THE USE OF STEEL REINFORCEMENT SYSTEMS TO IMPROVE …

THE USE OF STEEL REINFORCEMENT SYSTEMS TO IMPROVE THE STRENGTH ANO STIFFNESS OF LATERALLY LOADED CAVITY BRICK WALLS

P J MULLINS Enqineer Deoartment of Works Queensland, Brisbane, Australia

C O'CONNOR Professor Deoartment of Civil Engineering, University of Queensland, Brisbane, Australia.

ABSTRACT A vertical shear connector suitable for manufacture by automated sheet metal processes from steel coil is developed in an experimental program involving 90 small area hearing tests, 18 shear tests and 6 tension tests. A comparison of three full scale wall panel tests, (1) sta~dard cavity wall, (2) cavity wall with an unbonded intermediate steel mullion (76x51x3.2 R.H.S.), (3) cavity wall with a vertical shear connector, demonstrate that the connector siqnificantly increases both the post and pre-cracking strenqth and stiffness under out-of-plane loarts.

1. INTRODUCTION

The strength of a cavity brick wall subiected to out-of-olane loads such as wind and earthquake loads is limited.

The ability Qf the wall to soan horizontally between integral return walls is restricted by (a) the wall capacity, (b) the inclusion of windows and doors, (c) the trend for ooen planning with larqe distances between return walls and (d) the use of vertical ioints for crack c0ntrol.

The capacity of an unreinforced wall to soan vertically between floors or floor and roof structure is shown in FiQure 1. Australian codes of practice (Ref. 3) soecify that a low rise building on a non-exposed site in a non-cyclonic area such as Brisbane be desiqned for a wind velocity of 33 m/s (W33). Dependinq uoon building qeometry and oermeability this results in a design wind pressure ranqinq between 0.6 kPa inwards to 0.9 kPa outwards. A vertical soan of 2.4 m is oermissible therefore in normal cavity brick walls only in the most sheltered situ'1tions.

The obiectives of the experimental proqram presented in this paoer were to:- (a) investiqate a cavity brick wall with standard dual limb ties, (b) investigate a cavity wall reinforced with an unbonded intermediate steel mull ion (R.H.S. )* 1 in the wall cavitv (Figure 2a), (c) develop and investiqate a vertical shear connector* 2 (Figure 2b) to achieve shear transfer between the two leaves of the wall prior to crackinq and function as bonded reinforcement for increased post­crackinq strenqth and stiffness.

Previous work has been dane in Austral ia on an intermediate steel mullion by Lawrence (Ref. 2) who concluded that a 150 U.C.* 3 built into the leaf of a cavity brick wall has (a) little effect on the behaviour of the wall before cracking of the brickwork and (b) a maior influence in determininq the ultimate load capacity.

NoTES: * 1 Rectangular Hollow Sectlon. * 2 Patent Aoolication No. PG5960 by Uniquest, University of Queensland. * 3 Universal Column.

969

E

\tI33 \tII.2 \tI46\t1S1 WS8 W6S

W 3 W42 W46 \ti 1

\oIAll HEIGHTS ARE aASED UPON I ~ FOLL O\ol ING 'SSUHPT I ON~

t I NfINITE TlE S IIFFNE SS L BASE RES TRAINT MiJ"ENT (ORRESF'IlN()ING . TO ZERO H NSlLE STR(SS IN THE EXTREME

FIBRE 3. NO TQP RE 5 TRAINT HCl'1ENT ~. BRI(I( WIOTH· 11 0 mm

6 5. BR I(K \oIORK OENS ITY - 1800 log/ mJ

t1AJ(IMUM A.LlOWABLE TENSILE B(NO I NG ST Rt ssES

IF.I ANO Sl ENOERNESS RATlO AQE AS SPWF IEO

I M ASIHO

2

W 58

LATERAl PRESSURE I KPa)

FIGURE 1 - VERTICAL SPANNING CAPACITIES,

2. EXPERmENTAl PROGRAM

2.1 Materials

W6S

PlAN

SECTION SECTION

! (al-INTERMEOIATE STm MUlUlN I !Ibl VERTICAL SHEAR CONr-t:CTOR I

FIGURE 2 - VERTICAL REINFORCEMENT SYSTEMS.

The ranqe of parameters was limiteo to a sinqle brick and 1:1:6 mortar.

2.1.1 Bricks. The extruded clay bricks used in the investiqation were nominal 230 mm x 110 mm x 76 mm depth with three 40 mm diameter extrusion holes. Their ohysical and mechanical properties were determined in accordance with AS1226 (Ref. 4)*1 and were as follows:-

(a) Physical Properties. Averaqe actual dimensions of 24 bricks were 233 ll1l1 x 114 mm x 77 mm depth with 41 mm diameter extrusion holes; averaqe absorption coefficient was 10.5% with N* 2 = 6, S* 3 = 0.28%; sliqht efflorescence with no soalling; initial rate of absorption was 2.5 kg/m2 /min with N = 6, S = 0.45 kq/m 2 /min.

(b) Mechanical Properties. Averaqe brick compressive strenqth was 30.9 MPa with N = 12, S = 2.46 MPa, C*4 = 26.5 MPa; averaqe modulus of rupture was 1.07 MPa with N = 12, S 0.45 MPa, C = 0.26 MPa.

2.1.2 Mortar. The mortár used was batcheo in the proDortions and by the methods shown in Table 1. Sieve analyses for sand batches A & B a re shown in Fiqure 3. Any mortar remaininq after 90 minutes was discarded. Retemperinq was permitted. Control specimens (70x70x70 mm) were moist cured and tested under axial compression in accorrlance with AS A123 (Ref. 5) at 28 days and the results are shown in Tabl e 2.

NOTES: *1 AS - Australian Standard *2 N Number of Samples *3 S - Stanrlarrl Deviation *4 C = C,,", a r a c te r i s t i c St renqt,,", f)as erl upon a 95 oercentile.

970

Mortar Cement Lime Sand Water Sand Designation Ba tch

S 1 1 6 3.3 A

L 1 1 6 2 B

T~ble 1 - Mortar Mix Properties by Volume

Mortar Test Designation

Br i ckwo r k compress i on, S Small area bear i ng seri es 1.

Tab shea r seri es 1, S Small area bear ing ser ies 2.

Tab shear ser ies 2. S

Standard ca vi ty wall L

Intermediate steel mulli on wal l L

Verti cal shear conn ector wall L

100..--------='31"'""------.

Ba tch i ng Me thod

by Vo lume

by We i ght

~ 60 Vl

êt.

~ 40 >­z

~ if 20

SIEVE APERTURE (mm)

FIGURE 3- SIEVE ANALY SES.

Average Ul timate Number of Standard Compressive St ress Spec imens Devia t ion

(MPa ) (MPa)

4.3 6 0. 1

5. 7 10 1.3

6.0 9 1. 0

10. 1 31 0.8

8.9 20 0.6

8.9 18 0.6

Ta ble 2 - Mo rtar Compr essive Strengths

2.1.3 Brickwork (a) Compressive Strenqth. Four-hi gh brickwork piers constructed with type S mortar an d tested under ax ial compr ession in accordance with AS1640 (Ref. 1) at 28 days had an average ulti mate compressive strenqth of 12.9 MPa with N = 6, S = 1. O MPa.

(b) Bond Strenqths. Bond strengths were determined by (1) the bond in bending test on 9-hiqh brick piers similar to AS1640 and (2) the 'bond wrench' method developed by the B.D.R.I.* l . Bond strenqth values are shown in Table 3. Bond strenqth values were obtained from the standard cavity wall after the wall had failea under out-of-plane l oading - by progressively removinq the perpend mortar with non-percussion hiqh soeed drills and measurinq the bond strength of the bed ;oint with the 'bond wrench'. The bond in bendinq tests were performed in a comoression testing machine with the brick beam suoported on self-aliqninq rollers at 700 mm centres and load apolied by a central line load mounted on a soheri cal seat. The averaqe modul us of el asticity of the beams at 56 days was 4.9E3 MPa with N = 15, S = 1.IE3 MPa

NOTES: *1 BDRI = Brick Development Research Institute, Australia.

971

Bond Strength Standard Cavity In termed i at e Steel Vertical Shea r Co nnec tor Test Me thod Wa 11 Mu 11 ion Wa 11 Wa ll

AS16 40 -Bond i n Bendi ng

(a ) 9 high pi ers A 56 56 7 56 N 6 6 2 3 X 0.59 0.77 0.97 1.08 S 0.25 0.16 - -

C 0.09 0.45 - -

B.D.R . !. -Bond Wrench

(a) Remnants of A 56 56 7 56 bond i n bendi ng N 40 41 21 21 pie rs X 0.78 0.84 0 .94 0.98

S 0. 26 0. 17 0. 25 0.21 C 0.36 0.56 0. 51 0.62

(b) 4 hi gh piers 56 12

1. 13 0.20 0.77

(c) Remnants of A - 60 A = Age at test (days) tes t wa ll N 60 N = Number of tes t s

X 0.B9 X = Average ultimate bond strength (MPa) S 0.37 S = Standard deviat ion (MPa) C 0.29 C = Characteri stic streng t h based on a

95 jle rcen t i l e · (MPa)

Table 3 - Bond Strenqtns

2.2 Tab Develooment Tests

The vertical shear connector necessitates a tab which is bui l t into the brickwork and has sufficient capacity to transfer lonqitudinal (i .e. vertical) shear forces in the plane of the wa l l and out of olane tension and compression forces. Tests undertaken in the development of a possible tab are described in the fo 11 owi nq .

2.2.1 Small Area Bearinq Tests. A total of 90 small area bearing specimens consistinq of a steel bearinq plate embedded in mortar on a half brick were tested with the half brick mounted on 3 mm plywood in a compression testing machine. Load was applied throuqh a spherically seated loading head directly onto the steel hearing plate. Two series of tests we re performed. In series 1 bearing plates were located at a corner of the brick wnile in series 2 bearinq olates were located at an edqe and remote from a corner. Ultimate bearing stress based upon the area of the steel bearinq plate is plotted against morta r thickness in Fiqure 4. Predominantly speci mens failed by vertical splitting of the brick.

2.2.2 Tab Snear Tests. Five-course hiqh cavity bri ck walls were constructed with one tab built into tne central pe rpend in the second course of each leaf. Tne walls were cured under olastic sheeting in the laboratory for 28 days then tested as shown in Figure 5. Tab shear force was assumed to equal half the iack forc e

972

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20 :::> 20

O~ __ ~ __ ~ __ ~ __ ~~ __ ~ __ ~ __ ~ __ ~ O 6 B lO 12 1" 16

AVERA GE HORTAR TH ICKNE SS Imml

° 0~--~--~---76----~8--~10--~1~2--~14--~16 AVERAGE HORTAR THICKNESS /mm'

1(0)- SER/ ES 1 I HbJ - SER IES 2 I

FIGURE 4- SMALL AREA BEARING TESTS.

PROVING R/NG .

r------'===;;==I==;r==='-=I- 2.5,," PLATE 'AI/TH TABS

1=='!:=;;::=;;~n;:=::=;~=tMAG NET/C BA SE & ----l<é--r.=;t-i=!=l --..J,==dJ,I~~'====d.~[lAL GAUGE

SE(T/~ ELEVATION SECT/ON

FIGURE 5 - TAB SHEAR TEST ARRANGEMENT

Two series of tests were oerformed. Series 1 consisted of 12 single bed joint tab soecimens with varying perpenrl and bed ioint oroiections. Tab configuration and test results are shown in Figure 6a. After consirleration of the results a double bed ioint tab was proposed and 6 soecimens were constructed. Series 2 tab confiquration and test results are shown in Figure 6b. All 18 specimens failed by solittinq the five courses of a leaf vertically at the tab position.

973

40 11 b c 60 50 15 60 50 75 30 65 15 30 (Jj 75

li 30

Z Z = ~ u.J .... U u a: a: fi: 20 fi: 20

~ ~ u.J Z 1Il V'l

co co ;5 ;5

10

TAB ELEVATION SECTION

05 10 15 OEFLECTION Im ml OEFLECTION Imml

111l1 -SERiES 1 I I (bl- SERfES 2 t FIGURE 6 - TAS SHEAR TESTS.

2.2.3 Tab Tension Tests. The 6 unfailed tabs and attached brickwork leaves of the tab shear tests series 2 were tested in tension as shown in Fiqure 7a. Specimens 1 and 2 were supoorted on flexible material and tested at 126 days while soecimens 3 to 6 were bedded on mortar and tested at 140 days. All soecimens were air cured after 28 days. Test results are shown in Figure 7b. Pre~ominantly failure included splittinq of the brickwork through the plane of the oerpend at the tab location.

SfíTIONAL ELEVATION

I (Ilt TES T ARRANCi'lENT I

IlNEIT BASE' DIAL GAUGE.

LEAF DF B~(KWORK WITH UNFAILEO TA B

FIGURE 7-TAB TENSION TESTS .

ULT 21-5

ULT 168

O~ ________ ~~ ________ ~ ________ ~ o tO 2 o JO

DEFLECTIIl'j (mm)

11 bl- gST RESuLTS. I

974

2.3 Full Scale Wall Tests

A series of 3 test panels, (a) standard cavity wall, (b) cavity wall with an unbonded intermediate steel mullion (R.H.S.), (c) cavity wall with vertical shear connector, have been constructed and tested.

2.3.1 Test Arranqement. All walls were constructed in a similar manner and consisted of a 50 mm cavity with each leaf 6 bricks long and 35 courses high. Joints were 'struck-off flush'. The walls were air cured in the laboratory and tested at 56 days. Each wall was subiected to a line loading consisting of a dist~ibuted out 0f plane load apolied alonq a central vertical line. The load was applied by two Amsler iacks, mounted horizontally in parallel, to an articulated loadinq device which applied 8 equal ooint loads, distributed uniformly between horizontal restraints. The loading device was constructed to allow the vertical shorteninq necessary at larqe wall displacements. Figure 8 details the test arrangement and the base restraint. The top horizontal restraint for the standard cavity wall consisted of a 200 UB25 beam with a 20x20 mm continuous bead of non-shrink grout between the beam and the wall extending the lenqth of the wall. For the intermediate steel mullion wall and the . vertical shear connector wall the grout bead was replaced by 2 of 20x20x50 mm rubber blocks at 1400 mm centres and the mullion/connector was fixed with an M16 bolt to the reaction frame. A vertically slotted hole was provided in the joint to minimize vertical restraint. The vertical span between horizontal restraints was 2.9 m.

+ lB r

~ JdlQ

" A STANOARQ ~~llln: IlES

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eiAti

,

OCTAIL 5

f\ ::' 1,,;-: I:: ;:: ~ fi ... "

'~ ' [ITAIl4

r= IN IERMEOIAIE S IEEL MU LlION

OETAIl3 ~ OETAll2

I

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=eu OETAIL~

'-....-SEC T10N A-A SECI ION &8 VERTICAL SHEAR CONNECIOR

I 101- TEST ARRANGEMENT I I1 bl- DETAIL 6 - BASE RESTRAINT I

FIGURE 8- FULL SCALE WALL TESTS.

975

2.3.2 Standard Cav ity Wa 11 • Propri etary dual 1 imb cavity ti es manufactured from 3. 15 mm diameter wire with a 4 mm central kink were installed in the bed ;oints above the 1st, 7th, 14th, 21st, 28th and 34th courses. Ties were located centrally and at 115 mm from both ends of the course. Five of the ties were strain qauqed and calibrated to measure tie force. The ties were installed at locations as shown in Figure 9. Theoretical tie forces were calculated and are comoared with measured tie forces in Figure 9.

10 TIE 1

/ !

TIE 5

8

Z / :: 06 ~ <I. I ~4 >-j

/

TIE2 TIE 3

/ /

ACT UAl

CAl CU lATED (ASS UME D TIE STl f FNE SS 95KN/mm

/

TlE4

/ /

/

os 10

Total lateral load is plotted against central mid heiqht deflection of the rear leaf in Fiqure 10a. An initial crack was detected in the front leaf at a load of 6 kN but did not propagate until the rear leaf commenced to crack at a load of 8.2 ,<N. This load corresoonds to a bond stress of 0.46 MPa assuming simply supported conditions and the normal design assu mp tio'1 that the capacity is the sum of the capacities of the two leaves. This assumption leads to an uoper bound of capacity corresoondinq to infinite tie stiffness. Cracks were observed in the front leaf in the bed joint above the 19th course and to a lesser deqree above the 20th course. The rear leaf cr acked in the joint above the 21st course.

2.3 . 3 Intermediate Steel Mullion Wall. A 76x51x3.2 R.H.S. with a measured yield stress of 430 ~Pa was installed centrally within the cavity. Each leaf of the wall was built tight against the R.H.S. A vertical damp- proof course was provided between the back leaf and the mullion. Standard cavity ties as described in the standard cavity wall tests were used with the exceotion that additional ties were provided on both sides of the mullion and at half the vertical spacinq.

The wall was unloaded after the first and second cracks occurred in the wall at the ;oint above the 19th course of the rear and front leaves resoectively. Loading then continued with extensive cracking until the central deflection reached an arbitrary 130 mm. The load deflection plot is presented i n Figure 10b.

976

70

~ W

50

40

30

z '!';

o ~ ~ 20 ... a: .., ..... ... --'

10

I

°OL---~--~~----~---wL---~--~w MIO HEIGHT OEFLECTION (mm)

I (0)- STANOARO CAVIT Y \oIALL I

~ o

'" '" -... ~

60 ( \ 50

40

/ 30 /

z / "" o <l: o --' 20 I --' ... a: .., ..... :5

/

10

i ! O ~L-____ ~ __ ~ __ ~ ______ ~

O 20 W 60 MIO HEIGHT OEFLECTION (mm)

I (() - VERTICAL SHEAR COr-f-lECTOR WALL I

~r-~o~-------------------------------------------------------------' .., no :;:

30

/

/' ULTI MA1E LO AO CAPA( IT Y

/

... ~ . _ --- / --- ---

/ PERMJ')SABLE DESIG N l OAD

/

20 40 60 80 100 MIO HE IGHT OEFLECTION (mm)

[Jti[}NTERMEOIATE STEEL MULlION WALÇ)

FIGURE 10 - FULL SCALE WALL TESTS

977

i1ASE.D UPO N

A. 76x ')lx]2nttS

Fy :: 4]0 MPo

SIMPl't' SU PPQRl ED

120 1W

T~e mullion was strain qauged at the mid soan and quarter points. Mullion tension force and moment are plotted in Figure 11 for the loadinq after second crack.

....J «

~or-----------------------------'

ffi 16 I­« ....J

8

MULlION TENSION (KN)

I (gJ-MULlION TENSION I

FIGURE 11- MULLION TENSION & MOMENT

40

I

I <.n .

~I li o LL.

~ 16 ~I u.J I-« ....J ~I x:.

8

~I o..

o o~--7---~--~---+4--~~--~~

MULLlON MOMENT (KNH)

1(6)- MULLl ON HCi1ENT I

2.3.4 Vertical S'1ear Connector Wall. A vertical shear connector fabricated from 2.5 mm thick Lysaght Zinc Hi-Ten with a measured yield stress of 480 MPa was installed vertically in the centre of the wall. The connector had a tab confiquration as described in Fiqure 6b. Standard cavity ties were installed at 115 1m fr()Jn both ends of the bed joints and spaced vertically as defined for t'1e standard cavity wall testo

After the first crack occurred in t~e back leaf of the wall at the ioint above and below t~e 20th course on the riqht and left of the connector resoectively the wall was unloaded . The wall was also unloaded at an arbitrary load of 32 ~N and then loaded until the connector yielded after w'1ich the wall was unloaded and then reloaded until the wall failed. At the ultimate load the front leaf of t'1e wall solit vertically the full heiqht of the wall through the perpends in which the connector tabs were embedded . No additional horizontal cracks were observed. The load deflection plot is oresented in fiqure 10c .

The connector was strain qauged and the vertical tension force in the connector at t'1~ 19th course is olotted against total applied lo ad in Figure 12. The connector tension force is neqliq i ble before crackinq, but after crackinq increases with the aoolied load. The wall then acts as a composite (briçk/steel) beam with tension in the vertical connector and balancinq vertical compressive stresses in the front leaf of brickw0rk.

978

~r---------------------------------------------------,

40

30

l RA ( K !N BRILK .... ORK

20

FIGURE 12 - CONNECTOR TEN SION

3. REVIEW OF TEST RESUlTS

3.1 Tab Development Tests

30 40 ~ CO NNECTOR TENSION (KN I

o

~ .,

~ ;: o

60

-- - --------

70 80

3.1.1 Small Area Bearinq Tests. EXnmination of Fiqure 4 reveals a tendency of decreasinq ultimate bearinq stress with increasinq mortar thickness. AS1640 cOl1servatively defines the ultimate bearinq capacity of brickwork unrler small area bearinq plates for a mortar thickness of less t~an 12 mm.

3.1.2 Tah S~ear Tests. The load deflection plots presented in Fiqure 6 for t1e oroposed tnb exhibit a hiqh deqree of ul1iformity in both stiff~ess and ul timate load caoacity. The ul timate load cnpacity is clearly dependent upon the vertical sol ittinq strength of tfle brickwork.

3.1.3 Tab Tensiol1 Tests. The test specimens had been loaded in shenr to near failure prior to the tension tests hence the plots in Fiqure 7b represent a lower bounrl of tab ultimate tensile strenqth and stiffness.

3.2 Full Scale Wall Tests

3.2.1 Standard Cavity Wall. Figure 9 shows that tfle actual force carried by a dual limb cavity tie is hiqhly variable.

3.2.2 Intermediate Steel Mullion Wall. The normal desiqn office assumotion that the post crackil1q strenqth and stiffness of the wall be based uoon the oroperties of the R.H.S. mullion alone is shown in Figure 10b to be conservative as both tfle stiffness at permissible capacity and the ultimate capacity of the wall exceed twice that of the R.H.S. mullion. Fiqure 11a shows that tfle increases are due to lonqitudinal shear transfer between the R.H.S. and brickwork resultinq in a tension force in the R.H.S. The effect of (a) cyclic loadinq, (b) a vertical damp-proof membrane and (c) end plates are being investi gated.

3.2.3 Vertical Sflear Connector Wall. The post cracking stiffl1ess of the vertical shear connector wall is shown in Figure 10c to be of similar magnitude to the pre-crackinq stiffness while still exhibitinq ductility prior to failure.

979

3.2.4 Comp~rison of Wall Behaviour (Figure 10). (a) The load to cause crackin~ of the vertical shear connector wall was 2.6 times the load to crack the standard cavity wall and 2.1 times the load to crack the intermediate steel mullion wall.

(b) The maximum load aoolied to the vertical shear connector wall was 7.4 times the maximum loao of the standard cavity wall and 1.9 times the maximum load aoolied to the intermediate steel mullion wall .

(c) The central deflection of the vertical shear connector wall was within ~cceotable limits (h/360) up to a load of aporoximately 40 kN compared with a loao of approximately 10 kN ff)r the intermediate steel mullion wall.

( d) The verti cal shear connector wa 11 and the i ntermedi ate steel mull i on wa 11 would have recovered acceptably uo to loads of approximately 37 kN and 20 kN respectively; that is, followinq unloadinq the walls would almost, if not completely, return to their original locations and cracks could close to within acceptable limits, with fewer cracks in the vertical shear connector wall.

Though the base fixinq detail for the intermediate steel mullion wall and the vertical shear connector wall were similar (refer Figure 8b) it apoears that the latter developed larger base moments.

The weiqhts of steel required for the fabrication of the vertical shear connector and the intermediate steel mullion used in the tests were 3.3 kq/m and 5.3 kg/m resoectively.

4. CONCLUSION

It has been shown that:-(a) It is oossible to provide for effective shear transfer between the leaves of cavity brick walls, and for effective Dost-crackinq composite action (brick/steel) by means of a vertical shear connector of light qauqe metal.

(b) This shear transfer ano composite action siqnificantly increase the strenqth and stiffness of cavity brick walls unoer out-of-plane loads, both before and after crackinq.

(c) The estimate of the post-crackinq strenqth and stiffness of a cavity wall reinforced with an intermeoiate steel mullion (R.H.S.) within the cavity is conservative when based unon the properties of the mullion alone.

5. ACKNOWLEDGEMENT

This research was carried out within the University of Queensland Department of Civil Enqineerinq. The authors wish to thank P.G.H. Clay Bricks and Pavers for orovidinq the 2,000 bricks used in the investiqation.

6. REFERENCES (1) 'Bric kwork Code', AS1 640, Standard s Association of Aus tralia , Sydney, Aust ral ia 1974. (2) LAWREN CE, S.J . 'Behaviour of a Br ic k Cavity Wall Un der La te ra l Load , Inc luding the Effects of an

Intermediate Steel Mull ion', Techni cal Record 441, Exper imental Bu il di ng St ation , Departmen t of Construction, Au stralia, Feb . 1978.

(3) ' Loading Code, Part 1 - Dead and Live Loads, Part 2 - Wi nd Forces' , AS l1 70 , St andards Assoc iat ion of Au stralia, Sydney, Australia 1983

(4) ' Method of Test for Burnt Clay and Shale Bui l di ng Br i cks' , AS1226, Sta ndard s Associa ti on of Au s t ralia, Syd ney, Australia 1980.

(5) 'Mortar fo r Masonry Cons truction' , AS A1 23, Standards Assoc iati on of Austral ia, Sydney, Au st ra li a 1963.

980