ISSN: 0871-7869Rehabilitation and strengthening of old masonry buildings H. Meireles; R. Bento - Março de 2013 Relatório ICIST DTC nº 02/2013 ! Table&of&contents& ! & ! ! ! Introduction*..........................................................................................................................................................*3! Structural*interventions*related*to*the*foundations*...........................................................................*5! a)! Improvement!of!the!ground!soil!by!Jet9Grouting!.............................................................!5! b)! Improving!the!behaviour!of!foundations!by!enlargement!and/or!consolidation ! 5! c)! Strengthening!of!the!foundation!by!using!micro!piles!isolated!or!in!group!or!in! row!6! Local*interventions*for*structural*improvement*..................................................................................*8! a)! Injections!in!cracks!........................................................................................................................!8! b)! Strengthening!roof!diaphragms!with!plywood!.................................................................!9! c)! Transversal!anchorage!in!walls!...............................................................................................!9! d)! Strengthening!masonry!column!with!jacketing!............................................................!10! e)! Repair!of!damaged!wood!elements!.....................................................................................!10! Global*interventions*for*structural*improvement*.............................................................................*11! a)! Strengthening!of!masonry!walls!with!reinforced!cement!coating!.........................!11! b)! Strengthening!of!masonry!walls!with!polypropylene!meshing!..............................!11! c)! Strengthening!of!floors!and!improving!the!connection!floor/wall!.......................!12! d)! Strengthening!with!composite!materials!(CFRP!and!GFRP)!....................................!14! e)! The!use!of!horizontal!tie9rods!...............................................................................................!17! f)! Retrofitting!by!post9tensioning!.............................................................................................!19! f)! Strengthening!with!ring!beams!.............................................................................................!21! g)! Retrofitting!by!introducing!RC!shear!walls!.....................................................................!22! h)! Strengthening!with!RC!or!steel!frames!.............................................................................!22! REFERENCES!..........................................................................................................................................!25! ! 1! ! 2! . !except!for!Placa!buildings!as!previously! referred.!With!these!four!elements!men!was!able!to!build!spectacular!constructions! some! of! which! are! still! standing! nowadays.!On!the!ground!floor!one!can!find!masonry!walls.!the!iron!is!burnt!with!coal!and! its! impurities! decrease! giving! rise! to! cast! iron.!in!the!60’s!complete!reinforced! concrete!buildings!were!built!in!Portugal!and!this!is!the!most!common!practice.! They! were! built! with! stone!and/or!bricks.!! ! The! old! masonry! buildings! in! Lisbon! that! still! stand! nowadays! are! called! pre9 Pombalinos.! With! fewer! impurities.!Later!on.!the! problems!and/or!pathologies!must!be!encountered!and!only!then!one!can!start! prescribing!the!necessary!solutions!for!the!rehabilitation!or!strengthening.! Pombalinos.!sometimes!lime.!some!made!of!stone! masonry! others! of! brick! masonry.!assessing!its!performance!for!gravity!and!seismic!loads.! wood! and! natural! plants! fibres.! we! have! the! forged! iron/steel! and! later! the! steel.! where! carbon! is! mixed! with! iron! is! small! quantities!to!make!it!become!more!malleable.! In! Portugal! it! started! in! the! 40’s! only! by! introducing! some!concrete!elements.! ! 3! .!The!forged!steel!and!the!steel!are! used! mainly! in! tension! due! to! the! phenomena! of! buckling.! It! can! have! fungus! attack! or! insect! attack.! In! case! of! the! masonry! the! most! important! pathologies! have! structural! origin! and! can! be! translated! into! desegregation.!and!wood.! Foundations! were! built! with! a! large! masonry! footing! sometimes! settled! on! a! base! of! wooden! piles! (Pombalino! buildings).! later! on.!to!build!new!buildings.!! ! When!strengthening!an!old!building.! nowadays.!! ! Old!masonry!buildings!have!common!pathologies!that!are!mainly!related!to!their! age.!although!bad!to!tension.!For!instance!the!wood!can!be!damaged!due!to!the!changes!and!exposure!to! humidity.!! ! The! strengthening! of! old! masonry! buildings! is! an! important! issue! since! these! buildings! constitute! the! historical! centres! of! many! cities! and! thus! deserve! attention!from!the!state!authorities!for!preservation!purposes.! for! instance).! Gaioleiros! and! Placa! buildings.!to!build!floors!and!some!columns! such!how!it!is!found!in!Placa!buildings.Introduction! ! Men! with! mainly! four! materials! built! the! oldest! constructions! and! these! materials!lasted!thousands!of!years!for!construction!purposes.! While! the! iron! from! Nature! is! very! brittle.!These!were!earth! (from! which! bricks! come! from.! to! be! built! in! great! quantities.! It! is! also! possible! to! find! arches! made! of! masonry! very! common! on! the! ground! floor! of! Pombalino! buildings.! The! last! great! change! occurring! in! construction! materials! was! the! introduction! of! concrete.!and!can!be!used!as!a!structural!resisting! element! working! in! compression.! The! floors! and!the!roof!are!made!with!wood!joists.! with! the! beginning!of!the!industrial!revolution!in!England.! the! cast! iron! is! resisting! well! to! compression.! Later! in! the! XVIII! century.!one!must!focus!first!on!understanding!how! it!is!working.!(Placa!buildings!also!with!a!few! reinforced! concrete! structural! elements).! stone.! Steel! structures! are! common!nowadays!although!not!in!great!quantity!in!Portugal!when!compared!to! England.! On! the! other! hand! the! masonry! can! be! also! damaged.!reinforced!with!steel.!Then. !The! foundations!may!be!improved!also.! secondly..!! ! In! the! following! lines! it! is! presented! separately! structural! interventions.!the!introduction!of! elevators.g.! The! whole! structure! should! behave! like! a! box! where! all! the! structural!elements!are!having!similar!displacements!and!moving!together.!! ! The! existing! pathologies! should! be! tackled.!expose!the!masonry!to!the!action!of!the!atmospheric!agents!being! especially!relevant!the!action!of!the!wind!transporting!sands!and!dust!that!give! rise!to!erosion.!between!the!floors!and!walls!(and!frontal! walls!with!walls!in!Pombalino!buildings)!and!between!the!roof!and!the!top!of!the! walls.! the! existence! of! concentrated! and! high! loads! (generally! associated! with! adaptation! of! the! building! to! new! usages)! and! earthquakes!which!have!a!considerable!influence!in!a!material!that!is!both!heavy! and!brittle.!! ! The! iron! was! used! in! old! buildings! mainly! for! small! elements! such! as! nails.! firstly! ! 4! .! the! structural! system!of!the!building!may!be!assessed!and!improved!whenever!necessary.! screws! and! elements! with! anchor! shape.! the! effect! of! destruction! caused! by! the! increase! of! the! volume! of! the! iron! elements! that! may! cause! the! rupture!of!the!masonry.!air!conditioning.! for! instance.!For!instance!the!introduction!of!toilets.!! ! Moreover.!the!cracking!or!the!loss!of! these!coatings.! fracture! and! cracking.! movements! of! thermal! origin.! In! this! way! these! structural! elements! will! not! separate! when! the! earthquake!strikes!and!will!behave!together.crushing.!It!is!usually!also!important!in!any! building! to! strengthen! its! floors! given! the! wooden! floors! are! flexible! in! plan(while! the! masonry! is! rigid)! and! thus! they! do! not! transmit! forces! between! parallel! walls.!e.!The! changes!of!the!ground!water!flows!are!also!important.! The! main! problem! for! this! material! is! its! corrosion! given! the! lack! of! maintenance! because! of! the! inaccessibility!of!the!elements.! one! can! think! of! improving! the! structural! system! for! earthquake! resisting!purposes.! On! the! other! hand.! It! is! always! essential! to! improve! the! connections! between!the!structural!elements.!One! reason! for! improving! the! structural! system! of! a! given! building! may! be.! The! most! common! causes! are! related! with! foundation! settlements.! connect! masonry! walls! between! each! other! and! also! connect! wood! floors! with! masonry! walls.!the!widen!up!of!rooms.!in!first!place.!! ! The! foundation! settlements! are! usually! associated! with! the! construction! of! additional!floors!and/or!the!execution!of!excavations!in!the!adjacent!areas!of!the! building!and!have!has!a!result!the!decompression!and!dragging!of!the!soil.!The!risk!of!oxidation!is.!etc.! horizontal! thrusts! transmitted! by! inclined! roofs! or! arches.!the!objective!of!changing!its!use!or!merely!an!adaptation!to!nowadays! usages!and!facilities.! These! were! used! to! connect! wood! elements! between! each! other.!It!is!then!very!important!to!understand!very!well!the!original! behaviour! of! the! structure.!the!loss!of! useful! cross9section! of! the! elements! and.!! ! The!ageing!of!the!masonry!and!in!particular!its!desegregation!depends!in!a!great! deal!of!the!way!the!masonry!is!protected!by!coating. ! mixing! it! with! cement! grout! introduced! in! high! pressure! (values! between! 200! and! 800! bar)! and! velocity! in! the! order! of! 250! m/s.!it!can!be! applied! in! difficult! closed! areas! and! it! does! not! give! chance! to! significant! vibrations.related!to!the!foundations.!the!superficial!foundation!can!be!enlarged!with! concrete! as! is! depicted! in! Fig.!There!is!the!need!to! excavate!until!the!bottom!of!the!foundation!to!place!the!formwork!(“Cofragem”).! 2.!structural!interventions!herein!called!Local!and.&Lectures&UM&]& ! ! b) Improving!the!behaviour!of!foundations!by!enlargement!and/or! consolidation! As!explained!by!Appleton![2003].!then.!! ! The!advantages!of!this!technique!are:!it!can!be!applied!in!all!types!of!soil!(as!long! as!they!contain!small!sized!material!and!are!not!subjected!to!seepage).!It!was!introduced!in!Portugal!in!the!beginning!of!the!90s!due!to!the! construction!of!the!metropolitan!in!Lisbon.! This! results! in! a! material! with! mechanical!characteristics!with!higher!values!then!the!previous!ones!for!the!soil! and!with!less!permeability!(Fig.! internally! in! the! ground! without! previous! excavation.!1).&1&The&fases&of&jet–grouting&[Lourenço.! structural! interventions! that! are! affecting! the! whole! building! (Global)! behaviour.! finally.!It!consists!in!the!disaggregation!of!a! volume! of! soil.! The! connection! between! foundation! and! concrete!is!made!through!connectors!(“Grampo!de!ligação”).! ! Structural!interventions!related!to!the!foundations! ! a) Improvement!of!the!ground!soil!by!Jet:Grouting! ! This!technology!was!first!developed!in!the!70s!but!later!it!had!a!large!expansion! on!the!80s.!! ! ! ! Fig.! ! ! 5! . Reabilitação de Edifícios Antigos Patologias e tecnologias c) Strengthening!of!the!foundation!by!using!micro!piles!isolated!or!in!group!or! de intervenção. J.*.-+.#34'2)5 2. &'(&)*#+).-+.'01#2. 38 APPLETON.#34'2)56. Setembro de 2003.!as!can!be!seen!in!Fig. 1ª Edição.#34'2)5 2. Setembro de 2003.!3.*.&2&Enlargement&of&the&foundation&[Appleton.! This! typology! of! buildings! is! mainly! set! on! an! alluvium! filled! valley! with! a! weak! layer! of! material! over! the! bedrock.* DECivil a) Alargamento da fundação superficial existente APPLETON.-+.!working!by!point!resistance!and!lateral!friction).'01#2.2.'01#2. Setembro de 2003.).&3&Consolidation&of&the&foundation&[Appleton. 38 in!row! & The!foundation!layout!present!in!most!of!the!old!masonry!buildings!is!drawn!in! Fig.*. J.!Visibly. J.&2003]& ! APPLETON.* DECivil b) Consolidação da fundação (de alvenaria!) existente ! Fig.*. 1ª Edição.../01.#1# ! Additionally.-+.'01#2.#34'2)56. 37 ! Fig.!the!foundation!may!be!improved!by!filling!the!gaps!between!blocks! 2. Edições Orion.#1# ! 2.*.'01#2. Reabilitação de Edifícios Antigos Patologias e tecnologias Edições Orion. J./01.)#-.!One!uses! tubes! for!b) injection! (“Tubos! de! for! (de the! inner! holes! and! then! closes! Consolidação dainjecção”)! fundação alvenaria!) existente DECivil cracks!at!the!face!of!the!masonry!(“Selagem!das!juntas”). 1ª Edição.!4!a).#34'2)56.. Reabilitação de Edifícios Antigos Patologias e tecnologias de intervenção.! !"#$% !"#$%&'(&)*#+). Reabilitação de Edifícios Antigos Patologias e tecnologias de intervenção.).!4!b)!one!can!see!the!foundation!typical!of!a!Pombalino!building!in! downtown. 1ª Edição..!In!Fig. !"#$de%intervenção.-+.! ! ! 6! 19 .5! m! long)! used! in! these! buildings! are! meant! for! consolidation! of! the! topmost! layer!of!soil!and!cannot!be!seen!as!having!the!same!behaviour!as!nowadays!RC! piles!(which!are!usually!longer.)#-.* 37 with!mortar.&2003]& APPLETON. Edições Orion. Edições Orion. Setembro de 2003.!there!is!the!need!to!excavate!until! the!bottom!of!the!foundation!(“Vala!escavada”)!to!perform!these!tasks.! The! small! wood! piles! (average! 1. -).!#-+#/'%0#-+.soil! and! also! de Micro-esta mobilize!the!deepest!layers!of!soil.'.&b)µ&piles&casing&to&be&filled&with&cement&grout& [photos&by&Appleton.'.-).!When!they!are!built!they!do!not!receive!any!load.!Inside!the!casing!there! may!be!steel!rods.!Finally..&5&a)&Machine&to&drill&the&holes.!a!steel!casing!with!8. J.!!! ! They!are!composed!of!a!RC!heading.! It! is! for! increasing! loads! in! the! structure."+ "%!# 8 4 a) b) Abril de 2011 Fig.!at!the!bottom!there!is!usually!a!bulb!of!cement.!! grade e estacas de ! madeira To!be!noticed!that!the!piles!are!only!under!pressure!when!there!is!an!additional! load!in!the!structure. Setembro de 2003.! or! to! deal! with! settlement! de Fundações Execução !"#$%&'(#)*#+.&b)&Foundations&of&Pombalino& de intervenção.!#-+#/ #&1"/#!%#+"+2#. Edições Orion.!! & In!Fig.Execução de Micro-estacas ! "-'!.-).-). 1ª Edição. Reabilitação de Edifícios Antigos Patologias e tecnologias Fig.! ./0' Fundações correntes de edifícios antigos DECivil && a)! ! ! ! ! b)! APPLETON./ /0' !"#$%&'(#)*#+.!10!or!12!meters!long! Fundações de edifícios antigos em solo brando DECivil usually!to!be!filled!with!a!cement!grout!under!pressure./ !"#$%&'(#)*#+.! The! micro! piles! Consolidação consolidate! the! shallower! layers! of!.&4& a)&Common&foundations&of&old&masonry&buildings. problems.&2011]& ! ! ! 7! .! which! lead! to! increasing! loads! in! the! soil.!5!one!can!see!in!a)!the!machine!to!drill!the!holes!and!in!b)!the!micro!piles! casing!to!be!filled!with!cement!grout."%!# ! Using! micro! piles! to! strengthen! a! foundation! is! a! solution! reasonably! used! in! Portugal! in! monuments! or! common! buildings. 7 buildings& & !"#$%&%'#()*+."+"-'!.!"#$%&'(#)*#+. (6.! Depending! on! the! used! process.(%'. !Injection& trough& vacuum:& it! is! used! in! small! interventions.!$%!.*.&6&(a)&injection&in&external/face&diagonal&crack.! should! be! preferred! because! of! compatibility! issues! with! the! already! existing! mortars.'!(%'.%! '7.!%45)45.%45%1%45%!.! .67.&Injection& under& pressure:! it! is! frequently! used! in! masonry.4'/'5E43/)! throughout! the! wall.1/$)!$%'5)'!5=34/3)'.1)! '.!statues.! more! fluid.1)!)-(%'%45)67.! cracks!the!coating!should!be!removed!previously!(“remoção!de!reboco”)!and!the! injection!tubes!may!be!used!also.!<0)/D.4/3)45%'!%45(%!'/.!1)5%(/)*..')$)!.()!SQ.!used!frequently!because! they! preserve! the! original! the! exterior!%8%35.1!0%57.!3.2! 8)>F'%! '%+.!0%1!'.!$%!3.1.*.2!'%!.!& 3.!This!solution!is!based!on!the!injection! in! holes! previously! made! with! injection! tubes! (“tubos! de! injecção”)! and! spread! &)>/..!the!holes! are!done!from!bottom!to!top!and!from!side!to!centre.*.)$.!It!seems!a!better!application!in!stone! &)>/.!however.! I(%'%(&)1! .*)(1%45%! /4$/3)$)! -)()! )! (%)0/*/5)67.! L! -)(5/3.!etc.! &)>/.! To! avoid! structural!failure!of!the!wall!(that!can!be!in!very!bad!conditions).'! others!such!as!organic!resins!based!grout.1!C4$/3%!$%! used! a! grout! without! the! sand.)! )-*/3)67.! like! hydraulic! limes.()!SF!U4@%367.4&%4/%45%1%45%! indicated!for!the!rehabilitation!of!the!masonry!that!has!internal!cracks!connected! $/'5(/0.!Fig.!internal!or!at!the!face.!of!a!masonry!wall!are!a!solution! M'5)!'.!..!$)'!8%4$)'!.4A%3/$.!! 2.! This! technique! shows! improvements! in! the! mechanical!characteristics!of!the!masonry.! G-)''/&)H! %! /((%&%('C&%*.(! $)'! -)(%$%'! -%*.!a) )(:.! For!this!solution!a!cimenticious!based!grout!is!used!or!a!hydraulic!based!grout!or! &)>/.%1! .!%45(%!.!(%'.2! %! )! %D-%(/E43/)! $)! '.1)!)(+)1)'')!.)!'%1!)(%/)..! To! deliver! a! specific! injection! grout! one! must! carry! on! in9situ! and! ! laboratory! tests! to! refine! the! grout.! <'! &+.1)!8/4)!(%$%!$%!&)>/./5%35K4/3.*/$)67.!%1!+%()*! masonry.(.C$.!! ! ! a)! ! ! ! ! ! ! b)! ! ! c)! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!N)Q!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!N0Q0 !! Fig.'!3.! :.!$%!)*&%4)(/)'#!N)Q!'%*)+%1!$%!8%4$)'V!N0Q!3.4'.!M.! mainly! architectural..!M1!+%()*2!=!.4$%!%D/'5)!.'!/45%(/.1%5(/)!$)'!3)*$)'!$%!/4@%367.3%$/$)!%1!)*&%4)(/)'2!3.0(%!%$/8C3/.1!O+.1)!3)*$)!$%!*/+)45%!3.(!)(5C'5/3.'2! of! -(%&/)1%45%! %! It!3.&(c)&side&view& [Roque.'!SYX.4'5/5.'!$%!(%3.(%'2!3.!The!grout!is!very!fluid!(for!instance!resins!can!be! used)![Valluzzi.*5)$.! .(/+/4)*! %D5%(/.! The! organic! mortars! (polyester! or! epoxy).! Local!interventions!for!structural!improvement! ! 8(%:.1)!3)*$)!8*.5/*/>)$)!%1!/45%(&%46?%'!'.C$).'!'7.! should! only! be! used! when! there! are! needs! for! higher! resistance.!$%!+()4$%!$/1%4'7.*5)$.C$)!N3/1%45C3/)2!A/$(O.'.(%'2! '%@)1! %*)'! 8/''.!They!are.! )'-%35.!<!+()4.! ! ! The!aggregate!grading!of!the!grout!depends!on!the!size!of!the!cracks!but!it!can!be! <!%8/3O3/)!$%'5)!5=34/3)!5%1!'/$.&2002]& R/+.!T.()'! ..! ! NR/+.67.&Injection&trough&gravity:&it!is!used!to!highly!damaged!walls.'! of! the! wall./$)1%45%!.1!.! hopefully! without! ! 8! .4'/'5%!4)!%1/''7.'!WX!%!.(+P4/3)'Q2! %1! aspect! 8..! $%! )*&%4)(/)'! $%! ! -%$()!./"%! 3.! the! inorganic! grouts.1)! '.!&)*.*/3)!.4C&%/'! $)! /4&%'5/+)67.*.1-(%%4$/$.! non9cimenticious.'!'7.! of!strengthening!that!is!irreversible.! there! are!"! several!solutions!for!the!injections:! ! 1.'!! between!them.!! The!injections!in!cracks."-.!2000].!$%!WX!.&(b)&injection&for&the&internal&cracks.'! $/'-.67.!! ! In! old! structures.'2! -)()! -(%%43A%(! 3)&/$)$%'! /45%(/.2!=!-(%8%(C&%*!.!$%-%4$%!$)!$/1%4'7.! Injections!in!cracks! %J.! to! fill! with! the! grout! the! internal! cracks.!6!shows!these!considerations.! is! particularly! $%! (%'/4)'! .! $%! (%8.! For! the! external! 8*. .! Bars! were! placed! at! a! constant! xture was inserted in the hole and then the bar was inserted and rotated to distribute the resin.!One!example!of!intervention![Magenes!et!al.! The intervention consisted in adding 3 layers of plywood.ble walls. glu th polyurethane10!mm!diameter!threaded!steel!bars. Any discontinuity between t mber spreader beam and the ring beam was smoothed by the insertion of a plaster layer to create compromising!the!compatibility!between!the!materials![Roque.!although!providing!a! iginal timber structure. ! o improve the diaphragm behaviour of the roof. it was decided towhich! adoptare!anlighter! intervention wasto!compatible with t spruce! plywood! panels. eans of connecting steel bars chemically anchored by epoxy resin. & & Figure 3.!! ! 9! .!lime).3).&7& multilayer&panels&and&chemically&anchored&steel&connectors.!as!can!be!seen! in! Fig. at the between the two opposite purlins.! to! of a strut and ck) were connected all 5! along the perimeter to theall! roof. The matchboard was then placed b) contact Strengthening!roof!diaphragms!with!plywood! & p of the timber structure. which consisted of a steel shoe doweled to the concrete ring beam and bolted to the rid am.! The! interior! core! is! usually! constituted! by! rubble! of! low! quality. by adding multilayer spruce plywood panels. continuous steel plates (80 mm wide and 5 m To!improve!the!diaphragm!behaviour!of!the!roof.!The!roof!is!then!completed! echanism.! each! 21! mm! thick. Steel connecting elements were inserted at the top e ridge beam. The roof was then completed by adding plain roofing tiles nailed to the multilayer spru by!adding!plain!roofing!tiles!nailed!to!the!multilayer!spruce!plywood!panels.!binding!material!such!as!grout! (cement.! ply to an inclined plane in comparison to a reinforced concrete slab.!a! glue and connected to the purlins by means of chemically anchored. ring beam all along the perimeter. 10 m epoxy! having mixture! is! inserted! the! hole! the and! hole.&consisting&in&the&application&of& intervention on the roof diaphragm.polyurethane!glue!and!connected!to!the!purlins!by!means!of!chemically!anchored.! 7. The 8 cm x 12 cm joists were reshaped to create a horizontal seat on the rid ! am and on the longitudinal spreader beams.! one! can! adopt! an! o stiffen and strengthen thethat! roof diaphragmwith! (which originally was made by! only by a single layer intervention! is! compatible! the! original! timber! structure. tothe! favour the development favour!the!development!of!a!strut!and!tie!mechanism.! yers with the roof & structure (Fig.!!! ! c) Transversal!anchorage!in!walls! ! The!application!of!transversal!anchorage!in!walls!aims!to!connect!better!the!two! layers!of!the!wall!avoiding!their!separation!from!the!interior!core.!or!not.&[Magenes&et&al. Scheme of theScheme&of&the&intervention&on&the&roof&diaphragm. then! the! bar! is! ameter threadedtwo9component! steel bars. Ba spacing! of! 30! cm! and! penetrated! into! the! purlins! to! connect! the! upper! plank! ere placed at a constant spacing of 30 cm and penetrated into the purlins to connect the upper pla layers!with!the!roof!structure.!continuous!steel!plates!(80!mm! wide! and! mm! thick)! were! connected! along! perimeter! to! the! roof. although providing a significa Fig. To! stiffen! and! strengthen! the! roof! diaphragm! (which! may! be! originally! made! only! by! a! single! layer! of! boards! nailed! to! the! joists).! The! application!of!such!technique!may!include. Timber spreader beams were also doweled to the r. which are lighter and easier significant!stiffness!increase. After drilled andin! cleaned a two-component epo introduced! and! rotated! to! distribute! the! resin.!After!having!drilled!and!cleaned!the!hole. each 21 mm thick. consisting in the application of multilayer panel Fig.! ntinuous contact.! consists! in! adding! 3! layers! of! plywood.! and! easier!that to! apply! an! inclined!plane!in!comparison!to!a!reinforced!concrete!slab.! adding! ards nailed to multilayer! the joists).c.!2002].&2012] ! and chemically anchored steel connectors.! glued! with! ffness increase.!2012].! 8. !In!Fig.'&$'"-.'"-2*>-.!9!b)!more!rotten!wood!elements. falta de elementos metálicos) a)! ! ! ! ! ! b)! Fig.! The! damaged! wood! elements! may! be! replaced! by! glued! laminated! wood.&b)&Rotten&wood&elements&[Cruz.'-*).*#-51*2'21>*+#-C ! "#$%&$'(#)*+.! In!this!technique.'(#+.& 2012]& ! 20 Erros / problemas correntes ! 10! .! In! this! way! one! can! find! several! substitutes! of! wood.*1 H I1>*%&5-"'5E I1>*%&5-"'5E>1%&" H I1>*%&5-"'72-JE I1>*%&5-"'72-JE)-1" ! Fig.!!! ! e) Repair!of!damaged!wood!elements! ! These! are! repair! techniques! and! not! strengthening! solutions. fractura ou apodrecimento de pavimentos Apodrecimento das entregas + falta de solidarização (apoios curtos.! It! is! necessary! also! that! there! is! enough! protection! of! the! mortar! against! fire! given! the! susceptibility! of! this! material!to!high!temperatures.'A&5'.! The! reduced! existence!of!pieces!of!natural!wood!of!considerable!dimension!nowadays!makes! Introdução de casas de it! difficult! to! substitute! complete! pieces! of! damaged! wood! with! natural! wood! banho elements.!! & perda de secção.! 45->*>-+"'#5*+")-5"*1"?'%-"#1+*%*"'*'21>*5'*"'%17-5-+#-"'7&2@*"'%-'A*5-%45->*>-+"'#5*+")-5"*1"?'%-"#1+*%*"'*'21>*5'*"'%17-5-+#-"'7&2@*"'%-'A*5-%B8&.! The! damaged!wood!elements!can!be!replaced!also!with!epoxy!resin!mortar!and!this! mortar! has! similar! mechanical! characteristics! to! the! wood! to! be! reconstructed.&2007]& ! DE#&5'F6 #&5'F61*"?'9::G d) Strengthening!masonry!column!with!jacketing! & In! similarity! with! the! case! of! strengthening! the! masonry! walls! with! reinforced! cement!coating.&9&a)&Rotten&wood&joists&at&the&connection&to&the&wall.!the!masonry!piers!can!be!strengthened!with!reinforced!concrete! as! an! outside! layer.&8&Face&to&face&connector&in&wall&of&two&layers&[Cóias.!9!a)!it!is!depicted!rotten!wood!joists!and!in! Fig.! for! instance.!it!is!advisable!that!the!connection!between!existing!wood!and! mortar! be! enforced! by! mechanical! connectors.! The! steels! rods! are! placed! in! the! perimeter! of! the! pier! and! then!the!concrete!is!poured!covering!the!steel!rods.!The!rods!should!be!anchored! to!the!base!foundation!of!the!pier./*0'$&0'/*$. '.!The!coating!increases!the!walls!strength!and!ductility.!see!section!d))! on!masonry!walls.! preventing!both!collapse!and!the!escape!of!debris!during!earthquakes.! PP9meshing! has! been! applied! in! Nepal.!! ! It! is! thought! that! a! wall! of! rubble! (stone)! masonry! with! 0.! 11! a)).10!m! thickness!in!total.!10!a)!and!b))!one!places!thin!(less!than!10!cm)!layers!of!coatings! argamassa ou microbetão – Edifícios pombalinos em Lisboa of!cement!reinforced!with!steel!(or!glass!fiber!or!plastic!meshes.!! ! To! enable! the! behaviour! of! both! elements! (existing! and! new)! to! work! together! one!places!steel!connectors!on!the!wall.! Non9engineered! masonry! is! widespread! throughout! the! developing! world! and! replacement! of! all! such! dwellings! is! both! unfeasible! and! undesirable."%!# a)! ! ! ! ! b)! Fig.! argamassa ou microbetão – Edifícios pombalinos em Lisboa & !"#$%&%'#()*+. Global!interventions!for!structural!improvement! #&1"/#!%#+"+2#.!"#$%&%'#()*+.!at!least![Appleton.&b)&spraying&of&the&cement&grout& into&the&wall&[fotos&by&Appleton.'.!It!can! be! placed! in! the! outside! or! in! the! inside! or! both."%!# ! a) Strengthening!of!masonry!walls!with!reinforced!cement!coating! Reforço de paredes de alvenaria com recurso a lâminas armadas d ! In!this!case!(Fig.! It! is! therefore! often! more! feasible! to! consider! low9cost! retrofitting! of! ! 11! .! Pakistan! and! more! recently! China.60! m! of! thickness! Reforço de paredes de alvenaria com recurso a lâminas armadas reinforced!with!two!layers!of!cement!coating!with!steel!meshes!and!with!0.! given! that! they! are! often! the! embodiment! of! local! culture! and! tradition.&2011]& Abril& de 2011 b) Strengthening!of!masonry!walls!with!polypropylene!meshing!!! & Polypropylene! meshing! uses! common! polypropylene! packaging! straps!! (PP9bands)! to! form! a! mesh.! depending! on! the! most! accessible!areas.!#-+#/'%0#-+ #&1"/#!%#+"+2#.&10&a)&Masonry&wall&from&the&inside&with&steel&mesh.!may!have!increased!its!strength!in!compression!and!shear!of!3! to!6!times!its!original!strength.! which! is! used! to! encase! masonry! walls! (Fig.!#-+#/'%0#-+.! This! method! is! most! readily! applicable! in! terms! of! low9cost! Abril de in! 2011 upgrading! of! traditional! structures! to! limit! damage! caused! by! normal! earthquakes!and!give!occupants!a!good!chance!of!escape!in!an!once9in9a9lifetime! large! earthquake.!2009]."+"-'!.!PP9bands! are! used! for! packaging! all! over! the! world! and! are! therefore! cheap! and! readily! available! while! the! retrofitting! technique! itself! is! simple! enough! to! be! suitable! for! local! builders."+"-'!. &2012]! A& pilot scheme implementing the PP-Band technology in Nepal was conducted in a rural village just outside Bhaktapur. two!storeys.!For!this!reason. Under extremely strong ground motions.! especially! in! what! concerns! seismic!actions. focusing on polypropylene meshing. Pakistan and more recently in China.&11&Implementation&of&PP&band&method&of&retrofitting&in&Kathmandu&Valley&(a)&and& 3. behaves!like!a!box. mud is usedof! onboth! the outside.! capacities.!a!remarkable!rigidity!and! an! efficient! connection! to! the! supporting! walls.! Experiments! and! advanced! numerical! simulations! have! shown! that! PP9band! mesh! can! dramatically! increase! the! seismic! capacity! of! This method is most readily applicable in terms of low-cost upgrading of traditional structures to adobe/masonry!houses![P.! Under! moderate! ground! PP9band! meshes! retrofitting of such buildings. Mayorka and K the! retrofitted! structures.!by!strengthen!a!floor. found to be technically feasible and easily implemented. preventing both collapse and the escape of debris during earthquakes. PPmeshing has been applied in Nepal. providing adequate cover to ensure the together! durability of one!places!anchorages!throughout!the!wall!( Fig. PP-bands are used for packaging all over the world and are therefore cheap and readily available while the retrofitting technique itself is simple enough to be suitable for local builders. Non-engineered masonry is widespread throughout the developing world and replacement of allachieved! such dwellings both unfeasible undesirable.5 Implementation of PP band method of retrofitting in Kathmandu Valley (left) and anchorage throughout the wall (right) anchorage&throughout&the&wall&(b)&[Shrestha&et&al.!Mayorka!and!K.ductility! given that they often the This! is! mainly! by! isincreasing! the!andstructural! and!areenergy! embodiment of local culture and tradition. PP-band meshes provide enough seismic resistance to This!method!is!good!for!one9storey!buildings!and!can!be!used!for!a!maximum!of! guaranty limited and controlled cracking of the retrofitted structures.! Under! extremely! strong! ground! motions. This method is good for one storey ! buildings and can be used for a maximum of two storeys. used! on! the! outside. Under moderate ground motions. & & a)! ! ! ! ! b)! Fig Fig.! the seismically active Himalayan region. It is therefore often motions.! they! are! Meguro.!11 !b)).! A! significant! role! in! the!stability!of!the!entire!building!is!assigned!to!the!floors. they are expected to prevent or delay the collapse. Experiments and advanced numerical simulations have shown that PPprovide!enough!seismic!resistance!to!guaranty!limited!and!controlled!cracking!of! band mesh can dramatically increase the seismic capacity of adobe/masonry houses [P.! ! ! 12! .Engineered Buildings in the Himalayan Region’ ! and outlines training courses for rural masons and public demonstrations for community members in Traditional!masonry!buildings!have!timber!floors. This is mainly achieved by increasing the structural ductility and energy dissipation expected!to!prevent!or!delay!the!collapse. such! buildings.! more feasible to consider low-cost dissipation! capacities.!! the material.!(full providing! to! ensure! durability! of!Kthe! 2006 ] and also in Kathmandu. The project is titled ‘Improving the c) Strengthening!of!floors!and!improving!the!connection!floor/wall! Structural Strength under Seismic Loading of Non. by National Society for Earthquake Technology-Nepal (NSET) in collaboration with Mondialogo Engineering Award Team.!enables!the!horizontal!forces!to!be!redistributed!between! the!different!vertical!structural!elements.!on!has!an!opportunity!to! improve!the!behaviour!and!efficiency!of!the!entire!structure.of! The mainis! objective of the and! project is toeffective! disseminate method! of! improving! the! seismic! behaviour! of! old! masonry! structures. increasing the rates of survival. to promote seismic resistant building and retrofitting The! increase! of! the! in9plane! stiffness! floors! an! evident! most! techniques.!in!addition!to!an!adequate!performance!level. 2008].!and!they!are!typically!flexible. The masons were trained through hands on implementation.!! limit damage caused by normal earthquakes and give occupants a good chance of escape in a once-in& a-lifetime large earthquake.!To!protect!the!Polypropylene!from!ultra!violate!rays.!thus. (small scale 1:6) demonstrating reliable performance improvement in material![Shrestha!et!al.!These!structures!are! required.!and!then!the!horizontal!forces!of!failing! walls! can! be! redistributed!to! the! adjacent! remaining! walls.!i. To protect the Polypropylene from ultra To! enable! the!plaster behaviour! elements! (existing! and! new)! to! work! violate rays.!Meguro.!2012].!mud!plaster!is! Experimental verification scale) wasadequate! done in thecover! laboratory of Tokyothe! University [Nesheli et al.2 Polypropylene Meshing Polypropylene meshing uses common polypropylene packaging straps (pp-bands) to form a mesh which is used to encase masonry walls.!increasing!the!rates!of!survival.! the integrity of the structure and preventing material loss.e.3.! is! and transfer the PP-band retrofitting technique to the communities who cannot afford otherThis! expensive mainly!because!the!increase!of!in9plane!stiffness!of!floors!enables!the!structure! retrofitting technology. thus. in Nepal.!2008]. !and!anchored!to!the!existent!floor!by!pins!or!connectors!fixed!on! the! top! edge! of! the! beams.!The!technique!is!also!not!reversible.&12&a)&Example&of&the&reinforcement&of&a&wooden&floor&with&a&cooperating&reinforced` concrete&slab.!Thus.! allows! to! significantly! increase!the!floor’s!in9plane!bending!stiffness.! There! is! almost! no! advantage! in! overlaying! the! slab! without! linking! it! to! the! pre9existent! structure.&(www.! Finally.! developed! in! the! last! 20! years.! between! the! beams! and! slab.com)& The! structural! particularity! of! this! type! of! intervention! is! the! connection! between! wood! and! concrete.&b)&Basic&connectors&Tecnaria&(www.!it!leads!to!a!weight!gain! for!the!floor.! Care! is! taken! to! improve! the! connection! between! the! floor! and! the! masonry! wall! with! L9shaped! steel! plates! (Fig.!see!Fig.!resulting!in!increase!of!the!seismic!actions.! because! the! two! structures! would! work! independently.! designed! to! transmit! shear! forces! parallel! to! the! structure.& ! ! (a) ! (b) Fig.! consists!on!placing!over!the!existing!floor!a!concrete!slab.!usually!reinforced!with! a!metallic!net.! 13).! which! cross! the! planking! and! are! embedded! in! the! concrete!slab!and!connected!to!the!metallic!net.tecnaria.tecnaria.! On! the! contrary! to! the! previous! technique! this! one! does! not! increase! significantly!the!mass!of!the!floors!and!is!reversible.!however.!12!a)!and!b).!it!is!important!to! limit!the!concrete!thickness!to!5!to!10!cm.!! ! 13! .!! ! Another! possible! technique! is! the! idea! of! including! on! the! floor! a! horizontal! bracing! composed! of! steel! ties! and! arranged! in! crosses! (Fig.com).A! technique! well! spread! for! the! in9plane! reinforcement! of! wooden! floors.! 13)! and! this! technique! has! been! developed! for! many! decades.! it! should! be! noted! that! this! reinforcement! technique. ! The! strengthening! improves! flexural! behaviour! or! tension! and! compression! through! increasing! the! confinement! for! instance! in! columns.! ! ! Fig.&14&Photo&of&the&connection&with&L`shaped&steel&plates&between&wooden&floor&and& masonry&wall& ! d) Strengthening!with!composite!materials!(CFRP!and!GFRP)! & It! is! possible! to! strengthen! with! composite! materials! such! as! carbon! or! glass! fibres!reinforced!polymers!piers!and!spandrels!within!walls!and/or!columns!of! masonry.&13&In`plane&stiffening&with&metallic&diagonals&and&reinforcement&of&connection&floor` wall&(Pombalino&building)&[photo&from&Edifer]& ! In! the! Fig.DECivil F) Reforço da ligação dos pisos de madeira com alvenaria exterior com recurso a peças metálicas (cont.!15!it!is!shown!the!application!of!CFRP/GFRP!on!a! building.!In!Fig.! The! Carbon! Fiber! Reinforced!Polymer!(CFRP)!or!Glass!Fiber!Reinforced!Polymer!(GFRP)!layers!of! material!are!glued!with!epoxy!resin!to!the!cleaned!surface!of!masonry.! 14! one! can! see! a! photograph! of! the! connection! with! L9shaped! steel! plates!between!wooden!floor!and!masonry!wall.! ! 14! .!wall!and!column.!The!weak! element!is!the!masonry!or!the!glued!surface!if!the!biding!is!not!well!done.!But!the!application!of!such!method!on!masonry!is!still!scarcely!found.! so! that! the! material! is! well! bonded!to!the!masonry.! especially! on! walls.!There! can! be! placed! also! connectors.): Fixação de perfis de aço em paredes para reforço de frechais e apoio dos barrotes do pavimento (Edifer) !"#$"%& Fig. >6"1#&"'?@/4A'B/4C D 4*5-%-"A'E 4*5-%-"A'E>12*5-"F >12*5-"F -')1G*"'%-'8&5&*. The wall surface was first prepared prior to the application of CFRP. This is illustrated in Fig.&2007]& any damage during testing.!iv)!after!curing!for!a!day. ! 15! .!16.&wall&and&column&[Cóias."+-"*)*+)(%$&$.&15&Application&of&CFRP/GFRP&on&a&building. covering the entire surface of the wall.'. applied onfirst! one side CFRP! was! applied! the!oriented wet! layup! procedure. 2.&strengthened&with&CFRP&[Arifuzzaman& F igure 2. iv) afterputty!by!a!plastic!putty!knife.!They!were!applied!on! in each direction.! ii)!The preparation involved. i) surface cleaning by wire brush.! followed! by! air! pressure! to! remove! loose! mortar.!"##$%$&$'(')#*')*+).! i)! surface! wet cleaning! layup procedure.(-/" ! /-7&5. The concrete strength that was ordered.Geometric details of the masonry wall specimen H1#&5'I6 H1#&5'I61*"A'9::J ! The wall was built on an I-shaped concrete foundation.!iii)!removal!of!any!extra! bed joints and to smoothen the wall surface. by! wire! brush.-+#&'?81+#*"C ! "#$%&'%()#($*#+. ii) application of putty consisting of two-component epoxy and silica fume to cover head and head!and!bed!joints!and!to!smoothen!the!wall!surface. second!layer!had!fibers!oriented!900!with!the!horizontal.! curing.>6 &'8&.$/.!inspection!of!the!surface! curing for a day.!while!the!other!side!remained!with!exposed!block!masonry. The foundation concrete was supplied by a local ready-mix company.*#-51*1"'8&.&16&Wall&to&be&tested&in`plane&of&brick&masonry. /-7&5.! CFRP! sheets! are! applied! in! only! one! side! of! the! The! first! layer! had!layers fiber!oforientation! to!Polymer bed! joints! and! the! one Thespecimen. inspection of the surface and covering any noticeable air bubbles with putty and!covering!any!noticeable!air!bubbles!with!putty!using!the!same!plastic!knife! using the same plastic knife and finally v) sanding the surface by sand paper after two full days of and!finally!v)!sanding!the!surface!by!sand!paper!after!two!full!days!of!curing.! The! They wall! were surface! was! of the wall. the foundation cured at least for Fiber! Reinforced! Polymer! (CFRP)! sheets.&'8&.% ! "#$%&'%()#(-%. The first layer had fiber orientation parallel to bed joints and the second layerusing! had fibers 900 with the horizontal.2% F igure 1.Theand&Saatcioglu. The foundation was over reinforced to avoid Fig.! specimen was retrofitted with two Carbon Fiber parallel! Reinforced (CFRP) sheets.'. was 30 MPa.01#.! covering! the! 28 days. iii) removal of any extra putty by a plastic putty knife.! applied in only one side of the specimen.*#-51*1"'8&.! one! in! each! direction.! The! preparation! involved.!a!wall!specimen!to!be!tested!was!retrofitted!with!two!layers!of!Carbon! foundation during testing. entire! surface! of! the! wall. CFRP sheets wereone!side!of!the!wall.&2012]& Masonry wall retrofitted on one side. & & Fig. The foundation was designed to accommodate four large holes (approximately 100 mm in diameter each) to fit the holes in the Laboratory strong floor for securing ! the In!Fig. followed by air pressure to remove loose application!of!putty!consisting!of!two9component!epoxy!and!silica!fume!to!cover! mortar. while the to! other side remained with exposed block masonry. CFRP was applied using the prepared! prior! the! application! of! CFRP. After casting. The sample MS3 was then reinforced (MS3r) applying horizontal CFRP strips. 143. each wall was allowed to displace in its own plane. compression of 0.&2012]& Figure 2.1. &&The observed hysteresis response curve for& each a)! in Fig. concrete footing.the! Thewall! steelsurface! element was! was linked three tely fixed to the Tstiff concrete floor. Cured laminate (GFRP) properties after standard cure are given in Table 2. When the installation of the .!! distributed this vertical load uniformly on the top of the wall.!! at the right side of the tensile specimen. load against displacement (a). iii. ! ! ! ! b)! tested wall specimen is shown Fig. experimental model of the spandrel (b). Fig.32% 0. 2. To close the cracks.2.2 according to the eel element was placed on top of the pier and was connected to the datasheet made by the manufacturer.1.!saturated!in!epoxy. height Removal!of!extra!epoxy!and!air!pockets!by!means!of!a!ribbed!steel! The length. ! (b) all with openings (a). (a) (b) & (c) Fig.1. The loading beam distributed this concentrated load uniformly along the top of the wall to simulate floor or roof loads used in the actual masonry building construction. and thickness of these walls were 194. The test setup was similar for all of the test walls. GFRP properties used insizes! the experimental program xis belonging to a plane perpendicular to the wall and containing the involved!the!following!steps:!! 90 deg 90 deg 90 deg Tensile was Tensile Tensile ASTM test whereas the third actuator setApplication!of!a!layer!of!two9component!epoxy!on!the!surface. The after!saturating!it!in!epoxy!and!following!step!iii. The loading beam 3. (b) RBW-X-S1. This vertical load generated an average (b)and 0. The strengthening In! the! following! wall! specimen! to! be! tested! under! in9plane! loads. tensile tensile Thickness i.Application!of!another!layer!of!epoxy!prior!to!the!placement!of!the! After allowing the wall to cure (for at least 7 days). By means of the steel ties (two Dywidag bars 27 mm diameter) a horizontal 16! horizontal steel compressive force equal to 85 kN was applied to the spandrel. Inc. 2007) as shown in Fig.! the! sheets! ertical Dywidag steelOnce! bars. Specimen MS3r:view shear(b).1b the of specimen by means ofequal GFRPtowas relatively to specimen but.between cm!20Application!of!the!second!layer!of!CFRP!perpendicular!to!the!bed!joint! cm!24 cm and cm!16 transversal cm. respectively.! the! brick! correspondence of aRBW-X-S2 vertical displacement 0. The force required to push the wall and the corresponding displacement at each load interval were measured.2 kN was applied theunder! top of the wall byloads! a loading beamwith!the!spandrels!strengthened!with!CFRP!strips!(on!both!sides).!! directions.!! The relationship the shear load194 andcm!20 the relative displacement ofwalls the unreinforced were 240v. 3.! 18!stress a))! and! after! testing! (Fig. a gravity load of 41. can be seen cracks areof 17). ready!to for! the! application! of! CFRP! sheets. The test walls were constructed on a strong reinforced 3.the! masonry! face. Two couples of horizontal CFRP strips (four CFRP strips. respectively. diagonaltwo (shear cracks). After the and peakGFRP load astrengthened quite rapidwalls reduction in shear in capacity was observed and a residual unreinforced are illustrated Fig. the ! strength width valueofof about 40-50% of the maximum shear was reached at the end of the tests in the lower and upper diagonal GFRP strips was 15 and 18 cm.! implying! filledFigure with 210 lead weights and was subsequently placed on the loading beam.2. (c) RBW-X-S2 & Furthermore. a steel loading basket was constructed.(b) This steela!loading basket of!(a) the!theCFRP! strips! from! reduction! in!was CFRP strips (MS3r) (a).74.crack it had masonry!wall!was!strengthened!with!GFRP!strips!in!both!sides!of!the!wall!(Fig.&18&(a)&Wall&to&be&tested&in`plane&with&strengthened&spandrels&with&CFRP&(b)&view&of& (a) (b) (b) strengthened&spandrel&after&testing&showing&debonding&of&the&CFRP&[Amadio&et&al. The test reached a maximum value of52about 45 cm. 2. 3.modulus strength elongation (Fig.! sides. The unreinforced and GFRP strengthened test walls: (a) URBW.18 MPa in each wall and its piers (adjacent to the window). Adequate sliding26.! 18! shows! a! wall! specimen! to! be!along tested! in9plane! In this experimental study. In specimen RBW-X-S1. Horizontal cyclic load was applied manually in the plane of the wall to the loading beam (via steel plates which were connected to the loading beam during the construction) using two hydraulic jacks and hand pumps. These jacks could only produce compressive load and were mounted on rigid reaction frames. the roller. this axial load acting on the wall & was constant during cyclic loading as seen in the walls in real buildings under seismic loading.&17&Wall&to&be&tested&in`plane. axonometric Figure 3.! Fig. 120x1 mm) were glued on both sides of the spandrel.! The! application! cut! to! required! and! applied! ablewere! 2. 2.13 MPa (Fig. The selected loading procedure can simulate the earthquake actions and their effects on the walls.&strengthened&with&GFRP&[Kabir&et&al.49 devices provided at 23 brace-wall 537 MPa GPa were 2.&2012]& est arrangements: schematic drawing (a).1.8% of the similar spandrel length. and 16 cm.2.!before!testing! in a manner consistent with the floor or roof loading. Samples MS3-MS3r iv.5 mm D 3039 bed!joint. The foundation and loading beam dimensions next!layer. strength modulus elongation method positioned on both sidesii.! two vertical GFRPatstrips with width cm atAs theitbeginning andthe endmain of the surface pattern in theadditional spandrel’s back face the end ofathe testof is 15 shown. The length and height of this window were and 47 respectively. These test had a window spandrelopening MS3 is in shown Fig. respectively.! 18! b)).epoxy resin based adhesive (two component epoxy Sikadur 330) was used for bonding the glass fiber sheet. The test wall assembly was laterally supported along its top so as to restrict the out-of-plane displacement of the assembly.!! aspect ratio of the test walls was about 0. During the test. Thus. kN in both loading their in center.3).of the Application!of!the!first!layer!of!CFRP!whose!fibres!were!parallel!to!the! specimen so as to contrast out-of.. All these walls were tested under constant gravity load and incrementally increasing in-plane loading cycles according to (ICC Evaluation Service. Thus. Two actuators were arranged at on! the! wall! surface.07 GPa 0. InRBW-X-S1. a strong reinforced concrete loading beam was built on the top of the brick wall.2.!! s used to reduce possible friction.debonding! stone specimen with steel angle (MS4r) (b). crack pattern (b).1a. after completing the unreinforced tests.! After! testing! it! can! be! observed! the! respectively. ! 2. Specimen MS3: shear load against displacement (a) and crack pattern (b). shear!strength. For this purpose.21% MPa 7. a prestress was applied to the specimen using a couple of ! ties. /*)#!K@IM!N!A(.$! 9'-$(-$! %#$&$! :#)-5-$.!'+!'!/'72.'/01+"234"5'6)2117"'38+*+68'3("'3!0123+"68*+3(89+3'3(" ! B:$!.)#'(-$!#&!'12-3!5&$!:.% ! ! If!a!building!has!insuficient!shear!capacity!in!a!particular!direction.!they!can!avoid!or!at!least!decrease!the!probability!of!out9of9plane! .$%2%8+D!C277! e) The!use!of!horizontal!tie:rods!! F.#!5&!$.6$! &"! 2%3"#.$!$%"68:!+&($%8&:F!B'77$(!E627.!"%7)!E$!6%.$7&!5-!IJKL<!-!G*-!$-!(-7!)-2-3#5&!4#$(#'(-!-C.&20&Using&tie`rods&to&connect¶llel&walls&[A.!C.F!! Fig.$(-!'#!."$+!%"&!.?#+0&!5-!(./#+.'3$.?#+0&!5-!(.'*.%.$%2%8+!E$&C$$%!+7$%.! %&'$.$%2%8+!2%!'!+:$'(!C'77!($%.&2012]& &'()*+"!"#!".6$!+:"67.$+D! "(! '($! %"&! "0! +600232$%&! $M&$%&! 0"(! &:$+$!6.$%2%8+! 2+! 72<$7)! &"! E$! +"#$C:'&! ($/$(+2E7$! 20! .$@!! &! Fig.!"%7)!E$!6+$.&$! & 93./*)#!K@IM.?#7!&!$E&<!$0&!C*'5#7-'(#.)!#:&.!"!"#"$%&%'()*+./*)#!K@KQ@! #$'%!&:'&!&:2+!&$3:%2.&2E7$! &"! $'(&:.&19&Simple&and&visually&interesting&in`plane&strengthening&with&FRPs&[Ingham.6'<$!=$+2+&'%3$! ! %&4-)(*)#$<=!#$$-/*)#)!#$!%&'->.!".("/$! $00$3&2/$D!E6&!'8'2%!&:2+!+)+&$#!2+!72<$7)!&"!E$!:28:7)!/2+2E7$!'%.5#! -! (-7! 2.!4'+"%()!5627.%#! #&! 3&'/&! 5&$! (-7:&$.'(-)2-'+.!In! %&'(.$%2%8+!C277!$72#2%'&$! ! O$(#! (B%'.!the!capacity! "#$! %&'$()*+.-'(#5#$!'#!5./'$!+0!)-')"'-+! in! arches! to! absorb! horizontal! impulses! (Fig.62($! !& a)! ! ! ! ! b)! '.!22).2$(+D!C2&:"6&!$%"68:!.'3&!C277!.6'<$! ! Tie9rods! can! be! also! used!!"#$%!&'$%#())*)'(%+.8('.-".!C2&:!3"%3($&$D!&:$!C"(<!C277! E$! 7$++! ($/$(+2E7$! '%.6'<$F!-%02772%8!&:$!".!#'&3:2%8!E(23<!'%.'()&5*+0&!5-!(.!19!one!can!see!the!application!of!an!additional!layer!of!material!(CFRP!or! !"##$%&'()!&"!*++$++#$%&!'%.-$! )-%-'(-$! '&$! For!instance.5+3%6+%7./#)!&$! :#'&$! 5-! :#)-5-! &:&$(&$! 5-! #32-'#).! &:2+!.!#"(&'(!3"7"6(+! failure.!+:"67.2%8!0677! :$28:&!C'77+D!#$'%2%8!&:'&!&:$!C'77!'E"/$!'%.5#5-! -'()-! &$! 5.$(!.! :.! 21! and! ! .8('.2-)$&$! -3-7-'(&$! -$()*(*)#.G*-!:-)7.("E7$#!E)!#'<2%8!&:$!C'77!3"%&2%6"6+D!'%.&Costa.'+&F!G("E7$#+!C2&:!'7&$(2%8!&:$!3:'('3&$(!"0!&:$!E627.7$#$%&!&:$2(!2%:$($%&!+&($%8&:D!'+!&:$2(!0'3'.2$(+!C2&:!".!/2+6'7!2#.!-#.'()&5*?.("/2.'#'8$F!B:2+!+$3&2"%!..%.'5&! #! $-)! #:3.($0$('E7)!%"&!2%! parallel!walls!at!the!level!of!the!floors.%#5#! 5-! *7#! C&)7#! Tie9rods!in!steel!can!be!used!in!several!applications!of!old!masonry!buildings./"3'&$.!! 9'(&:.$(&'<$%!C:$%! 2&!.!C.$(-76(.! +&$$7! 3("++! E('32%8! %$'(! ".7:3-7-'(#5#!'#! D3E#!5&!F#.! & ! ! 17! .$+!"0&$%! F.(-7!3.-'(-.#3.!Fig.2%8+!0"(! >?@?A>> GFRP)!bonded!to!the!surface!of!the!URM!wall!aiming!to!increase!its!strength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of!existing!walls!can!be!increased!instead!of!inserting!an!additional!structure.!+"76&2"%!2%!&:$! $.89):*.)#'(-$!:#)#!3.)-%+0&!5&$!4#))&(-$!G*-!)-#3.%/0123%43./#!9.-$! #'(./#)!:#)-5-$! 72<$7)!E$!&:$!02(+&!'($'+!&"!0'27!2%!&:$!$/$%&!"0!'%!$'(&:.2%8!L&($%8&:$%2%8!L)+&$#+! 1=4! C'77+! C277! "0&$%! E$! 6%+62&'E7$! 0"(! +&($%8&:! 6.2%8+!2%!.6$+!C:23:!3'%!E$!6&272+$.6$%&7)!($.$&$! -! the!Fig.-./*)#! K@IJ! -! (#74B7! -7! .$%.$.%#! -$(6! #7:3#7-'(-! 5.2%8F!! !>IFJ !K$C!5627.'&2E7$! +&200%$++$+F! H"3'72+$.$&('3&!0("#!&:$!3:'('3&$(!"0!&:$!E627.7'%'(!+6(0'3$+! ! &"!& 0"(#! $00$3&2/$! +:$'(! C'77+F! *+! +:"C%! 2%! N286($! !>I">OD! &:$+$! '($! +6+3$..!20!a)!and!b)!show!the!application!of!horizontal!tie9rods!to!connect! P+&)-$.C*'5.("/$#$%&!"0!1%($2%0"(3$.%#!5-!)-C&)+&!4#$(#'(-!#'(.($+$%3$!"0!"./#)!:#)-5-$! Fig.$&$.63&27$! E$:'/2"6(! "0! &:$! C'77! #')! E$! '00$3&$.&2008]& 3"%+2+&!"0!'!+$(2$+!"0!.3.! ./#$! #! #%(*#+0&! #&! '12-3! /3&4#3! 5-2-)6! %&'$.-$<!-'()-!-$$-$!-3-7-'(&$!-!.$(+!&:'&!+$3&2"%!7$++!+&200!&:'%!&:$!+6(("6%.-. )./"0%--"+%1-(2/"3(/")*" 4*.&Photograph&of&damage&in&the&2010&Darfield& c) Towers and chimneys (Canterbury)&earthquake&due&to&deficient&anchorages&[Ingham.&Costa.!spaced!close!together.)"*2"%58/."*+".&2008]& components (in steel or timber). steel 3/+141/. or by wrapping them with glued composites (CFRP. In the case of filled vaults.8"*+"9%5-/"%.4:*2%9/" $%&"'()!*+!.23!4'#0&1. in steel.4:1.*"%. 18! Figure 32: Tying of masonry tower w . glued to the extrados of the masonry./'$!+0!)-')"'-+!! $5&"6/7%1.=" because!the!plate!was!too!small. one possible solution will be the reduction of weight or. the adjustment of its distribution.4:*2%9/"+%1-(2/" The most common solution for the 4*.! When blocks have become out of position.! ! has been heavily changed. GRC. In the case of floors made with brick vaults supported on steel beams./4)1*. 32).4:*2%9/8" strips or cables (Fig.& ! ! Fig. for the confinement of the walls. usually. very useful in particular & situations.--". an adequate measure to restrict their lateral separation will consist in the placing of tie-rods.&22&Tying&of&masonry&vaults&with&tie`rods&in&steel&(Santos.4:*2%9/" correct position.:2%978")*"0%--" $3&"<(. Fig. In very severe situations.%/4'0!</!3#$'-=5!/12&/!>'&/</0!6(*8! ! ! !"#$%&'!()*!" +.&2003)& ! Figure 30 Tying of masonry vaults with tie-rods in ! steel (21) ! Figure 31: Strengthening of masonry va timber ribs glued on the extrados ( In!Fig. 31).%2)1%-"%./01. will be the insertion !of stren which provides "#$%&'!()(?!+!@#&'12/0!>'&'!'A05&B/&!'0!C54>51/12/0!D5&#E512'#0!<50!#4>%3050! to the vault and in which the barrier effect is much less sensitive (Fig. an adequate solution will be dismantling.!In!Fig. if appropriate.&23&Close&up&of&partial&anchorage&failure./4)1*.+!()-')!. it can be more appropriate to demolish the element.9"8:/%2"+%1-(2/"*+"4%.4:*2%9/"+%1-(2/"%)"2**+"31%.! ! ! "#$%&'!()(9!+!:0."):/"#A"A"B%2+1/-3"$!%.:8"*+"3%7%9/"1.%.*.&2012]& /&">.4:*2%9/"*+"31%.. "#!#" ! ! In the case of prismatic towers an appropriate measure will be the provision of diaphragms (in concrete or steel). etc. when the shape of the the!tie9rods.!23!one!can!see!a!failure!of!the!anchorage!of!the!tie9rod!after!an!earthquake.-%.2"5 ! An alternative solution.." ! strengthening of this type of element consists 9(2/"!"#!"@"<:*)*92%.)"31%92%7"%. ! ! ! ! ! !"#$%!&'$%#())*)'(%+.&21&Utilizing&tie`rods&to&absorb&horizontal&impulses&in&arches&[A. fol its reconstruction using materials similar to the original ones. 4&". at intermediate levels.%.:2%97" $+&"!-*8/"(.!24!it!is!shown!the!successful!behaviour!of! by rebuilding in the%."+%1-(2/" ! ! Fig.)/25(2=&"/%2):C(%D/"3(/")*" ofn tying them with horizontal ties. welded onto the bottom flange of the beams. 5!'&$!.+88<.1+"!"#!#>""(?&)46+8"0<"9&66!.'.%.$"! %'>&13.! :"! 58>>%#%"'$! $&! .5&'1=!<.5!'&$!"5$."78. & $%&'!50&8-.".+.85"! 55!$&!$0"!%'5%.B! .! 5%3/-"! #0"#9! &>! $0"! "F/"#$".&2012]& possible collapse as a rigid block.!<%$0! "!()*"KA#B!..9"!5822"5$!$0.'#0&15! 0.%'$5!:"!/1&.1!18/$81"! 3:"1! $".! The! first! procedure! involves! coring! a! cavity! from! the! top! of! the! URM! wall! right! through! to! the! foundations.55&#%.5&4/1&2)"&-.&Parisi&et&al.A."!&>!$0"!:8%-.$".%'2!<.. an post9tensioning! retrofit! is!spaced applied! either! placing! post9tensioning! tendons! apparently strange situation which.$"1%. The roof had undergone intervention with light elements to improve its interior and exterior connectivity and remove thrusts.! ..!! ! ! Fig.BC! ! M"#. this case.! 5%'2-"! :".1$%#8-.! 26! a)! shows! the! procedure! of! coring!a!cavity!and!Fig.!! probably collapse of a significant part of the building.2"5! .&2012]& "#$%&'5! 50&8-.'. The strengthening intervention that had been recently performed on the roof may be seen in fig..B!<.%-81"?! 85$1.2"[email protected]"!>.! .'#0&1. but it seems interesting because the intervention recognizes a 5%&'C! Retrofitting!by!post:tensioning! possiblef)problem in case of horizontal longitudinal motion of the truss top and takes care of it.$!>.! &8$! >1&3! 3.! .1.1%-=! ./01. This crack pattern typically evolves into the detachment of the angle and of its subsequent Fig.%-81"!&>!$0"!5$""-!A&1!&$0"1!3"$.$%&'! 1"2.5&'1=!.'. near the roof.."! :""'! /8--".! %$! %5! 1"#&33"'.5! &:5"1..".608+" %&' ()*+.. which were irregularly because oneby! truss was missing at the intended spacing.!$0"!5$""-!"F0%:%$!5%2'5!&>! The second case is still under analysis.-B! "#$%&'!-%'9%'2!$0"!. 19! .--!%5!-"55!-%9"-=!$0.-! #0.1"&8$! <.1".1"55!$0%5!%558"C! roof covered an important historical building in the town center."'!$&!$0"!">>"#$%.6" Finally.! [Ingham.#$"1%5$%#5! &>! $0"! 5$""-5! & %'! $0"5"! .!50&8-.!in!Fig.1>%"-.:-%50". Trusses of the church of St. the bracing element is visible.%'2! $0"! 3.%>!5. This inside view was possible from the opening caused by the unfortunate collapse of a vault.%-81"!3&."3/+"9&66" & restraining action had occurred in this area. like many similar buildings in town. indicating that a 1+831&5-+."!#1&55"5"#$%&'. 6.1.'#0&1.5&'1=!<. but became narrower and was barely visible at the top. .1"! "3:".$! /.%1"#$-=! .%. The & of St Michele.%-81"!intervention 3"1%$5! #-&5"1! ! N.!25!one!can!see!the!utilization!of!tie9rods!in!a!wooden!roof. 2011b).55&#%.%-81"!&>!$0"!#&''"#$%&'!."../"$5! .'..&24&Successful&anchorages&spaced&close&together.1.1. In order to appreciate the positive effect of this work.C! "'$-=! $0"1"! %5! %'.'!3./"$5! . the Carli-Benedetti palace."$"13%'"! >.!3.! @%281"!()*"KA:B! <0"1"! .1! Fig.--!<%$0&8$!18/$81"C!!L&<".+."1?!>.8"!$&!"%$0"1!:.!@%281"!()*"KA.'. in Vimercate. The building is currently under repair."!.:&.-!./01&2+"3/&3"4&135&667" Darfield&(Canterbury)&earthquake&[Ingham.%-81"5! 1..&Photograph&of&building&after&the&2010& %*' In :.! <%$0! /./01&2+8"84&..-! 5$1"55"5! %'! $0"5"! Fig.:-"?!$0"!5/"#%>%#!>. the crack was well open up to the mid-height of the 302+3/+1" walls./01&2+8"3/&3"9+1+"4&135&667"01"<..$".2"! $=/"5?! :8$! . Vimercate.! %'$&! . into!cored!cavities!located!at!the!centre!of!the!wall!or!by!placing!post9tensioning! #!$" ! tendons! externally! at! discrete! locations. Michael.&C+" ! CG !$""-!4'#0&1.&25&Using&tie`rods&in&roofs&[M."! %5! /1%3.F%.667"8.1$078.'#0&1.%-.!$&!.!26!b)!shows!the!bar!post9tensioning.".. The roof action avoided more dramatic damage and .! Fig.23!. 5. it must be considered that the earthquake had caused the ! opening of a significant crack on both sides of !the corner corresponding to the picture. was found also in other cases (Parisi et al.5$""-! Low-mass on a 5#18$%'=C! timber roof in L’Aquila.! $0.$".!From!discussions!with!specialized!New!Zealander! constructors. on the contrary. near Milano presents a roof structure composed of a series of king church postA! trusses.$%&'5!>1&3!$0"!*I)I!J.!:"!2%.5! 50&<'! %'! @%281"!()*"KA#B! .+88<.".."&-.!one!knows!that!it!is!possible!to!core!a!cavity!up!to!four!stories!with! a! precision! of! +9! 10! mm."+&13/B.6"&-.15-2"3/+"#@"@"A&1<5+6.! D&%'$C! ! E0%5! "! 3&."! <0"1"! 38-$%/-"! .!".! %'! @%281"!()*"KA.! 2012]..! then! placing! a! tendon! into! the! cored! cavity! and! finally! the! application! of! a! post9 tensioning!force!to!the!tendon.! @%281"! ()*"KA. that suffered severe damage in various parts. &2012]& %&'"!()*+.! 7"C$(!C'77!+$8#$%&+!+&'(&! &"!("&'&$!'%.! orated masonryb) c)!!!Keep!integrity!of!the!structure!with!minor!changes.<)/"!"#!"=":(70!0/+7*(+*+.$72%$J! ucture with minor 2 1 Total Lateral Force (kN) Total Lateral Force (kN) nce 4 3 3 4 2 1 ! 1 Fig.("/$#$%&!"0!1%($2%0"(3$."+&"&$%+2"%$.+"F*G*0"50&0/7" of! confinement.Nominal Strength 4 .2%8! &:$! 0'276($! 72#2&! +&'&$! 3" ('%8$I! &:$!%"#2%'7! +&($%8&:! 72#2&! +&'&$I! '%.! as! suggested!.$(! B$:'/2"6(! &"! 2%&$(.+!&"!C'77!.!E+$$!F286($!!>G"?HD!C:$($!02(+&!3('3<2%8!2+!&:$!72#2&!+&'&$!C:$%!&:$!02(+&!3('3<!'.!-#.! e) Easy!to!apply.! tendon! type! and! spacing.$+28%!2+!7$0&!&"!&:$!.$ '%. ! ! !! !& a)! ! ! ! ! b)! Fig.($&! +$2+#23! B$:'/2"6(! "0! .Hinge Formation 2 ..$02%$./)&0*(+" %&'"!()*+.! Post9tensioning! can! either! be! bonded! !"#CDCD E/7*.!the! technique!is!deemed!to!be!a!desirable!retrofit!solution!for!URM!buildings!having! '($!.! '%.First Cracking .+"F*G*0"50&0/7" when! tendons! are! fully! restrained.!E+$$!F286($!!>G"?HD!C:$($!02(+&!3('3<2%8!2+!&:$!72#2&!+&'&$!C:$% '($!.! -%! "(.6'<$!=$+2+&'%3$! ! 9'(&:.$(!'%.&(b)&Bar&post`tensioning&[Ingham.Failure According!to!Ahmad![2012]!some!advantages!of!this!technique!for!URM!are:! 4 .$(0"(#'%3$!2%!&:$!$7'+&23!('%8$I!&:$!:2%8$!0"(# '%.! restraint! conditions! and!!"#CDCD the! level!E/7*.!.!4'+"% 9'(&:./)&0*(+" %1'"230/)+&4"50)&+67" %1'"230/)+&4"50)&+67" %8'"9&)" :(70!0/+7*(+*+.! not simple Top Displacement (mm) ! Top Displacement (mm) ! .">/0)(?*0"@/8A+*B</" buildings.!-#.2%8J!K:$!+$7$3&2"%!"0!'!72#2&!+&'&$!0"(!($&("02&!.6'&2"%+!0"(!&:$!%"#2%'7!72#2&!+&'&$!'($!($."%.$02%$." :(70!0/+7*(+*+.!3"(($+.! C:$%!&:$! 6.*.&27&Close`up&view&of&a&post`tensioning&anchorage&[Ahmad."+&"&$%+2"%$.!27!one!can!see!in!close!up!view!a!post9tensioning!anchorage."-.![Ingham.$+28%!$..*.+!&"!&:$!+$(/23$'B272&)! ion under service ! ning ('%8$I! &:$!%"#2%'7! 72#2&!72#2&! +&'&$I! '%.!!The!performance!of!post9tensioned!URM!walls!depends! upon! the! initial! post9tensioning! force.!Because!unbounded!post9tensioning!is!reversible!to! "(."%."% C:$%!&:$! 6.2+ )2$7.! #'+"%()! C'77+D! 0"6(! 72#2&!#'+"%() +&'&$+!! some!extent!and!has!minimal!impact!on!the!architectural!fabric!of!a!building.!3"(($+.$(! &"! 2%&$(."%.!3"(($+."%."(&$.+!&"!C'77!.*.First Cracking 2 ..<)/"!"#!D="E/?*+*0*(+"(?"F*G*0"50&0/7" 20! .!"##$%&'()!&"!*++$++#$%&!'%.$'(+! important!heritage!value."-.*.2+3($&2"%!"0!&:$!.Nominal Strength 3 ."%! )2$7.!3"(($+.!or!both!types.$(0"(#'%3$!2%!&:$!$7'+&23!('%8$I!&:$!:2%8$!0"(#'&2"%!72#2&!+&'&$!"336(+! ! In!Fig.2%8J!K:$!+$7$3&2"%!"0!'!72#2&!+&'&$!0"(!($&("02&!.!3"(($+.$+28%!$.!4'+"%()!5627."(&$.!+&($%8&:! &:$! 0'276($! +&'&$! &"! &$%.Hinge Formation ! 3 .$+28%$(D! trength and ductility '%.$+28%!2+!7$0&!&"!&:$!.<)/"!"#!"=":(70!0/+7*(+*+.Failure a) Reducing!cracking/deflection!under!service!loads." %8'"9&)" %6'"50)&+6" :(70!0/+7*(+*+.!2012].&26&(a)&Coring&operation.">/0)(?*0"@/8A+*B</ by! Meireles! [2012]! for! Pombalino! .$(!'%.2%8+!0"(! >?@?A>> !"##$%&'()!&"!*++$++#$%&!'%.!2%!&:$!862.($&! &:$!-%! +$2+#23! "0!&:$! .!2%!&:$!862.("/$#$%&!"0!1%($2%0"(3$.!ჼ! d shrinkage of d) Reversible.! by! grouting! the! cavity! or! left! unbounded! by! leaving!the!cavities!unfilled.6'&2"%+!0"(!&:$!%"#2%'7!72#2&!+&'&$!'($!($.&2012]& 1 .!.! Significant!increase!in!strength!and!ductility." & There! can! be! done! vertical! post9tensioning! for! piers! or! horizontal! post9 tensioning! for! spandrels.<)/"!"#!D="E/?*+*0*(+"(?"F*G*0"50&0/7" .! 7"C$(!C'77!+$8#$%&+!+&'(&! &"!("&'&$!'%. / Engineering laboratory.! Ma! et! al! [2012]! placed! vertical! and! cross! bracing! struts! at! a! building! in! the! 301 Ma et al. f) Strengthening!with!ring!beams! & RC!ring!beams!can!be!placed!along!the!perimeter!of!the!walls!in!the!last!floor!if! tion is shown in the! roof! can! be! temporarily! removed! and/or! at! the! level! of! the! floors. Two groups (see Fig.!28). Fig. The first group of connector plates was set able prestressing in the ring beam beneath the floor slab at storey 2 and the second self-weight was ! group was set in the ring beam beneath the floor slab at storey 3 21! red.! However!some!disadvantages!may!be:! a) Not!applicable!to!deteriorated!masonry.! Structures 42 (2012) 297–307 ! by side. storey 1 duced cross-secshear strength Therefore. cross & alls along axis B Fig.! 29! a).&[Ahmad. with&ring&beams.! b)! and! c). Cross bracing struts at the first two storeys of Model B.&28&Cross&bracing&struts&at&the&first&two&storeys& & ! Fig.&2012]& along axis B at discussed previously. 11). Fig. with a nominal ess of 600 MPa. a.! The! behaviour!of!the!different!possibilities!without!or!with!ring!beams!for!flexible!or! rigid! diaphragms! can! be! seen! in! Fig. egments of preThe overview of the completed Model B is shown in Fig.!the!situation!(c)!is!the! B as shown in best!situation.&b)&Wood&diaphragm& stance capacity. 11.!This!is!to!improve!the!shear!capacity!of!the!walls!(Fig.!! Wall and Diaphragm Interaction B is reduced due her compressive rs (e. Connector plate. 13.Rigid diaphragm with tie beams .g.Wood ( flexible) diaphragm without ties b-Wood diaphragm with ties c.! b) Losses!due!to!creep!and!shrinkage!of!masonry. 12.&c)&rigid&diaphragm&with&ring&beams.&29&Behaviour&of&a)&Wood&(flexible)&diaphragm&without&ring&beams.! ! Regarding!the!placing!of!post9tensioning!tendons!externally!at!discrete!locations.!In!this!case.! c)!!!Guiding!the!tendons!is!not!simple.! Out9of9plane! behaviour! should!always!be!avoided!and!the!in9plane!behaviour!of!the!walls!encouraged!for! a!better!performance!of!a!masonry!building. a reinforced concrete b))! in! the! experimental! work! of! Magenes! et! al.! 31! is!inserted depicted! this! n calculating of these shear walls. Bars Fig. glued with polyurethane glue and connected to the purlins by means of chemically anchored.! The! of! this! system!inis! it! is! comprised! of! Figure 3. to favour the development of a strut and tie mechanism.! 20! cm! high! and! 32! cm! wide! (as! the! wall! in!! Fig. The &strengthening of the roof envisaged the improvement of the connection of the ridge beam with the gableIf!walls.! The! strength! of! the! masonry! building! is! neglected! in! continuous contact. 20 cm high and 32 cm wide (as the wall below). In this method. beam andcalculation! on the longitudinal beams. arrangements and thickness of shotcrete are determined h) Strengthening!with!RC!or!steel!frames! ateral earthquake force.&2012]& The &original timber roof structure of the unstrengthened building included one 20cm x 32 cm ridge beam. . and shear capacity of The! introducing! of! moment! frames! is! a! common! strength! method! aiming! to! increase! additional! horizontal! resistance. increased!by!the!placement!of!RC!shear!walls.!was!cast!at!the!roof!level.!! at a spacing of 20 cm. which are lighter and easier to apply to an inclined plane in comparison to a reinforced concrete slab. The matchboard was then placed on & the timber structure. ring beam all along the perimeter. Weight of slab and masonry walls are considered in calculation of & masonry walls are neglected in calculation of the shotcrete. the peripheral of one! story masonry building ed completely.! perimeter façades (Fig. Bars dimension. consisting thethat! application of multilayer panels beams! and! columns.&31& Photo&of&the&reinforcement&of&two&perpendicular&shear&walls&[ et al.&30& Details&of&the&reinforcement&of&the&ring&beam&(left)&and&view&of&the&ring&beam&after& timber spreader beam and the concrete ring beam (right) filling&with&the&concrete&(right)&[Magenes&et&al.! so!and is!chemically fully! customizable! there! is! space! between! the! anchored steeland! connectors. a two-component epoxy mixture was inserted in the hole and then the bar was inserted and rotated & to distribute the resin. Operation of drilling the Fig. each 21 mm thick. left). The roof was then completed by adding plain roofing tiles nailed to the multilayer spruce ! F igure 7: typical retrofitting by peripheral shotcrete 22! . coherently with the prescriptions of the Italian Building Code (NTC08. on top of the consisted! in! 4φ16! longitudinal! bars! and! φ8! stirrups! at! a! spacing! of! 20! cm. by adding multilayer spruce plywood panels. The 8 cm x 12 cm joists were reshaped to create a horizontal seat on the ridge the! of! the!spreader shear! walls. The intervention consisted in adding 3 layers of plywood. which consisted of a steel shoe doweled the concrete ring beam and boltedcan! to the the! rigidity! of! the! slab! is! sufficient! then!tolateral! strength! of! a! building! be!ridge beam. Scheme of the intervention onadvantage! the roof diaphragm. it was decided to adopt an intervention that was compatible with the original timber structure. & & a)! ! ! ! ! b)! Figure 2. continuous steel plates (80 mm wide and 5 mm thick) were connected all along the perimeter to the roof. Timber spreader beams were also doweled to the r. In! Steel connecting elements were at the top of retrofitting!solution!in!a!school!building. plank F igure 6: typical retrofitting by shear wall ! were placed at a constant spacing of 30 cm and penetrated into the purlins toMahdizadeh connect the upper 2012] layers with the roof structure (Fig. After having drilled and cleaned the hole. 2. vertical! and! horizontal! elements.!! the ridge beam. two segmented 32cm x 12cm spreader beams on top of the longitudinal walls and 8cm x 12 cm g) Retrofitting!by!introducing!RC!shear!walls! purlins every 50 cm forming the two pitches with 30 mm thick planks. although providing a significant stiffness increase.! the! following! Fig.! Moment! frames! allow! full! visual! and! physical! To improve the diaphragm behaviour of the roof. was cast at the roof level. 2008).!A!structural!engineer!can!rapidly! by means of connecting steelof! bars chemically by lengths! epoxy resin.!on!top!of!the!perimeter!façades!(Fig.!30!a)!and! Simulating an intervention where the roof structure can be temporarily removed. The reinforcement consisted in 4!16 longitudinal bars and !8 stirrups coherently!with!the!prescriptions!of!the!Italian!Building!Code. at the contact between the two opposite purlins.! which! can! also! be! used! as! a! local! strengthening! solution.!30). top of To stiffen and strengthen the roof diaphragm (which originally was made only by a single layer of boards nailed to the joists).3). 10 mm diameter threaded steel bars. discontinuity between calculate! number! shear! walls! anchored and! their! and!Any bars! arrangement! by! the timber spreader beam and the ring beam was smoothed by the insertion of a plaster layer to create a calculation! of! base! shear.! [2012]. l shotc rete: This method was achieved by experience of other countries and different tal tests in masonry buildings.& A! reinforced! concrete! ring! beam.! The! reinforcement! ring beam.c. Detail of the reinforcement of the joint at the base of the gable wall (left). !steel!braced!frames!have!a!good! .!&"!B$!.! Braced! frames! are! also! generally! constructed! of! steel! $33$%&(23D! '%.! 2012].($376.! & Care! needs! to! be! taken! with! steel! frames! in! particular! to! ensure! stiffness! compatibility!with!the!existing!structure![Robinson!and!Bowman.! however.!33!a)!and!b)!show!braced!frames!inside!two!different!buildings.&32&A&concrete&moment&frame&inside&the&façade&of&a&large&URM&building&in&Wellington& &'()*+"!"#!$.<=">)':7'1("'1" (Dunning&Thornton&Consultants)& ?+::'1(201"@A)11'1("B80*1201"!016):25126CD" ! Braced!frames!are!also!a!plausible!solution!for!strengthening.! O286($! !>P"??! +:"J! B('3$.!&"!/$()!8"".!&:'%!#"#$%&!0('#$+H! presence!of!windows!as!diagonal!braces!crossing!window!openings!are!generally! considered!to!be!poor!design.!3'%!B$!#'.! they! can! be! used! to! very! good! +$&B'3<+D! '%.!Steel!is! a! ductile! material! but! URM! is! not.'()!+.($+$%3$! "0! J2%.! braced! frames! prevent! physical!3"%3$%&(23D! continuity!&$%+2"%! between! spaces! on! 5('3$.!0('#$+!'($!'!/$()!$00232$%&!#$&:".!.! '7+"!is!8$%$('77)! +&$$7! significant! setbacks! their! use! in! 0('#$+! façade!'($! walls! usually!3"%+&(63&$.$('&2"%H! O286($! !>P"?>! '%.!2012].! 0('#$+! '($! '/'27'B7$! 2%! /'(2"6+! 3"%0286('&2"%+C! "%7)! 3"%3$%&(23D! either! side! of! the! frame.! B)! &:$! .$%2%8+!'($!8$%$('77)!3"%+2.:)+23'7! 3"%&2%62&)! B$&J$$%! frames! are! a! very! efficient! method! of! transferring! horizontal! forces! but! have! +.2002367&!&"!8$&!'!B('3$.!'($!#63:!#"($!(282."J!".$.!32!shows!a!large!new!moment!frame!of!RC!inside!an!URM!building.!It!is!also!difficult!to!get!a!braced!frame!to!conform! 5('3$.'3$+! "%! $2&:$(! +2.!'.!2000].-".$! "0!and! &:$! 0('#$H! 5('3$..!The!key!functional! !"#D%D$ E*5/+7"&*53+6" difference! between! braced! frames! and! moment! frames! is! that! due! to! the! diagonal! braces.$'<2%8D!+&$$7!B('3$.! #"#$%&! rather! than! concrete! and! are! much! more! rigid! than! moment! frames.!$00$3&!J2&:2%!+$3"%.! Fig.! &:$2(! 6+$! 2%! 0'L'.$8($$!"0!($/$(+2B272&)!'%.!Generally.$!&"!02&!'(3:2&$3&6('77)! [Ingham."J+D! '+! effect! within! secondary! spaces! and! can! be! made! to! fit! architecturally! in! some! .!4'+"%()!5627.($/$%&! .!0('#$!&"!3"%0"(#!&"!'%!$M2+&2%8!'(3:2&$3&6('7!3:'('3&$(N!:"J$/$(!&:$)! degree! of! reversibility! and! provide! excellent! strengthening! when! appropriately! 3'%!B$!6+$.("/2.!! ! Steel! moment! frames! have! a! high! degree! of! reversibility! as! they! rely! on! mechanical! connections! and! relatively! small! ties! to! connect! to! the! existing! structure.("/$#$%&!"0!1%($2%0"(3$.2'8"%'7! B('3$+D! B('3$.""(!.! precluded!0("#! by! the! ('&:$(!&:'%!3"%3($&$D!'%.!! 0('#$+!2%!6+$H!Q$%$('77)!+.6'<$!=$+2+&'%3$! ! & &! Fig.'3$+D!'%.! the! frame! needs! to! be! fixed! either! directly! to! the! URM! using!bolted!connections!into!the!wall!or!to!the!diaphragm![Ingham.! Braced! 0('#$+! 2+! &:'&! .! ! 3'%!.!If!a!steel!frame!is!erected! against! an! existing! wall.! 2%!! +"#$! +2&6'&2"%+! J2&:! 3'($067! 3"%+2.! 0('#$+! .$+28%H!-&!2+!'7+"! situations!with!careful!consideration.!Concrete!frames!are!generally!far!less!reversible.$($.!"0!&('%+0$((2%8!:"(2K"%&'7!0"(3$+!B6&!:'/$!+28%2023'%&! to! an! existing! architectural! character.$! J'77+! 2+! 6+6'77)! .! access!between!each!side!of!the!frame!and!minimal!spatial!disruption![Ingham.!0('#$+!:'/$!'!8"".!! & !"##$%&'()!&"!*++$++#$%&!'%.!! 9'(&:.(".(2'&$7)H! ! 23! ."/01/*+2+"303+12"4*53+"'16'7+"28+"45957+"04"5":5*(+".! 0('#$+! '%.6$! &"! &:$! .$!$M3$77$%&!+&($%8&:$%2%8!J:$%!6+$.! meaning! that! under! earthquake! loads! the! added! stiffness! of! the! steel! might! not! come! into! effect! until! a! load! is! reached! where!the!URM!has!already!been!extensively!cracked.! EFG! B('32%8H! I:$! <$)! 06%3&2"%'7! .!-#.200$($%3$! B$&J$$%! B('3$.!2012].2%8+!0"(! >?@?A>> Fig.2'8"%'7!B('3$+!3("++2%8!J2%. (".!$00$3&!J2&:2%!+$3"%.! O286($! !>P"??! +:"J! B('3$.$'<2%8D!+&$$7!B('3$.(2'&$7)H! a)! ! ! ! ! ! ! b)! &'()*+"!"#!$"-"F//+12*'/">*5/'1("'1"5" &'()*+"!"#!$$-".!&"!/$()!8"".$!$M3$77$%&!+&($%8&:$%2%8!J:$%!6+$.$8($$!"0!($/$(+2B272&)!'%.$!&"!02&!'(3:2&$3&6('77)! 2%! +"#$! +2&6'&2"%+! J2&:! 3'($067! 3"%+2.!.&b)&Eccentric&bracing&core&(Dunning&Thornton& Consultants)&@A)11'1("B80*1201"!016):25126CD" G5:HG5I"@A)11'1("B80*1201"!016):25126CD" ! &! ! !"#!$% ! ! 24! .3'%!B$!6+$.!0('#$+!:'/$!'!8"".! 3'%!.$('&2"%H! O286($! !>P"?>! '%.&33 &a)&Eccentric&bracing&in&a&walkway.'()!+.!3'%!B$!#'.!'.! 0('#$+!2%!6+$H!Q$%$('77)!+.1"+//+12*'/5::I">*5/+7"/0*+" Fig.("/2.'3$+D!'%.. !! ! Arifuzzaman!S.!Liang!F.!Setembro!de!2003![in!Portuguese].! Seminar! “! Patologia.!2012.! ! Magenes!G.! pp! 4501.!Portugal.! ! Ingham.!Portugal.!Lisbon..!Franceschinis!R..!Experimental!investigations!on!masonry!structures! using! external! prestressing! techniques! for! improving! seismic! performance..!wood!structures.!FUNDEC!course!on! Lisbon.!Rota!M.! PhD! Thesis.! J.!Jiang!L.! ! Appleton! J..! Seismic! vulnerability! of! Pombalino! buildings.!Dudine!A..!IST.!pp!5320.!Borzouie!J.!and!Meguro!K.! of! the! 15th! World! conference! on! Earthquake! Engineering.!pp!2851..! ! Mayorka!P.! ! Cruz!H.! Portugal! (in! English)..!Ed.!Fang!C.!FUNDEC!course!on!Rehabilitation!techniques!of!constructions.!1ªEdição.!Gattesco!N.! Kalali! A..! Lisbon.REFERENCES! & Ahmad!Hamid.!He!M.!2012..!2012.!Penna!A.!and!Saatcioglu!M.!2012.. P...!Portugal!(in!Portuguese).!Notes!from!the!post9graduation!course!on!rehabilitation!of!constructions!–!Stone! Masonry!structures.! ! Cóias! e! Silva! V! (2007)! Reabilitação! Estrutural! de! Edifícios! Antigos—Alvenaria.!Proc.!2008.! Reabilitação! de! Edifícios! Antigos! Patologias! e! tecnologias! de! intervenção..!Galasco!A..! Edições! Orion.! Proc.!2012.! of! the! 15th! World! conference! on! Earthquake! Engineering.! Engineering! Structures!42!(2012)!297–307.!Rinaldin!G.!Beijing..!Senaldi!I..! HA.!New!Approach!to!seismic!Rehabilitation!of!Masonry! School!Buildings.! Shahmoradi! R.!2008.!Portugal.!2012. “Reabilitação de edifícios de alvenaria e adobe”..!Portugal.!Shaking!table!test!of!a!full!scale!stone! masonry!building!with!stiffened!floor!and!roof!diaphragms..!! ! Kabir! M..! IST.!of!the!15th!World!conference!on!Earthquake!Engineering.! 2009. Lectures on the rehabilitation of masonry structures.!!.!IST!9!23! Jan!to!3!Fev!2012.! 14th! World! Conference! on! Earthquake!! Engineering. University of Minho.! ! Amadio!C.! 2012.!pp!3734.!Proc.! Z.!J...!FUNDEC!one!day!lecture!on!the!“Seismic!assessment!and!improvement!of! unreinforced!masonry!buildings”.!Lisbon.!Lisbon.!of!the!15th!World!conference!on! Earthquake!Engineering.! 2012..!! ! Appleton.!Raessi!M.!Seismic!Retrofit!of!Load!Bearing!Masonry!Walls!by!FRP! sheets! and! Anchors.! Inspecção!e!Reabilitação!de!Edificios!tradicionais”!(in!Portuguese).!February!6.! Madeira— Técnicas!pouco!intrusivas. Ma!R.!"A!step!towards!the!formulation!of!a!simple!method!to!design! PP9Band! mesh! retrofitting! for! Adobe/Masonry! houses".!Design!and!Retrofit!of!unreinforced!Masonry!Structures..!of!the!15th!World!conference!on!Earthquake! Engineering.!Lisbon..! ! Costa!A.!October!2008.!Proc.!Lisbon.!Structural!performance!of! spandrels! in! stone! masonry! buildings.!pp!5077.! Proc.! Cyclic! Behavior! of! Perforated! Masonry! Walls! Strengthened!with!Fiber!Reinforced!Polymers.! ! Lourenço.! Portugal..!Argumentum!&!Gecorpa.! ! Mahdizadeh!A.! ! 25! .!2012.! Técnicas! de! reabilitação! de! estruturas! de! alvenaria.! ! Meireles.!2012. ! ! Santos! S.' “Reabilitação' Estrutural' de' Paredes' Antigas' de' Alvenaria”.!Portugal.!40th!Meeting!of!Commission! CIB!W023.!.!Padova.! ! Santos..!Setembro!2002..!Wellington.!“Comportamento!meccanico!di!murature!consolidate!con!materiali!e!tecniche! a!base!di!calce”.!(www.! ! Robinson! L.!2012.A.! (reporter).' 2002.!Chesi!C.!pp!2012.!Experiences!on!Retrofitting!of!Low!Strength!Masonry! Buildings! by! Different! Retrofitting! Techniques! in! Nepal.!S..!Italy.! 2000.! ! Shrestha!H.!(in!Italian).! Lisbon.! Guide! for! the! Structural! Rehabilitation! of! Heritage! Buildings.!Pradhan!S.pt/masonry)!(in!Portuguese).!NZ..! 2010.!Italy.!pp!2394.!2003..!M.P.!Università!di!Padova.!of!the!15th!World!conference!on!Earthquake!Engineering.uminho.' J.Parisi!M.! ! Valluzzi.Tardini!C..! of! the! 15th! World! conference! on! Earthquake!Engineering.!Guragain!R.! Guidelines! for! Earthquake! Strengthening.' Master' Thesis' University!of!Minho.!2012.!Proc.!! ! Roque.!“Structural!Rehabilitation!of!Historic!Buildings”.civil.! Historic! Places!Trust.! Proc..!June!2010.! Bowman! I.' A.P.!Portugal.! ! 26! .! New! Zealand.!2000.!Lisbon.! CIB! Publication!335.!The!Role!of!Timber!Roof!Structures!in!the!Seismic!Response! of!Traditional!Buildings.!(in!CD9ROM)..
Report "Rehabilitation and Strengthening of Old Masonry Buildings H. Meireles; R. Bento Março de 2013"