AU1007899A - A wall assembly - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor: Address for Service: JAMES HARDIE RESEARCH PTY.

LIMITED

066 114 092) Bradley John DRUMMOND CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, QId. 4000, Australia.

Invention Title: A WALL ASSEMBLY Details of Associated Provisional Applications: No. PP1991 filed on 26 February 1998 The following statement is a full description of this invention, including the best method of performing it known to us: A WALL ASSEMBLY This invention relates to a wall assembly and particularly relates to a wall assembly consisting of an outer portal frame and an inner stud frame which are fastened together to provide superior horizontal stiffness.

Wall assemblies for buildings include brick, block or concrete walls, and structural steel frames, which provide excellent stiffness and resistance to horizontal displacement, but are heavy and not suited for transportable buildings or light-weight prefabricated buildings.

The latter buildings are preferably formed from stud wall assemblies which comprise a number of vertical studs having a top plate and a bottom plate, the studs and plates typically being made from wood, or from light-gauge roll-formed metal section.

°These stud wall systems, and similar systems have fairly distinct limitations on bracing (horizontal force) resistance; the horizontal 15 force resistance being required in resisting horizontal forces caused by wind, or earthquake loadings.

In conventional construction, where higher capacities are required, brick or concrete walls are used or structural steel frames are used, but as mentioned above, these systems are not well suited to transportable buildings or light-weight prefabricated building systems. The horizontal force applied to a wall assembly is illustrated in Figure 2 which shows that an upper force causes deflection of the wall assembly. Such deflection must be reduced or minimised and for a wall having a height of about 2.4m, a horizontal deflection should be approximately 12mm or thereabouts.

S 25 To improve the stiffness of wall assemblies, it is known to attach a lining sheet to the stud wall assembly. The lining sheet reduces the deflection caused by a horizontal force. The lining sheet must be carefully attached to the stud frame, and regulations require close spacings of screw or nail fixings between the lining sheet and the stud frame. Adjacent lining sheets must be closely butted together and a relatively large number of screws or nails must be used to provide a total diaphragm action of the individual lining sheets.

It would be advantageous to glue the lining sheet to the stud frame, but on site attachment of the lining frame by gluing requires a high level of supervision to ensure adequate quality and requires proper clamping or pressing between the lining sheet and the stud which is often difficult or impossible to do.

A lined (or sheeted) stud frame while having improved resistance to deflection, is still subject to horizontal displacement and (b) tipping (overturning) displacement due to an applied force.

The shear (horizontal) and tie-down (tipping) resistance is conventionally achieved by bolts anchoring the base of the stud wall to the sub-structure (typically a concrete slab), or by full height anchor rods extending from the top plate through the stud wall and into the sub-structure to tie the entire stud wall to the sub-structure.

This conventional technique provides resistance to horizontal 15 displacement and overturning of the stud wall. Slight improvements can be made by varying the anchors, the size and thickness of the lining sheets, using stiffening gussets, reinforcing angles and the like, but even with all these variations, the conventional arrangements still suffer from excessive deflection with a fairly low force.

Figure 3 illustrates this graphically with the graph lines represented by showing conventional arrangements, and clearly showing that even with variations to lining sheets and anchors, etc., the stud walls all still excessively deflect with a force of about 15kN or more (an excessive S: deflection being more than 12mm of thereabouts).

S 25 The present invention is directed to a wall assembly which can significantly improve the force/deflection ratio by having the wall assembly formed from an outer portal frame and an inner stud frame assembly. This combination provides surprising and unexpected and synergistic improvements and allows much greater forces to be applied to the wall assembly before excessive deflection occurs.

It is an object of the invention to provide a wall assembly which may overcome the abovementioned disadvantages or provide the public with a useful or commercial choice.

In one form, the invention resides in a wall assembly comprising: an outer portal frame which has a pair of spaced apart portal frame posts, means to anchor the posts to a sub structure, and an upper portal frame beam which is attached adjacent upper ends of the posts, and an inner stud frame assembly which has a plurality of stud posts and a lining sheet which is attached to at least two of the stud posts, the inner stud frame assembly being fixed to the portal frame.

In another form, the invention resides in a wall assembly comprising: an outer portal frame which has a pair of spaced apart portal frame posts, means to anchor the posts to a sub structure, and an upper portal frame 15 beam which is pinned or pinned attached adjacent upper ends of the posts, and an inner stud frame assembly which has a plurality of stud posts and a lining sheet which is attached to at least two of the stud posts, the inner stud frame assembly being fixed to the portal frame.

While not wishing to be bound by theory, it appears that the portal frame and the inner stud frame assembly have some form of cooperative interrelationship which provides markedly improved stiffness without requiring the use of concrete blocks, structural steel frames, and the S 25 like.

The wall assembly according to the invention finds use in transportable buildings and light-weight prefabricated building systems, and seems to be applicable for multi-story buildings and buildings which are subject to extreme loading conditions such as in high wind areas, or in earthquake prone areas.

The portal frame may be pin jointed and can be made from metal section, for instance box section and the length of the posts and the beam may vary depending on the size of the required wall assembly.

The portal frame typically has two spaced apart frame posts and a top frame beam with the beam being pinned or otherwise secured to upper ends of each post. The posts can be pinned or anchored to the substructure (typically a concrete slab or wooden floor).

The arrangement is such that the portal frame itself, is unstable with horizontal loads, but by being anchored to the substructure is stable against horizontal displacement or overturning.

The inner stud frame assembly can be formed in a conventional manner and consist of a number of spaced apart vertical parallel studs, a bottom stud plate and a top stud plate to provide a rectangular arrangement.

The studs can be attached by usual methods including nails or screws. The stud frame has a lining sheet attached to it and to at least two of the stud posts. In practice, it is preferred that the lining sheet lines the entire stud

I.

frame assembly. A lining sheet can be provided on one side of the stud frame assembly or on both sides of the stud frame assembly. The lining sheet can be attached by nails or screws and this can be done off site. If the manufacture of the stud frame assembly is done off site, the lining sheets can be glued to the stud frame as a higher degree of quality can be obtained.

The stud frame assembly is fitted inside the portal frame and is fastened to at least one of the posts or beam of the portal frame, but preferably is fastened to both portal frame posts and the upper portal frame beam.

The graph of Figure 3 clearly illustrates the advantages of the S 25 combination with Test 1, Test 2 and Test 3 showing three variations of the wall assembly according to the invention but clearly demonstrating that in each variation the amount of force required to provide a 12mm displacement is markedly higher than existing wall systems.

An embodiment of the invention will be described with reference to the following drawings in which Figure 1 is a side view of a wall assembly according an embodiment of the invention.

Figure 2 shows diagrammatically a stud frame assembly defecting under a force.

Figure 3 shows graphically the results of the wall assembly according to an embodiment of the invention and existing stud wall assemblies.

Referring initially to Figure 1 there is shown a wall assembly which consists of an outer pin jointed portal frame formed from two spaced apart portal frame posts 11,12 and a top portal frame beam 13. Beam 13 is pinned to the top of posts 11 and 12 through pins 14, 15. The bottom of posts 11 and 12 are pinned to the substructure 16 by pins 17, 18. The portal frame arrangement is such that it is easy to transport and assemble but itself provides no or very low resistance against a horizontal force of the type illustrated in Figure 2.

"'"Inside the portal frame is a lined stud wall assembly 19 which is o 15 formed from a number of spaced apart vertical studs 20A, 20B, 20C, etc., a bottom horizontal base plate 21 and upper horizontal top plate 22. The vertical and horizontal studs are all nailed, welded or otherwise attached together, and a lining sheet is glued, nailed, screwed or otherwise attached to the one side of both sides of the stud frame assembly.

The stud frame assembly is fixed to the posts 11, 12 and beam 13 of the portal frame using an array of fixings 23A.

Referring to Figure 3, the advantages of the wall assembly according to the embodiments are illustrated.

Test 1 is directed to a wall assembly being 5m long and 2.4m high with 9mm thick lining sheet of each side of the stud frame. It can be seen that in this arrangement, a deflection of about 12mm does not occur until a force of between 45 to 55kN is applied.

Test 2 shows a wall assembly 3m long and 2.4m high with a lining sheet on one side of the stud frame assembly and in this test, a deflection of 12mm does not occur until about 30kN force is applied.

Test 3 shows a 3m long wall which is 2.4m high with a thinner 3mm ply lining sheet on each side of the stud frame assembly and again it can be seen that a similar force to that of Test 2 is required in order to provide a deflection of about 12mm.

This is in contrast to existing stud frame assemblies which are illustrated by the letter in Figure 3. The various tests of existing stud frame assemblies are with walls 3m long and between 2.4 to 2.7m high with a variety of linings, full height anchors, stiffening gussets, reinforcing angles and the like, and these various tests can be considered indicative of current methods of steel frame performance.

It should be appreciated that various other changes and modifications can be made without departing from the spirit and scope of the Invention as described and/or claimed.

Claims (14)

1. A wall assembly comprising an outer portal frame which has a pair of spaced apart portal frame posts, means to anchor the posts to a sub structure, and an upper portal frame beam which is attached adjacent upper ends of the posts, and an inner stud frame assembly which has a plurality of stud posts and a lining sheet which is attached to at least two of the stud posts, the inner stud frame assembly being fixed to the portal frame.

2. The assembly of claim 1, wherein the beam is pinned to the lo portal frame posts.

3. The assembly of claim 1 or claim 2, wherein a lower end of at least one portal frame post is pinned relative to the sub structure.

4. The assembly of claim 3, wherein each said post is pinned to i' the sub structure. 15

5. The assembly of any one of the preceding claims, wherein the portal frame is pin jointed and is made from metal section, for instance box section, the length of the posts and the beam able to be varied depending on the size of the required wall assembly.

6. The assembly of any one of the preceding claims, wherein the inner stud frame assembly has a number of spaced apart vertical parallel studs, a bottom stud plate and a top stud plate to provide a rectangular arrangement.

7. The assembly of claim 6, wherein the stud frame assembly has 4**o a lining sheet attached to it and to at least two of the stud posts. 25

8. The assembly of any one of the preceding claims, wherein the lining sheet lines all or substantially all of one side of the stud frame assembly.

9. The assembly of any one of the preceding claims, wherein a said lining sheet is provided on both sides of the stud frame assembly.

10. The assembly of any one of the preceding claims, wherein the stud frame assembly is fitted within the portal frame.

11. The assembly of any one of the preceding claims, wherein the stud frame assembly is fastened to at least one of the posts or beam of the portal frame.

12. The assembly of any one of the preceding claims, wherein the stud frame assembly is fastened both portal frame posts and the upper portal frame beam.

13. The wall assembly of any one of the preceding claims, and which has a force/deflection ratio as illustrated in Test 1, 2 and 3 in Figure 3 of the drawings.

14. A wall assembly substantially as hereinbefore described with reference to the drawings A transportable building, light-weight prefabricated building system, multi-story building, and/or buildings which are subject to extreme loading conditions such as in high wind areas, or in earthquake prone areas, which contain at least one wall assembly as claimed in any one of the 15 preceding claims. a. a a a DATED this 11 th day of January 1999 JAMES HARDIE RESEARCH PTY. LIMITED 066114 092) By their Patent Attorneys CULLEN CO. a a a. a a a a