-
=
OMVT=
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consider=outdated=some=of=the=principles=underlying=the=text=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=
emanòamp]yahooKcom=
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=
OMVU=
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=
-
=
OMVV=
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=
-
=
ONMM=
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=
-
=
ONMN=
–= 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=
O
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=
ONMO=
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=