Genral code sub floor

AS 1684 SECTION 2 - TERMINOLOGY AND DEFINITIONS

1

SECTION 2 -

TERMINOLOGY AND GENERAL


2

2.1 GENERAL

The terminology and definitions given in this Section shall be used in conjunction with the requirements of this Standard.The terminology used by the building industry varies greatly between states, regions within states and even between those working in the same region. Where possible, the more commonly used terms have been adopted by this standard.


3

FIGURE 2.1 FRAMING MEMBERS — FLOOR, WALL AND CEILING


4

2.3 VERTICAL NAIL LAMINATION

Vertical nail lamination shall be permitted to achieve the required breadth for larger section sizes given in the Span Tables in the Supplements using thinner and more readily obtainable sections.This is only permissible using seasoned timber laminations of the same timber type (e.g. hardwood + hardwood, softwood + softwood) and stress grade.


5

D irection of load

D irection of load

The term 'vertical nail lamination' is used because the loads applied to a house frame are predominantly vertical.

The load applied to nail laminated timber must always be in the direction of the depth of the timber and at 90O to the nails.


6

Load

Load

Movement occurs between the pieces

If the load on a nail laminated member is in the opposite direction to the depth and in line with the nails, the nails will be insufficient to prevent movement between the two pieces.

Due to this movement or 'slippage' between the pieces they will act individually rather than as a single member.


7

D irection of load

D irection of load

The nail size and spacing that applies to 'vertical nail lamination' is also applicable to members used horizontally where the direction of the applied load is horizontal.


8

Loads are distributed equally between points of support.

Of the total load on MEMBER X, half (2000mm) will be supported by the beam or wall at A and half (2000mm) will be supported by the beam or wall at B.

BA

M EM BER X


9

If MEMBER X is supported at 3 or more points, it is assumed that half the load carried by the spans either side of supports will be equally distributed.

A B C

M EM BER X

Beam A will carry 1000 mm of load, Beam B will carry 1000 mm plus the 2000 mm on the other side, and Beam C will carry 2000 mm.


10

2.6.2 Floor load width

Floor load width (FLW) is the contributory width of floor, measured horizontally, that imparts floor load to a supporting member. FLW shall be used as an input to Span Tables in the Supplements for all bearers and lower storey wall framing members


11

Of the load on a floor joist, it is assumed that half will go to the bearer on one end and half to the bearer on the other end.

So floor load width (FLW) is simply half the floor joist span on either side of the bearer, added together. The only exception is where there is a cantilever. In this situation, the total cantilever distance is included.

A B C

FLW for Bearer or wall at = 1/2 floor joist span =

A

1 0 0 0 m m

FLW for Bearer or wall at = 1/2 floor jo ist span on either side = 1000 +2000 m m =

B

3000 m m

FLW for Bearer or wall at = 1/2 floor joist span = 2

C

0 0 0 m m


12

Of the roof load on members such as rafters and trusses, half will go to the supporting wall or beam on one end and half to

the supporting wall or beam on the other end.

2.6.4 Roof load width (RLW) cont’d.

Roof load width (RLW) is simply half the particular member’s span, between support point, plus any overhang, and is measured on the rake of

the roof. A B

Half tota l load = RLW Half to tal load = R LW


13

2.7.5.3 Single Span The span of a member supported at or near both ends with no immediate supports. This includes the case where members are partially cut through over intermediate supports to remove spring (see Figures 2.18(c) and 2.18(d)).

S i n g l e s p a n

S i n g le s p a n S i n g le s p a n

S a w c u t J o in t o r l a p

(c) Two supports (d) Joint or sawcut over supports

FIGURE 2.18 SPACING AND SPAN


14

2.7.5.4 Continuous Span The term applied to members supported at or near both ends and at one or more intermediate points such that no span is greater than twice another (see Figure 2.18(e)).


(d) Continuous span

C o n t i n u o u s s p a n

C o n t i n u o u s s p a n

NOTE: The design span is the average span unless one span is more than 10% longer than another, in which case the design span is the longest span.


15

Span 1 (2000m m) Span 2 (3930m m)

1/3 (2000mm)

The centre support must be wholly w ithin

the m iddle third.

Span 2 is not to be greater than tw ice Span 1.This span is used to determ ine the size using the continuous span tables.

6000m m

1/3 (2000mm) 1/3 (2000mm)

75mm 75mm 75mm

Example:Continuous Span


16

J o is t s s p a c in g( c e n t r e - l in e to c e n t r e - l i n e )

B e a r e r s p a c in g( c e n t r e - l in e to c e n t r e - l in e )

J o is t s s p a n ( b e t w e e n i n te r n a lf a c e s o f s u p p o r t m e m b e rs )

(a) Bearers and joists



17

1.12 BEARINGWhere the bearing area is achieved using a non-rectangular area such as a splayed joint, the equivalent bearing area shall not be less than that required above.

7 0 m m

= 3150 m m 2

Bearing area = x 45m m70m m2

70 m m45

mm

= 3150 m m 2

Bearing area = x 45m m70m m2

45 m

m


18

This Standard does not preclude the use of framing or fastening methods or materials other than those specified. Alternatives may be used, provided they satisfy the requirements of the Building Code of Australia.

1.3 USE OF ALTERNATIVE MATERIALS OR METHODS


19

This Standard does not preclude the use of framing or fastening methods or materials other than those specified. Alternatives may be used, provided they satisfy the requirements of the Building Code of Australia.

1.3 USE OF ALTERNATIVE MATERIALS OR METHODS


20

• Dead Loads - the forces arising from the weight of the building components themselves.

• Live Loads - the forces arising from the weight of persons using the building and moveable furniture.

• Wind Loads - the forces arising from - gales, thunderstorms & tropical cyclones.

The main forces acting on buildings are:


21

• Dead Loads - the forces arising from the weight of the building components themselves.

• Live Loads - the forces arising from the weight of persons using the building and moveable furniture.

• Wind Loads - the forces arising from - gales, thunderstorms & tropical cyclones.

The main forces acting on buildings are:


22

Cantilever1.5 D

Roof or floor load

Support

D The 1.5 tim es the depth of the member is measured between the support mem ber and the side of the point load

This m em ber can be designed as notsupporting load if the cantilever is no more than 1.5 x D

This may be any member that supports roof and/or floor loads


23

Cantilever1.5 D

Roof or floor load

Support

D The 1.5 tim es the depth of the member is measured between the support mem ber and the side of the point load

This m em ber can be designed as notsupporting load if the cantilever is no more than 1.5 x D



24

O f f s e t 1 . 5 m a x .D

R o o f o r f lo o r l o a d

S u p p o r t

T h is m e m b e rd e s ig n e d a s n o ts u p p o r t in g lo a d

D



25

O f f s e t 1 . 5 m a x .D

R o o f o r f lo o r l o a d

S u p p o r t

T h is m e m b e rd e s ig n e d a s n o ts u p p o r t in g lo a d

D



26

Top plate

Lintel

Strutting Beam, G irder Truss etc.creating a point load on Top plateand LintelAn example of this is

where a strutting beam or girder truss is supported by a lintel. This lintel needs to be designed for this point load. The jamb studs will also need to be designed to carry this extra load as well as the structure that supports these jamb studs.


27

Top plate

Lintel

Strutting Beam, G irder Truss etc.creating a point load on Top plateand LintelAn example of this is

where a strutting beam or girder truss is supported by a lintel. This lintel needs to be designed for this point load. The jamb studs will also need to be designed to carry this extra load as well as the structure that supports these jamb studs.

Documents

Genral code sub floor