Download - Masonry Construction Manual - The Building of Masonry

8/14/2019 Masonry Construction Manual - The Building of Masonry

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Suitabilitynd qualityests

l v l a s o n r y d > 11 5 m m

mm

2.5.1 Arrangement f perpends

rotecting masonry against moisture

Masonry nits re usually elivered rapped nlastic heeting n pallets nd hence are pro-cted against aturation p to the ime of lay-

ng.As saturated masonry nitsdo not developdequate dhesion o the mortar nd, urth er-

more, ncrease he energy equired or drying

ut heprimary

tructure, ricks and blockswaitlng aying, s well as he unprotectedoos an d sides f ndividual lements uc h asalls, pandrel anels nd openings, ust berotected gainst rolonged ainfall y meansf arpaulins r plastic heeting. hese houlde secured gainst plift by way of battensailed ownor by heavy materials. n addition,

emporary rainage measures houldbe takeneneath oof gutters f he rainwater ownpipesave not yet been connected n order o pre-ent ocal saturation f the masonry. ollowing

hese ecommendations il lensure hat hereno damage o the masonry n he orm of, or

xample, hrinkage racks, efflorescence reduced trength 175].

ayingduring cold weather

Masonrymay be built during rosty onditionsnly f certain rotectivemeasures re carriedut.These nclude overing he aggregate or

he mortarwith nsulating lankets or he em-erature ange rom O o +5'C; covering he

masonry nitswaiting o be ai dwith nsulatinglankets or he emperature ange rom 5 o"C;heating he mixing water and he aggre-ate and working n ents or protective helters.

As he emperature rops still ufther, evelop-ment of he mortar trength lows down andractically omes o a halt at about 10'C.

Whenevei ossible, masonry hould not beuiltat such ow emperatures.rozen uildingmaterialsmay not be used atny emper ature. urthermore, ewlybuilt

masonry, elicate lements nd columns narticular, houldbe protected gainst rostnd precipitation y a covering f insulatinglankets. f such measures re not carried ut,o urther masonry nitsmay be laid on

masonry lready rozen. Sections f masonryamaged y rost must be removed efore

workcontinues, n no account use antifreezegents r de-icing alts because his can eado efflorescence e.9. salt deposits) ppearing

'Tipped and ailed" Full mortar illing

on he masonry nd o damage e.9. pallingcaused by he ormation f salt crystals) 54,164,2141.

Suitabilityand quality ests

According o DIN1053, he properties f he

buildingmaterials ust be verified. hi srequirements ulfilled y suitability nd qualitytests. The suitability es t stipulates hether hetypes and quantities f certain aw materialsar e suitable or he production f a buildingmaterial ithdefined properties, .g. strength,gross density tc .This est s carried utbefore he actual roduction f he buildingmaterial r he building f he masonry. hequality est s carried out on random amplesof he buildingmaterial roduced or use onth e building ite an d simultaneously ith heactual onstruction, n order o verify hat heintended material roperties ave beenachieved. he quality ontrol f masonry nitsis carried ut within he scope of he manu-facturer's wn quality ontrolmeasures, ndthose of outside entres, t regular ntervals.The equirements or his are stipulated n heindividual tandards overing he differenttypes of masonry nits.The manufacturer'sow n quality ontrol uring roductionncludeconstant monitoring f he production rocessto guarantee hat he masonry nits producedcomplywith he critical eohnical arameters.Monitoring y approved utside e ntres akesthe orm of checking he manufacturer's ualitycontrolmeasures uring roduction nd en .suring hat he personnel nd equipment sed

meet he required tandards.In he case of mortars, suitabilityes t accord-ing o DIN1053part 1 appendix .5 s neces-sary only f he serviceability f he aggregatehas o be verified r if admixtures nd addi-tives are o be used.Furthermore, he suitability es t needs o becarried ut as a preliminaryest or premixedmortars, ncluding ightweight nd hin-bedmodars nly or structures ith more han sixfullmasonry toreys se e .1.28).The building ontractor s responsible or car-ryingout on-site uality ests or mortarwithinth e scope of checking n d assessing he qua-

lityofprescribed

masonryRM)

or masonryaccording o suitabilityes t EM).

Mortar n groove only No mortar, ongue andgroove connection

Quality control of prescribed masonry (RM)

Suitability nd quality ests are not required orprescribed masonry ecause his ype ofmasonry s based on many years of experienceof using a "prescribed" ombination f stan-dard masonry nits and standard mortar.. he .building ontractor must check hat he detailson he delivery lip or he packaging f mason-

ry unitsor prescribed masonry match hose on

the building uthority ocumentation. ortarmixedon site or prescribed masonry nust bechecked egularly uring onstruction gainst'table A.1 of DIN 1053 part 1 (see Lable .1 25)or using a suitability est o ensure hat he mix-ing ratio s being maintained. or premixedmortars, he details f he ype of mortar ndmortar roup on the delivery lip or packagingmust be compared with he echnical ocu-mentation, nd he grade number nd hesupplyingworkscompared with he order.Mortars f group ll amust undergo com-pressive trength est according o DIN18555part 3 carried ut on hree prisms rom hreedifferentmix batches er storey, ut at eastevery 10 m3 of mortar, nd be checked againstthe requirements f Dl-N 053parl 1 table A.2.Buildings ith more ha n six ullmasonrystoreys equire quality est o be carried utper storey, but at least or every 20 ms of mor-tar, even or normal mortars f groups l, llaan d ll as wellas or ightweight nd hin-bedmortars. his akes aecount.of he higherrequirements laced on the oad-carryingcapacity f such masonry nd hence on herequired onsistency f he mortar ropertiesin he ower toreys. s the ncreased equire-ments do not apply o the op three storeys,

this extra quality es t s unnecessary or hosesroreys,

Quality control of masonry according tosuitability test (EM)

Suitabilityests according o DIN 1053part 2are required o establish he strength l ass ofmasonry ccording o suitabilityest. Thisinvolves llocati;rg he masonry o a strengthclass by way of a compressive trength es tcarried ut on est samples ccording o DIN18554 ar t1 and he subsequent ssue f aclassification ertificate. his must be provided

to he building iteprior o commencing on -

struction orkwithsuch masonry. he suitabil-ity est must be carried ut by an approved

Joint

M a s o n r y d > 1 1 5 m m

Joint


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The building f masonry

materials esting aboratory. t must be repeat-ed ifmasonry nitswitha different rrange-ment of perforations re o be used or hemasonry r f changes o the combination fraw materials r he method f production fth e masonry nits ould nfluence he strengthof he masonry. Masonry ccording o suitabili-ty test does not need o undergo quality est.ln order o check he aw materials n site,every elivery f masonry nitsmust ncludedocument hich ncludes etails f he DINdesignation f he masonry nit,EM designa-tion,compressive trength classification er-tificate), ype of mortar nd mortar roup,masonry trength lass, classification er.tifi-cate number nd esting entre. he deliveryslipor packaging s o be checked o ensurethat t matches he echnical ocumentation.Mortarmixedon site should be checked atregular ntervals uringconstruction o ensurethat t continues o comply with he mixing a tioon he classification ertificate. n he case ofpremixedmortars, he details n he deliveryslip egarding ype of mortar nd mortar group,th e supplying orks nd he grade numbermust be checked o ensure hey complywiththe details n he classification eftificate. s

with he quality ontrol fprescribed masonry,the compressive trength f he mortar must bedetermined ccording o DIN18555 ar l3 andcompared ith he equirements f DIN1053part 1 ables .2 ,A.3 an d A.4.These ualitycontrolmeasures must be carried ut or every10 m3of mortar, ut at least or every storey.

Perpends nd bed oints

The principal asks of he oints n masonry reto ensure hat he masonry nitsare uniformlyloaded and o guarantee he ransfer f orcesfrom

unit o unit. Furthermore, hey compensatefor he (permissible) eviationsn he sizes fthe masonry nitsand play a major ole with

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respect o building cience roperties nd heresistance f any endering o driving ain andcracking.Moftar houldalways e applied over he ullbed ointbecause his ointhas an important

structural unction or he o adbearing ehav-iourof masonry, .e. he uniform ransfer f ver-tical comoressive tresses s well as ensileand shear tresses yway of adhesion ndfriction. oids n he bed oints nd varying ointthicknesses ead o stress oncentrationswhich n urn educe he oad-carrying apacityand ncrease he isk of cracking.Th e hickness f he be d oint nfluenceshetransverse ensile tress n he masonry nitsthrough he ateral train ehaviour nd stherefore artly esponsible or he compres-sive strength f the masonry. her efore, hickbed ointsare structurally ess avourable, ut

on he other an d a minimum hickness s nec-essary o compensate or he (permissible)deviationsn he sizes f he masonry nits ndto allow or practical uilding onsiderations.The hickness f he be d oint s about 12 mmfor normal nd ightweight ortars, etweenand 7 mm or medium-bed mortars, ndbetween and 3 mm or hin-bed monars nconjunction ith gauged brickwork.Th e peroends re much ess elevant han hebed oints n erms of structural unctionbecause hey do not help o accommodatetensile nd shear tresses. herefore, t s per-missible o either il lperpends ompletely ithmortar, nly parilywithmortar "tipped ndtailed"), r eave hem without ny mortar. How-ever, t should be noted hat es istance ocracking ecreases oticeably hen he per-pends are only illed partlywithmoftaror leftwithoutmonar because he masonry nits canno onger uppofteach other as s he casewhen he perpends re completelyilledwithmortar see ig .2.5.1).

Laying with mortar to the perpends

It s necessary o provide mortar n he per-pends when building einforced asonry,single-leaf nplastered asonry hich has o

be sealed gainst in dan d driving ain, n hecomoression on e above hallow intels nd nexternal asement alls but depending n heloadbearing ystem). he perpends re classedas ull y illed withmortarwhen at east half hewall hickness s providedwithmortar.The arrangement fmortar o the perpends e-pends on he ype of masonry nits used. A fullmoftar illingo he perpend s principallyar -ried out withsmall- nd medium-format ason-ry units. he hick ness f he perpends houldbe 10 mm or normal nd ightweight ortars,and 1-3 mm or hin-bed mortars.Masonry nitswithmortargrooves n heir end

faces either have mortar oolied o the aceseither ide of he groove o produce isibleperpends ith hicknesses orrespondingo a

fullmortar illing, r he units re aid brick obrickand he grooves illed ater. n he brick-to-brickmethod, he units are aid as closetogether s he unevenness f he end a cesdue o the manufacturing rocess willallow.

Generally, he gap between he units houldnot be more han 5 mm. f his dimension sexceeded, he n he oints hould e illedwithmortar n both sides of he wall n order oguarantee n even substrate or plaster.

Laying without mortar to the perpends

Th e perpend ithoutmortar s gaining n popu-larity ecause t speeds p construction ndrequires ess mortar. However, ertain meas-ures must be taken o ensure hat he reouire-ments o be met by the component egardingprotection gainst riving ain e.9. endering,

cladding); hermal nsulatione.9.

dequatewall hickness , dditional ayers f hermalinsulation);ound nsulationweight er m2byway of heavy masonry nits); nd ire protec-tion are still maintained. asonry ithout mor-tar o the perpends s constructed ither withthe bricks simplybutt-jointedogether r byusingmasonry nits withan ntegral ongueand groove ystem. his aying echniqueachieves masonry onstruction ithoptimumhomogeneity.Peroends ider han 5 mm must be illedwithmodar on both sides of the wall n order oguarantee n even substrate or plaster. nterms of the structural nalysis f masonrywithoutmortar o the perpends, t should benoted hat when analysing hear he permis-sible educed adhesive hear trength oHSmust be halved and hat n he case of base-ment walls he earth pressure may onlybecarried niaxiallyn he vertical irection.

Junctions with intersecting walls

During onstruction, he contractor must makesure hat mmovable upports or a wall sup-ported on wo, hree or four sides) as assumedin he structural nalysis re actually ealized

on site. An immovable upport o a shear wall,fo rexample, s onlyguaranteed hen he sup-poding walland he shear wallare both con-structed f materials ithapproximately qualdeformation ehaviour, he connectionbetween he walls can resist ension nd com'pression, nd when separation f he wallsasa result f severe differential eformation s notexpected see Lateral estraint o walls").A tension- nd compression-resistant onnec-tioncan be achieved y building ot hwallssimultaneously nd ullybonded ogether utalso via a butt oint.

2.5.2 Butt oinl


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Junctions ith ntersecting alls

onded unctionsA fully onded unction also alid as such

uring onstruction is guaranteed ith ack-ngor oothed rrangements nlywhere heength f he return s at east one ifth he

eight f he wall se e ig .2.5.3).Both ypes of unction onsume aluable pacen he building iteand his s often not desir-ble due o operational easons, .g. or easierrection f scaffolds, o maintain nobstructe dccess outes tc .herefore, o aid building perations he struc-

urally quivalent oothing r reverse oothingma y be used se e ig .2.5.3). n his ype of

onded unction,he wallsare no t built imulta-eously support nd bracing o the wall arechieved t a later date. The ension- ndompression-resistant onnection s createdhrough he ransfer f compression ia he

masonry ond and ension with he aid of rein-orcement. his hould e built nto he bedointswithsufficient mbedment ength androtected gainst orrosion. f tensile orces dootneed o be ransferred, hese wo orms ofonded unction re only considered occommodate omDression.

utt-iointed junctions

Th e butt ointtechnique nables he unctionso be simplified. n his method he walls reutt-jointed ithout aking account of he bond-

ng ules.Consequenily, hey may be offset at-raly (see'fig. .5.2). tension-resistant on -ection s achieved y anchors forwhichatructural nalysis s required) laced n heed oints. f he walls are not built simultane-usly, hen he anchors re eftprojecting ndent aside until equired n order o preventnjuriessee ig .2.5.q.

The butt oint echnique may be used only ornternal alls;external orners hould alwayse ormed s ullybonded unctions. ut t ointsre ully illed withmortar n every ourse onsure dequate ransfer f compression ndontinuity f he acoustic nsulation ropertiesf he wall.The anchors re o be designedccording o DI N1045 ection 9.8.3 n such a

way hat 1/100 f he vertical oad of he oad-

bearingwallcan be ransferred t each of thehird-points f he wall height. Under such con-

ditions, he supported wallcan be analysed sbeing upported n hree r our sides. henchors may be distributed ver he height ofhe storey o avoid an accumulation t hird-points, .g. n all or alternate ed oints.t s recommended hat walls uppofted n onlywosides be connected o intersecting alls

withnon-structural nchors.n he structural nalysis f he walls, only ec-angular nd not compound ross-sections ay

be used desoite he nclusion f anchors.The best anchors ave proved o be perforated

latbars of stalnless teel measuring 00 x 22 x0.75 mm or pairs of V4Asteel wire ies (asused or win-leaf alls).

2.5,3 Arrangement f wall ntersections

2.5.4 Butt-jointedunctionwithvarious ypes of anchors

Perforated lat bar

Masonry nchor

Mild steel o DI N 488

Wire ie

147

Wall o be supported


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2.5.5 Chases an d recesses ermissible n oadbearing alls without tructural nalysis dimensions n mm)

Horizontal nd inclined hasesrr

Length ofc h a s e ] < 1 . 2 5 m l o n g ? tunlimited I Depth

Vertical chases and recessescut subsequently

Depthat IWidth of I Distance ofsingle i chases an dchases' I recesses ro m

> 1 1 5> 1 1 5> 1 1 5> 1 1 5> 1 1 5

> 2 x w i d t h o fchaseor >24O

Wallthickness

Vertical hases and recesses uilt n masonry ond

Min.distanceof chases andrecesses rom

Min.spacingof chases andrecesses

> width of^ L ^ ^ ^

> 1 .15> 175>240> 300> 365

chases ar e permissible nly n an area < 0. 4 m above or below he structural on one side of a wall. They are not permissible nhorizontally erforated lay bricks.

2)Min.distance rom openings n ongitudinal irection 49 0 mm, rom next horizontal hase 2 x length of chase,3)The depth may be increa sed y 10 mm when using ools where he depth can be accur ately maintained, .g . masonry millers,masonry lo tsaws, etc. When using such ools,

chases 10 mm deep on both sides ma y be cut in walls > 240 mm hick.4)Chases hat extend max. 1 m above loor evel ma y be cut up to 80 mm deep and 120 mm wide n walls > 240 mm thick.5) The otal widthof chases according o column 5 and column 7 pe t 2 m of wall ength may not exceed he dimension iven n column 7. For walls ess han 2 m lo ng, he values n

column 7 should be reduced n proportion o the enqth of he wall.

The use of he butt oint echnique as severalimportant dvantages or on-site perationsand he ater behaviour f he walls:

'The walls an be built eparately ithoutinconvenientoothing n one operation. heomission f toothing peeds up operationsquite onsiderably. n addition, he lush wallsurfaces nd avoidance f short eturnseases he erection nd movement f workingplatforms nd scaffolds.

' The lushwallconnection means hat ewermake-up nitsare required nd here are nobonding problems t intersections.

'The two ntersecting alls an be builtwithdifferent ourse heights without ondingproblems, .e. ts s easy o combine alls funitswithdifferent eights nd ormats butstillcomplyingwith he "octametric" ystem).

. The butt oint echnique voids he creation fthermal ridges at unctions etween nternalwallswithhighbulkdensity nd external allswitha lower bulk density.

' The use of different ypes of masonry nits nthe wo walls means hat he effects f long-

term deformations re ess critical ecausethe anchors reserve certain ertical efor-mation apability hile at he same ime pro-viding tension- nd compression-resistantconnection etween he walls171,211,2141.

Chases and recesses

Chases nd recesses re required or all ypesof building ervices, .g . heating, ater ndwaste water pipes, electric ables, entilationducts.Owing o heir ignificanceor he stabil-ityof a wall, drawings howing he sizes andpositions f chases nd recesses houldbeprovided t an early stage so hat hey can betaken nto account n he structural nalvsis f

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the masonry. t the very east, he arrangementof chases nd recesses houldbe checked ortheirstructural mplications rior o construction.Planned hases and recesses ormedwithinthe masonry ond, or provided n he orm ofchannel locks, r service uc tor pre-chasedunits se e Special ormats, pecial nits"),should be taken nto account n he workingdrawings. s a rule, hese are more accurateand es s ime-consuming nd costly han chas-es cut subsequently. he n utting hases, tmust be ensured hat he ntended imensionsare not exceeded. Chases nd recesses anconsiderably ower he oad -carrying apacityof a wall because esides educing he cross-section hey also decrease, n particular, hebending trength f he walland alter heeccentricity n he remainder f he wall.Vertical hases n walls panning n on e direc-tion only educe he cross-sectional rea; heirinfluence n he oad-carrying apacity f thewall s hence f onlyminor mportance. n heother and, ertical hases n walls panning ntwo directions, hose ncrease n oad-carryingcapacity s due o lateral estraint nd hence s

reliant n horizontal endingmoments, anhave a severe ffecton he horizontal oan.Therefore, heir nfluence s aken nto accountwhen determining hether wall s supportedon hree r our ides by using nly he esid-ua lwall hickness n he design f he sectionadjacent o a vertical hase, or by assuming nunsupported dge at hi sposition. e alsoassume n unsupported dge f he esidualwall hickness s ess han half he ota l wallthickness r < 115 mm .Horizontal hases houldbe avoided f oossi-ble because hey educe he cross-sectionalarea, nd hence he bending trength, longtheir ull ength. t

he same ime, hey have nunfavourable ffecton he eccentricitv n herest of he wall.

To simplify tructural nalysis, IN 1053 part 1table 10 specifies aximum imensions orchases and recesses. f these dimensions renot exceeded, he effect of such chases ndrecesses n he oad-carrying apacity f awall s so minor hat hey can be gnored hendesigning he masonry se e able2.5.5 nd ig.2.5.6). n addition, n analysis s no t necessaryfor vertical hases and recesses fthe reduc-tion n he cross-sec tion per m of wall ength- is no more han 6% and he wall s notassumed o be supported n hree or oursides. n his case, residual all hicknessaccording o DIN1053part 1 able 10 column8 and a minimum pacing ccording o column9 must be maintained se e able 2.5.5). f hedimensions f he chases and recesses ifferfrom he values given n he ables or rom heextra equirement or vertical hases, heymust be taken ntoaccount n he design of hemasonry. s the requirements f able 10appear ery complicated or he practicallyminded espite he graphic resentation n ig.2.5.6, he ollowingecommendations houldbe adhered o during construction:

' Chases nd recesses houldbe positionedwellclear of heavily oaded ections fmasonry, .g .bearings eneath intels, pen-ings. hey hould ot be positionedn piersand chimney ambs.

. The deoth of a chase or recess houldbe assmall s possible, ax .30 mm, n order no tto weaken he cross-sectio n ore han nec-essary,

. Horizontal hases hould onlybe positionedimmediately elow loor/roof offits r mmedi-ately above loor evel because n hesezones such chases have very i ttle nfluenceon he oadbearing ehaviour f the wall (sta-

bility gainst uckling).. Walls 175 mm hick hould ot be chased fat all possible.


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Building nd cleaning acingmasonry

As chases nd recesses re detrimental othe acoustic nd hermal nsulation ropertiesof a wallas wellas its oadbearing ehaviour,"falsewall" nstallations re o be preferredwherever ossible, .e .al lservices re

installed n he ace of the wallor in serviceshafts. During he nterior orks, he servicesare concealed ehind masonrv r some otherformof cladding.

Buildingand cleaning acing masonry

Certain ules have o be followedwhen plan-ingan d constructingacingmasonry ndaced walls n order o guarantee he appear-nce, erviceability nd durability f he

masonry. his s especially he case or exter-a lwallsof acing masonry which are requent-

yexposed o driving ain. n particular,he is kf saturation ue o inadequate orkmanshipr he wrong choice of material s requentlynderestimated. he damage aused o theacingmasonry s often extensive nd necessi-ates major epairs.

onstruction principles

Facingmasonry nd aced walls hould nl ye built rom ree-standing caffold, ecauseutlog r other scaffold ixingholes are difficult

o make good subsequently. he op course ofmasonry hould e covered uring ongernterruptionsn he work and during ain. fossible, asonry nits hould otbe aid n

he ain, nd n cold weather hould ot be ai delow ertain emperatures see Laying ur-

n gduring old weather")Facing masonry must be built very carefullybecause ven er y mall rregularities,.g .misaligned erpends bove nd belowheader, re disagreeable o the observer andt s often iewed rom close ouarters. er -

pends r headers, hich according o hebond hould e aligned eftically, ust beplumbed, ecause eviations f us t a fe w mil-imetres an add up o considerable iscrep-ncies ver he ull height f he wall.All he

acing masonry nits equired or a certain ec-ionof he construction hould be ordered romne supplier n d nter mixed etween everal

oallets n order o avoid colour ariations n heinished ork. f necessary, refere nce anelor assessing material consistency fcolourn d dimensional ccuracy), ond, ointing tc .hould e produced n site.

Facingmasonry nits must be carefully rans-ported nd stacked n pallets, n packaging rncontainers n order o avoid damaging orners

and edges. Furthermore, hey are o be pro-ected against he weather, oiling nd mech-

anical amage. amaged nits hould e

ejected r used n such a way hat he dam-aged section s not visible n he inished all.On e mportant onditionor building urable

facingmasonry s hat he units hould e aidand worked n a way appropriate o the mate-rial.The different uc tion ates of differentma-terials must be taken nto account. Absorbent.units must be prewetted efore aying o hat

they do not extract oo much mixingwaterfrom h e mortar. he maximum ate or his s1.5 kg/m2lmin. rewetting s not necessary tlower uction ates. f prewetting s not carriedou twhen equired, hrinkage racks etweenunitsand mortar r dehydrated dhesionzones n he mortar an or mand help drivingrain o penetrate he acing masonry. essabsorbent masonry nits, owever, must belaiddry. nsome ircumstances he plasticityof he mortar must be reduced n order o pre-vent such units rom "floating" n he mortardue o their ow suction ate.Complete ointswithout oids are produced by

applying he mortar o the end of he masonryunitand hen pressing t against ts neighbour,thereby queezing ut surplus mortar.Walljoints emain pen at irstand are illedwithgroutupon completion f each course ofmasonry 162] .Fresh ointsmust be cured or at least 3-5 days(see Mixing nd usingmortar n site").Please efer o "Jointing" elow or urtherdetails f oints.

Cleaning facing masonryFirst f all, or effective leaning we must dis-tinguish etween he differentypes f soiling.The most requen t ype of soiling, ut he easi-est o remove, s hat caused by mortar ndcement during construction. econd, fflores-cence an d im e taining an occur upon om-pletion f he acing masonry. inally; tmos-pheric ollution an spoil he appearance ffacing masonry ver ime.Th e soiling f acingmasonry uring onstruc-tion s most easily ealt with by removing mor-ta r droppings nd cement plashes mmedi-ately s he workproceeds r when buildingthe next section. Water, rushes nd spongesar e adequate or such cleaning.Th e avoidance f soiling s also mportantn

this context: dequate learance etweentubs of mortar nd acade, newlybuiltmasonrycovered withplastic heeting o protect gainstmortar roppings nd cement plashes ragainst plashes f concrete nd plaster.Efflorescence ftenoccurs when arger quanti-ties of water e.9. mixingwater rom he mortar,poorly esigned/built aves etails, eakingcopings etc.) penetrate he masonry nd washout efflorescent ubstances, .g . calciumhydroxide, odium nd magnesium ulphate,chlorides nd nitrates, rom he mortar ndmasonry nits. The absorbency f he unitsallows he dissolved ubstances o be trans-

ported o the surface, where hey are depo-sited at a pointwhere h e water can readilyevaporate, .g. at projecting iers and at he

2.5.6 Diagram f chases and recesses ermissible nloadbearing allswithout tructural nalysis(dimensions n mm )

Chase of unlimitedlength

O

v o

- E

i _ c

2c

O

> 490 mm, from next horizontal chase 2 x length of '

cnase,3)The depth may be increased y 10 mm When using

tools where he depth can be accurately maintained,e,g. masonry millers, lot saws etc. When using such

tools, chases 10 mm deep on both sides may be cut nwalls> 240 mm hick.

Opening

For d > 240:depth of chase < 80widthof chase < 12 0

\+- -l+ 4dge distance> ts

Depth ofchase

E

6+ -l-L >d O L

6 6 |

- t s 1

: o I; B Iu J 6 I

4'

Widthof chase

cu t up to 80 mm deep and 120 mm wide n walls> 240 mm thick.

lL1zPAPZ-- ,

Edge rstanceo Lengln oT cnase

ffiquently

Vertical hases and recesses ut subsequently

> 1 1 5> 1 1 5> 1 1 5> 1 1 5> 1 1 5

max. 1 m above loor evel may be

14 9


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The building fmasonry

2.5.7 Forming lush and"bucket handle"joints

corners f buildings, here igher indspeeos ccur.Efflorescence, hichoccurs during construc-tion by he dissolving f efflorescent ubstan-ces n he mortar calcium arbonate), an beavoided by prewetting nd hence educingthe absorbency f the masonry nits.Mostefflorescence isappears ftera relativelyshort period of exposure o the weather. Other-wise, he most effectivemethod or removal scleaning he masonry rywithspatulas, uit-able smallwooden boards and bristle rushes.Sandblasting ay be employed n certaincases, lthough his may place severe tresseson he acing masonry; r cleaning wet withacleaning gent. n his case he masonry mustbe prewetted tarting at the bottom before hecleaning gent s applied n concentrated rdiluted orm n accordance ith he manu-facturer's nstructions. hese methods are oftenemployed or ol d im e taining nd eaching f,for example, alcium arbonate. ery effectivecleaning gents or clay brickwork aveproved o be hose based on hydrochloric ,phosphoric r ormicacid. The masonry houldbe rinsed horoughly ith water after cleaningto make sure hat al l mpurities re removed. talso prevents he masonry rom eabsorbingth e solution gain s t dries.Masonry oiledby many years of atmospheric

pollution hould nl ybe cleaned y specialistcontractors. t is essential o carry out a c lean-ing est irst n such cases o establish he mostsuitable method f cleaning so hat hemasonry emains lean and does not sufferan y significant amage.High-pressureets of cold and hot water, ets ofwater withadditives, ompressed-air ater etswithadditives nd chemical leaning rocess-es nvolving he application fwetting gents,acidic r alkali leaners nd subsequent ins-ing have al l proved o be suitable methods fcleaning.When choosing method, he effec-tiveness f safety equirements nd disposal f

the cleaning water must also be.taken ntoaccount 52, 175].One common roblemthese days s graffiti meared ver acades.

15 0

They can generally e removed y water ets

withadditives u t softer urfaces willsufferunder his reatment. pecial raffiti leanersbased on y-butyrolactone ave proved o be agood alternative o mechanical leaning.This pecial lastic-dissolvingroduct it hapH value etween .5 an d 6.0 s applied o hefacing masonry nd washed off afterwards ithcold water without amaging he surface.

Jointing

Jointing laysa special ole n acing masonryand aced walls: t seals he masonry gainstdriving ain, nd ends tthe desired ppear-ance. The composition f the mortar, he set- .back, consistency nd position f he ointsur-faces, and he way hey are made are crucialto the weather-tightness f acing masonryexposed o driving ain. Therefore, o be effec-tive, oints houldbe water-repellent nd in-ished lush with he surface f the masonrywhenever ossible. he oints orma fine atticeover he whole surface f he wall and so heiraooearance as a decisive nfluence n hecharacter nd overall olo ur of exposedmasonry. ointing an be carried ut duringconstruction, efore he mortar as ullyhard-ened e.9. lush, bucket andle"), r ater,after aking ut he oints pointing)162,164].

Flush and "bucket handle" joints

The lush oint equires he visible ointsof hemasonry o be filledcompletely ith mortar.Surplusmortar s rimmed ffwith he rowel.The "bucket handle" oint s ormed after he , '

mortar has started o harden by "ironing n" o adepth of 2 mm, compacting nd smoothingwitha sliver of wood, ointing ronor piece of

plastic hose diameter pprox.1.5 o 2 timesth e widthof he oint). he smoothing ust.always e carried ut at exactly he right imeand starting rom he irst oint ormed o ensurea consistent oint olour se e .5.7).The advantage f these oints s hat hey are 'carried ut mmediately fterbuilding hemasonry nd so provide homogeneous, ell-compacted oints ormed fromone mould", o ,to speak, hroughout heir depth.However, his ype of ointing an be carriedout properly nlywhen bed oints nd perpendsare completely illedwithmortar, o avoid hav-'ing o make good when smoothing he oints.

Thispresupposes areful ricklaying.The disadvantage, hat he acing masonrymust be kept clean during construction

/

2 m m


8/16

Jointdesign

5.8 Point ing

ecause ubsequent leaning f the acade

ould ead o cement being washed out of heoints, an be avoided by using a mortar withood cohesion nd water-retention roperties.hisprevents he mortar unning o wn he acef he masonry hen t nevitably queezes utf he oints.

ointinghis equires he ointsof exposed urfaces oe raked out o deoth of 15-20 mm but not asaras he irst ow of any perforations n henits immediately fterconstruction y usingslightly apered trip of hardwood.

Attemptingo construct acing masonry ithhe mortar eftback rom he edge o save ak-ngout he oints ater s not a properway ofreparing he outer ointsubstrate, nd s

herefore ot permitted. t is also consideredoorworkmanshio o rake out he mortar V-haped. alf-round r bevelled n he middle f

oint,because hen he pointingmortar oesotachieve proper bond with he units and

he mortar f he oints, nd consequently oesot protect he masonry gains t riving ain.

After aking ut, any oose pieces of mortarhould e removed rom he acade surfacesn d he oints y brushing nd insing ith

water, ossiblywith he addition f a cleaning

gent. rioro pointing,he acade hould eaturated with water starting at the bottom. Theointingmortar mixed y machine o a "plastic"onsistency) s hen pressed nto he ointsand

wellcompacted n wo operations, nd excessmortar emoved,n he irst operation he perpends re irstompacted nd hen he bed oint; n heecond peration he bed oints irstand henh e perpends see ig .2.5.8).uitablemeasures, .g. spraying withwater,overing ith plastic heeting, hould be akeno protect he resh pointing gainst rematurerying-out aused y draughts, unshine tc.

he composition f he pointingmortar houldorrespondmore or less with hat of he mortarf he oints, nd should be preferably f mor-

tar group la , l lor l la .

The disadvantages fpointing

re hat tencourages he production f masonrywithoutfully illedoints, nd hat ointing nd pointingmortarswithdifferentmixes, r pointingmortarwhich s oo dry, e ads o diminished dhesionbetween ointing nd moftaror masonry nit.Both hese disadvantages eaken he driving.rain esistance f he acing masonry nd, as aresult, mpair he durability f he wallconstruc-tion.Therefore, ointing houldbe used onlywhen a particular ffect e.9. colour) s desired,or when he surface f he masonrv nit sunsuited o a flush oint.

Joint design

The components f a building re subjected ostresses nd strains uch as hose caused bytemperature, reep and shrinkage eforma-tions;Preventing uch deformations ausesrestraint tresses, hich can ead o cracksappearing n he structure. herefore, hedesigner hould neludemovement oints s apreventive easure o avoid cracking.Besidesaccommodating eformation,ointsmust com-pensate or manufacturing nd assembly oler-ances, and at he same ime complywithbuild-in g science equirements thermal nd sound.insulation, eather nd ire protection), o dothis, hey must be wide enough nd be illed'withsuitable materials.As ointsaffect he appearance fmasonry,they should be considered s architectural le-ments n he planning. owever, he y shouldbe included nly where absolutely ecessary,because heir construction nd maintenanceare costly and nvolved. oints hould bestraight nd positioned ogically, theruuisethey become omplicated nd may not be ullyeffective.

Types of joints

Joints are divided ntomovement oints, igid

joints nd dummy oints.Movement oints nclude ettlement nd expan-sion oints.Settlement oints e.9. betweenbuildings) re called or when significant iffer-ential ettlement s exoected etween wo ormore sections f a building. hey extend verthe ull height f he building nd also passthrough he oundations. n such situations tmust be ensured hat he separate arts of hebuilding ac h have an ndependent hree-dimensional racing ystem. he isk of differ-ential ettlement riseswhen different ectionsof the building mpose ifferent round pres-sures on a subsoil usceptible o settlement r

when he ype of subsoil hanges beneathhe

building, xpansionoints e.9. ertical ndhorizontal oints n acing work)are required n

151


9/16


Wall expanded

2,5,9 Feasible movement oint detail

',/,/,/

large components hat undergo eformation sa result f shrinkage nd emperature luctua-tions.As a rule, ertical xpansion oints on-tinue down as ar as he oo of the oundations.This ype of deformation s ess damaging o

foundations nd undivided oundations end ocompensate or settlement. igid oints e.9.assembly oints, onstruction oints, ointsbetween refabricated lements) rise as aresult f he.type f construction r buildingoperations. uch oints an also act as move-ment oints, nwhich ase hey should e ormedand sealed as or such oints,Dummy ointsareproduced nly or appearance nd have nofunctions egarding he accommodation fdeformations r olerances,

The sealing of ioints

Sealing ompounds, reformed ealingas -

kets and cover strips are used o seal oints(see ig .2.5.9) 9] .

Sealing compoundsHere, he oint s sealed by permanently lasticand permanently lastoplastic ne- and wo-part compounds, .g . polysulphide, iliconerubber, olyurethane r acrylic ispersions.These materials re permanently lasticbutdeform lastically nder he nfluence f ong-term oading nd hence educe tresses ithinth e oint. hey ar e available n various oloursand can be expected o last 15-20 ears. Seal-in gcompounds ust be applied n dry condi-tions at emperatures bove +5"C.The mason-ry ointson both sides of he movement ointshould e ully illedwithmortar, nd he open-ing or he oint tselfmust be free rom dust,mortar roppings, ilan d grease n order oachieve ptimum dhesion etween ealingcompound nd masonry nd o avoid cracks nthe ong erm.A round backing trip of lexible oamed mater-ial s nserted nto he opening before he seal-in g compound o as o be able o nject hecompound withsufficient ressure nd at hesame ime give t a suitable orm. his o-called acking ord must have a diameter f

about 1.5 imes he widthof he oint,must becompatible ith he sealing ompound ndmust not absorb any water. After njecting hesealing ompound sing hand-operated rcompressed-air un , he oint,is enerally ub-sequently iven slightly oncave rofile.

Preformed ealing gasketsJointsma y be illedwithpreformed ealinggaskets made rom open-cell lastic.foamimpregnated ith a special bitumen r poly-acrylate. herefore, he gaskets emain erma-nently lastic, o not crack or become brittle,

and are resistant o ultraviolet adiation ndalkaline olutions. he preforrned asket ssqueezed ogether efore being nserted, nd

aligned with he oint.As it attempts o regainit soriginal iz eand shape, t presses gainstthe sides of the ointwithsufficient dhesion oseal t mmediately.ndoing o, he gasket ls ocomoensates or he unevenness f he sides

of he oint.Preformed askets ompressed oone hird heir riginal ize ar e adequate ocreate a dust-tight nd airtight oint;a gasketcompressed o one ifth ts original izecreatesa watertight oint.

Cover stripsA cover stripcan be clamped r glued nto hejoint o seal t, The contact pressure f coverstrips clamped nto place must be adequate oprevent he strip dropping ut f he gapwidens as a result f, or example, drop ntemperature.The adhesion f the glue o the substrate s

decisive orglued

strips.To mprove he adhe-

sion, he sides of he ointmay be carefullypainted r, n he case of a highly absorbentmaterial, ealed withan epoxy esin olution.

Drained ointsVerticalmovement oints n acing masonry anbe designed s drained, .e .open, oints nbuildings ocated n regions here es s drivingrain s o be expected, rovided he backingmasonry nd any nsulation re permanentlyprotected gainstmoisture, .g .an airspace,plaster r plastic heeting. uch ointsare 'restricted o a maximum idthof15 mm and reouire n outer eaf hickness f atleast 0 mm .

The spacing and width of joints

Th e design f he oints, .e .establishinghewidths of he ointsand he distances etweenthem, s carried ut by he structural ngineeran d deoends n numerous ariables:hestructural oncept of he respecttve tructure;'the dimensions f the structure; he stiffness fthe construction ith espect o changes nlength; he arrangement f stiffening lements;temperature hanges; he nsulation o theexternal alls; he shrinkage nd creep behav-

iourof the walls and loors; he settlement ianticipated tc.Outer eaves f masonry ndergo reaterchanges n ength ha n nner eaves ecausethey are subjected o greater emperaturechanges. Added o this we have he differentialdeformation f the eaves aused by differentmaterial roperties nd different oads on heinnerand outer eaves. he advice belowshould be followedwhen designing movementjoints n outer eaves f masonry:

' Verlicalmovement ointsare required t hecorners f buildings nd also n on gwalls t

a spacing of max. 6.0 m for ightweighton-

crete units,max. 8.0 m for calcium ilicateunits, nd 1O-16 or clay brickwork. hese

Wall contracted

,/././.Round losed-cell/2strc/cotdPrimeroradhesion7//.Compressed gaskel

< 1 5 m m

Compressed asket

Cover strips

ffi\kp&

ffiffiW

Self-adhesive id e

152


10/16

Mechanicalixingsn masonry

different igures do not represent ifferentstandards ut are he result f he differentdeformation roperties f h ese acing mater-ials. f a facade s aken around he corner ofth e building ithout oint, he eturn hould

no tbe onger ha n 5. 0 m. In he case of intelsover argewindow nd door openings, ove-ment oints re positioned n inewith he win-dow and door eveals bove and below heopenrngs.Horizontal ovement ointsare requiredbeneath arapets nd roof overhangs, elowbalcony loorsand beams, below oists andpurlins, eneath indows nd hresholds,and below upports or outer eaves whenthey are more han 6.0 m high withan outerleaf< 115 mm hick,and when hey are morethan 12.0m high withan outer eaf > 115 mmthick.

Thewidthof he ointdepends on he antici-ated deformation f the components nd heeformability f he material o be used o seal

h e oint. he width s usually ive o sevenimes he change n ength o be accommo-ated by he oint. ointwidthsof 15-25 mmre normally hosen nd he oints paced ouit hiswidth.Wider ointsare difficult o sealropeny.

Gauged rickwork

When uilding ith normal r ightweight or-ar, he different ositions nd heights f henits an be compensated or o a cedainxtent y adjusting he hicknesses f he bedoints.However, auged brickwork nd hin-ed mortar withoint hicknesses f 1-3 mm)ermit nlyminimal djustment f position ndeight. he esult f this s hat he base course

must be aid withextreme are because t alsoerves s he course or adjusting he height as

well s he ongitudinal nd ransverse lanari-y.

The base course s aid on a bed of normal mo-tar f group ll an d he n aligned orizontally.mall- nd medium-format nits r evelling

nits 50-125 mm hlgh and up o 500 mm ongare oftenused n he base course n conjunc-onwith he actual gauged bricks.

Once he base course has hardened, heauged brickswith heir associated hin-bed

mortar re used, starting rom he secondourse. he bed aces fthe gauged rickshould e brushed efore he hin-bed mortars applied n order o ensure clean, moothed ace, whichhelps o guarantee he adhe-ion between nit and mortar. he hin-bed

mortar s applied o he be d ointeither y dip-ing he gauged ricks pprox.mm nto he mortar r by spreading he mor-

ar directly nto he bedoint

using a specialrowel, oller r mortar ledge, hich ppliesonstant ayer of mortar o the oint.The width

of he rowel or roller r sledge should matchthe hickness f the wall. When using a trowel,th e hin-bedmortar s onlyapplied o he be djoint wo or hree bricksahead of the brickbeing aid, ut when using roller r sledge,

rationalization easures ictate hat he mortarbe applied o he whole ength f wall. heroller an also be used o place glass ibremat between wo ayers f hin-bed mortareach approx. mm hick. he high earingresistance f he rnat ncreases he compres-sive strength f he masonry nd he adhesiveshear trength etween auged bricksandmortar.After he gauged brick s aid, he aces andedges are aligned accurately efore apping tintoplace witha rubber ammer. ny hin-bedmortar hat squeezes ut s rimmed ff withametal patula nce t has started o harden. Atth e same ime, ny laws, .g. unfilled er -pends r bed oints r damaged dges, remade good.From ime o time, after a brick s aid t shouldbe removed gain mmediately n order ocheck whether complete ed of mortar sbeing achieved with he respective method fapplication.

Mechanical ixings n masonry

Very many different ypes of neighbouring on-structions, omponents nd ittings ave o befixed o masonry sing anchors, rive screwsan d nails. hese resubjected o ension,compression, hear, nclined ension ndbending.Neither tandards or guidelines re availablefor assessing uch connections. herefore, oad-bearing ixingsmay onlyuse anchors overedby a buitding uthority ertificate.Other ypes of fixing anchors nd nailswithoutcertificates) ay be used or minor applica-tions. However, hese may not be us ed or ix-lng constructions n he ension ones of roofand loor slabs and also not o r attaching ur-tain wall acades and hermal nsulation om-posite ystems 43 ,49 , 78 , 109,110].

Anchors

Anchors re ixings nserted nd secured ntoholes rillednt o olidmaterials. heirmainpurpose s o permit he attachment f a wholerange of minor tems but hey may also beused o anchor oadbearing omponents.Regardless f he ype of application, heyshould lways e properly lanned nd sized.Anchors an be classified ccording o variouscriteria. ne commonmethod s o distinguish'between he ype of anchorage n he drilledhole undercut, echanical xpansion,ric-

tion,grouting,

.dhesion and he material fthe anchor, Up o now, only plastic expansionanchors nd njected routanchors ave been

2.5.10 Examples f plastic and njection nchorscovered by building authority ertificates 15 ]

lnjectionwallplugs

ililwwPlasticwallplugs

153


11/16

The building fmasonry

2.5.11 Method of functioningof anchors 13]

approved or ixings n masonry see ig.2.5.10).There are also special anchors or ixing her-mal nsulation omposite ystems nd oranchoring all ies or win-leaf masonry ndfacing masonry. hese anchor ystems re nturn based on he plastic expansion nchorsand he njection nchors. inally,here respecialwallplugs or autoclaved erated on-crete, which permit omponents o be attachedto this verysoft naterial.

Plastic anchorscan be used or ixings n concrete s wellasin masonry f solidand perforated nits.Theyare normally nserted hrough he tem o befixedand nto he wall. The anchors onsist fa plastic leeve, esigned ot o urn n hehole, nd an associated crew r nail. heminimum epth f anchorage s marked nthe olastic leeve. collar at he outer end of

th e sleeve revents he anchor eing pushedtoo ar nto he hole during ssembly.The geometry nd ength f he screw or nailare matched o the nternal eometry ndlength f he sleeve o hat he anchor s prop-erlyexpanded nce he screw r nail s nplace. However, xpanding lastic nchorswithnailsma y onlybe used or ixing acadesin concrete nd solidmasonry nits.Plastic nchorsmay not be used or pure axialtension, ut only or nclined ension t anangle f at east 0'. n solidmaterials he en-sion s ransferred y riction. he expandedpart of he anchor s pressed gainst he side

of he drilledhole and hence activates he ric-tion. n hollowmasonry nits he ension s alsotransferred y he nterlock etween he anchor

1 U

geometry nd he shape of he substrate seef i g . . 5 . 11 ) .

lnjectionanchorsare nserted nto he wallbefore ffering p theitem o be attached nd up to now have onlybeen approved or ixings n hollow masonryunrts.They workby way of he bond between heanchor r anchor leeve nd he substrate. hebond s achieved y way of an njected routbased n rapid-hardening ement r artificialresin. However, njection nchors itted n voidsalso ransfer he ension ia he mechanicalinterlock f the njected rout orced nto hevoid see ig .2 .5 .11) .When using apid-hardening ement, he mor-tar s mixed witha prescribed mount f waterbefore being orced nto he void by a hand-operated ump. The esult s hat he void n

th e masonry s more r ess illed. he amountof mortar equired s minimized y usinganchors urrounded y a polyamide esh.Injection nchors ased on aftificial esin con-sist of a mesh sleeve nd a threaded ar withnut and centering ing,or a metal le eve withinternal hread, plus he artificial esin mortar.The separate omponents, esin and hardener,are orced hrough mixing ube and njected- thoroughly ixed into he mesh leeve. hethreaded ar or he sleeve with nternal hreadis subsequently ushed nto he mesh leeve.Anchoringhe wallplug n he we b of a mason-ry unit equires he drilled ole o be carefully

cleaned y brushing nd compressed ir norder o guarantee n adequate ond o trans-fer he ension.

Anchors or autoclaved aerated concretePlastic xpans ion nd njection nchors withacylindrical rilledhole are not suitable or auto-claved aerated oncrete ecause his materialis very soft, s damaged by the expansionforces and also cannot ccommodate nysignificant onding orces. Therefore, pecialanchors ave been developed or ixings nautoclaved erated oncrete. hey areanchored yway of conical rilled undercutsvirtually ithout ny compression ue oexpansion, r njection, r a special rfoflge:ment which allows ow expansion orces o betransferred, hanks o a suitable ur face esignand partial ompaction f he autoclaved er-ated concrete see ig. 2.5.12). he ixing ofcomponents ubjected o heavy r dynamicloads may equire he use of bolts passedthrough he aerated oncrete wall.In his case he wall s drilled ight hrough o

match he diameter f he bolt and a widerpocket ormed on he rear ace. The tem o befixed s itted over he bolt, whichpassesthrough he walland s secured n he rearface, and pressed up against he autoclavedaerated oncrete. arge washers r anchorolates are itted o the bolt on both sides of hewall o distribute he oad

lnstallinganchorsAnchors equire he hole o be carefully rilled;lack of care when drilling an ead o an over-size hole,which esults n a rapiddecrease nthe pull-out trength f he ixing.Holes or

anchorsn masonry an be drilled witha nor-

mal otary drill,a percussion rill rotation lusrapid percussion ction) r a hammer rill

z


12/16

Rationalization easures

(rotation lusslower but more powerful ercus-sion ction). ercussion nd hammer rillsma ybe used n solid unitswitha dense microstruc-ture,but oniy otary rillsmay be used n per-forated, utoclaved erated oncrete nd ow-

strength nits o hat he hole emains heproper izeand he webs and wallsof per-forated nitsare not damaged by the percus-siveaction. t is recommended o grind normalcarbide rills,whichare designed or rotationplus ercussion ction, harp n he directionof rotation, imilaro a steel drill, o achieveoptimum rogress he n drilling hole purelyby rotation.With ew exceptions, he hole must be drilled atleast 0 mm deeper han he depth of anchor-age. This eaves oom or any dust or for hepoint f he screw o protrude hrough he endofthewallplug, nd hence uarantees he cor-

rect unctioning f he anchor.ln solid ross-sectio ns, us t esulting rom hedrillinghould e removed rom he holedur-in gan d after rillingn order o avoid imin-ished riction nd bond effects, nd o guaran-tee he oad-carrying apacity f the anchor.There re variousways of fixing he actualneighbouring onstruction, omponent tc.Theholes an be drilled afterhaving irst usedthe ixingholes n he component o establishthe positions f he holes n he wall) and heanchors nserted efore positioning he com-ponent gainst he wall and screwing t intoplace. n his case he anchor sually inishesflushwith he surface f the walland he diam-eter of he hole n he wall s arger han hat ofthe hole n he component. lternatively,heholes n he wallcan be drilled sing he ixingholes n he component s a template whichguarantees ccuracy) nd he anchors nsed-ed nto he wall hrough he component. n hiscase he diameter f the hole n he comoonentis at east s arge as hat of he hole n hewall. his rocedure s particularlyuitablewheneach component equires more han woanchors nd or arge umbers f ixings. t salsopossible o attach a component t a cer-taindistance rom he wall. A tension- ndcompression-resistant ixing s achieved y

using n njection nchor av ing metric n-ternal hread nto which a screw, bolt orthreaded ar with ocknuts s itted,

Modes of failure of anchorsAnchors an ai las a result f overloadedanchorage oints, ncorrect nstallation r heinadequate oad-carrying apacity f he sub-strate. lastic nchors an ai lby being pulledoutof he substrate, lthough his does notseriously amage. A pull-out ailuremeans hatan excessive.load as overcome he riction rbond n he hole; a ruptured ixing means hatthe strength f he screw material as not ade-

quate or he oad.Fracture f he masonry material tself s henormalmode of failure or an niection nchor.

This haooens when he ension oads are oohigh, he masonry s not strong enough r hedepth of anchorage s nadequate. wall canfracture f t is not arge enough o carry heloads r f he edge distances r spacings f

fixingsare oo small or he expansion orcesintroduced.

Nail anchorsNailsand drive screws are employed nly orminor onstructions ith ow anchorage oads,and primarilyn aerated oncrete masonry.Lightweighttems, .g. battens or woodenpanelling, re ixed n place by driving he nailsor drive screws directly nto he autoclavedaerated oncrete.The best nails or his are apered, alvanizedsquare ails 0-180mm ong witha rough ur -

face inish. hey should be hammered omefromalternate ngles. Other ypes of nailsinclude wisted ails nd special ai lanchorsand hammered lugs or autoclaved era tedconcrete. he wisted nailgains ts anchorageby way of riction nd expansion, he other woforms by way of a mechanical nterlock seef i9 .2 .5 .13 ) .

Rationalization measures

Building to save space and costsThe ising ost of buildingmeans hat he opti-mization f costs and space n he housingmarket s becoming ncreasingly mportant.The potential or optimizing he use of he avail-able space s o be ound rincipallyn exploit-ing he options or optimizinghe oadbearingstructure s contained n standards nd regu-lations. hese ootions must be taken ntoaccount arly n he planning tage f a build-ing project.One undamental ptimization ption or heloadbearing tructure s he regular rrange-ment f shear walls. regular rrangementprovides xcellent tability nd minimizes allthicknesses. n addition,he spans f he loors

can be made equal,which n urn minimizesslab depths and he amount f reinforcementrequired.Anothermeasure or saving money and spaceis o reduce he hicknesses f oadbearingwalls o he minimum imension ecessary osatisfy tr uctural nd building cience equire-ments by employing he more accurate methodof analysis. ccording o DIN1053 part 1 heminimum hickness or oadbearing nternaland external alls,as wellas he oadbearingleafof win-leaf xternal alls, s 115 mm. How-ever, minimum all hickness f 17 5 mm srecommended or single-leaf xternal alls

witha thermal nsulation ystem n order o.complywith hermal nd sound nsulationrequirements. nternal artitions 115 mm may

2,5.12 Examples f anchors or autoclaved eratedconcrete

Expansion al l plug with compaction

Wallplug expands when expandingshell s orced over cone.

Through{ixing or particu-larlyheavy or dynamic oads

2.5.13 Nail anchors or autoclaved erated oncrete, masonry

Square nail

Twisted nail

P r + Aerated concretenailanchor

Aerated concretehammered lu gP,-,

P.-b,

15 5


13/16


/ q

4. O

3. 5

2.5

2 .0

2.5.14 Working hours guidance igures h/m3]

Conventional- masonry2 D F 3 D F

be considered s oadbearing. he gain nfloorarea when using masonry alls with heseminimum hicknesses s aoprox. -7o/o om-pared o the common wall hicknesses f 240-365 mm. n addition, ewer masonry nits and

less mortar re required. urthermore, hinmasonry s more lexible nd he refore es sliable o crack han hickermasonry, n whichthe structural tresses re ower. he use of askim coat nstead f 15-20mm "normal laster"ca n also achieve n additional ai n n loorarea amounting o approx. % depending nthe size of he room. However,masonry wallswith arge slenderness atios al l or he use ofmasonry nitswith high strength nd highgross density, s well as high-quality ortar(MG ll ,MG l la ,DM). he actual u i ld ing fmasonry t an optimized o st s ess a questionof optimizing he oadbearing tructure han a

matter or rationalized uilding perations, heuse of large-format asonry nitsand specialbuildingmethods e.9. refabricated onstruc-t ion) 139, 40] .

Rational laying techniquesThe aim of rational rick laying s o minimizethe number f operations o be carried ut bythe bricklayer he n building wall, nd at hesame ime o adapt he ergonomics f he workto meet he needs of he bricklayer etter,The handling f the masonry nits hemselvesis crucial o manual ricklaying. herefore, or '

example, he calcium ilicate ndustry asdeveloped ri paids withgripba r and humb-hole especially or heir heavy blocks or brick-layers o be able o handle he blocks easily.The bricklayer o onger has o relyon he ric-tion between is ingers and he surface f themasonry nit o grip t. Apart rom hat, hereare also blocks withgripaids at he bottom orwhen he bricklayer as o workon sectionsm o r e t h a n l m h i g h .Above'a ertain eight, andling evices reused o reduce he physical train f liftingsuch heavy masonry nits.At the same ime,productivitys mproved see Large-formatelements"). urther ationalization easures or

bricklaying re he use of masonry ithout mor-tar o the perpends see Layingwithoutmortarto he perpends"), he us e of hin-bedmasonryand he omission f bonded ntersectionsbetween walls see Butt-jointedunctions").Building allswithoutmortar o he perpendsinvolves sing masonry nits withan ntegraltongue and groove ystem,whichcan hen beinterlocked ithout sing mortar. ilted bricksar e avoided y guiding ach ongue ndgroove ogether, hichhelps roduce .planewallsurface. he construction f masonrywithconventional 0-12mm perpends nd bedjointsmeans hat 55% of he bricklayer'sime s

spent with he mortar. he use of he hin-bedtechnique n conjunction ith ongue ndgroovemasonry nits cuts he consumption f

mortar rom 50 l/m3 or a thick oint o 5 l/ms ora thin oint.Moreover, he application f a con-stant bed of modar using a modar sledge orspecial rowel, nd he resulting aying f a rowof masonry n its, chieves time saving f up

1o25o/o. he bricklayers ork n pairs, onespreading he hin-bed mortar long he wallwith he mortar ledge or special rowel, ndthe other aying ows of masonry nits n heprepared mortar ed [75;.Further ationalizationn masonry onstr uctioncan be achieved y using he various pecialunitsand special omponents roduced y hemasonry ndustry see Special ormats, pe-cialunits"). he ai m here, n padicular, s ointegrate ther materials steel and concreterequired or structural easons ntoan essen-tiallyhomogeneous asonry onstruction,while reducing he work equired o integrate

such materials.

The quantities f materials and number ofworking hours requiredcan be determined heoretically ut are subjectto considerable luctuationin ractice.Organi-zation n the building ite s critical or his. Tocalculate he number f units equired, t simportant, or example, o know whether heunitswillbe cut on site witha hammer r withasaw. The amount f mortar equired s, orexample, pprox. 5-30o/oower or masonrywithoutmortar o the perpends han o r mason-ry withmortar o the perpends. n Germany,comprehensive uidance igures or workinghours av e been published y he FederalCommittee or Performance-lin ked ay.Theseinclude ncillary orksuch as nstruction, ix-:ing mortar, moving caffolds, etting ut andbuilding penings, leaning he workplace tc.The igures learly eveal he nfluences f thesize of he masonry nit; whether ricklaying scarried ut by hand or witha handling evice;the use of hin-bed mortar nd he omission fmortar o he perpends see ig .2.5.14).Thespeeding-up f operations hen using arge-format nstead f small-format nitscan beattributed o the size of he units but also he

technique f laying ows of units n hin-bedmodar. he economic dv antage rowswiththe manufacturing ccuracy f he masonryunits because s deviations iminish o hemortar bed can be reduced o a minimum: av-ings n ime and materials re he result. t hesame ime, he wall becomes more homoge-neous with al l he advantages his mplies nterms f structure nd building cience.

Organizing hebuitding site and btuitdingoperationsRational onstruction fmasonry lso meanscarefulplanning f site and operations n order

to avoid ramework onditions hat make tunnecessarily ifficult.his ncludes he ightuse of personnel; hoice of materials; imely

I

4.60 h/m'

gauged elements999 x 623 x 300 mm

156


14/16


organization nd suitable ocation f storedmaterials; reparations or optimum se ofmaterials the use of premixed mortar, retreat-ment f masonry nitsetc.); and he rightuseof resources or bricklaying perations e.9.

handling evices,workingplatforms,mortarsledge tc.).Disruptions o on-site perationshave greater ffecton the degree of rational-ization hen using arge-format asonry nits,which esult n ewer workinghours per m2ofwall, han when workingwithsmail-format nits.Thecorrect rovision f masonry nitsandmortar t he right ime, n sufficient uantitiesand at he right place s especially mportant fthe bricklayer s o avoid unnecessary alkingand movements hen working. his s also ruewhen sing andling evices. o achieve pti.mum andling imes, t must be ensured hat-each delivery fmasonry nits s stacked at

the place of work n a row without ny gaps.Thisguarantees hat he optimum umber funits s aid per handling outinewith he presethandling arameters. owever, oo manymaterials tored ithin he building an also bea disadvantage ecause his can hamper hemovement f scaffolds r handling evices.Thedistance etween ricklayers houldbeabout ,5-3.0 n order o achieve regularworking hythm,One bricklayer er 3.0 m ofwall ength ringsabout a 25/o nc rease n per-formance ve rone bricklayer er 2.0 mbecause here are ess nterruptions o theworking hythm.Theuse of a mortar ledge means hat he dis-tance between ricklayers nd o the ub ofmortar an be increased till urtherbecause,with ne illing,onger engths f wallcan beprovided itha constant ed of mortar han sthe case when using a trowel. he bricklayerhas o walk and move ess and so he workingrhythm s again made more consistent.

ScaffoldsThe height f he work s critical o the perfor-mance, atigue nd health f he bricklayer,

particularly hen aying arge-format asonryunits. he ime and effort equire d o lay a unitis owest or working heights etween 00 and80 0 mm . Scaffold eights hould e variableso hat his optimumworkingheight an bemaintained or he entire wall.Modern teelscaffolds re useful ere beeause hey permitscaffold oards o be placed every500 mm nheight. n addition, ltension brackets an besuspended 00 mm below each working evelon he wallside o avoid nnecessary ending,Trestles nd scaffolds n screw supports withinfinite eight adjustment ean hat he work-ing height an be adjusted o suit he brick-layer, nd so improves he ergonomics f heWOTK.ln contrast o scaffolds n adjustable upports,the bricklayer's latform ithor without ntegralhoist rovides larger orking re a enabling

th e building f walls up o 4.0 m long.Sucholatforms lso have heirown wheels nd socan be readily moved o a new ocation, reasily iftedby crane representing majoreconomic dvantage. Withan ntegral oist,even arger masonry ormats an be laid quick-ly ,accurately nd without atigue.

TemplatesTh e building f corners r window nd doorreveals re particularly omplicated perationsbecause f he amount fplumbing nd meas-uringwork nvolved. eusable orner ndopening emplates, hich ndicate he verticaland horizontal ositions f courses nd units,ca n make uc hworkmuch easier. uilding hecorners irst with he associated ackingbackis no onger necessary. When aying he basecourse, n which ny unevenness n he loorhas o be comoensated or and so establishesthe basis or he accuracy f subsequentcourses, noticeable ationalization ffect sachieved hen using template, bove ll nthe next course. An increase n productivitysparticularly videntwhen doors and windows,or at east heir rames, re ncorporated s

prefabricated lements nd simply builtaroundin one ooeration.

Rational working with large-format masonry units

Large-format asonry nitq nd elements rethose with ength s f 498-998 mm and heightsof 373-623mm. The ength nd height esultfrom he use of hin-bed mortarwithbed ointan d perpend hicknesses f 1-3mm .Toreduce costs still urther, he perpends re re-quently ongue and groove unitsbutted ogeth-er withoutmortar see Large-format le-ments").Th e high aying ates withhandling evicesand wo-man eams, he use of thin-bed mortarand he reduction n subsequent orkowing othe simple and accurate aying f he units arethe rationalization ossibilities hichcan be

expected rom h e use of arge{ormat masonryunits. he ational ayingprocess means hat alength f up to 1.25 m of masonry n courseheights f375-750 mm can be constructed none operation. hiscorresponds o rates of upto approx. .94 m2of inished masonry eroperation. his s especially orthwhileorlarge uninterrupted reas of wall,but n othersituations he rationalization ffect an still beguaranteed y using supplementary ormats,make-up ieces r specials.The wo-man eam ationalizes ricklayingactivities ecause ne man operates he han-dlingdevice nd s only esponsible orpreparatory ork (supplyingmasonry nits andmoftar, ickingup units and ransporting hemto the place where hey are o be laid),whilethe other man carries ut he actual bricklay-ing, ,e. preading he ayer fmortar ith amortar ledge r similarool, aying nd align-ing he units, Consequently, orking ates ofapprox. .33 h/m2 or uninterrupted la twallsandO.42h/m2'for therwalls an be achieved.In order o limit he physical train n he brick-layer, he use of large-format asonry nitshas ed o the ntroduction f a maximum er-


15/16


2.5.15 Installation rawings or modular masonry

Calcium ilicate auged eiement wallwith ew interruptions

Gable wall

3300 1200 3300 I- - - -3900 3900 |

7800 |- -

missible eight including evels f moisturecommon n site for masonry nitswhen ay-in g by hand, he maximum eight imits r emandatory nd are stipulated n an nformationsheet published y he Bau-Berufsgenossen-schaften Building mployers' iabilitynsur-ance Associations)132], nd ar e based nextensive rgonomic tudies. he nfor ma,tionsheet istinguishes etween he one-hand ndthe wo-hand ift.The one-hand iftmeans hat he masonry nitca n be picked p withon e hand and aid with-ou t unnecessary hysical train. he maximumpermissible eight f a unlt s 7.5 kg or a gripwidthof up to 70 mm, and 6.0 kg for a gripwidth f up o 115 mm.The wo-hand iftmeans hat he masonry nitexceeds he maximum alues or he one-handlift.The maximum eight of a unit s 25 kg.Such unitsmust be provided it hgripaids orbe designed n such a way hat hey can begripped n both hands sing uitable ools ndlaidmanually, eavy nits hould e ifted ndlaidby means f a handling evice.

Masonry unithandling devicesTh e use of ifting quipment r handlingdevices s necessary or masonry nit ormatslarger ha n 16 DF or 240 mm hickwalls nd10 DF or 365 mm hick wallsor or masonryunitsweighing ore han 25 kg. Travellingmini-cranes ith a load-carrying apacity f upto 300 kg situated n he respective loorareincreasingly eing mployed or his work.Depending n he size of he units, p o iv elarge-format nits an be gripped nd ai dsideby side n one ift, .e. approx. m2 f wall areacan be produced n wo ifts.Handling evices

are normally sed n conjunction ith he wo-man eams escribed bove. he y onsider-ably elieve he physical train n he ndividual

15 8

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Y Ny $( , O- 1 3 7 1 0 + o 2 9 8 2 +.* 26T0 += ^ - ^ - 9 2 6 1 5_ 7595 + qJ ^-^--

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bricklayer espite he act hat mproved ro-ductivity s expected rom a smaller umber fbricklayers. he us e of a handling evice n atwo-man eam only contributes o more atronalmasonry onstructi on hen he perpendsmake use of he ongue and groove ystemwithoutmodar because everal nits aregripped imultaneously),hen he eam s ullyfamiliar ith his system nd each other, andwhen a continuous ransport hain rom pro-duction o placement s guaranteed. herefore,th e groups fmasonry nits hould e alignedin rows with he ongue and groove nd acesinterlocking o hat hey can be readily iftedintoplace by the handling evice. he astestworking imes re achieved hen he groups fmasonry nitsare stacked between he han-dlingdevice nd he bricklayer. owever, tshould be noted hat a concentrated rrange-ment of masonry nits nd handling eviceplaces a heavy oad on he loor whichmayneed o be carried by temporary dditionalsupports eneath he loor. Adequate ircula-tion zones are necessary n order o be able o

move he handling evice ro mplace o place.This s helped by using butt-jointed all nter-sections, hich avoid he need or projectingracking r oothed eturns, o hat crosswallscan be built at a later date.

The cutting of large-format masonry unitsThe production fproper masonry onds, aswellas he need o cons truct ivenwallandcolumn izes, makes t necessary o divide,cut and bevel arge-format nits.While mall-formatunitscan be cut witha brick or scutchhammer, his s not a suitable ethod or arge-formatunits because t would create oo much

unnecessary astage. Moreover, utting withahammer r similar ool s naccurate. n mason-ry of arge-format nits his eads o incorrect

bonding ecause he ower umber f per-pends and requentlyhe us e of perpendswithoutmortar)means ewer opporiunities orcompensation long he ength f he wall.Thislimits he oad-carryin g apacity f he mason-ry .Consequently, arge-format nitsmust be di-vided witha bolster hisel or a mason's am-me r or better till especially or hin-bedmasonry by accurate awing. Handsaws itha hardened lade, iamond utting iscs,bandsaws r chainsaws may be used. Cleanedges an be produced ith he ai d of guidesand emplates. utiing discs generally as tlonger han bandsaws r chainsaws.

Modular asonryThe dea of modularmasonry as developedby the calcium ilicate nd autoclaved eratedconcrete ndustries. he benefit hat modularmasonry rings o rationalizations hat helarge-format asonry nits or each wallaredelivered o site as actory-made all kits",

including ll make-up nd complementaryunits, ogether withcomputer-produced nstal-lation rawings or a fixed price se e .5.15).ln addition, he manufacturer f the masonryunits rovides he hin-bed mortar, andlingdevices nd accessories.Th e design f he walls dimensions,ayoutand sizes of openings) must be coordinatedwith he building ystem r he arge-formatunits n order o minimizehe number f precutmake-up nd complementary nitsand hencethe cost of materials. lat panels f masonrywithout nterruptions n cellular onstruction readvantageous.

The nstallation rawings nd nstructions im-plifyand accelerate he erection f masonryunitsdelivered s kits.This eads o a

2.5.16 Prefabricated yslem walls


16/16


5,17 Gable n he orm of a clav brickwork a nel 2.5.18 Clay acade elements Schatz-Preton ystem)

onsiderable eduction n abour osts, lsoelped y he complementary nits upplied.n addition, utting he units n site and heostly isposal f waste are avoided. he sim-le nstallation f wallkitscan also be carriedut by he unskilled n a "do-it-yourself"ype ofonstruction, hichagain aves abour osts.

Dry wallings built y ayingmasonry nits n a bond bu t

without ny mortar o the perpends r he bedoints. o achieve his, he masonry nitsmustxhibit very high tandard f quality it hegard o deviations rom he ntended eightimensions nd n erms f he latness ndarallelism f bed aces. aying he unitswith-ut mortar o perpends r bed ointsachievesurther ationalizationn he construction f

masonry ecause he operations or supplyingh e mortar, pplyingtand emoving urplusmortar fter aying he units re al leliminated,

his mproves he ergonomics f bricklayingnumber f bending nd urning movements)nd hence makes he working h ythm fthe

ricklayer ore uniform. his eads o less imeeing equired o construct ach square metrefwall. n addition,he omission f hin-bed

mortar aves not only abour osts but materialosts as well.

As so ar he re s very ittle xperience f drywallingn practice, ts use s currently egul-

ted by way of general uilding uthority er-ficates, hese estrict he use of dry walling

o buildings ith up to three storeys r aeight bove round evel fmax. 10 m, olear torey eights f max. 2.75 m, and oloor pans of max. 6.0 m, Apart rom hat,rywallingmay not be used or reinforced

masonry, aulting, rches, rick arch loorsr cnrmneys.Drywallingmust be loaded by floorsalong ts

entire ength, whereby he depth of bearing orwallswith loor oads o one side onlymust beat east half he hicknes s f he wallor 120 mm,The loors also oofs) re o be formed as rigidplates equivalent easures e.9. tructurallydesigned apping eams) re no t permitted.Th e stability f dry walling hould e verifiedby way of various omponent ests as well asspecial tructural nalyses ith egard o buck-ling engths, onds tc. 79].

Prefa i c ated con tru cti nThe advantages nd economic ffectivenessof orefabricated onstruction ie n he rationalprefabrication f wallelements nder ptimum,industrial onditions n he actory, he ast erec-tionusing ranes nd he subsequent implestructural onnection f elements n site othus orm a homogeneous allor structure.The elements re manufactured n he actoryas brickwork anels, as t panels r compositepanels see Prefabricated asonry lements")to match he respective torey heights ndincorporate llnecessary penings nd ser-

vice ducts. They are reinforced orizontallyand verticallyor ransport nd erectlon. ndus-trialprefabrication enders ossible he use ofcomputer-assisted achinery e.9.masonryrobots) o achieve high dailyoutputwithaconsistently igh tandard f quality utat hesame ime ow abour osts .Deliveringhe elements o he building ite justin ime" nd heir apid and economic rectionspeeds p progress n site an d equires nlyafewpersonnel. mooth rection n site demandsgood preparations instrugtion f personnel,specification f erection rocedure, repara-tion of crane hardstanding nd emporary up-

ports tc.) nd usually he us e of a mobilecrane. Above basement evel, his method fconstruction llows he primary tructure f a

detached ouse o be completed n ust 3-5days. Onlyminimal ite acilities re equiredan d at he same ime he environmental ollu-tion due o noise and dirt rom he bllilding iteis minimized. nother ost-saving esults romthe act hat actory prefabrication eans hecomponents re essentially rywhen deliv-ered, whichmeans ha t ess nergy s requiredfo rdrying ut he building se e igs.2.5.1 and2.5 .17) .Besides heirus e or oadbearing, ingle-leafmasonry, refabricated lements re ncreas-ingly eing used or curtain al lmasonryfacades. uch acade lements up o 8.0 mlongan d 3. 6 m high are produced ationallyand unaffected y the weather n he actoryaccording o he guidelinesor einforcedmasonry with rost-resistant acing or engineer-ing bricks.Factory roduction nsures con-sistent nd high-quality uter eafwith espectto ointpattern, olourof units and mortar, ulljoints ithout oids, ven ointing tc . n addi-tion, linds, intels nd arches s wellasspecial extures an be ncorporated see ig .

2 . 5 . 1 8 ) .

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