener in the row, Fv d, will be nef k mod Fv,Rk nais Fv,d - ' --(IZ.JI) where the symbols are as previously defined and Fv Rk is the characteristic load-carrying capacity of the fastener, derived as described in Chapters 10 and 11 for metal dowel type fasteners...

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...

Terms and definitions EC

Some of the terms and definitions used in EC0 are slightly different to those normally used in UK timber design practice and the following, including some terms for those not familiar with limit states design, are to be noted Action. This is the term used for a load or force applied to the structure (i.e. a direct action). This term is also used for imposed displacements, e.g. settlement (i.e. an indirect action). Effect of action. This is the term used for the internal stress resultants or...

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...

Table 8.6 In Ec5

In the draft proposal, the content of Table 8.6 in EC5 is to be altered and the minimum end and edge distances are to be based on the distance to the centre of gravity of the threaded part of the screw in the relevant member. Providing the timber thickness is gt 12 d, where d is the screw diameter, for joints formed as indicated in Figure C2, the minimum spacings, edge and end distances are to be as follows Minimum screw spacing in a plane parallel to the grain, a1 5d. Minimum screw spacing...

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...