4 . d . 7

BRICKWORK - PHYSICAL BEHAVIOUR

FINDINGS AT THE 2ND NORDIC SYMPOSIUM ON BRICK WORK

JORG EN BRYRUP

Civil Znoinee!' Danish ;-lasonry I'1.fornntion C~unoi l > Copenhagen> Denmark

BRICKWORK - PHYSICAL BEHA VIOUR

FINDINGS AT THE 2ND iVORDIC SY!1POSIUM ON BRICKf/OHK>

COPENHAGEN> OCTOBE:R 1975

Congresses > symposiums and oonferenoes alZ [oous the

attention upon thei r items . Long before the aotual

events extra researoh is dane > and during the

meetings you find people with the same professional

interests . It may be a diffi ou lt task to refer the

41 papers presented at our Nordio Symposium on Briok­

work> however> the results of it are of more genera l

interest than geographioally related to Soandinavia>

so a few of the most interesting papers - coveY'ing

non- statio items - sha ll be dealt with below . Those

coveY'ing statio items are dealt with by Professor

Svenn Risagel' .

MACONNERIE E:N BRIQUES - COMPORTEMENT PHYSIQUE

CONCLUSIONS DU 2eme SYMPOSIUM NORDIQUE CONCERWANT

LA CONSTRUCTION EN MACONNERIE, OCTOBRE 1975

Malgré qu 'il soit impossible de se référer aux 41 ex-, , , eme . d ' lq poses presentes au 2 Sympos&um nor &que, que ues

prob leme s d ' intérêt général - oonoernant des problemes

non statiques - sont discutés .

Le prof esse1.l1' Svenn Risager donne un aperçu sommaire

des exposés oonoernant la statique de la maçonneY'ie .

ZIEGELMAUERf~RK - BAUPHYSIKALISCHES VE:RHALTEN

AUSZUEGE DES 2. NORDISCHEN SYMPOSIUM UEBER

MAUERWERK - KOPENHAGEN 1975

Es dürfte sohwierig se in, über die 41 Beitrage zu

r e f eY'ieren, die beim Nordisohen Symposium über Maue r ­

werk vorgelegt wurden . Einige de r Ergebnisse jedooh

sind von allgemeinerem Interesse , so werden im fol ­

genden einige Beitrage, die den Bereioh a1.lBserhalb

de r Statik betreffen, im folgenden behandelt . Bei ­

trage über Statik behandel t Prof. Svenn Risager .

BAKSTEENMETSELWE:RK - FYSISCH GEDRAG

BEVINDINGEN OP HET 2de SYMPOSIUM OVE:R BAKSTEEN-

METSELWE:RK VAN DE NOORSE LANDEN, OKTOBE:R 1975

Alhoewel het onmogelijk i s alle 41 bijdragen te be­

spreken die op het 2de Symposium over metselwerk der

Noorse landen werden voorgedragen, worden tooh enkele

mededelingen van algemeen belang - gaande over niet­

statisohe problemen - besproken . Deze handelend over

statica worden behandeld door Pro f . Svenn Risager .

I

6RICKWORK ANO I,JORKING TECHN IQUE

Research in this field has lately been undertake n by the Oanish Masonry Research Centre , and a progressi ve report WbS presented. 6illions Df bricks a laid down i mortar to make brickwork alI ov e r the world; bricks , morta r and technique may differ , but principally the job is the same . and that is why research to improve productivity here is 50 important. The most appropri ­ate way to e xamine productivity by meas urin g man-hours per sq . metre brickwork . but by means of pulse-fre­quency measurements combined with .cilming Df the work being done . This has been significantly demonstrated during the pilot work . thus this work is going into its next pha5e : Evaluation of the influence of working methods. design of scaffoloing , etc . on producti vi Ly .

From the ConsulLi~g Servics of ~~son Contractors a MTM (Method - Time - ManagemenLl E,alysis ~as pre ­sented, showing that handling - time is Df the same magnitude as the "professional " time. 58e figo 1.

vlork Handling "Profession "

1 . Turn against materiaIs 147

2 . Take mortar 60

3. Tu rn against bricks 110

4 . Take a b rick 78

5. Turn against wa ll 93

6a. Place facing brick in mortar 124

6b . Place common brick I

in mortar 1 73

350 335

Total 685 MTM , 24.6 sec o 51 % 49%

Fig. 1

The high handling-ratio is a good argument for the so­called Russian brick - Iaying procedure, in which f.i. a bricklayer and one or two worKers cooperate. one placing the bricks and the others laying the mo rtar be d and handling the bricks . Several arguments. however. are against this technique. but it should be worth-while to examine it closer . Director 60 Goran Hellers. SIPOREX . presented a new technique based on lightweight concrete beams and columns . The system replaces a timoer frame . and - as you know - severa I argumencs can be put forward for using an inorganic construction instead of timber, 5ee figo 2.

4 . d . 7-1

Fig . 2 Oesign Df Wall

Ventilated board. nailed into the lightweight concrete

2 Thin layer givi ng wind protection

3 100 mm minera l wool

4 150 mm lightweight concrete

5 250 mm

6 100 mm

I-Ia ll treatmen t

6RICKWDRK - HEAT SOUNO, FROST

Dne Df the best arguments f o r the us e of it i s the heat capacity Df th e he avy mas on r y , because Df the ma i nta ining Df the i nh abi ta nt s' health , Or o Aittoma ki, Finn ish Research Cent ra l, pointed out in his paper , and as illustrated t he graph on f i g o 3 was given .

Lightweight expanded c l ay aggregate is needed for bricks, bloc ks. s labs and panels . The names Df the firms LECA and FI60 are becoming more and more world­known . Civil engineer Tore 6ech presented a pape r on sound insulation Df walls including LECA , based on measu reme nts at the No rwegi an Acoustic Laboratory . Trondheim. The results are presented in fig o 4 .

One of the most inte r est ing papers in this group was presented by Jorgen Pete rsen. consult ing engineer. Acoustic qua lity Df a room is not obtained by so­called "acoustic panels " for walls and ceilings . but by means Df other items . thus the intelligent use of bri c ks a nd wood . In the relevant literature you may find figures for unplas t e r ed brick walls with absorp ­tion ratios from 0.02 to 0 . 05 . The wri ter has examined several types Df brick walls and proved that thoS8 wit h coarse gra de mo r t a r in a depth Df 12 mm in the joints gi ve unexpec t e dly good results .

As known the surface treatment s Df a brick wall may influence - in a negative way - on its frost resistance. Engineer Waldum ,the Norwegian Ins titute for House Construct ion, points out th i s fact o based on tests Df masonry samples . yet t he laboratory test is not con ­sidered satisfactory e nough compared with practica l conditions.

4 . d . 7-2

,r

.r 16

16 " "

o o o o o

o " I)

o o D

o Q

" o C

o OC!

" 1

4

o o

o o °0 o

00

O

O O

0 0

O l)0

Leca tI

l' 16

o o

9

o o

Mortar

Fig . 4, 1

2

5

- 6 .

I

Fig . 3

Room temperat ure an d hea ting effect during a co ld períod under i nf luence by sun radi ation.

Room temperature

2 Operative Room temperature

3 Heat i ng effect

4 Out do or tempera tu re

5 Infallíng sun radiation

Continued line : Heavy construction

Oo t ted line : Light

3

v 16 '1

O o

O o o O o

O o <l

o o Q

o o o o O o O o

jl-" -<1..J" ,""v,=-~v~- '=:~~§J; ~">ç' .. ,, ;17' ;

6

1 Mineral wool Gypsom cladding

The walls ' construction .

o o o o o '

Wa ll Nr .

2

3

4

5

6

7

8

radon, pCi/1

25

20

10

5

o

o o o

," ,,' ,

I< 16 1

o

c>

C> o 9

O

O o

' <I ' <) '<J

t5 r II

f

Q C

Q O o

(J o o

o D O

1,

7 8

8 9

RESULTS

Measured

46 d8

51 "

57 "

45 "

56 "

56 "

76 "

62 "

Fig . 4 , 7 - 8 and results

10 11

APRIL, 1974

Fig . 5

12

Norm

45

51

58

43

52

52

69

54

pressure, mm Hg

770

760

750

740

13

Atmosphere pressure and Radon concentration in unventi l ated basement-room .

4 . d . 7- 3

4 . d.7-4

OAMAGE ON BRICKWORK - REASONS ANO MENOING

It is extremely important to handle cases Df damage in such a way that the reasons why are cleared up. Others should l earn from the experience gained by scientists . Several papers covered this topic.

One dealt with claddings of brick on high-rise con­s t ru ction , a more central paper by engineer Kobler desc r ibes faults on the appearance of non-rendered f acing brickwork . Reasons for faults may come from the materia I s used , design and workmanship. To cut it short : Uneven colour-distribution of bricks on palle t s , marks from the setting of green bricks in the kiln , uneven colour addition (manganel , surface faults , dirty bricks due to improper storing at , for instance , the building site, cracks, etc . are the main faults connected with the materiaIs . As to design the attention paid to an adequate protection Df the top of the wall is sometimes too poor, which ca n l ead to discolouring Df the wall. As to workman­sh i p fa ults may be done with mixing Df mortar , cleani ng of the surface and with possible silicone treatments, whi ch we are not too enthusiastic to recommend.

BRICKWORK ANO THE ENVIRONMENT

One of the most interesting fields of research is connected with environmental circumstances. Based on an architect ' s competition arranged by the Oanish Masonry Information Council the advantages connected with designing of summer cottage areas in a more con­ce ntrated manner than what hitherto has been common practice were described by academical architect, Erik Berg from Oenmark; the point is that the surrounding nat ure can be kept unspoiled, if the summer houses are placed very near to each other in a sort Df village wi th field of natural vegetation surrounding it. This invites masonry because Df its better sound insulating and fire protecting qualities compared with the trad­it i onal wooden cottage building .

Some aspects of the physical climate were presented, thus emanation of gases in test-chambers of brickwork and concrete . Hygienic Institute of Aarhus presented t his paper , which demonstrated the advantages of porous bricks .

Or . Techn, Niels Jonassen, Laboratory of Technical Physics I , Technical University of Oenmark, referred the results of his measurements on radioactive emission from buildi ng materials , the so - called · Radon-daughters ~

In ho uses with masonry walls the permissible value 0 . 01 WL was only passed once , namely in a basement-room (belo nging to Or Jonassen himselfl, which was not ven­ti l ated . In inhabited rooms, the level was far below the permissible value . In concrete houses many in­habited rooms showed figures below 0.01 WL, especially in storey flats with mechanical ventilation , but in one and two-storey houses without mechanical venti­l ation there were found values being 10 to 13 times the permissib l e one . The conclusion, as illust rated in fig o 5 , shows that effective ventilation is a necessity in concrete building destined for people to l ive or work in . The pilot project has proved that concentration of Radon emission represents a serious r i s k for the health of people living in such surround­i ngs . Thus a br oader and more extensive search pro­ject i s p lan ned .

Techn . lic . Kari Makela , the Brick Manufacturer~ Association of Finland , presented a paper on Finnish Brick Panels in 6 paragraphs treating the elements ' types , dimensions , construction, manufacturers and strength and finally some lines about the quality control o

The magnitude and reinforcement of Finnish Br i ck Panels are not f ixed , but l arge l y depend i ng on the user ' s wants . As the rei nfo r cement can vary the design of window a nd door panelsit is also to some extent dependa nt on the single custome r . The tables on Fig. 6 give ma ximum and minimum limits of characteristic di mensio ns of panels wi th one r esp . two windows .

Engineer Kj aer gave on beh alf of t he Oanish As s oci­ation of Br ick Pane l Manu f acture r s a presentation of the met hods used by th em to in cr ease the heat insu l ating abilities of their pane l s , due to the so-ca l led oil cris i s . Insulation capacities equiv­alen t to a t least 100 mm mineral wool are considered a must .

Two other papers dea l t with the use of bricks , one with typical brick construct i on , a nd one with patents inside masonry industry .

It is my hope that this short survey has been useful to you in showing in a most general manner , what the problems are , which we a r e working with and trying to solve . I have on purpose kept this paper at a purely reference leve l, as it is my opinion that this sort of information exchange as well as the more scientific one , is an important part of the idea of making inter­national masonry conferences .

Table 1 Sandwich element with one window

o o N

(Y)

\/1

~t,OO

L

v

hy

ha

V 71

~ 400

'-- I Table 2

~(

H d

/j

Sandwich element with two windows 11

hy

t h min I L max ! Y r.rn nm

2400 400 3200 600 3600 700

O

h a mi n

mn

.100 400 SOO

d

I

I 4 . d . 7- 5

Fig . 6

. Design of Finnish Brick Panels

f--------. -_ .. -

I ha

-

L max I H max d min D min I hy min \ ha min

mn nrn 11m rrm n1l1 mn

4800 3200 400 400 7200 2900 600 700 7200 3200 600 700 I

I -----,A ,a , I I

elosing reinforeement

Seetion C- C

Fi r· ? Dani sh brick panel , sandWich type

~ .0 o · .0 " "" ..

c:: I

CIl :J PJ

'CJ (J)

o. I-j (J) 1-' . ::s H;) o I-j ()

(J)

3 (J)

::s IT

'CJ (J). I-j

0\ o ()

3

See t . A- A · Seet. -E-B

em l ightweight eonerete SW ea. 1100 kg/m

per 40 em in bóth direetions

1 00 mm mi neral wool

4 . 5 em eementmortar