DRAFT MALAYSIAN MTIB15TC2006R1 STANDARDsda.mtib.gov.my/wp-content/uploads/2017/10/DMS-544-PART... · 2017-10-09 · DEVELOPMENT OF MALAYSIAN STANDARDS The Department of Standards

DRAFT

MALAYSIAN MTIB15TC2006R1

STANDARD

STAGE: PUBLIC COMMENT (40.20) DATE: 9 OCTOBER 2017 - 7 DECEMBER 2017

Code of practice for structural use of timber -

Part 5: timber joints

ICS: 91.080.20

Descriptors: code of practice, structural use of timber, timber joints

© Copyright 2017

DEPARTMENT OF STANDARDS MALAYSIA

DEVELOPMENT OF MALAYSIAN STANDARDS

The Department of Standards Malaysia (Standards Malaysia) is the national

standardisation and accreditation body.

The main function of the Department is to foster and promote standards,

standardisation and accreditation as a means of advancing the national economy,

promoting industrial efficiency and development, benefiting the health and safety of the

public, protecting the consumers, facilitating domestic and international trade and

furthering international cooperation in relation to standards and standardisation.

Malaysian Standards are developed through consensus by committees which

comprise of balanced representation of producers, users, consumers and others with

relevant interests, as may be appropriate to the subject in hand. To the greatest extent

possible, Malaysian Standards are aligned to or are adoption of international

standards. Approval of a standard as a Malaysian Standard is governed by the

Standards of Malaysia Act 1996 (Act 549). Malaysian Standards are reviewed

periodically. The use of Malaysian Standards is voluntary except in so far as they are

made mandatory by regulatory authorities by means of regulations, local by-laws or

any other similar ways.

The Department of Standards appoints Malaysian Timber Industry Board as the

agent to develop Malaysian Standards. The Department also appoints Malaysian

Timber Industry Board as the agent for distribution and sale of Malaysian Standards.

For further information on Malaysian Standards, please contact: Department of Standards Malaysia OR Malaysian Timber Industry Board Century Square, Level 1 & 2, Block 2300, (Company No. 367474 - V) JalanUsahawan, Level 13 - 17 Menara PGRM, 63000 Cyberjaya No. 8, JalanPudu Ulu, Selangor 56100 Cheras MALAYSIA Kuala Lumpur Tel: 60 3 8318 0002 Tel: 60 3 9282 2235 Fax: 60 3 8319 3131 Fax: 60 3 9200 3769 http://www.jsm.gov.my/ http://www.mtib.gov.my/ E-mail: [email protected]

http://www.jsm.gov.my/

http://www.mtib.gov.my/

mailto:[email protected]

MTIB15TC2005R1

© STANDARDS MALAYSIA 2017 - All rights reserved i

Contents

Page Committee representatives ......................................................................................................... ii Foreword .................................................................................................................................... iii 1 Scope ............................................................................................................................. 1 2 Normative References ................................................................................................... 1 3 Terms, definitions and abreviated terms ....................................................................... 2 4 Joints group ................................................................................................................... 2 5 Timber quality ................................................................................................................ 3 6 Anti-corrosion treatment ................................................................................................ 3 7 Tendency to split............................................................................................................ 3 8 Eccentric joints ............................................................................................................... 4 9 Shear stress in the jointer member................................................................................ 5 10 Nailed joints ................................................................................................................... 6 11 Screwed joints……… .................................................................................................. 13 12 Bolted joints ................................................................................................................. 15 13 Coach screws .............................................................................................................. 24 14 Split-ring connectors .................................................................................................... 27 15 Shear plate connectors ................................................................................................ 35 16 Steel dowels ................................................................................................................ 39 Bibliography .............................................................................................................................. 40

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Committee representation

The Industry Standards Committee on Timber, Timber Products and Timber Structures, under whose authority this Malaysian Standard is developed, comprises representatives from the following organisations: Construction Industry Development Board Malaysia Department of Standards Malaysia Forest Research Institute Malaysia Jabatan Kerajaan Tempatan Jabatan Kerja Raya Malaysia Malaysian Furniture Promotion Council Malaysian Panel-Products Manufacturers’ Association Malaysian Timber Council Malaysian Timber Industry Board (Secretariat) Malaysian Wood Industries Association Malaysian Wood Moulding & Joinery Council Malaysian Wood Preserving Association Sabah Timber Industries Association Sarawak Timber Industry Development Corporation Timber Exporters’ Association of Malaysia Universiti Putra Malaysia Universiti Teknologi MARA

The Technical Committee on Timber Structure which supervised the development of this Malaysian Standard consists

of representatives from the following organisations:

Construction Industry Development Board Malaysia Construction Research Institute of Malaysia Fire and Rescue Department of Malaysia Forest Research Institute Malaysia Jabatan Kerja Raya Malaysia Malaysian Timber Council Malaysian Timber Industry Board (Secretariat) Malaysian Wood Industries Association Malaysian Wood Moulding Joinery & Council Ministry of Urban Wellbeing, Housing and Local Government Multinail Asia Sdn Bhd MyGlam Sdn Bhd Persatuan Pengusaha Kayu-Kayan dan Perabot Bumiputera, Malaysia Pertubuhan Akitek Malaysia The Institution of Engineers, Malaysia Universiti Putra Malaysia Universiti Sains Malaysia Universiti Teknologi MARA Woodsfield Glulam Manufacturing Sdn Bhd The Working Group on Timber Joints which developed this Malaysian Standard consists of representatives from the

following organisations:

Malaysian Timber Industry Board (Secretariat) Malaysian Wood Industries Association Multinail Asia (M) Sdn Bhd Universiti Putra Malaysia Universiti Sains Malaysia Universiti Teknologi MARA

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© STANDARDS MALAYSIA 2017 - All rights reserved iii

Foreword

This Malaysian Standard was developed by the Working Group on Structural Use of Timber Part 5 under the authority of the Industry Standards Committee on Timber, Timber products and Timber Structures. This Malaysian Standard is the first revision of MS 544 - 5, Code of practice for structural use of timber – Part 5: Timber Joints Major modifications in this revision are as follows: a) incorporation of new scope on “steel dowels”; b) incorporation of new clauses on “terms, definitions and abbreviated terms” and “steel dowel”; c) incorporation of new figures on “eccentric joints” and “split ring connectors”; d) subclause 10.1.6 has been modified to “skew or slant nailing”; and e) deletions of Table 11 on “maximum permissible withdrawal load per screw”, Table 18 on “maximum permissible withdrawal loads per coach screws” and Table 30 on “limiting values for permissible loads on one shear plate connectors unit. MS 544 consists of the following parts and sections, under the general title Code of practice for structural use of timber: Part 1: General Part 2: Permissible stress design of solid timber Part 3: Permissible design of glued laminated timber Part 4: Timber panel products Part 5: Timber joints Part 6: Workmanship, inspection and maintenance Part 7: Testing Part 8: Design, fabrication and installation of prefabricated timber roof trusses using toothed metal plate connectors Part 9: Fire resistance of timber structures Part 10: Preservative treatment of structural timbers Part 11: Recommendations for the calculation basis for span tables Part 12 : Structural laminated veneer lumber for structural application

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Foreword (continued)

Part 4 is further subdivided into a number of sections as follows: Section 1: Structural plywood Section 2: Marine plywood Section 3: Cement bonded particleboard (CBP) Part 9 is further subdivided into a section as follows: Section 1: Method of calculating fire resistance of timber members Part 11 is further subdivided into a number of sections as follows: Section 1: Domestic floor joists Section 2: Ceiling joists Section 3: Ceiling binders Section 4: Domestic rafters This Malaysian Standard cancels and replaces MS 544-5: 2001. Compliance with a Malaysian Standard does not of itself confer immunity from legal obligations.

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© STANDARDS MALAYSIA 2017 - All rights reserved 1

Code of practice for structural use of timber - Part 5: Timber joints

1 Scope This part of standard applies to joints in solid timbers fabricated with mechanical fasteners described by Malaysian Standard. These include joints fabricated with the following fasteners: a) nails; b) wood screws; c) bolts; d) coach screws; e) split-ring connectors; f) shear-plate connectors; and h) steel dowels For mechanical fasteners used in connections for engineered timber components (e.g glue laminated timber or glulam, laminated veneer lumber (LVL), etc), guidance is recommended to be obtained from their manufacturers on whether the joint design values based on solid timber are applicable for their products. The effect of the orientation of the individual laminates in the laminated component on the connector performance, if any, should be taken into consideration. NOTES: 1. Design rules for specialised and patented mechanical fasteners and for variants of conventional fasteners are not included in this code. 2. This Standard does not specifically cover glued timber-to-timber or timber-to-plywood connections as occurred in fabricated components such as stressed skin panels or plywood webbed beams. In such cases, joint design can be based on the timber components in the connection, provided that the joints is fabricated using a rigid, durable adhesive. Phenolic type adhesives meet these requirements. The design of fabricated components comprising glued connections is therefore based on the fact that with correct bonding practice and quality control, a joint is developed in which the adhesive bond strength and durability will be superior to the components comprising the joints. Reference may be made to AS 1720.1: 1997, Appendix C3 for information on methods for assessing the deformation of joints.

2 Normative references The following normative references are indispensable for the application of this standard. For

dated references, only the edition cited applies. For undated references, the latest edition of

the normative reference (including amendments) applies.

MS 544 – 1, Code of practice for structural use of timber - Part 1:General MS 544 – 2, Code of practice for structural use of timber - Part 2:Permissible stress design of solid timber MS 544 - 4 - 1, Code of practice for structural use of timber - Part 4:Timber panel products - Section 1 : Structural plywood

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2 © STANDARDS MALAYSIA 2017 - All rights reserved

MS 544 - 4 - 2, Code of practice for structural use of timber - Part 4:Timber panel products Section 2:Marine plywood BS EN 912, Timber fasteners. Specifications for connectors for timbers AS 1393, Coach screws (metric series) (with ISO hexagon heads) AS 1476, Metric wood screws AS 2334, Steel nails - Metric series AS 1111.1, ISO metric hexagon bolts and screws - Product Grade C, Part 1: Bolts AS 1111.2, ISO metric hexagon bolts and screws - Product Grade C - Part 2:Screws AS 1720.1:1997, Timber structures - Part 1:Design methods ASTM D143, Standard methods of testing small clear specimens of timber Air seasoning properties of some Malaysian timber - Malaysian Forest Service Trade Leaflet No. 41 - MTIB The strength properties of some Malaysian timbers - Malaysian Forest Service Trade Leaflet No. 34 - MTIB

3 Terms, definitions and abbreviated terms 3.1 Terms and definitions

For the purposes of this standard, the terms and definition given in MS 544-1 apply.

3.2 Abbreviated terms The abbreviation used in this standard are given as follows: Par : parallel; Perp : perpendicular; and SWG : standard wire gauge;

4 Joints group For the purpose of joints design, timber species have been classified into five joint groups: J1, J2, J3, J4 and J5. The joint group classifications for specific timbers are shown in Table 1.

MTIB14TC2005R1


Table 1. Group classification of timbers for use in joints design

Joint group

Strength group

Timbers

J1 SG1 Balau Bitis Chengal Penaga

J2 SG2/SG3 Agoho Dedaru Kelat Merbatu Pauh Kijang Ranggau

Bekak Delek KembangSemangkok Mertas Penyau Tualang

Belian Kempas Kekatong Mata Ulat Petaling

Balau, red Keranji Kulim Perah Surian batu

J3 SG4 Berangan Kapur Malabera Meransi Merpauh Rengas

Dedali Kasai Meranti bakau Nyalin Resak

Derum Keruntum Merawan Perupok Simpoh

Giam Mempening Merbau Punah

J4 SG5 Alan bunga Brazil Nut Kungkur Meranti, dark red Meranti, white Ramin Tembusu

Babai Gerutu Kelendang Melunak Nyatoh Rubberwood Teak

Balik angin bopeng Kedondong Keruing Mempisang Petai Sepetir

Bintangor Kayu Kundur Ketapang Mengkulang Penarahan Sengkuang

J5 SG6/SG7 Ara Damar minyak Jenitri Machang Mersawa Terap

Bayur Geronggang Kasah Medang Pelajau Terentang

Batai Jelutong Laran Melantai/Kawang Pulai

Durian Jongkong Meranti, light red Meranti, yellow Sesendok

Where joints comprise more than one species of timber, the design load to be used in the absence of other information is that appropriate to the weakest species in the joint.

5 Timber quality Design loads for joints have been based on the assumption that there are no loose knots, severe sloping grain, gum veins, gum or resin pockets, pith, holes or splits near any fastener. Accordingly, all of these defects shall be avoided at fastener locations.

6 Anti-corrosion treatment Fasteners used in wet timber or in timber, which will be exposed to the wet exposure condition, shall be resistant to corrosion or are treated by an anti-corrosion process. Some forms of preservative treatment for timber may affect fastener performance.

7 Tendency to split Special precautions shall be specified in the use of timber that has a tendency to split to an extent that may be detrimental to connector strength. In the absence of other guidance, the criterion for tendency to split shall be based on the parameter α as defined by:

MTIB14TC2005R1


𝛼 =𝜖2

𝛾

where 𝜀 is the tangential shrinkage, in percentage (%); and 𝛾 is the tangential cleavage strength of green timber, in Newton per millimetre (N/mm),

as measured by BS 373 or ASTM D143. Species for which 𝛼> 0.8 often have a high tendency to split, particularly in exposed locations;

species for which 𝛼< 0.55 may be considered to have a negligible tendency to split. NOTE. Information on shrinkage and cleavage for specific species can be obtained from the following: a) Malaysian Forest Service Trade Leaflet No: 41: Air-seasoning properties of some Malaysian timbers. b) Malaysian Forest Service Trade Leaflet No: 34: The strength properties of some Malaysian timbers.

8 Eccentric joints If the line of action of a force in a member does not pass through the centroid of the group of fasteners transmitting load to it, account should be taken of the stresses and loads due to the secondary moments and shear stress induced by the eccentricity (see Figure 1).

Key D is depth of primary member ds is the depth of member less the distance from the loaded edge to the centre of the bolt F is a force in a member

Figure 1. Eccentric joints

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V2

Unloaded edge

9 Shear stress in the jointed member The effective cross-section of a jointed member should be used when calculating its strength. The method of determining the effective cross-section is given in the appropriate clauses for each type of fastener. In addition, it should be shown that the shear stress condition in Figure 2 is satisfied in the jointed member. Key V=F sin 𝛼

Shear stress, 𝜏 =3𝑉

2𝑏ℎ𝑒

shall not exceed 𝜏𝑎𝑑𝑚 where V is the maximum shearing force per member at the joint; (V1 + V2 = F sin α) h is the thickness of the member; he is the depth of member less the distance from the unloaded edge to the centre of the

bolt; and T𝑎𝑑𝑚 permissible shear stress as given in MS 544: Part 2.

Figure 2. Shear stress in the jointed member

V1

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10 Nailed joints 10.1 General 10.1.1 Basic working loads The basic working loads for plain shank, low carbon steel nails specified in AS 2334 or equivalent whether driven by hand or by nail-gun, in single shear in timber fabricated in the dry condition is given in Table 2. For plywood to timber joints the basic working loads are given in Table 3. A nailed joint should normally contain at least two nails. In general, the species in joint groups J1, J2 and J3 of Table 1 require to be pre-drilled. Driving nails into holes pre-drilled to a diameter slightly less than the diameter of the nail results in a small increase in the holding power. The diameter of the pre-drilled holes should not be greater than four-fifths of the diameter of the nail. Table 2. Dry basic single shear lateral loads for one nail inserted at right angles to side

grain

Diameter of nail Standard thickness of

members (mm)

Basic lateral load (N) for timber in joint group:

(mm) SWG Head side

Point-side

J1 J2 J3 J4 J5

2.0 2.3 2.6

14 13 12

13 16 19

19 22 25

248 310 377

197 246 300

158 197 239

126 157 191

99 123 150

3.0 3.3 3.7

11 10 9

22 25 29

29 32 38

473 551 660

375 437 523

300 350 419

240 280 335

188 219 262

4.1 4.5 4.9

8 7 6

32 38 44

44 51 57

779 900 1035

618 715 822

495 572 657

395 457 526

309 359 411

5.4 5.9 6.4

5 4 3

51 57 64

67 76 89

1205 1390 1575

958 1103 1250

767 882 1000

613 703 801

480 555 626

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Table 3. Dry basic single shear lateral load for one nail in a plywood to timber joint

Nominal1) plywood thickness

(mm)

Nail (mm) Penetration of nail to timber2) (mm)

Basic Lateral load (N) for timber in group

Diameter Minimum length

Standard Minimum J1 J2 J3 J4 J5

6

2.6 3.0 3.3 3.7 4.1

40 45 45 55 60

34 39 39 49 55

13 15 17 19 21

339 426 496 594 701

270 337 393 471 556

215 270 315 377 445

172 216 252 301 355

135 169 197 236 278

9

2.6 3.0 3.3 3.7 4.1

40 45 45 55 60

31 36 36 46 51

13 15 17 19 21

342 429 494 597 704

273 340 396 474 559

218 273 318 380 448

175 219 255 304 358

138 172 200 239 281

12

2.6 3.0 3.3 3.7 4.1

40 45 45 55 60

28 33 33 43 48

13 15 17 19 21

345 432 502 600 707

276 343 399 477 562

221 276 321 383 451

178 222 258 307 361

141 175 203 242 284

15

2.6 3.0 3.3 3.7 4.1

40 45 45 55 60

25 30 32 40 45

13 15 17 19 21

348 435 505 603 710

279 346 402 480 565

224 279 324 386 454

181 225 261 310 364

144 178 206 245 287

18

2.6 3.0 3.3 3.7 4.1

43 47 50 56 62

25 29 32 38 44

13 15 17 19 21

351 438 508 606 713

282 349 405 483 568

227 282 327 389 457

184 228 264 313 367

147 181 209 248 290

21

2.6 3.0 3.3 3.7 4.1

46 50 53 59 65

25 29 32 38 44

13 15 17 19 21

354 441 511 609 716

285 352 408 486 571

230 285 33 392 460

187 231 267 316 370

150 184 212 251 293

NOTES: 1. Plywood should be structural or marine plywood depending on service condition, see MS 544:Part 4:Section 1 and 2.

2. The basic load is based on the standard nail penetration. If the penetration is less than the standard but not less than the minimum, the basic load should be reduced proportionately. If the penetration is more than the standard, no increase in basic load is allowed.

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10.1.2 Permissible loads The permissible load Fadm of a laterally loaded joint consisting n nails shall be given by: Fadm = n K1 K2 K13 K14 K16 K17 F where K1 = the factor for duration of load given in Table 4; K2 = 1.0 for dry timber = 1.0 for annular ring shank and helical threaded shank nails under all exposure

conditions = 0.7 for wet timber; K13 = 1.0 for nails in side grain

= 0.7 for nails in end grain; K14 = 1.0 for nails in single grain = 0.9 times the numbers of shear plane, provided that each of the member in a

multiple shear joint has a thickness of not less than 0.7 of the standard thickness for point side member given in Table 2;

K16 = 1.25 for nails driven through close fitting holes into metal side plates = 1.0 for timber to timber joint; K17 = factor for multiple nailed joints given in Table 5.1 for longitudinal joints and

Table 5.2 for rotational joints; and F = basic working load given in Table 2. n is number of nails

For rotational joints containing n nails, Mn, the design in-plane moment capacity of the joint,

shall be taken to be given by

𝑀𝑛 = 𝐹𝑎𝑑𝑚𝑟𝑚𝑎𝑥 ∑ (𝑟𝑖

𝑟𝑚𝑎𝑥

)

32⁄

𝑛

𝑖=1

where ri is the distance from the ith nail group; and rmax is the maximum value of ri Longitudinal and rotational joints are illustrated in Figure 3.

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Fn Fn

Circle of radius 0.7 r max

(a) Longitudinal joint

(b) Rotational joint Key Fn is design force capacity of the joint

Mn is design in-plane the moment capacity of the joint nal is number of nails within the circle of radius 0.7 rmax

rl is distance from ith nail to centroid on nail group rmax is maximum value of rl

Figure 3. Illustration of a longitudinal and rotational joint

nal = 7

r max

nal = 14

Mn

Mn

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Table 4. Modification factor K1 for duration of loading for different fasteners

Fastener Duration of loading

Long term Medium term Short term

Nails and screws 1.0 1.125 1.25

Bolts, coach screw, split-rings and shear-plates

1.0 1.25 1.5

Table 5. Values of factor K17 for use in the design of multiple nail and screw joints (Comprising of Table 5.1 and 5.2)

Table 5.1 For longitudinal tension joints

Condition of timber

Value of K17

Fasteners

nal≤ 4 nal= 5 nal = 10 nal ≥ 20

Wet Dry

1.00 1.00

0.90 0.94

0.80 0.90

0.75 0.85

NOTE. nal is the number of fasteners in each row per interface. See Figure 2 (a)

Table 5.2 For rotational joints

number of nails per interface K17

2 5

10 20

100 or greater

1.00 1.05 1.10 1.15 1.20

10.1.3 Spacings, edge and end distances Table 6 provides recommended minimum spacings, edge and end distances for nails in terms of nail diameter, d. For spacings at an angle to the grain, interpolation by means of Hankinson’s

formula as shown in Figure 4 may be used. NOTE. For timber that has a tendency to split (see Clause 7) some mitigation measures such as pre-drilling or increased spacing are recommended. The fabrication of prototype joints is a useful method for checking the efficacy of mitigation measures.

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Table 6. Minimum spacing, edge and end distances for nails

Spacing type Minimum distance

Holes not pre-drilled Holes pre-drilled to 80 % of nail diameter

End distance Edge distance Between nails - Along grain - Across grain

20 d 5 d

20 d 10 d

10 d 5 d

10 d 3 d

10.1.4 Nail length and timber thickness For the basic loads to apply, the nails shall fully penetrate the tabulated standard thickness of members or, for members receiving the nail point, shall penetrate to an equivalent depth. Where the thickness of members is less than those tabulated, the basic load shall be reduced proportionately. No increase in basic load is allowed for thickness of members greater than in Table 2. The nail shall be considered as non-load bearing if the penetration of the head side or point side is less than 5d. 10.1.5 Improved nails For ringed-shank or annularly-threaded nails of steel with a yield stress of not less than 375 N/mm2, the basic loads given in Table 2 shall be multiplied by 1.2. The nominal diameter of the nail shall be taken as 0.75 times the distance between diagonally opposite corners of the cross-section. 10.1.6 Skew or slant nailing Skew or slant nailing slightly increase the resistance to withdrawal. Nails loaded laterally shall not be skew-driven except at joints where no reversal of stress can occur in service and where the direction of the skew is such that the joint will tend to tighten under load. Opposed double skew nailing is preferable to parallel skew nailing. 10.1.7 Avoidance of splitting The basic loads for nails have been derived on the assumption that splitting of the timber does not occur to any significant extent. In wet timber which shows a marked tendency to split, (see Clause 7), the use of pre-drilled holes of diameter 80 percent of the nail diameter is recommended. 10.2 Withdrawal loads 10.2.1 Basic working loads The basic working loads in withdrawal for plain shank, low carbon steel nails as specified in AS 2334 driven by hand, into side grain of timber are given in Table 7.

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Table 7. Basic withdrawal loads for one nail inserted at right angles to side grain

Diameter of nail Basic withdrawal load (N/mm of penetration) for timber in group

(mm) SWG J1 J2 J3 J4 J5

2.0 2.3 2.6 3.0 3.3 3.7 4.1 4.5 4.9 5.4 5.9 6.4

14 13 12 11 10 9 8 7 6 5 4 3

5.8 6.7 7.6 8.7 9.6 10.7 11.9 13.1 14.2 15.7 17.1 18.6

4.1 4.7 5.3 6.1 6.7 7.5 8.3 9.1 9.9 10.9 11.9 13.0

2.9 3.3 3.7 4.3 4.7 5.3 5.9 6.5 7.0 7.7 8.5 9.2

2.0 2.3 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.5 6.0 6.5

1.4 1.6 1.8 2.1 2.3 2.6 2.8 3.1 3.4 3.7 4.1 4.4

NOTES: 1. No withdrawal load should be carried by a nail driven into the end grain of timbers. 2. The penetration of the nail should not be less than 15 mm.

10.2.2 Permissible loads The permissible load Fadm of a joint consisting of n nails subject to withdrawal load from side

grain shall be given by :

Fadm = n K1 K2 K17 K27 F

where K27 = 1.0 for both wet and dry timber which subsequently will not change appreciably in

moisture content. = 0.25 where cyclic changes in moisture content can occur after nailing; and F = the basic worKing load in withdrawal given in Table 7.

10.2.3 Changes in moisture content The values of basic resistance to withdrawal given in Table 7 apply to round wire nails driven into timber which subsequently will not change appreciably in moisture content. Where cyclic changes in moisture content can occur in the timber subsequent to nailing, the values given in Table 7 shall be multiplied by 0.25. 10.2.4 Improved nails The values of basic resistance to withdrawal given in Table 7 shall be multiplied by 1.5 for ringed-shank or annularly-threaded nails. However, no load in withdrawal shall be carried by ringed-shank or annularly-threaded nails driven into the end grain of the timber.

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11 Screwed joints 11.1 Lateral loads 11.1.1 Basic working loads The basic working loads for plain steel wood screws as specified in AS 1476 and AS 1111.2, whether driven by hand or by machine, in single shear in dry timber are given in Table 8. NOTE. In the absence of specific data, these loads may also be used for other forms of steel screws intended for the fabrication of timber joints. Loads for other diameters may be derived by linear interpolation in direct proportion to diameter raised to the power of 1.7.

Table 8. Dry basic single shear lateral loads for one wood screw inserted at right angles to side grain

Diameter of screw

Standard thickness of

members (mm)

Basic lateral load (N) for timber in group:

(mm) SWG Head-side

Point-side

J1 J2 J3 J4 J5

2.7 3.1 3.4 3.8 4.2 4.5 4.9 5.2 5.6 6.3 7.0 7.7

4 5 6 7 8 9 10 11 12 14 16 18

10 11 12 13 15 16 17 18 20 22 25 27

19 22 24 27 29 32 34 37 39 44 49 54

498 587 655 748 843 915 1012 1087 1187 1366 1548 1734

410 484 540 617 695 755 835 897 976 1126 1276 1430

340 401 448 511 576 625 692 742 811 933 1057 1184

282 333 371 424 477 518 574 616 672 774 877 982

229 270 302 344 388 421 466 500 546 628 712 798

11.1.2 Permissible loads The permissible load Fadm for a laterally loaded joint consisting n screws shall be given by:

Fadm = n K1 K2 K13 K16 K17 K27 F where F = basic working load given in Table 8. 11.1.3 Spacings, edge and end distances Table 9 provides recommended minimum spacing, edge and end distances for screws stated in terms of the shank diameter, d.

MTIB14TC2005R1


Table 9. Minimum spacings, edge and end distances for screws

Spacing type Minimum distance

End distance 10 d

Edge distance 5 d

Between screws -along grain -across grain

10 d 3 d

NOTE. d is shank diameter of screws.

For spacing at an angle to the grain, interpolation according to Hankinson’s formula may be used (See Figure 4). 11.1.4 Screw length and timber thickness For the basic loads in Table 8 to apply, the head side member thickness shall not be less than the value given in the table, and the penetration of the screw in the point side member shall be at least that given in the table. Where the thickness of the head side member is less than the value given in Table 8, the tabulated basic load shall be multiplied by the ratio of the actual to the standard head side thickness, provided that the point side screw penetration is at least twice the actual head side thickness. The minimum head side member thickness shall not be less than twice the shank diameter. The penetration of the point shall not be less than 0.6 of the standard point side member. 11.1.5 Pre-drilling The screws shall be turned, not hammered, into pre-drilled holes. The hole for the shank shall have a diameter equal to the shank diameter and be not deeper than the length of the shank. The lead hole for the threaded portion of the screw shall have a diameter of 7/8 of the shank diameter. Screws installed directly without pre-drilling shall have the same value given in Table 8, provided that the timber does not split. 11.2 Withdrawal loads 11.2.1 Basic working loads The basic working loads for plain steel wood screws as specified in AS 1476 driven by hand or by machine into the side grain of dry timber are given in Table 10. Loads for other diameters may be obtained by linear interpolation in Table 10. The basic working loads for wood screws driven into end grain shall not exceed 70 % of the values given in Table 10.

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Table 10. Dry basic withdrawal loads for one wood screw inserted at right angles to side grain

Diameter of screw Basic withdrawal loads (N/mm of penetration for timber) in group

(mm) SWG J1 J2 J3 J4 J5

2.7 3.1 3.4 3.8 4.2 4.5 4.9 5.2 5.6 6.3 7.0 7.7

4 5 6 7 8 9 10 11 12 14 16 18

26.5 30.2 33.0 36.8 40.5 43.2 46.9 49.7 53.3 59.7 66.1 72.4

19.2 21.9 24.0 26.7 29.4 31.4 34.0 36.0 38.7 43.3 47.9 52.5

14.1 16.1 17.6 19.6 21.5 23.0 25.0 26.4 28.4 31.8 35.2 38.5

10.3 11.8 12.9 14.3 15.8 16.9 18.3 19.4 20.8 23.3 25.8 28.2

7.3 8.4 9.1 10.2 11.2 12.0 13.0 13.8 14.8 16.5 18.3 20.0

11.2.2 Permissible loads

The permissible load Fadm for n screws in withdrawal shall be given by:

F adm = n K1 K2 K13 K27 F

where F = basic working load given in Table 10. 11.2.3 Basic withdrawal loads The basic withdrawal loads for the single screw inserted at right angels to the side grain of timber in service classes 1 and 2 (See MS 544-1) are given in Table 10. These apply to each 1 mm depth of penetration and, for a particular screw, shall be multiplied by the actual point side penetration achieved by the threaded part of the screw. The penetration of the screw point shall not be less than 15 mm. No withdrawal load shall be carried by a screw driven into the end side grain of timber. The basic loads given in this clause for each screw shall be modified in accordance with Clause 11.2.2 to determine the permissible load for a joint.

12 Bolted joints 12.1 General The basic working loads given in Clauses 12.2.1 and 12.2.2 are applicable to steel bolts are specified in AS 1111.1, when fitted into pre-drilled holes of diameter approximately 10 % greater than the bolt diameter and when fitted with washers as given in Clause 12.2.5.

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12.2 Lateral Loads 12.2.1 Basic working load parallel and perpendicular to grain The dry basic working load F for a single bolt bearing parallel and perpendicular to the grain and acting in single shear is given for a selection of bolt diameter and effective timber thickness in Table 11.

Table 11. Dry basic loads for one bolt in single shear

Effective1)

timber thickness,

b (mm)

Bolt diameter

(mm)

Basic load (kN) for timber in group

J1 J2 J3 J4 J5

Par Perp Par Perp Par Perp Par Perp Par Perp

38 6 10 12 16 20 22 24

1.30 2.84 4.22 5.28 6.29 7.16 8.32

1.34 1.87 2.24 2.54 2.84 3.12 3.40

1.14 2.38 3.41 4.25 5.04 5.72 6.62

1.03 1.37 1.60 1.80 2.02 2.21 2.40

0.95 1.92 2.70 3.36 3.96 4.51 5.21

0.76 1.00 1.16 1.32 1.46 1.62 1.75

0.76 1.58 2.20 2.71 3.20 3.63 4.19

0.56 0.72 0.84 0.95 1.07 1.16 1.27

0.55 1.12 1.54 1.88 2.22 2.50 2.89

0.36 0.47 0.54 0.61 0.68 0.76 0.82

50 6 10 12 16 20 22 24

1.30 2.84 4.94 6.65 8.00 9.18 10.37

1.34 2.34 2.92 3.37 3.79 4.16 4.52

1.14 2.50 4.10 5.38 6.44 7.37 8.30

1.10 1.76 2.11 2.40 2.69 2.95 3.20

0.95 2.08 3.06 4.28 5.10 5.83 6.55

0.86 1.28 1.55 1.75 1.96 2.15 2.34

0.76 1.76 2.74 3.48 4.14 4.72 528

0.66 0.95 1.13 1.27 1.42 1.56 1.69

0.55 1.27 1.93 2.44 2.88 3.28 3.66

0.44 0.60 0.72 0.82 0.91 1.10 1.09

75 10 12 16 20 22 24 28

2.84 4.94 7.43 10.30 12.58 14.52 15.94

2.56 3.84 4.75 50 6.18 6.74 7.33

2.50 4.33 6.53 8.57 10.22 11.71 12.85

1.81 2.98 3.50 3.98 4.40 4.80 5.20

2.08 3.60 5.41 6.91 8.17 9.31 10.16

1.58 2.17 2.56 2.92 3.23 3.50 3.79

1.76 3.06 4.61 5.71 6.67 7.56 8.23

1.22 1.61 1.90 2.11 2.34 2.53 2.74

1.27 2.22 3.17 4.04 4.68 5.27 5.75

0.82 1.03 1.20 1.37 1.51 1.63 1.76

100 12 16 20 22 24 28 32

4.94 7.43 10.30 13.43 16.99 19.62 21.74

3.98 5.62 6.85 7.86 8.74 9.61 10.41

4.33 6.53 9.02 11.80 14.11 15.96 17.59

3.16 4.37 5.15 5.77 6.34 6.89 7.46

3.60 5.41 7.49 9.79 11.40 12.80 14.02

2.47 3.20 3.76 4.22 4.63 5.05 5.45

3.06 4.61 6.38 8.14 9.42 10.48 11.44

1.90 2.38 2.76 3.08 3.37 3.66 3.94

2.22 3.17 4.39 5.76 6.66 7.36 7.99

1.26 1.55 1.76 1.98 2.17 2.36 2.54

125 16 20 22 24 28 32

7.43 10.30 13.43 16.99 20.53 24.31

5.62 7.49 9.12 10.42 11.53 12.72

6.53 9.02 11.80 14.92 18.02 20.22

4.45 5.94 6.92 7.73 8.48 9.23

5.41 7.49 9.79 12.38 14.72 16.33

3.48 4.39 5.08 5.65 6.20 6.74

4.61 6.38 8.34 10.55 12.20 13.50

2.68 3.28 3.73 4.15 4.52 4.90

3.17 4.39 6.02 7.62 8.65 9.55

1.78 2.14 2.40 2.66 2.92 3.17

1) The loads for intermediate thickness may be obtained by linear interpolation.

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Table 11. Dry basic loads for one bolt in single shear (Continued)

Effective1) timber

thickness, b (mm)

Bolt diameter

(mm)

Basic load (kN) for timber in group

J1 J2 J3 J4 J5


150 20 22 24 28 32

10.30 13.43 16.99 20.53 24.31

7.49 9.61 11.94 13.26 14.74

9.02 11.80 14.92 18.02 21.34

5.94 7.63 8.93 9.91 10.85

7.49 9.79 12.38 14.98 17.72

4.64 5.72 6.52 7.26 7.94

6.38 8.34 10.55 12.74 15.08

3.56 4.27 4.82 5.34 5.83

4.39 6.02 7.62 9.20 10.75

2.36 2.78 3.11 3.42 3.73

200 22 24 28 32

13.43 16.99 20.53 24.31

9.61 11.94 14.52 17.36

11.80 14.92 18.02 21.34

7.63 9.48 11.53 13.56

9.79 12.38 14.98 17.72

5.95 7.40 8.82 9.92

8.34 10.55 12.74 15.08

4.57 5.69 6.62 7.36

6.02 7.62 9.20 10.90

3.05 3.78 7.32 4.79

1) The loads for intermediate thickness may be obtained by linear interpolation.

12.2.2 Basic working load for a bolted joints system a) Parallel and perpendicular to grain For a bolt in other than a two-member joint, the basic working load shall be multiples of

𝐹∥ for parallel loading as shown in Table 12 and 𝐹⊥ for perpendicular loading as shown

in Table 13 for the type of joint accordingly. b) Other angles to grain For systems loaded at an angle α to the grain, the basic working load is given by use

of Hankinson’s formula as follows:-

F =𝐹∥F⊥

F∥sin2α+ F⊥cos

2α

Hankinson’s formula is conveniently evaluated by means of the nomogram given in Figure 4.

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EXAMPLE

Given 𝐹∥ = 9.0 𝑘𝑁, 𝐹⊥ = 6.0 𝑘𝑁, 𝛼 = 60°

To find Fα connect 𝐹∥ = 9.0 𝑡𝑜 𝐹⊥ = 6.0 At intersection with 60° line, construct line parallel to grid line to axis at Fα = 6.5.

Figure 4. Graph of Hankinson’s formula

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Table 12. Basic working loads for a bolted joint system loaded parallel to grain

Type of joint

Effective timber

thickness, b Basic load, F∥

1. Two member

Thinner of 2b1 and 2b2

F∥

2. Three member

Thinner of 2b1 and b2

2 𝐹∥

3. Multiple member

i) Between A and B – thinner of b1 and b2

ii) Between B and C –

thinner of b2 and b3

iii) Between C and D – thinner of b3 and b4

iv) Between D and E – thinner of b4 and b5

i) F∥AB

ii) F∥BC

iii) F∥CD

Total basic load, F∥ = F∥AB+F∥BC + F∥CD + F∥DE

b1

b2

b1

b2

b1

E

D

C

B

A

b2

b1

b3

b4

b5

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Table 13. Basic working loads for a bolted joint system loaded perpendicular to grain

Type of joint

Effective timber

thickness, b Basic load 𝑭⊥

1. Two member

2b1 but not exceeding twice thickness of side member

F⊥

2. Three member

i) ii)

i) b1 but not exceeding

twice thickness of thinner side member

ii) 2b1 but not exceeding

thickness of inner member

i) 2 F

⊥

ii) 2 F⊥

3. Multiple member

i) Between A and B –


ii) Between B and C –


iii) Between C and D –

thinner of b3 and b4 iv) Between D and E – thinner of b4 and b5

i) F

⊥AB

ii) F⊥BC

iii) F⊥CD

iv) F⊥DE

Total basic load, F⊥ = F⊥AB+F⊥BC + F⊥CD + F⊥DE

b1

b1

b1 b2 b1

b5 b4

b3 b2 b1

A B C D E

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12.2.3 Permissible loads

The permissible load Fadm for a laterally loaded joint consisting n bolt shall be given by:

Fadm = n K1 K2 K16 K17 F

where

K16 = 1.25 for bolts that transfer load through metal side plates of adequate strength and

the bolts are a close fit to the holes in these plates provided that b/d > 10 for loads acting perpendicular to the grain (where b denotes the effective timber thickness and d is the bolt diameter);

= 1.0 otherwise;

K17 = factor for multiple bolted joint given in Table 14; and

F = basic working load as derived in Clause 11.2.2.

Table 14. Value of factor K17 for use in the design of multiple connector

joints of bolts, coach screws, split ring and shear plates

Type of joint Value of K17

na ≤ 4 na = 5 na = 10 na = 15 na ≥ 16

Dry timber Wet timber (no transverse restraint 1)) Wet timber (transverse restraint 1))

1.00

1.00

0.50

0.95

0.95

0.50

0.80

0.80

0.50

0.65

0.55

0.50

0.62

0.50

0.50

NOTE. na is the total number of fasteners in each row per interface.

1) The term ‘transverse restraint’ refers to the possibility of restraint to timber shrinkage due to the joint detail.

12.2.4 Spacings, edge and end distances Spacings, edge and end distances shall comply with the following requirements: a) Loads parallel to grain The basic working loads given in Table 11 and 12 apply to joints which the edge, end

between-fastener spacings are not less than those shown in Figure 5a. The distance a indicated in the figure shall be at least (n – 2) d with a minimum of 2.5 d, where n is the total number of bolts in the joint and d is the diameter of the bolt.

Similarly, the required end distance 𝑙∥/ shall be at least 7 d in tension joints in both wet

and dry timber and 4 d in compression joints and in joints subjected to bending moment for both moisture conditions. However, lesser end distances may be used in tension joint provided that the basic load is reduced in proportion to the reduction in end distance.

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Nevertheless, in no case shall the end distance for tension joints be less than 6 d for

wet timber and 4 d for dry timber.

b) Loads perpendicular to grain The minimum edge, end and between-fastener spacing shall not be less than those

shown in Figure 5b. The distance a shall be at least 2.5 d for a b/d ratio of 2, and it shall be increased proportionately so that it is at least 5 d for a b/d ratio of 6 or more, where b is the thickness of the member loaded perpendicular to the grain.

c) Loads acting at an angle to the grain For loads acting at an angle 0° to 30° to the grain, the spacings, edge and end distances

may be taken as for loads parallel to the grain. For loads acting at an angle of 30° to 90° to the grain, the spacings, edge and end distances may be taken as for loads acting perpendicular to the grain.

(a) Load applied parallel to grain

l par 4 d 4 d

1.5 d

1.5 d

a

l par

4 d

4 d

4 d a

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(b) Load applied perpendicular to grain

Figure 5. Spacing, edge and end distance for bolted joints 12.2.5 Washers In all timber-to-timber bolted structural joints, every bolt shall be provided with a washer at each end, of a size not less than that stated in Table 15. If smaller washers are used, then the basic working load given in Clause 11.2 shall be reduced in proportion to the dimension of the washer diameter or side length.

Table 15. Minimum required size of washers for structural bolted joints

Bolt diameter (mm)

Washer size (mm)

Thickness Min. diameter for round washers

Min. side length for square washers

M6 1.6 30 25

M8 2.0 36 32

M10 2.5 45 40

M12 3.0 55 50

M16 4.0 65 57

M20 5.0 75 65

>M20 6.0 85 75

12.3 Axial loads Where bolts are loaded axially, the basic working load of the bolt shall be taken as the lesser of the axial strength of the bolt and the bearing strength of the timber under the washer when loaded perpendicular to the grain. The design axial strength of bolts and the effective diameter for use in computing the bearing pressure on the timber are given in Table 16.

4 d

4 d

4 d

l par

a

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Table 16. Design parameters for bolts under axial load

Bolt diameter (mm)

Axial strength of bolt (kN)

Effective diameter of a standard washer 1) in bearing

(mm)

M6 4.0 16

M8 7.5 21

M10 11.5 27

M12 17 31

M16 32 31

M20 50 50

M24 72 60

M30 115 69

M36 165 78

1) Standard washers are washers having the minimum dimensions shown in Table 15. The effective diameter is less than the actual diameter because it includes an allowances for bending of the washer.

13. Coach screws 13.1 General The basic working loads given in the following clauses are applicable to steel coach screws as specified in AS 1393 and as shown in Figure 6. 13.2 Lateral loads For coach screws bearing laterally in dry timber, the provision of Clause 12 for bolts shall apply, subject to the following conditions: a) for the purpose of Clause 12, a coach screw diameter, d is as shown in Figure 6. b) the screws shall be fitted with washers as specified in Clause 12.2.5; c) in a two-member joint, the thinner member shall have a minimum thickness of three times

the shank diameter of the coach screw; d) the diameter of the hole for the shank shall not be less than the shank diameter of the

screw nor exceed it by more than 1 mm or 10 percent of the shank diameter, whichever is the lesser. The diameter of the hole for the threaded portion of the screw shall not exceed the root diameter of the screw. The depth of the hole shall not be less than the intended depth to which the screw is to be driven. The screw shall not be hammered into place but turned with a hand operated or machine operated wrench; and

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e) timber thickness and screw lengths as shown in the Figure 7 shall be such that: i) thickness of first member, t1> 3 d; and ii) depth of penetration, tp into second member, for species in joint groups: J1 and J2 tp> 7 d J3 tp> 8 d J4 and J5 tp> 10 d For the lesser values of tp, the basic load shall be reduced in proportion to the

decrease in tp and the coach screw shall be considered as non-load bearing if tp is less than 4d.

Key d is shank or nominal diameter s is length of shank or unthreaded portion T is length of threaded portion

L is length of screw

Figure 6. Coach screw

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Key t1 is thickness of first member tp is depth of penetration

Figure 7. Timber thicknesses and fastener lengths for coach screws 13.3 Withdrawal loads 13.3.1 Basic working loads The basic working loads for coach screw in withdrawal from the side grain are given in Table 17. 13.3.2 Permissible loads The permissible load Fadm for n coach screws in withdrawal shall be given by:

Fadm = n K1 K2 K13 F

but not greater than the value given in Table 18. where F = basic working load for coach screws in side grain, given in Table 17

Table 17. Dry basic withdrawal loads for one coach screw in side grain

Shank diameter

(mm)

Basic withdrawal load, N per mm penetration of tread for timber in group

J1 J2 J3 J4 J5

6 57 41 30 22 16

8 75 54 40 29 21

10 93 68 50 36 26

12 111 80 59 43 31

16 146 106 78 57 40

20 181 131 96 71 50

t1

tp

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14. Split-ring connectors 14.1 General 14.1.1 Connector sizes The recommendations contained in this clause are applicable to the sizes of split-ring connectors (see Figure 8) given in Table 18 in accordance with BS EN 912.

Table 18. Sizes of split-ring connectors and minimum sizes of washers

Nominal size of connectors (mm)

Nominal size and thread diameter of

bolt

Minimum size of round or square washers

Diameter or length of side (mm)

Thickness (mm)

64 M12 50 3

102 M20 75 5

Figure 8. Split ring connectors 14.1.2 Bolts and washers The diameter of the bolts to be used with the connectors are given in Table 18. Round or square washers should be fitted between the timber and the head and nut of the bolt. The minimum size of washer to be used with each connector is given in Table 18. 14.1.3 Joint preparation To prepare a connectored joint, the positions of the bolt holes should be set out accurately with reference to the point of intersection of the centre-lines of the members. One of the following procedures shall be used when drilling the bolt holes: a) fit the members together in their correct positions and clamp while drilling the bolt holes

through all the members; and b) drill the bolt holes in the individual members using jigs or templates to locate the bolt

holes accurately. Bolt holes shall be within 2 mm of their specified position. The contact surfaces of the timber members shall be grooved to the dimensions given in Table 19.

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0.75 Ks

0.75 Ks

The grooves for split-rings may be cut simultaneously with the drilling of the bolt holes if procedure b) is used.

Table 19. Dimensions of circular grooves for split-ring connectors

Dimensions in millimetres

Split-ring size

Dimensions of groove

Inside diameter Width Depth

64 65.0 4.6 9.5

102 104.0 5.3 12.7

14.2 Effective cross section The effective cross-section of each member at a joint should be determined by deducting the projected area from the gross area of the cross-section of the connector recess (i.e. 705 mm2 for each 64 mm split-ring, or 1 455 mm2 for each 102 mm split-ring) and the projected area of the groove. The depths of the connector grooves are given in Table 19. When assessing the effective cross-section of multiple connector joints, all connectors and their bolts that lie within a distance of 0.75 connector diameters, measured parallel to the grain from a given cross-section should be considered as occurring at that cross-section (see Figure 9). Then the effective cross section should be determined by deducting the given net projected areas of the connector grooves and bolt holes from the gross area of the cross-section being considered. Key Ks is spacing of connectors measured centre to centre

Figure 9. Effective cross section

14.3 Basic loads The basic working loads for parallel and perpendicular to the joint in dry timber are given in Table 20. These loads apply to a connector unit comprising one split-ring in the contact faces of a timber-to-timber joint with its bolt in single shear. When loaded at an angle α to the grain, the basic load is given by use of Hankinson’s formula or evaluated by means of the graph as given in Figure 4.

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Table 20. Dry basic loads for one split-ring connector unit

Actual thickness of members 1) Basic load1) (kN) for timber in group

Split-ring

diameter

(mm)

Bolt diameter

(mm)

Connectors on one side

only

(mm)

Connectors on both sides and on same bolt

(mm)

J1 J2 J3 J4 J5


64

M12

22 25 ≥29

32 40 ≥50

10.37 12.69 15.48

6.77 8.27 10.08

7.82 9.57 11.67

5.16 6.31 7.70

5.96 7.29 8.89

3.97 4.86 5.93

4.54 5.55 6.77

3.06 3.75 4.57

3.36 4.11 5.01

2.29 2.80 3.42

102

M20

29 32 36 ≥41

41 50 63 ≥75

22.34 26.67 31.34 33.34

13.57 16.20 19.03 20.25

17.55 20.96 24.63 26.20

10.62 12.68 14.90 15.85

13.52 16.14 18.97 20.18

8.38 10.01 11.76 12.51

10.41 12.43 14.61 15.54

6.62 7.90 9.29 9.88

7.8 9.31 10.94 11.64

5.09 6.08 7.14 7.60

1) Loads for intermediate thickness may be obtained by linear interpolation.

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14.4 Permissible loads The permissible load Fadm for n split-ring connector shall be given by: Fadm = n K1 K2 K17 K18 F where K18 = 1.0 for standard and end distance, edge distance and connector spacing as

given in Tables 21, 22 and 23 respectively. = modification factor for the relevant connector spacing (KS), end distance (KC)

and edge distance (KD) which are less than the corresponding standard values as given in Tables 21, 22 and 23 respectively.

(The lowest factor of the values of Ks, Kc, and KD is to be used (see 14.5); and

F = basic load given in Table 20.

Table 21. End distance for split-ring and shear-plate connectors

Type of end distance

Angle 1) of load to grain α

(degrees)

End 1) distance (mm)

Connector size

64 mm split-ring or 67 mm

Shear-plate


Shear-plate

Minimum Standard Minimum Standard

Unloaded 0 45 90

64 67 70

102 121 140

83 86 89

140 159 178

Loaded 0 to 90 70 140 89 178

1) For intermediate angles and end distances, values should be obtained by linear interpolation.

Table 22. Edge distance for split-ring and shear-plate connectors

Type of edge distance


(degrees)

Edge 1) distance (mm)

Connector size


Shear-plate


Shear-plate

Minimum Standard Minimum Standard

Unloaded 0 to 90 44 44 70 70

Loaded 0 45 90 45 to 90

44 44 44 44

44 54 64 70

70 70 70 70

70 79 87 95

1) For intermediate angles and edge distances, values should be obtained by linear interpolation.

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Table 23. Spacing modification factor, Ks, for split-ring and shear-plate connectors

Angle of load to grain α

(degrees)

Angle 1) of connector axis

to grain θ

(degrees)

Spacing (mm)

Ks = 0.75 Minimum

Ks= 0.80

Ks = 0.85

Ks = 0.90

Ks = 0.95

Ks = 1.00 Standard

64 mm split-ring or 67 mm shear-plate

0 0 15 30 45 60 75 90

89 89 89 89 89 89 89

105 102 98 92 92 89 89

121 117 108 95 92 89 89

140 130 114 105 95 92 89

156 146 124 108 95 92 89

171 157 132 112 98 91 89

15 0 15 30 45 60 75 90

89 89 89 89 89 89 89

102 102 98 95 92 92 89

114 111 105 98 95 92 92

127 124 114 105 98 95 92

140 133 124 108 102 95 95

152 145 129 114 103 97 95

30 0 15 30 45 60 75 90

89 89 89 89 89 89 89

98 95 95 92 92 92 92

105 105 102 95 95 92 92

114 111 108 105 98 95 95

124 121 114 108 102 95 95

130 127 119 111 104 99 98

45 0 15 30 45 60 75 90

89 89 89 89 89 89 89

92 92 92 92 92 92 92

95 95 95 95 95 95 95

102 102 102 102 98 98 98

105 105 105 105 102 102 102

108 108 107 106 106 105 105

60 to 90 0 15 30 45 60 75 90

89 89 89 89 89 89 89

89 89 89 92 92 92 92

89 89 80 92 92 95 95

89 89 92 95 95 98 102

89 89 92 95 98 102 105

89 90 93 97 102 106 108

1) For intermediate angles and end distances, values should be obtained by liner interpolation.

MTIB14TC2005R1


Table 23. Spacing modification factor, Ks, for split-ring and shear-plate connectors (continued)

Angle of load to grain α

(degrees)

Angle 1) of connector

axis to grain θ

(degrees)

Spacing (mm)

Ks = 0.75 Minimum

Ks= 0.80

Ks = 0.85

Ks = 0.90

Ks = 0.95

Ks = 1.00 Standard


0 0 15 30 45 60 75 90

127 127 127 127 127 127 127

146 143 140 133 130 127 127

168 162 149 140 133 127 127

187 178 162 146 133 130 127

210 197 171 149 142 130 127

229 213 183 157 140 130 127

15 0 15 30 45 60 75 90

127 127 127 127 127 127 127

143 140 137 133 130 130 130

159 152 146 140 133 133 130

171 168 159 149 140 133 133

187 181 168 156 142 137 137

203 195 178 161 147 140 137

30 0 15 30 45 60 75 90

127 127 127 127 127 127 127

137 137 133 133 133 130 130

146 146 143 140 137 137 137

159 156 149 146 143 140 140

168 165 159 152 146 145 143

178 175 168 160 152 148 146

45 0 15 30 45 60 75 90

127 127 127 127 127 127 127

133 133 133 133 133 133 133

137 137 137 137 140 140 140

143 143 143 143 146 146 146

146 146 146 146 149 149 149

152 152 153 154 155 156 156

60 to 90 0 15 30 45 60 75 90

127 127 127 127 127 127 127

127 127 127 130 133 133 133

127 127 130 133 137 140 143

427 127 130 133 143 146 149

127 127 133 137 146 152 159

127 129 134 142 152 161 165


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Table 24. End distances modification factor, Kc, for split-ring and shear-plate connectors

End distance

(mm)

Value of Kc

Unloaded Loaded

Connector size Connector size

64 mm split-ring or 67 mm Shear-plate

102 mm split-ring or 102 mm Shear-plate

64 mm split-ring or shear-

plate

102 mm split-ring

or 102 mm

shear-plate


0 45 90 0 45 90 0 to 90 0 to 90

60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180

- 0.63 0.68 0.73 0.78 0.83 0.88 0.93 0.98 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

- -

0.64 0.68 0.71 0.75 0.78 0.82 0.85 0.89 0.92 0.96 0.99 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

- -

0.62 0.65 0.67 0.70 0.73 0.76 0.78 0.81 0.84 0.86 0.89 0.92 0.95 0.97 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

- - - - -

0.63 0.67 0.70 0.73 0.77 0.80 0.83 0.87 0.90 0.93 0.97 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

- - - - - -

0.64 0.67 0.69 0.72 0.74 0.77 0.80 0.82 0.85 0.88 0.90 0.93 0.95 0.98 1.00 1.00 1.00 1.00 1.00

- - - - - -

0.62 0.65 0.67 0.69 0.71 0.73 0.75 0.77 0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.97 0.99 1.00

- -

0.62 0.65 0.67 0.70 0.73 0.76 0.78 0.81 0.84 0.86 0.89 0.92 0.95 0.97 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

- - - - - -

0.62 0.65 0.67 0.69 0.71 0.73 0.75 0.77 0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.97 0.99 1.00


MTIB14TC2005R1


Table 25. Loaded, edge distances modification factor, KD, for split-ring and shear-plate connectors

Edge Distance

(mm) Value of KD

Connector size



Angel 1) of load to grain α

0 15 30 45 0 15 30 45 to 90

45 50 55

1.00 1.00 1.00

0.94 0.98 1.00

0.89 0.93 0.96

0.83 0.87 0.90

- - -

- - -

- - -

- - -

60 65 70

1.00 1.00 1.00

1.00 1.00 1.00

0.99 1.00 1.00

0.93 0.97 1.00

- -

1.00

- -

0.94

- -

0.89

- -

0.83

75 80 85

1.00 1.00 1.00

1.00 1.00 1.00

1.00 1.00 1.00

1.00 1.00 1.00

1.00 1.00 1.00

0.98 1.00 1.00

0.92 0.95 0.99

0.86 0.90 0.93

90 95

1.00 1.00

1.00 1.00

1.00 1.00

1.00 1.00

1.00 1.00

1.00 1.00

1.00 1.00

0.97 1.00


14.5 Spacing, edge and end distances The end and edge distances for split ring connectors are given in Tables 21 and 22. If the end distance, edge distance or spacing is less than the standard, but more than the minimum, the basic load should be modified as given in Clause 14.4. No increase in load is permitted if end distance, edge distance or centre spacing exceed the standard values. The definition of end distance, edge distance and spacing is illustrated in Figure 10.

MTIB14TC2005R1


where a1 is spacing parallel to grain; a2 is spacing perpendicular to grain; a3 is end distance; and a4 is edge distance. Figure 10. Spacing, Edge and End distance for split-ring and shear-plate connectors

If split-ring connectors are used in wet timber, the standard end distance should be multiplied by 1.5. One-half of this increased end distance should be taken as the minimum end distance, with a permissible load of one-half of that permitted for the standard end distance.

15 Shear plate connectors 15.1 General 15.1.1 Connector sizes The recommendations contained in this clause are applicable to the sizes of shear-plate connectors given in Table 26 in accordance with BS EN 912. The following requirements relate to shear plate connectors of nominal 67 mm and 102 mm sizes.

Table 26. Sizes of shear-plate connectors and minimum sizes of washers

Dimensions in millimetres

Nominal size of connector

Nominal size and thread diameter of

bolt

Minimum size of round or square washers

Diameter or length of side

Thickness

67 M20 75 5

102 M20 75 5

15.1.2 Bolts and washers The diameter of the bolts and the minimum size of washer to be used with each connectors are given in Table 18. Round or square washers shall be fitted between the timber and the head and nut of the bolt. 15.1.3 Joint preparation To prepare a connectored joint, the positions of the bolt holes should be set out accurately with reference to the point of intersection of the centre-lines of the members. One of the following procedures shall be used when drilling the bolt holes:

MTIB14TC2005R1


a) fit the members together in their correct positions and clamp while drilling the bolt holes

through all the members; and b) drill the bolt holes in the individual members using jigs or templates to locate the bolt

holes accurately. Bolt holes shall be within 2 mm of their specified position. The contact surfaces of the timber members shall be recessed to the dimensions shown in Figure 11. The recesses for shear-plates may be cut simultaneously with the drilling of the bolt holes if procedure b) is used.

a) Recess for 67 mm connector

b) Recess for 102 mm connector

NOTE. All dimensions are in millimetres.

Figure 11. Dimension of circular recesses for shear-plate connector

MTIB14TC2005R1


15.2 Effective cross section The effective cross-section of each member at a joint shall be determined by deducting the projected area from the gross area of the cross-section of the connector recess (i.e. 770 mm2 for each 67 mm shear-plate, or 1 690 mm2 for each 102 mm shear-plate) and the projected area of the bolt hole not within the projected area of the recess. The depths of the connector recess are 11.5 mm and 16.5 mm for the 67 mm and 102 mm shear-plates, respectively. When assessing the effective cross-section of multiple connector joints, all connectors and their bolts that lie within a distance of 0.75 connector diameters, measured parallel to the grain from a given cross-section shall be considered as occurring at that cross-section. Then the effective cross section shall be determined by deducting the given net projected areas of the connector recesses and bolt holes from gross area of the cross-section being considered. 15.3 Basic loads The basic working loads for parallel and perpendicular to the grain in dry timber are given in Table 27. These basic loads apply to a connector unit either: a) one shear plate with its bolt in single shear in a steel plate-to timber joint; or b) two shear plate back to back with the bolt in single shear, in a timber-to timber joint. When loaded at an angle α to the grain, the basic load is given by use of Hankinson’s formula or evaluated by means of the graph as given in Figure 4.

MTIB14TC2005R1


Table 27. Dry basic loads for one shear plate connector

Actual thickness of members 1) Basic load 1) (kN) for timber in group

Shear-plate

diameter

(mm)

Bolt diameter

(mm)

Connectors on one side

only

(mm)

Connectors on both

sides and on same

bolt (mm)

J1

J2 J3 J4 J5


67

M20

-

-

≥41

41

50

≥67

11.9

14.62)

15.482)

7.8

9.5

10.1

9.0

11.0

11.7

6.0

7.2

7.7

6.8

8.4

8.9

4.6

5.6

5.9

5.2

6.4

6.8

3.5

4.3

4.6

3.86

4.71

5.01

2.63

3.21

3.42

102

M20

-

-

41

≥44

50

67

75

≥92

20.5

24.12)

25.72)

27.72)

12.5

14.6

15.6

16.8

16.3

19.1

20.5

22.1

9.7

11.5

12.2

13.2

13.0

15.3

16.3

17.6

7.7

9.0

9.7

10.4

10.4

12.2

13.0

14.0

6.1

7.1

7.6

8.2

8.05

9.47

10.12

10.88

4.67

5.49

5.87

6.31

1) Loads for intermediate thickness may be obtained by linear interpolation.

2) see clause 15.4

MTIB14TC2005R1


15.4 Permissible loads The permissible load Fadm for n shear plate connectors shall be given by: Fadm = n K1 K2 K17 K18 F where K1 K2 K17and K18 are as defined in 14.4 and F is the basic load given in Table 27. 15.5 Spacing, edge and end distance As defined in Clause 14.5 where the given data for split-ring connectors are applicable to shear plate connectors

16 Steel dowels

16.1 General The recommendations contained in Clause 12 are applicable to plain steel dowels with a minimum tensile strength of 400 N/mm2 and a minimum dowel diameter of 6 mm. For the recommendations of Clause 12 to apply, the tolerance range on the specified dowel diameter shall be 0.0 mm to 0.1 mm and the dowels shall be inserted in pre-bored holes in the timber members having a diameter not greater than the dowel itself. Where a dowel does not extend to the surface of the outer members, for example, for reasons of appearance, the thickness of the member for calculation purposes shall be taken as the actual embedment length of the dowel. Care shall be taken to avoid axial forces being set up in dowelled joints as a result of asymmetrical, eccentric or oscillating loads. Steel plates shall have a minimum thickness of 2.5 mm or 0.3 times the bolt diameter, whichever is the greater, for the modification factor in Clause 12.2.3 to apply. 16.2 Effective cross-section When assessing the effective cross-section of multiple dowel joints, all dowels that lie within a distance of two dowel diameters measured parallel to the grain from a given cross-section shall be considered as occurring at that cross-section. Then the effective cross-section shall be determined by deducting the net projected area of the dowel holes from the gross area of the cross-section. 16.3 Dowel spacing The values relating to bolts in Clause 12.2.4apply. 16.4 Permissible load for a joint The permissible load for a dowelled joint should be calculated in accordance with Clause 12.2.3 and as appropriate using either the values given in Table 11, multiplied by the factor Kdowel = 0.75.

MTIB14TC2005R1


Bibliography [1] Timber design handbook-Malaysian Forest Record No. 42 – FRIM [2] Structural timber joints-Malaysia Forest Record No. 32 – FRIM

Acknowledgements Members of Technical Committee on Timber Structures Prof Dr Badorul Hisham Abu Bakar (Chairman) Universiti Sains Malaysia Ms Mahsuri Mat Dris (Secretary) Malaysian Timber Industry Board Mr Mohd Idrus Din/ Mr Ahmad Nuhairi Abdul Razak

Construction Industry Development Board Malaysia

Ir Dr Zuhairi Abd. Hamid/ Mr Ahmad Hazim Abdul Rahim

Construction Research Institute of Malaysia

Mr Muhammad Salleh Abdul/ Mr Abu Bakar Katain

Fire and Rescue Department of Malaysia

Dr Gan Kee Seng/ Dr Mohamad Omar Mohamad Khaidzir

Forest Research Institute Malaysia

Ir Ihsan@Hasni Atan/Ms Melati Mudzaffar Ali Jabatan Kerja Raya Malaysia Ms Hamidah Abdullah/Ms Rachel Joanes Ling Malaysian Timber Council Mr Muhammad Shaiful Nordin Malaysian Timber Industry Board Mr Saw Eng Thai/Mr Goh Yen Song/ Ms Pang Suet Kum

Malaysian Wood Industries Association

Mr Lim Choon Liat/Mr Jerry Tan Kuan Yee Malaysian Wood Moulding Joinery & Council

Mr Shahruddin Shahril/ Ar Shahrina Intan Abdullah

Ministry of Urban Wellbeing, Housing and Local Government

Mr Ng Wun Pin Multinail Asia Sdn Bhd Mr Ahmad Asmadi Mohamad/ Mr Muhamad Syamsul Nizam Md Sepian

MyGlam Sdn Bhd

Mr Lokman Mohamad/Mr Mansor Abas Persatuan Pengusaha Kayu-Kayan dan Perabot Bumiputera, Malaysia

Ar Ahmad Najib Ariffin Pertubuhan Akitek Malaysia Ir Prof Dr Mohd Zamin Jumaat The Institute of Engineers, Malaysia Assoc Prof Dr H’ng Paik San/ Dr Adlin Sabrina Muhammad Roseley

Universiti Putra Malaysia

Dr Izwan Johari/Dr Fadzli Mohamed Nazri Universiti Sains Malaysia Assoc Prof Dr Mohd Ariff Jamaluddin/ Prof Dr Zakiah Ahmad

Universiti Teknologi MARA

Mr Eddie Ling Lee Tee/Mr Ghaffar Ibrahim Woodsfield Glulam Manufacturing Sdn Bhd

Members of WorKing Group on Structural Use of Timber Part 5

Assoc Prof Dr Mohd Ariff Jamaludin (Chairman)

Universiti TeKnologi MARA

Ms Nor Shahira Mat Nasir/ Mr Muhamad Basri Md Daud (Secretary)

Malaysian Timber Industry Board

Mr Corsia Tan Koh Shior Individual Expert Ms Mahsuri Mat Dris/ Mr Muhammad Shaiful Nordin

Malaysian Timber Industry Board

Ms Pang Suet Kum Malaysian Wood Industries Association Mr Ng Wun Pin Multinail Asia (M) SdnBhd Dr Adlin Sabrina Muhammad Roseley Universiti Putra Malaysia Prof Dr Badorul Hisham Abu Bakar Universiti Sains Malaysia Assoc Prof Dr. Rohana binti Hassan

Universiti TeKnologi MARA


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DRAFT MALAYSIAN MTIB15TC2006R1 STANDARDsda.mtib.gov.my/wp-content/uploads/2017/10/DMS-544-PART... · 2017-10-09 · DEVELOPMENT OF MALAYSIAN STANDARDS The Department of Standards