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SWrucWural Analysis of HisWorical ConsWrucWions – Jerzy Jasieńko (ed) © 2012 DPNH ProcławH PolandH ISSN 0860-2395H ISBN 978-83-7125-216-7

AuflildfCAi AmmolACe Tl pTobNdTebNfNd lc TfMBbo ilAa BbAofNd cillo pTorCTrobp bmanuele wamperiniN ABpToACT =qimber= load=bearing=floor= structures=of= ftalian=historical=constructions= are=complex=systems= made=of=girdersI= joistsI= subfloorI= and=completing= components= Elath= to= cover= planking= jointsI= small= boards= to=cover=the=link=between=joists=and=girdersI=etcKFK=qhese=floors=are=placed=in=and=connected=with=the=load=bearing=wallsI=thus=constituting=a=more=complex=structural=systemK=qhe=need=of=strengthening=of=timber=load=bearing=floors=could=issue=fromW=timber=decay=Edue=to=insectsI=fungiI=fireI=or=creepFI=increase=in=loadsI=changes=in=safety=and=serviceability=standardsK=Actual=cases=show=countless=states=with=regard=toW=building=techniques;=material=state=of=preservation;=siòe= of= the= gap= between= required= and= provided= performances;= aestheticalI= historical= and= material=interest=of=ceiling=and=flooringK=fn= the= light= of= contemporary= architectural= preservation= theoriesI= several= values= must= be= considered=while=choosing=from=among=the=conceivable=systems=for=the=strengthening=of=timber=floorsW=aesthetical=quality;= signs= of= usage;= technological= features;= material= characteristicsK= lther= needs= must= also= be=evaluated= along= with= those= valuesW= the= requirement= to= assure=physical= and=aesthetical= fruition= of= the=building;=the=need=to=respect=the=original=technological=conception=of=the=structure;=the=compatibility=of=the=strengthening=solutions=with=the=existing=structureI=the=possibility=to=remove=itI=and=maintain=it=in=efficiency;=moreover=the=added=elements=should=be=clearly=recognisable=as=contemporaryK=qhis=paper= aims= to=single=out= the=primary=values= to=be= consideredI= and= to=assess= the=most= common=strengthening=solutions=with=regard=to=these=aspects=and=to=the=actual=state=of=the=floor=structureK==heywordsW qimber floor structuresI mreservationI ptrengtheningI ftaly N. BbTtbbN sAirbp ANa aATAW plMb ApmbCTp lc ClNpbosATflN

N.N. Alois oiegl’s theory of values At=the=beginning=of=OMth=century=Alois=oiegl=proposed=to=study=monuments=with=reference=to=multiple=valuesI= often= in= conflict= xNzK= Although= one= century= of= historiographical= studies= lead= to= consider=outdated=some=of=the=principles=underlying=the=text= Eas=oiegl’s=evolutionist=view=of=historyFI=oiegl’s=theory of values provides=a=logical=method=that=can=still=be=used=for=the=analysis=of=cultural=and=artistic=heritage=that=needs=conservationK=fn= aer Moderne aenkmalkultus=oiegl= identifies= two= main=categories= of= valuesW= memory=values= and=presentJday=valuesK==N.O. Memory values qhe=category=of=memory=values=encompassesW=–= qhe= intentional= commemorative= valueI= iKeK= the= potentiality= of= the= monument= to= convey= the=

message=for=the=transfer=of=which=it=was=createdK=–= qhe=historical=valueI=which=point=out=the=aptitude=of=the=monument=to=represent=a=precise=moment=

in=the=history=of=development=of=creative=skills=of=craftsmen=or=artistsK=–= qhe=age=valueI=that=is=the=capability=of=the=monument=to=witness=the=set=of=natural=phenomena=that=

have=led=to=its=evolution=from=the=original=state=to=its=present=conditionK=

================================================N=bngineerI=mha=candidateI=rniversity=of=maviaI=`ivil=bngineering=and=Architecture=aepartmentI=

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N.P. mresent-day values qhe=category=of=presentJday=values=encompassesW=–= qhe=use=valueI= which= measure= the= functionality= and= safety=of= the= monument= in= the=use=both= as=

common=building=and=as=a=museum=of=itselfK=–= qhe=art=valueI=subdivided=inW=

–= qhe=newness=valueI=that=descend=from=formal=integrity=and=unharmed=polychromyK=–= qhe=relative=art=valueI=which=promote=the=aesthetic=appreciation=of=the=monument= in=relation=

with=original=and=contemporary=hunstwollenK==N.4. curther considerations on the theory of values After= Alois= oieglI= many= other= theoreticians= have= studied= restoration= as= a= intervention= that= must=reconcile=the=contrast=between=the=various=values=of=cultural=propertiesK=cor=example=`esare=Brandi=defined=restoration=as=“the=methodological=moment=of=the=recognition=of=work= of= art= in= its= physical= concreteness= and= in= its= dual= historical= and= aesthetical= polarityI= for= the=transfer= to= future”= xOzI= thus= he= implicitly= outlined= two= fundamental= valuesW= the= historical= and= the=aesthetical=oneK=Brandi’s=theory=was=elaborated=for=works=of=artI=and=it=stated=the=clear=prevalence=of=aesthetic=instance=against=the=historical=oneK=oecently=some=researchers=also=developed=procedures=and=algorithms= to=analyòe=the=conflict=between=values=in=the=conservation=and=strengthening=of=cultural=heritage=from=a=quantitative=point=of=view=xPzK=`ontemporary= theoreticians= of= conservation= elaborated= a= new= approach= to= the= study= of= values;=Amedeo=Bellini=affirm=that=…to=restore=an=object=x…z=is=an=indicative=act=of=the=recogniòing=of=a=value=and=of=the=will=to=maintain=the=possibility=to=experience=it=in=the=future»I=but=he=opposes=to=the=use=of=the=judgment=of=historical=and=aesthetic=value=as=a=tool=for= restoration=worksK=Bellini=affirms=also=that=the=basis= for= the=conservation=works= should=be= found= in=a= technical=and= ethical= judgementI= the= first=related= to= the= contemporary= cultureI= the= second= with= the= limited= economic= resources= that= can= be=devoted= to= conservation= xQzK= joreover= maolo= qorsello= affirms= that= the= idea= of= “value”= must= be=substituted=by= the= idea= of= “datum”W= …qhe=concept= of= value= implies= involvement=and= judgmentI= thus=choiceI=possessionI=preferenceI=privilegeI=but= also=exclusionI= denialI= rejection=and= so= on;= the= one=of=datum= involves= detachmentI= suspensionI= deferment»I= and= the= datum= …stands= as= a= virtually=inexhaustible=source=of=knowledgeI=as=an=ever=new=start=x…z=of=processes=of=interpretation»K=qherefore=we=have=no=right=to=alter= the=data=on=the=basis=of=a=judgment= that= is=always=and=inescapably=relativeI=preventing=subsequent=reinterpretations=xRzK===N.R. Timber floorsW several issues to be considered `ontemporary=historiography= extended= its= studies= from=great= events= and=works= of= artI= to= every= day=history=and=material= culture=xSzK= fn= the= light= of= these=new=approach= to= the=historical= studiesI= several=valuesLdata= must=be=consideredI= all= of= them=must=be= seen= in=an=historical= point= of=viewW=aesthetical=quality=Eof=the=bottom=face=of=the=timber=frameI=of=the=flooring=and=of=the=ceiling=in=case=there=is=oneF;=signs=of=usage;=technological=features=Eoriginal=structural=conception=and=its=change=over=time;=signs=of=original= manufacturing= and= of= successive= works;= choice= of= materials;= etcKF;= material= characteristics=Einterest= of= the=materials= in= itself= and=as= a= document= of= natural=history;= signs= of= aging;= etcKFK= thile=choosing= from= among= the= conceivable= solutions= for= the= strengthening= of= timber= floorsI= other= needs=must=be=evaluated=along=with=those=issuesW=the=requirement=to=assure=physical=and=aesthetical=fruition=of=the=floor=and=of=the=whole=building;=the=need=to=respect=the=original=technological=conception=of=the=structure;= the=opportuneness= that=strengthening=solutions=don’t=contribute=to=decay=or= damage=of= the=existing= structure= EcompatibilityFI= that= they=can=be= removed= or= substituted=with= little= damage= to= the=existing= structure= EreversibilityFI= and= maintained= in= efficiency= EdurabilityF;= in= addition= strengthening=solutions= should= not= disguise= themselves= as= part= of= the= existing= structuresI= but= they= must= openly=declare=their=being=contemporary=ErecognisabilityFK= O. TfMBbo ilAa BbAofNd cillo pTorCTrobp lc fTAifAN ToAafTflN O.N. deneral features Before= talking= about= strengthening= of= timber= load= bearing= floor= structuresI= we= must= set= out= how= these=building=elements=areK=qimber=load=bearing=floor=structures=of=ftalian=historical=constructions=are=complex=systems= made= of= girdersI= joistsI= subfloorI= and= completing= componentsK= qhese= floors= are= placed= in= and=connected=with=the=load=bearing=wallsI=thus=constituting=a=more=complex=structural=system=xTI=UzK=

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O.O. mrincipal load bearing elements qhe=principal= load=bearing=elements=of= these= structures= are=the=girders= and=the= joists= that= constitute=a=horiòontal=frame=whose=complexity=depends=on=various=circumstancesK=rsually=floors=haveW=–= lne=way=structureI=made=only=by=joists=parallel=to=the=shorter=side=of=the=room=used=for=spans=

up=to=PJQ=mK=–= qwo=way=structureI=made=by=one=or= more=bearer=parallel=to=the=shorter= side=of= the=roomI=OJP= m=

distant=from=each=otherI=and=joists=perpendicular=to=themK=jore=complex=frames=Esuch=as=the=perlio=floorsF=and=floors=with=three=tiers=of=beams=are=very=unusualK==O.P. pubfloor and floor Above=the=timber=frame=the=subfloor=is=usually=made=of=timber=boards=or=thin=bricksK=qraditionally=the=subfloor=supports=a=rubble=screed=that=serves=as=a=basis=for=the=flooring;=however=many=historical=floors=have= already= been= refurbished= by= removing= the= original= rubble= screed= and= substituting= it= with=a=modern=cement=screedK==O.4. Complementary elements qhere= is= a= wide=range=of= complementary=elements;= we=have=more=and=more=elements= that= serves=functional=and=aesthetic=purposesI=going=from=simple=to=more=complex=and=refined=floorsK=fn=this=short= introduction= we= will= deal= only= with= the= more= common= onesI= that= play= a= considerable=functional=roleI=but=analysing=real=cases=we=must=consider=all=of= themI= while=becoming=aware=of=the=values=of=a=floorK=qhe=first=of=these=complementary=elements=are=the=joint= laths;=when=the=subfloor=are=made=of=timber=boardsI= usually= laths= are= used= to= sealed= from= below= the= planking= joints= to= prevent= the= downfall= of=powder=from=the=rubble=screed=EcigK=OFK=qhe=other=important=complementary=elements=are=the=soJcalled=bussoleW=small=boards=utiliòed=to=close=the=space=above=the=girder=and=between=the=ends=of=the=joistsI=and=prevent=dust=and=dirt=to=settle=EcigK=NFK=pometimes= in= the=NVth= and=OMth= centuries= timber= floors=were=hidden= from=view=by=adding=a= ceilingI=often=decorated=with=paintingsK==O.R. oole of the beams in the structural system fn=the=structural=system=made=of=the=walls=and=the=timber=floorsI=girders=and=joists=have=also=a=role=in=connecting=opposing=walls=acting=as=tie=beamsK=rsually=this=role=is=carried=out=only=due=to=the=friction=between=the=ends=of=the=beams=and=the=supporting=wallsK=pometimesI=usually=in=areas=where=architects=and=master=builders=were=aware=of=seismic=haòardI=the=beams=are=anchored=in=the=walls=with=a=wrought=iron=strap=ending=with=a=pole=or=a=plate=xTzK==P. Teb obAplNp clo pTobNdTebNfNd P.N. thy we need to strengthen? thile= talking= about= strengtheningI= first= of= all= we= need= to= point= out= why= we= do= itK= qhe= need= of=strengthening= could= issue= fromW=material= decay= or= damageI= increase= in= loadsI= changes= of= safety=and=serviceability=standardsK==P.O. Material decay qimber= ageing= does= not= lead= to= a= significant= progressive= loss= of= structural= performanceW= in= optimal=environmental= conditions= structural= timber= elements= maintain= their= load= bearing=capacity= over= time=xVI=NMzK=qhe=exposure=to=lightI=rain=and=air=leads=to=a=superficial=degradation=of=woodK=rs=light=causes=a=photodegradation=of= lignin=and=the=products=of=degradation=could=be=solubilised=and=washed=away;=wind=contributes=to=superficial=erosion=by=mechanical=action=xNNI=NOzK=tood=isI=howeverI=a=material=of=biological=originI=thus=in=natural=environment=it=tends=to=complete=its=life=cycle=with=a=progressive=deterioration=and=a=complete=destruction=by=saprophytesW=detritivores=and=decomposerK=qhe=principal=saprophytes=of=wood=are=xilophagous=insects=and=fungiK=ff=we=exclude=termites=and=few=other=speciesI= woodJboring= insects=causes= little=structural=damageI= while=fungi=can=quite=rapidly=lead=a=structure=to=collapseK=iuckily=most=of=the=saprophytes=fungi=of=wood=needs=a=timber= moisture=content=exceeding=NU÷OMB=to=carry=out=an=attack;= thus= it= is=sufficient= to=protect=wood=from=water=in=all=of=its=forms=Eair=humidityI=capillary=water=present=in=wallsI=rainwater=or=pipeline=leakagesI=etcKF=to=eliminate=most=of=the=risks=of=significant=biological=degradation=xVI=NNI=NPzK=

=

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bven=if=quite=smallI=longJduration=loads=bring=a=progressive=increase=in=deformations=due=to=creepI=that=can=cause=the=damaging=of=flooringI=partitionsI=or=equipments=xTzK==P.P. Material damage qhe= loss= of= strength= of= structural= timber= elements= could=also=be=due= to= damages= caused= by= high=temperatureI=fire=or=excessive=loads=that=have=occurred=at=any=time=in=the=history=of=the=structureK=qemperature=below=NMM°`=lead=to=a=reversible=loss=of=moisture=in=the=woodK=Between=NMM°`=and=about=OMMJORM°`=pyrolysis=takes=placeW=it=causes=the=distillation=of=wood=with=the=emission=of=gases=due=to=the=degradation=of=the=ligninK=At=temperature=of=about=OMMJORM°`=the=reaction=becomes=exothermic=and=the=combustion=of=the=external=part=of=timber=startsI=while=the=inner=part=remains=unaltered=xNOzK=te=can=find=timber=elements=exteriorly=damaged=by=pyrolysis=or=fire=that=keep=much=of=their=original=load=bearing=capacity=xNQzK=bxcessive=loads=and=unexpected=or=anomalous=load=conditions=may=have=acted=on=the=structure=in=the=past=damaging=its=bearing=elementsI= that=are=now=unable=to=bear=ordinary= loads=due=to=fracturesK= ft= is=however= necessary= to=be=careful= not= to= confuse=physiological= shrinkage=cracks= with= fracture=due= to=excessive= stressW= the= mere= presence= of= shrinkage= cracks= almost= never= indicate= a= loss= of= bearing=capacity=of=timber=elements=xNRzK==P.4. fncrease in loads ioads=could=increase=due=to=refurbishment=works=or=to=change=of=useK=oefurbishment=works=could=lead=to= the=growth=of=nonJstructural=permanent= weights= Enew=screedsI= flooringsI= ceilingsI=partition=wallsI=equipmentsI=etcKFI=while=change=of=use=could=increase=imposed=actionsK==P.R. Changes of safety and serviceability standards qhe= carpenters= and= architects= of= the= past= based= their= projects= on= empirical= evaluations= of= the= loads=acting=on=a=structural=elements=or=system=and=of=its=strengthK=jodern=building=regulations=provide=the=careful=calculation=of=self=weight=and=specify=imposed=loadsI=furthermore= the= recent= ftalian= building= code= xNSz= imposes= seismic= assessment= of= buildings= all= over=ftalian=national=territoryK=fn=seismic=structural=models= for=buildingsI=floors=act=as=rigid=diaphragms=to=divide= seismic= actions= on= vertical= load= bearing= elementsK= ftalian= building= code= demands= to= assess=existing=building=while=doing=restoration=or=refurbishment=worksK=joreover=building=codes=define=serviceability=standards=and=request=limitations=of=deformations=and=of=vibrationsK= qhe= reasons= for= these= limitations= are= related= to= damaging= of= nonJstructural= elements=EflooringI= partitionsI= equipmentsI= etcKFI= and= to=human= discomfort= Eannoying= effects= of= sloping= floors=and=footstepJinduced=vibrationsFK==4. Teb MbTelap clo pTobNdTebNfNd 4.N. lverall considerations about structural models qhe=carpenters=and=architects=of=the=past=based=their=projects=on=empirical=evaluations=of=the=overall=behaviour= of= the=buildingK= qhe=first= structural=models= Ealmost= until= the=beginning= of=OMth=centuryF=were= not= able= to= consider= the= structural= system= of= a= building= as= a= wholeI= thus= they= decomposed=building= into=simple=parts= Ea= wallI= a= pillarI= a= beamI= a= trussI= etcKFI= often= losing= sight= of= the=overall=behaviourK= jodern= engineering= elaborated=new=complex= structural=models=based=on= the=structural=conception= of= new= steel= or= reinforced= concrete= frame= structureK= pubsequently= models= for= modern=conceived=and=designed=masonry=structure=were=elaborated;=however= these=model=were=not=able=to=interpret=the=real=structural=behaviour=of=traditional=buildingsK=qhis=misunderstanding=lead=in=the=past=to=profound=alterations=of=this=heritageI=due=to=the=need=to=adapt=the=existing=buildings=to=the=abstract=models=xNTzK=kowadays= we= must= critically= evaluate= the= structural= models= conceived= for= modern= structures;=eventually=we=must=refuse=themI=and=elaborate=or=choose=other=models=more=suitable=to=understand=the=real=behaviour=of=the=structureK==4.O. massive and active strengthening systems ptrengthening=systems=can=be=classified=into=two=categoriesW=passive=systems=and=active=systemsW=–= massive=strengthening=systems=start=contributing=to=the=load=bearing=and=to=the=overall=resistance=

of=the=existing=structure=when=its=deformations=are=increased=by=external=loadsK=

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–= Active=strengthening=systems= involve= the= introduction=of= internal= forces= in= the=system=made= of=strengthened=and= strengthener= structuresK= qhis= ensures= an= immediate=efficiency= of= the= strengthJeningI=and=the=possibility=of=eliminatingI=at=least=in=partI=the=existing=deflectionsK=

then=possible=active=strengthening=systems=must=be=preferred=to=the=passive=ones=because=they=do=not=require=a=further=increase=of=deformations=Eand=hence=of=stressesF=in=the=existing=structure=to=carry=out=their=effectivenessK=then=using=tieJrodsI=active=strengthening=can=be=easily=obtained=by=means=of=screw=nutsI=while=in=the=other=cases=a=different=approach=must=be=followedW=a=simple=way=to=obtain=an=active=strengthening=is=to=reverse= the= deflection= of= the= beam= by= means= of= telescopic= propsI= and= then= apply= the= reinforcing=systemsK=

4.P. A rational classification of strengthening systems for timber floors qhe= wide= variety= of= strengthening= systems= for= timber= floors= requests= us= to= make= a= rational=classification=of=themK=A=first=distinction=must=be=made=between=systems=that=enhance=only=flexural=strength=and=stiffnessI=and=the=one= that= increase=also= the= inJplane=stiffness=of= the=floorK=qhe=former= ones= don’t=alter= the=overall=behaviour= of= the= structureI= while= the= second= ones= transform= the= floor= into= a= rigid= or= semiJrigid=diaphragmI= giving= the= building= a= boxJlike= behaviourI= and= the= opportunity= of= this= change= must= be=carefully=evaluatedK=aealing= with= the= systems= to= improve= flexural= behaviourI= we= will= follow= and= revise= the= governing=approach=proposed=by=cranco=ianer=xVzK=qhe= linear= equations= for= determining= the= maximum= bending= moment= ENFI= bending= stress= EOF= and=deflection=EPF=in=a=rectangular=beam=under=simple=bending=areW=== ENF==== EOF==== EPF===whereW=α=and=β=Z=two=coefficients=depending=from=the=restraintsI=q=Z=the=linear=span=load=acting=on=the=beamI=ℓ=Z=the=length=of=the=beamI=t=Z=the=section=modulusI=g=Z=the=moment=of=inertiaI=b=Z=the=width=of=the=section=of=the=beamI=h=Z=the=height=of=the=section=of=the=beamI=b=Z=the=modulus=of=elasticityK=A=reduction= of= stresses= is= necessary= to= enhance=the= safetyI=while= a=decrease=of= deflection= reveal= an=improvement=of=serviceabilityK=fn=both=cases=we=can=act=on=many=issuesI=individually=or=in=a=combined=wayW= the= loadsI= the= restraintsI= the= length= of= the=beamI= the= modulus= of= elasticityI= the= dimension=and=shape=of=the=beamK=te=can=also=enhance=the=safety=increasing=the=unit=bending=strength=of=the=materialI=or=adding=new=materials=that=have=a=higher=unit=strengthK=fn=the=light=of=these=considerationsI=we=can=now=analyòe=the=various=strategies=for=the=strengthening=of=a=timber=floorK==4KPK1K oeduction of the loads qhe= simplest= method= is= the= reduction= of= the= estimated= loadsK= qhis= strategy= can= be= pursued= by=decreasing=Eor=not=increasingF=the=nonJstructural=permanent=weights=or=by=limiting=imposed=actionsK=ft=is=very=difficult=to=obtain=a=considerable=reduction=of=permanent=weightI=because=almost=always=the=selfJweight= of= timber= floors= is= quite= lowI= and= the= screed= is= the= only= part= that= can= be= removed= and=substituted=with=a=lighter=one=xNQz;=at=best=a=reduction=of=only=MIR=kkLmO=can=be=obtained=against=works=for=a=complete=renovation=of=flooringsK=Both=limiting=the=imposed=actions=and=not=increasing=the=permanent=weights=provide=strong=restrictions=on=the=useK=qherefore=this=solution=can=be=used=only=when=the=timber=beams=keep=a=good=load=bearing=capacityI=and=the=floor=demand=the=maximum=degree=of=conservationI=both=of=the=flooring=and=of=the=ceilingI=thus=preventing=the=pursuing=of=other=strategiesK=An=alternative= solution= to=reduce= the= loads= is= the=addition=of= further= beams= supporting=a=part=of= the=load=before=borne=by=the=existing=beams=xVI=NUzK=

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4KPK2K Action on restraints and length of the beam qhe=second=strategy=acts=on=the=changing=of=restraints=and=of=length=of=the=beamK=A=simple=increasing=of=the=degree=of=restraint=could=be=obtained=making=a=better=connection=with=the=wallsK= qhis= involves= the= partial= demolition= and= reconstruction= of= the= masonry= portion= around= the=supports=of=the=beam;=to=obtain=a=higher=degree=of=restraint=is=necessary=to=fix=the=end=of=the=beam=in=the=masonryI=thus=impeding=timber=ventilation=and=probably=promoting=decayK=Better=results=can=be=obtained=by=a=simultaneous=modification=of=restraints=and=lengthW=operating=at=the=end=of=the=beam=or=near=the=midspanK=qhe=operations=on=the=end=of=the=beams=can=be=implemented=by=adding=a=supporting=corbel=or=a=beam=adherent=to=the=wallW=–= qhe=addition=of=a=corbel=implies=a=broad=demolition=of=the=masonryI=an=evident=change=in=the=floor=

appearanceI= and= it= could=be= mistaken=for= an=preJexisting= element= if= made= of= timber;= given= the=high=invasivenessI=corbels=could=be=used=only=for=girders=and=not=for=joists=xUI=VI=NVzK=

–= qhe=application=of=a=supporting=beam=adherent=to=the=wall=Ethe=soJcalled=dormienteF=is=suitable=for=the=strengthening=of=joistsI=is=minimally=invasive=because=it=could=be=fixed=to=the=wall=by=a=small=number=of=anchorages;=even=if=realised=in=timber=these=beams=could=be=immediately=recognisable=thanks=to=the=bolts=used=for=anchorage=xUI=VI=NUzK=

cor=intervention=near=to=the=midspan=we=have=many=alternativesW=–= qo=operate=from=aboveI=hanging=the=beams=to=an=upper=structureK=qhis=solution=is=suitable=to=the=

case=in=whichW=there=isI=or=it=can=be=realiòed=an=upper=structure=that=is=capable=of=supporting=the=floor; =it =is =allowed =to =partially =occupy =the =upper =storey =with =the =tie =rod; =the =flooring =can =be =pierced=for=passing=the=tieJrodK=All=these=conditions=rarely=occur=togetherI=so=this=solution=is=not=easily=exploitable=xVzK=

–= qo=insert=one=or=more=crosspiece=beamK=te=can=use=this=system=when=the=transversal=span=of=the=floor= is= not= excessiveI= otherwise= the= crossbeams= would= need= to= be= too= bigK= curthermore= the=insertion=of=crosspiece=in=the=walls=implies=a=broad=demolition=of=the=masonry=xVzK=

– = qo=reinforce=the=girders =with=a =system=of =struts =and=tieJrods=EcigK =NFK =lne=or =two=vertical =struts =could=be=placed=below=each=girderI=pushed=up=by=a=bent=tieJrod=to=provide=one=or=two=intermediate=supportI=creating=a=kind=of=overturned=king=or=queenJpost=truss=xTI=VI=NQI=NUI=NVzK=fn=this=system=the=steel= tieJrod= is= anchored=by= the= mean=of= screw= nutsI= thus= allowing= to=adjust= its= tension;= the=possibility= to= regulate= the= tension= of= the= tie= rod= ensures= an= immediate= efficiency= Eactive=strengtheningF=and=the=possibility=of=periodic=maintenance=of=the=system=xVzK=

=

==cig. N `onsolidation= of= a= girder= with= a= system= of= a= vertical= strut= and= bent= tieJrod= EbK= wamperini= OMMVFK= =qhe=tension=in=the=tieJrod=has=been=regulated=by=a=torque=wrenchI=immediately=imposing=the=right=collaboration==

with=the=existing=beamK=qhe=choice=of=this=system=was=suggested=by=the=inaccessibility=of=the=upper=floor==–= qo=place= a= couple= of= struts= for= each= girder= to= create= one= Eif= the= struts= converge= to= the= same=

pointF=or= two=intermediate=supports=xVI=NQzK=ff=the=struts=are=made=of=timberI=their=section=must=be= quite= big= and= they= will= severely= interfere= with= the= physical= and= aesthetical= fruition= of= the=roomK=qhus=this=method=of=strengthening=is=suitable=only=for=principal=beams=in=rough=rooms=in=which= the= alteration= of= the= aesthetic= has= little= importanceK= qhe= strengthener= structure= can= be=lightened=with=the=employment=of=steelI=this=makes=also=the=work=fully=recognisableI=extending=the=possibility=of=using=this=solution=xNUzK=

=

ONMP=

4KPKPK Actions on the cross section of the beam qhe=actions=on=the=cross=section=of=the=beam=are=the=sum=of=the=works=finalised=to=modify=individually=or=in=a=combined=wayW=the=modulus=of=elasticity=and=the=unit=strength=of=the=materials=constituting=the=sectionI=the=shape=and=dimensions=of=the=beamK=qhese=strategies=can=be=pursued=in=various=waysW=–= qrying=to=increase=the=stiffness=and=the=strength=of=the=existing=timber=by=injecting=resin=inside=it=

xOMz;= this= procedure=profoundly=and= irreversibly=alters= the=original= material= and= moreover= there=are=strong=doubts=about=its=effectiveness=xNVzK=

–= oeplacing=the=portions=of=degraded=wood=with=newly=added=materials=Enew=timberI=glulamI=epoxy=conglomerateF=fixed=to=the=existing=beam=by=glued=rod=Esteel=or=fibreglassFI=steel=platesI=boltsI=or=pegsK= qhis= operation= implies= an= unrecoverable= loss= of= the= original= materials= and= it= is= therefore=strongly=criticised=by=more=conservative=techniciansK=curthermore=if=the=added=material=is=a=resin=conglomerateI=it=has=a=completely=different=rheology=from=the=rest=of=the=beamI=and=it=is=likely=to=disconnect=from=it=due=to=moisture=variations=and=differential=shrinkage=xNQI=NVzK=

–= bnhancing=the=stiffness=and=strength=of=existing=cross=section=by=inserting=and=gluing=materials=with=higher=modulus=of=elasticity=and=strengthK=qhe=new=materials=could=beW=glulam=elements=xUzI=fibreglass=rods=xNQzI=steel=rods=xNVzI=steel=plates=xNQzI=i=or=q=steel=sections=xNQI=NUzI=plate=or=rods=of=dcom=and=`com=xONzK=All=these=solutions= involve=the= loss=of=a=part=of= the=original=material;= in=addition= if= the=housings=for=these=elements=are=made=from=above=Ethus=requiring=the=dismantling=of=the=flooringF=the=appearance= of= the= beam= remains= unchangedI= otherwise= these= grooves= also= disfigure= the= original=appearance=of=the=beamK=

–= bnhancing=the=stiffness=and=strength=of=the=beam=by=making=it=collaborate=with=other=added=elementsK=qhese =could =beW =solid =timber =boards =EcigK =OF =or =wood =based =panels; =timber =or =glulam=beams; =steel =plates= or= beams;= pultruded= com= elements= xOPz;= com= tapes;= a= reinforced= concrete= slab= xOQzK= qhe=addition=could=be=doneW=in=the=upper=partI=in=the=lower=partI=or=on=the=sides=of=the=existing=beamK=

=

==

cig. O ptrengthening=of=a=timber=floor=with= timber=elements=EbK=wamperini=OMMVFK=ln=the=leftW=the=timber=floor=after=the=reinforcementK=ln=the=rightW=section=of=the=girder=before=EaboveF=and=after=EbelowF=the=strengtheningK=After= the=dismantling=of= the=flooring=and=of= the=rubble=screedI= the=deflection= of= the=beam= was= reversed= using=telescopic=propsK=pubsequently=the=board=above=the=girder=was=removed=and=a=series=of=portions=of=beam=were=forced=into=the=space=between=the=joists=and=fixed=with=screws=to=the=girderK=After=thatI=the=original=board=was=put=back=in=placeI=and=another=thick=board=was=fixed=with=screws=to=the=added=partitioned=beamK=lther=thick=boards=were= placed= orthogonally= to= the= existing= plankingI= one= above= each= joistI= and= fixed= with= screwsK= cinally= the=telescopic=props=were=released=and=the=strengthening=system=immediately=started=to=carry=out=its=effectiveness==ff=the=addition=is=made=on=the=sides=of=the=existing=beamI=old=and=new=elements=act=in=parallelI= each=supporting=a=portion=of=the=load=proportional=to=its=own=stiffness;=the=same=behaviour=is=obtained=if=the=addition=is=positioned=above=or=below=the=beamI=but=is=not=connected=to=itK=eowever=the=best=solution=is=to=make=the=new=elements=work=together=with=the=beamI=fixing=the=former=ones= to= the=other= by=means= of= shear= connections= to=prevent= mutual= slidingK= qhis= connection=can=be=pursued= withW= gluesI= nailsI= screwsI= glued= rodsI= boltsI= pegsI= indentationsI= special= connectors= Ein=particular=for=the=connection=with=reinforced=concreteF=xVzK=

=

ONMQ=

lperating=from=above=imposes=the=irreversible=dismantling=or=damaging=of=the=flooringI=but=allows=to=limit= or=avoid=the=visual= impact;=operating=from=below=or=on=the=sides=can=allow=a= minor= impact=on=material=conservationI=but=it=could=lead=to=a=total=change=of=the=appearanceK=ppecial= considerations= could= be= done= about= two= strengthening= solutions= that= present= similar=behaviourI= increasing=also= the= inJplane= stiffness= of= the= floorW= the=use= of= timber= boards= or= wood=based=panels=and=of= reinforced=concrete= slabsK= fncreasing= the=thickness=of= the= floor=of= the= same=quantityI= the= former= can= provide= a= greater= net= increase= in= carrying= capacityI= due= to= the= limited=weight=of= the=added=partsI= but= involves= some=problems= that=have=made= the=system=still=not=very=commonW=the=need=to=put=side=by=side=many=panelsI= making=behaviour=along=the= joint=uncertain;=the= lack= of= adaptability= to= irregular= rooms;= the= difficult= connection= to= the= wallsK= oeinforced=concrete= slabs= have= the= advantage= of= great= adaptability= to= irregular= plans= and= to= deflected=plankingI= but= it= requires= a= careful= study= of= the= connections= to= the= masonryI= and= implies=a=considerable=load=increase=on=the=wallsI=which=can=be=only=partially=limited=by=using=lightweight=structural=concreteK=curthermore=over=time=creep=and=shrinkage=of=concrete=can=lead=to=a=migration=of=stresses=from=the=slab=to=the=timber=beamK==4.4. Thermal behaviour of the strengthened structure thile= evaluating=a= strengthening= system= it= is= very= important= to= study= the= thermal= behaviour= of= the=strengthened=structureW= if=added= elements=have=a=coefficient= of= thermal=expansion=different= from=the=one=of=timber=Efor=example=if=the=added=elements=are=made=of=steelFI=the=behaviour=of=the=strengthened=structure=will=vary=depending=on= the=temperature=of= the= roomK=qhus= in=areas= EeKgK=atticsF=exposed=to=strong=temperature=changesI=systems=that=use=more=than=one=material=should=be=studied=carefullyK=

=R. ClNCirpflNp =qimber=load=bearing=floor=structures=of=ftalian=historical=constructions=are=complex=systems=that=show=countless= states= with= regard= toW= aestheticalI= historical= and= material= interest;= building= techniques;=material= state= of= preservation;= siòe= of= the= gap= between= required= and= provided= performances;= the=requirement=to=assure=physical=and=aesthetical=fruitionK=qhe= choice= among= the= possible= strategies= for= strengtheningI= and= –= defined= a= strategy= –= among= the=various= systems= must= start= from=the=knowledge=of= those=states= and= it=must= respect= the=principles=of=conservationW= need= to= preserve= the= original= technological= conception= of= the= structure= and=opportuneness= that= the= adopted= solutions= don’t= contribute= to= decay= or= damage= of= the= structure=EcompatibilityF;= = necessity= that= added= elements= can= be= maintained= in= efficiency= EdurabilityF= and=removed= or= substituted= with= little= damage= to= the= existing= structure= EreversibilityF;= in= addition=strengthening=solutions=should=not=disguise=themselves=as=part=of=the=existing=structuresI=but=they=must=openly=declare=their=being=contemporary=ErecognisabilityFK=eoweverI= within= the= limits= related= to= conservationI= it= is= important= to= uphold= the= right= to= formal=autonomy= for= the=project= of= technical= and= functional= additionsI=because= this= seems= the=only= way= to=pursue=quality=in=what=we=add=to=the=built=palimpsestK=fn=factI==although=distant=from=the=existing=“text”=in= terms= of= style= and= morphology= and= even= if= complicating= its= the= interpretationI= only= highJquality=architectural=elements=can=enrich=the=complex=built=context=xOQzK= obcbobNCbp =xNz oiegl=AK=ENVMPF=aer=joderne=aenkmalkultusK=pein=tesen=und=seine=bntstehungK=tienJiiepòigI=

Braumüller=serlagK=xOz Brandi=`K=ENVSPF=qeoria del restauroK=oomaI=bdiòioni=di=storia=e=letteraturaK=xPz qassios=qKmK=EOMNNF=mroblemi assiologici nel restauro strutturale dei monumentiK=kapoliI=iiguoriK=xQz Bellini=AKEOMMRF=Amedeo=BelliniK=fn=qorsello=BKmK=EedFI=`he cos’è il restauro?=seneòiaI=jarsilioI=ONJOQK=xRz qorsello= BKmK= ENVUUF= …salori»= e= …dati»K= fn= qorsello= BKmK= ia materia del restauroK qecniche e

teorie analiticheK=seneòiaI=jarsilioK=xSz Bellini=AKENVUSF=qeorie=del=restauro=e=conservaòione=architettonicaK=fn=Bellini=AK=EedFI=qecniche

della conservazioneK=jilanoI=cranco=AngeliI=VJRSK=xTz Barbisan=rKI=ianer=cK=ENVVQF=f solai in legnoK=jilanoI=cranco=AngeliK=xUz junafò=mK=ENVVMF=oecupero dei solai in legnoK=malermoI=aario=claccovioK=

=

ONMR=

xVz ianer=cK=EOMNNF=fl restauro delle strutture di legnoK=malermoI=drafillK=xNMz Bonamini =dK =ENVVRF =oestoring =timber =structuresK =fnspection =and =evaluationK =fn =Blass =eKgK =et =alK =

EedKF=qimber bngineeringK pqbm 2K=`entrum=eoutI=AlmereI=aPLNJaPLVK=xNNz oidout=BK=EOMMMF=qimber decay in buildingsK qhe conservation approach to treatmentK=iondonJ

kew=vorkI=ppoon=mressK=xNOz diordano=dK=ENVUNF=qecnologia del legnoK solume fK ia materia primaK=qorinoI=rqbqK=xNPz dambetta=AK=EOMNMF=cunghi e insetti nel legnoK aiagnosiI prevenzioneI controlloK=cirenòeI=kardini=xNQz qampone=dK=ENVVSF=fl restauro delle strutture di legnoK=jilanoI=eoepliK=xNRz ianer=cK=EOMMPF=`apire le fessure nel legno strutturaleK=jilanoI=iegnoindustriaK=xNSz jinistero=delle= infrastrutture=EOMMUF=aKjK=NQ=gennaio=OMMUK=korme= tecniche=per= le=costruòioniK

dazzetta rfficiale della oepubblica ftaliana=SPEOVFW=pupplemento=ordinario=nK=PMK=xNTz aoglioni= cK= EOMMMF= `odice= di= pratica= Eiinee= duidaF= per= la= progettaòione= degli= interventi= di=

riparaòioneI= miglioramento= sismico= e= restauro= dei=beni= architettonici= danneggiati= dal= terremoto=rmbroJjarchigiano=del=NVVTK=Bollettino rfficiale oegione Marche=bdiòione=ptraordinaria=nKNRK=

xNUz jariani=jK=EOMMQF=`onsolidamento delle strutture lignee con l’acciaioK=oomaI=abfK=xNVz ròielli=iK=ENVVRF=oestoring=timber=structuresK=oepair=and=strengtheningK=fn=Blass=eKgK=et=alK=EedF=

qimber bngineeringK pqbm 2K=`entrum=eoutI=AlmereI=aQLNJaQLNMK=xOMz Aveta=AKI=jonaco=iKjK=EOMMTF=`onsolidamento delle strutture in legnoK aiagnostica e interventi

conservativiK=kapoliI=bdiòioni=pcientifiche=ftalianeK=xONz Borri= AKI= `orradi= jKI= draòini= AK= EOMMSF= pull’utiliòòo= dei= materiali= com= per= il= rinforòo= delle=

strutture=ligneeK=fn=Borri=AK=EedF=iignea materiaK=merugiaI=nuattroemmeI=PQVJPVUK=xOOz Borri=AKI=diacomin=dKI=diannantoni=AK=EOMMRF=pperimentaòioni=ed=applicaòioni=dei=pultrusi=per=il=

rinforòo= di= elementi= ligneiK= fnW= qampone= dK= EedF= `onservation of historic wooden structuresK=cirenòeI=`ollegio=degli=fngegneri=della=qoscanaI=SPJSVK=

xOPz `eccotti =AK =ENVVRF =qimberJconcrete =composite =structuresK =fn =Blass =eKgK =et =alK =EedF =qimber bngineeringK pqbm 2K=`entrum=eoutI=AlmereI=bNPLNJbNPLNOK=

xOQz aeòòi=Bardeschi=jK=ENVUOF=ia=materia=e=il=tempoI=ovvero=la=permanenòa=e=la=mutaòioneK=fnW=aeòòi=Bardeschi=jK=ENVVNF=oestauroW punto e da capoK=jilanoI=cranco=AngeliK=