UNIT-I Z

lLarts Question& Answer

l. l

Lat do you_ mean by deterioradoD? (NOV/DEC 2003) The process that adversEly olfeils the performance ofa jructural ovcl tilDe due to defecls and damages- ocaurled by natumlly occurring chemical, physical or biological actions,

rcpoated actions such as those causing fatigues, influe.nces.

2.

5.

6,

eiyironmental

Write short trotes on the importatrce of mrltrtetraDce. (MAy/JlrLE 2009) ! Improves life ofbuilding ! Improved liG period gives better rclation on i[veshent

> >

Betier appeaianc€ and aesthetically appearing Prevents major deterioration and leuaiog to "ollap""2009) Whal do_you mear by structural cracks? (MAYIUI.IE Stn chral c.acks due to incorect desigq faulty conshuction or overloading. For example, Extensive cracking ofa RCC bearn.

_1 d

normj o, .erere

Why ls itrsp€ctiotr ueeded for damaged structurqs? 0{OV/DEC 20ll) Occunence of deterioration and or change in its peri'ormancc of a structure should be detected though inspection. The inilial iDspection G carried out before the slruchnE is put

into aller completion ofconstruction. Detailed inspectioa is calried out to obtain -opeiation detailed and specific itrformation ofthe structurc. Vrhat is Drintenance? (MAY/JIINE 2010) The term maidtonance cdm€s from the Freoch vetb Maintainer which carDot to iold. It mealls t9 h9ld, keep, susain ot preseree equipmenq building or shuctue to ao acc€ptable standard of serviceability. What are (be objectiyes of mairtenatrce? (NOV/DEC 20f l) To preservc buildings To restore buildings To make improvements in serviceability

r' / r'

?.

What are the factoB inlluetrcitrg maintetrance?

&

There a.e various factors which influence the dccision to carryout preveDtive or corective maintenatc€, Therefore it is necessary to consider these factors foi effective mainterunce ofbuilding i) cost, ii) Age ofbuildin& iii) Availability ofphysical resouces, iv) Uryency ofmaintenancg y) futrre use and vii) Social considerations. Delitre th_e_fo]loring temrs i) Repair, ii) Retrofit, iii) Relabilirafon, fu) Restoraliotr.

Repair: (NOV/DEC 2007) Actions that improve the fitnctioning ofa membel ofa shuctue. The member is lighter dete.ioraM or damaged due to ally rcason such as eartlquakeq cyclorg 1"f"1,r-" flood, fuq explosiyq vehicle collisions, corosion crackh& irs€ct infutiot e!c. Tbe actiotr may not be iotended regain the original shength ofthe membe. completely. Rehabilitation: Actions that improve the sbelgth of a shucture or a member which is deicriorated or dimaged due to.vadous reasons. Rehabilitation inoludes repair, the action is intended to regain the original strength ofthe structure or member.

-

Retroliti Actiotrs that impmve the shength and othe. athibules of fhe iniegdt, ofa struclue or a mcmber with respect to resisting seismic force* The structure or member rced Dot be

.f

'

del.eriorared or rehabilitation. The action is intended to mitigate rhe effects eatthquakes.

of a ftture

Restoratiotr: Actions that improve theshenoih,and appearance ofa shuchtle. The tentr is used mos*y struaures. Resto-ration ;p"tu or dumaged 9. Deline Maintenance. yailtenance is the.act ofkeeping something in good conditioD by checking or repaEng it regularly. l0.Define Repair.

*"fi#::ledflffi:t I

;;;#H#",

dil;J;;;

li;j,,#.,-

"f

restoring somethins that is damaged or deteriorated or bioken,

l.Defire Rehabilitatioo. Rehabilitation is the process ofrctuming a building or an area to its previous good

I2.What are the two facels ofmaintenrn.., ,,., Eoance? rNrtw/TrE,(NOV/DEC .^^6\ 2009) rf," n o fu""s ii.lln- (i)Preventiotr (ii)Repair

l3.What are the

i)

causes of deterioratiotr?

(MAY/JUM 2009)

Deterioration du€ to corrosion

ii) Environmental effects

iii) Poor quality material used iv) Quality of supervision v) Design ard construaion flaws

l4.Define ptysical irspectioD of damaged structure. Jome oI the use full information may be obtained fiom the physical iospectioo o[ damaged structue, like nature otdistress, type ofdishess" extent dama;e and its classificatjon etc, their causes DaeDar ,u,pr"" roi ruio*ffi envrronmental effects which have not heeni^".ra.3i1.',i.I'lLllil'li:.'F"'1, -tJJ,.u|ffi;;;:T':1:"nsidered at the desisn st,b; and inrormaton on ttre

#il il:T,:ii.il,,rirffi

:1T::li:,-,i-ffi

[T"T jffi,ff :Hr,*,

;"#T#;:"::l',1T"'ffi"ff

may warraot urgent executioE.

*

::*:ffi :iiiliffiH'"h,

ls..How deterioratioo occuIs due to corrosiotr? . spa||tng of concrele cover . Cmcks parallel to the rcinforcement . Spalling at edges . Swelling ofconcrete .Dislocation .

. ..Irtemal

cracking and reduction in area ofsoeel reinforcement. -"" sete*ing a repair

pr*"o,."r'--"

'ty3:ffi"":i:;,,""A1tr

> Do repairjob in time > Ifdefects are few &

isolated repair

o[

an individual basis. Otherwise do in generalized

_1.

.,

manner > Ensure

repair prevents frfiher development ofdelects of tosrshength reirairs should > lt appearance is a probleh, lhe number ofapplicable tfres ofiepairs become limited & > the repairs must be covered 2 Repair works should not inte.face witb facilities ofthe structure > Take care in addilion ofsectioD to a memU", aoa in .ejist iUuiing live loads and otlrcr sctccring a suihble m"th"d of iolsiaring alt ttre ralnlflcatto_ns ot its applicatio4 lhe last step is to prepare plans & specificatior and p.oceed with the work. lT.Discuss about tte etrvir.otrmetrt effects which leads to deterioralion of concrete

'

>In

th-e

case

reir"-;;;,"";;

ll,:3.*:y,:"ger

;p"t;;;;liJr

s]ltucttrreMicro-cracks present in the coicaete are the sources of hgress of moistures a&nosphedo carbon di-oxide hto the collqete which attack reinfolcemeot and with various ingredients ofconqete. In aggressive ,tau"t re be severely reduc€s. "rrLn-"arrt "or"a"t" I&What is the elfrct of selecting loor quatig halerial for conshuction? (MAY/JUM

*ill

Quality ofmaterials, lo be used in constructio4 shodd bc ens.ured by;""* tests as sp€cified in the IS code,!. Alkali-aggregat" ,*"ti"" -J*fpiur" "n"J.*.ft" iD early deteriomtiotr- Clayey materials in tie in",ggr"gut"";"rk; aggregare bofil and reduce the streogth. salinity causes corrosion ofreinforcing bars rs well as deterioration ofcrncrcte_ l9Jow catr ye determine the cause for deterioralion of corcrere structure? a) Inspect & obs€rve the structure b) Observe in bad & good weadrer c) Comparc with other constructions on the area or els€wberE & be Datient d) Study the problem & allow enough time to do tbejob 2o.Tvhat are the factors to be coEsidered by the design;r rt tte coDstructiotr sile. Minimum and maximum temperatures temperatue cycles exposure to ultra violet radiation amount ofmoisture wet/dry oycles presence ofaggrcssive chemicals

-n :'' -;,;

--

! > > ) )

Zr.Wta-t arc ahe steps h repair arpect? (NOV/DEC 200S) fmding tbe deterioratioD

i. i.

determining the caus€ fr. evaluating the st eogrh ofexisting building o. strrcture hr. evaluating the need of repair Selecting & implementing a repair procedure

v.

b

22.Define the fixed perceDtage meihod of evaluating the streDgth oferistitrg strocture. It is !o assume rhat all members which have losr lJss than. soTe-preA-e?rmiEnea Z of their strength are stiti adeqlare and that memO"^ [ri-ri_" ,i#,1r" inadequare. rt is usua v from i57o onwar.ds "r,r"i,i"* "*rgth tor piting"r" X stifhess bcaring plares ;rc. 2.3.Di$uss alrout t[e dBign and corstructioD errors leading to deteriorntion of a slructure.

a

Desig!

of

hted;;lrJ;;;;;ti'caite

concrete srucfures

govems the performanc€ of concrete strucfuaes. well designed and detailed coocrete siucture will t"", a"terloiutioo-ii parison wirh poorly designed and detailed concrots in the simil;;;;i;;;.iii"-iuil_"orr.n.;oiot" are particularly prone to defective concrete, if detailine i" not.done properly. Ioadequaoe concrete cover may lead-to cartonati"on deith reactring up lhe reinforcemenq thus, increasing the.isk ofco.rosion o-f the-*i"i.*#"",. - . _to 24, Discu$r about the quality ofsupervision to be followed at a siie. uonstuction work should be carried orlt as per the laid down spe;ification. Adberence to specified water-cement ratio conbols shengtl, p".r*Liffty Insufficient vibmtion may resutt in porous ani tron"y .".uir1J""r"*i1,"r"i"** excess vibration may cause segregatlorl 25. Wuhat are the possible decisious t-hat can be made after evalutliog lhe

ito*

;; pil;; llaio.""r"ot

ir."'Ui;;;;;"".*.

stretrgtt ofa

a. To permit deterioration to continue b. To make measures to preserve tfiestrucfure inirs present condition withoul strengthen iDg c. To strengtherirhe "o,irr"tion Seyier, to d. Ifdeterioration is exceptiolally rcconstruction are possibly abandoD ir.

26. How caD we evaluate the strebgth oferistiIg structure by stress analvsis? This method is to make detaitii .,."r" ."d,"'nil ir"ruau, altowanc€s for loss of section where it has Here also lhe first stop is to make preliminary analysis "rp_rive. Uy fixed percino*"'i"*oa *a it appears.that major repairs wifl be required, tr,e st engrtr is reevatuateJ&si on aelarea analysis, considering all contribuiion" ro .rct .6ngrh. ^_ Define -sh-ess the load test 27. trlethod ofevaluatiDg the strenglh oiexistinp

iliiilro.

*Ji"i. oi't"

J"r*;. ifu.j;;; Iifti i '-

Inad tests may be required by the loiat

if

'iri struchrre'iiirra

UrirarrE-

,iJy U pertbrmed whe.e computarion indicated "#"r"a, that tr,"* ii r""r"'naif" ""r, #i"r,,y collapse,lesr the test bring rhe shuchre sown. Load tesr show strengh?muci-greater than computed strengths when performed. on-a.ruul ,t r"tur".. ^"""-" o, u"*a structures. In repair work every little bir of srr""grh i.

..gii

i.;;;;.

"g"i*

wr,i.ip".i"r."i -'

''

28. What are ahe possible decisiotrs after litrdiDg a structure to be inadeouate?

> If rhe appearafte of the eisting conditi'onl" :';;i.;; ) Ifappearance is not a problem ihen "1j;;;;; > Put the condition under observation to check ifit isdormanl. or ! progressive. > Ifdormant - Do repair ) If progressive _ check the feasibility & relative economics of permitting dere orarion to continue and Derformin; ;fi;,;;;t"# iut""i. otarutiog the repair " right away

a I

,

I]NII.I

16 neri
@Dcscribc ate steps itr ahe assessDeoa pro.edure for cyahale damag€s (*laylJunc 2009) &(Nov/Dec 20tt)

i,

s san cturc,

The foltowing steps may be neccssary

fJ rh iii. iv. v. vi. vii. '

DiagnGis

viii.

Taking preventive steps mt to causc

ix

Rebospecrive amb.sis to get the diagnosis coofirmed

h xi. xii. Xi\

mysicat tnspectioo ofdemged strucrur€. Preparation ard doc.urtenting the damages.

Collection ofsampl€s Studying the

ad

ca.D,idg

od

t€sG

docuEfits itrcluding silrucatral

bofr itr situ md in laborafor),. aspec,s.

Eslfuration ofloads acting o( ole *uctur€ Estimation ofenviromcnfal etrecs inchnting soil stlcture iot€ractiotr

fErther

damagc

Arsessment ofstruchnal adequacy

Eslimation orl futuIr use Remedial meas:urEs nrc€$sary to $Engrh and rEpaidtrg tt€ 3tructua Post repair evaluatiotr through tqsls

)afl hd

to $udy tte bclravior tru. Choic€ ofcouse ofsdior for the rEstGatioo ofslnrohre. t€st

A .ix'pte flow chart incqporathg &e above poiab

nr FEsco&d in Figure,

t

EMMA'IE Of iUruRE USE

T(,ADIESTS

CHOICE OF COURSES OF

ACI|Oir

.

Erplaitr the vadgur caus$ for detedoiatiotr bfcotrcrele saructu€s.(M.yfiunc 2009) 'Some'ofthecausesofdeterioralionolconqetes0rcturesarcdiscuss€dinoflhecbapters

devoted for this purpose.

i)

Design

A

few details are presented here.

ald colglructioD flaws

Design of,concrete stn otures goyems the pcrformarce of conqete structEes WoII designed and detailed conqete shucbrre will show less deredoration in comparison with poorly

ir tle similar condition The beam-columnjoints are pa*icutarty pione to defective conc.etg if detailing and placing of reinforrement is trot done plop€rly. Inodcquate concrolo gover rnty llitd to carbonadon depth realhitrg up to tie reinforcemer4 thus, increasing the risk o[corrosion ofthe reinforcemert. designed and detailed concretd,

i) EtrviroDmetrtal effects Mic.o-cracks present in the concrete ate lhe sourEes ofingress ofmoistures atmos?heric cartoa di-oxide into the conc.ete which attaok roinforc€ment alld with vadous itgedients of @icrete- In aggtessive e[vironme4nt coDcrete strucfurc will be severcly reduc€s.

ii)Poor quality materiat used Quality ofmaterials, to be used in conshuctiotr, should be etsured by means various tests in the IS codes- Alkali-agg.egare reaclion and sulphat atrack results in ea.ly &terioration, Clayoy matgrials ir the fide aggrsgates weaketr &e morta. agg.egate bond aid rcduce the sheng&. Salinity causes conosion of reinforcing bars as well as dek.ioratio[ of @nqEte. as specified

IvlQuality of supereisioD Construction

wo*

should be caded out as pe. the laid doim spelifrcation. AdherencE to E€cified waterc€ircnt mtio cofirols suength, pem€ability durability of co,!c.€le. Insuffcie

vfumtion may result in porous and honey combined concrcte, whercas excess vibr"ation rray eause s€gegation. Y)

Deterioration due to corrosiot

. . . . . .

Spelling ofconcrete cover

Crack parallel to the rginforcendsnt Spelling at edges Swellitrg ofcotrcrete Dislocatioo Intemal cracking atrd rcduction in al€a ofsteol reinforcement,

3. Describ'e iD detail about the

pieieutiiru aspect of mrirrenarce.(Iyoy/Dec 2013)

Of the two consideBtions - prevention & repair, prevention is more jmporiant.

Dufing construction lhe defeds that may seem minot will have serious consequences. The design engineer is responsible for the selection ofproper materials suitable for the exposure conditions of site, detailing of the structure in a manner to prevent serious deterioration at least for the assumed sorvica life and thmugh the inspeotion ttoffmust consist on propcr constflction, These 3 points - proper matedals, proper detail& and proper conskuctidnl:lrquire knowledge of what is imFoper at a site or construction; about the various ways of deterioraiion and about their causes. But these are some geneml considerations that should be lakel into account for both the construction ofner{ concrete structures and the repat ofdetedomt€d structues. They are as follows

i) Match the materials to the environment: Durability becames an issue when a material's resistance to deteriorarion is less than rhat rcquired to withstand the aggressiveness of the environment in which it is to fimction. For e.g,:Steel will not conode in a dry.and salt free enyironment, but it will do so in the ptesence of moisture and chloridc ions.

To ensure the choice of an apprcpriate material, the environmental conditions to which lhe, material will be exposed must be known so that its behayior under these conditions can be predicted and addressed in the design. When a designer contemplates using a new material, problerns may arise if there has not been sullicient experience with the material to adequately unde.statrd it's behavior or to allow fol the development of standards.

In the abs€nc€ of standards, seyeral factors should be critically evaluate4 among them lhe relevance of the tsst data provided ia product literatuie, and the limitations & requirem€nts associated with the envirofinental conditions ofthe pmject. The followilg factors should be considered by the designer

.t

the coustructioD site.

Minimum and maximum temperatues Tempemtue cycles Exposuie to ulha yiolet mdiation

Amount of moistue wet/dry cycles presence of aggressiv€ chemicals

ii)

Combine only material$ with similar properaies: Concrete is a solidifigd

mixtue ofdiyeBe materials. When these materials are incompatible with one another, the concrete cmcks & spallq rcsulting in unsightly surfaces and the need of oxpensivo rehabilitalion work. Materials are considered to be incompatible when the differences their physical or chemical properties exact a state ofinstability.

ir

For e.g.i Galvanic conosion is promoted when 2 metals with d'iferent electrochemical

propehies arotordbined in

'

; buildin!

.isseinbly.

The use oi riaterials with differeirt fhermal coefficients or differenr module of elasicity should also be avoHea. Since they exf,and and cont act at different rates, and their defomation chara$rrizes are significarily rliiferent. In both insrances, the incompatibility of the selected materials will ledd to deterioralion of the concrete, When the load pelpendicular ro the bond litrq the diffcrcncc in itodulus does not cause. problems, however, when it is pamllel to the bond lioe, deformation of the mate al with the lower modulus transfers load to the material with the higher modulus, which may then Factule.

iii)

Assess thc

lirnitatious ola paraicllrr mrtGrlal

h

lts Rhetionsl contc,rt

The s€lection of materials, particulady those used in repairs, must based on knowledge of their functions & of the environment in which the materials have to fimction. Their physical & chemical properties as well as their limilations with respect to installation & performance must also b€ considered. In padicula., the designer should anticipale rhe degree ofabrasion ot w€at to which a surface will be subjected. For €g:. parking ga.ages should be desigted to rcsist more abrasion by using special cast concre& and on applied polym€ric coating impregnated with an abrasion rcsistant malerial such as corundum.

In choosing a material the designer should b€ awaro not only ofthe properties that seerE to addr€ss the intended fimction but also the auxiliary Foperties thar did not constitute the basis for selectiug the material, For eg: - Air ent ainment is used !o provide durability with rcspect to fteeze & llraw cycles but it also enhances workability.

iv)

Protect materials from seneral deterioration:

Most concrete detorial-atiod can be attributed to u/ater p€netration. Source concrete abso s moistue until it become, saturate4 p.evenl entry water fiom collecting on surfac.es is of prime importarce. Moistue foslers doteriomiioll Dot only become it cardes dissolved chemicals that can

with steel time, and other components in the concrete, it also plays a major role in concrete detedomtion th.ough f.ecze) thaw cycles. By providiDg sufficient slopes and effective drai.ages, it is possible to prevent water fiom pordiiag & tius b€ing absorbed. Coocrete design stould accentuatg water shedding oharacteristics for vertjcal elements. For egi prop€r whdow shade prevent the wall frcm wettiog. Sealing the surface with a penekating concrotE s€aling & lhe use of react

50 mm thick reinforcemonl corer lo protect sleel are other means

v)

D$iqn

ofprotection.

'

level tr'actors:

Concrete structues arc an assembly of operating syst€ms that experisnce temperature, air l,ressule aod vapour plqssuie, gradientr Seasonal and diumal fluctuations o, outdoor condiliols

Eovide va.iability and direction of the gradients. These operating cooditiorc can acc€lerate prematurc failure of the coDponcnts in a repair. The relative severity of drcse factors will vary depending otr the use and location ofthe stmctu!€; and the types ofrepair matodal used and so on.

Predictiflg these fluctuarions and accomtnodating them al a design $age is imporlant.

Allow for change in use in design:

Duing the service life of a structure, its environment and occupancy may change. As a will have to withstand stresses di{rerent fom those fo. which it was originally

result, the stucture intedded.

For e.g.:- Addition of roof gardcn to parking lot rcquires additional probction

against

ponding ofwatcr on dre roofofparking lot.

4. Describe itr detail about the

repair aspect of maintenatrce. (Apr/M.y 2010)

Eyen though designers allow a large margin of safety in their desigts, once deterioration reaches a critical limit, immediate repair is needed to restore the level ofperfomalce to its intended Ieyel of seryice. In fact ifthe rehabilitation work is not carried out in timq the shucturc may not b€ repairablc to the required level of service. The execution of such a repair is an exacting technical matter involving 5 basic steps.

1,

finding the deteriotation

2. determining the cause 3. evaluating tbe strength ofexisting buildiog or structue 4. evaluating the treed ofrepair 5. Selecting & implementing a repair procedure.

i)

Findins the deterioration

Before the repai. can be effected, there must be a .ealizatioo that something is wrong and the realizatioo must come before it is too late to; make a repair, ie before the structure has collapsed For eg:- timbers and timber piling can be damaged by insects or marine organisms, virtually to the point ofcollapse, without exhibiting any extemal evidence which would be apparcnt except to a hained obseryod' Eyen a common defect like corosion of steel cao be diffi.ult to dctect because

occus,

p ocipally, in the most

inaccessible parts of the stucture. The reason acoessible parts arc painfe4 but the inaccessible parts ofien are neglected.

if

is simple. The

Thc point to be made is that is that rhe engiDeer charged or interested in maintenanco ll]ust be traine4 terhnically, in where to loolg how to look & what to look for, before he can evea be expected & realize that there is houble knowing all these iequircs a knowledge ofyarious kitrds & causes ofdeterioration

.

il)

&

before checking the engineer must know all these.

Delermine the Cruse

To select the repair step, the cause has to be identified. In case ofconcrete the specific cause might not be known due to seveml agenls acting. What can be done is to eliminate possibilities and design repair procrdures for any ofthe remaining few. In such cases the cost

.

Will go higler. But it should;tso be noted'that tho failuie to undersand the cause ofa defect &o le€d to the selectiotr ofa repair prccedure which woutd be harmfirl, mttrer than helpfirl. There ae ro s€{ rules for determining the car$e but with expe ence you caa detemine. For e.g.i (racks in sralls due the foundatior settlements run diagonally

(Crack due to corosion of reinforEcorent run sbaight

&

parallel at urifonn interyels

&

show

evidflc€s of rusL staining

. . . . .

A

few tips are as follows

Inspcct & obscrvc ihe structwe Observe in bad & good weather Compare with othe. constructioDs on the arca or elsowhere & be patient Study the problern

& allow

iii) Evaloate the streneih of

the

enough time to do

thejob

Existirs structure

This should be dons to know whether it is safe to continu€ using lhe st uctur€ or Iimit it to a lcss seyere oxtend of usage if tlle shrrcture has rct completely deteriorated the adeqoacy of &€imination ofstrength becomes important for dlar the following methods can be used

a)

trfued percentrge mcthod

It

is to assume that all memben which have lost less than some predetr.mircd yo of their shength arc still adequate aod lhat all memb€Is which have lost more lhan fhe strength are inadequate. It is usually from 15% onwads higher velucs are applicable fo.

piliry % stifiress

bearing plates etc

b) Analysis of the Actual

strcss conditioD:

This method is to make detailed sk€ss analysis of the shucture, as it stands includiag allowances for loss of seciion where it has occuned. This is more difficult & €,eeosive, Here also thc first stop is to make preliminary a{alysis by fixed percentage metM aod it appears tbat major rcpails will be rcquire4 the shength is rcevaluated bascd on detailed s1rcss analysis, considering all conkibuliotrs to such strcngth

if

c) Lo.d test Third step is load test. Irad tests may be rcquired by the Iocal building ofleted, but they should onty be perfonned where computation i[dicaled that there is reasonable margin of safety agai{st collapse, Iest the trest bdng the structue sorvo. Irad te$ show stretrgths much greater than oomputed shengths when performed on actual stsuctu.es, When perfouned on actual structues. In repair work cvery linle bil of sferyth is inportant. Acco.dingly the use of l@d test is recommelded but with a firll & clrxr understanding of their limiktiors and raoge of applicability.

Whe4 the cause of the deterio.ation has been detcrmined and the strengfh of ttre existing structue bos been checke4 a decision must be made whether a.

to permit deie oration to continue

b.

to make measures to prcserve

theshucture

in its

present conditioo

Without strergtheniDg

c,

to strengrhen the construction

d. .

ifdeterioration is exc€ptionally sever, toreconstruct or possibly abandon

decisions are based on

a) safety b) economy & c) a.ppearance subject to various

it.

These

principles differefi decision may b€ app.opdate for

diferent elements of same struchtre

> > > > >

ifthe appeaance ofthe existing condition isobjectionable - rcpair rcw ifappeamoce is not a problem tben Pur the condition under observation to check

ifit

is dormanlor progessive.

ifdormant - no repair

if

progressive - check the feasibility & relative economics deterioration to contitrue and performing a repair at some later date & repair right away

of

permitting

"f;"kL;,h,

Either .epair it or Rebuild il or Abandon it, paniy or completely or consider a change ofuse iv)Select

& ipplement a Repair procedurei Select the least expensive that can suit

Consider total

tbejob

Steps

ofRepair

coit

Do repairjob in fime

Ifdefecs are few &

isolated repair on 6rl individual basis. Otherwise do in

.

.

geneialized

manner

1_..

,.

t,

Ensurc lhe ref,oir prevcnts ftmher dcvelopmenl ofdefech

'

>

If-appearance is a iroblern, tlre numbe. of applicable types ofrepair$ t€eome . limited & the rcpai^ mug be covered > Repair wo.ks should not inte.face wilh facilities ofthe structure > Take care in addilioo ofseotion to a memb€r ard in resftibuting live 1006 otrd other live load momoDts- Aftcr sclccrilg a ;;pairs, aad !fttr amsidering "ri,"il ;;;

all

ramiffortions of ih apprlicotioq specification and proceed with the wort.

i

re

Errhin b detail abotrt ahe permeabiliay ofconcrete.

>

Nov/Dec

Sitrc€ concrete is a permeable aod porous natutg lhe inside the concrete and is called ,,1

aoncrete is determined

> flrs

o, t*

##ffil'o

*c

tast

*ef

is

Lu

plrprur pms C

20ll

liquid and

can

gases moye ie' Tb€ liquids and gases that caD movo in the

ttrc is muclr atrected by the nahEe of the porcus, both their sbe @d ry.rm_eablity € rent ill which they aie inter_contrected-

he

Ctorrctoristic study of pcrme.bility:

>

Ille tadeled

cement paste coNists of gel porgus to the exted of about 2g9l. buf 0re gel porcus a.c so small lhat waae. caD pass_through under normal coaditions. ft€ pere€ability of gel is Ul00 of that of pa$6. TheE

ad thd ofcapillary

fore rh" g"r p_* cavities depeads on the narion.

a.r;i*rJi",L

o"

*r""unr,,

Caiccs!

>

The higher permeabitity ofcorcert fstructure is due to,

> Iotmatioo ofmioro-oracks due to long telm drying shdlkage. > Ruptr.e ofinternal facq bond between agg and past. > DtG 10 yolumc chatrge caused i,l the coocl€te oa accoutrt

ofvarious mirot

lpasorE-

>

.

C..trd

> >

E)dsterce ofertrapped air due to i,rsufroierrt compaction.

qf pcnp.a bility: The use of azoladc maferials in optimurD proportions skill reduce pemeability. Tbii h drc to thc. cooversioo ofeql, hldroxide, otherwise solublc and leachable into cemeuatios Tbougb aL entrainmetrt makcs th c@c mo.e impervious

*t ry,"'ffirffl

klben rued up to abut 8%

wiict m*es

r

.Elfechl of pe.meability on coricrete mqierial rcipforcement sleel:

> >

The permeability of moisfirc or gas is impodant embedded relief or sleel.

i,

relatior wi6 th€ protection atrorded to

The rcaction of watEr with the steel bars so that lhe ba.s sray be co[oded (and rusting steel occuls),

of

Elfecb of petureability on cotrcrete:

> > >

Penneability characteristios ofconoEte is ofgrcater bearing on its durability. The penetration ofaggEssive liquid or gas in concrete depend upon the extent oflhe degr€9 of pelmeability of coocr€te.

The permeability chamct€ristics of concrete (hadened) consists of gel pouts and capillary caviti€s- The gels arc pours to tbe exteoa of about 28olo but tbe gel porous arc so small that hadly any water can pass though under larrow conditions. The permgability ofgel is Ul00 of thal of paste. Therefoq the gel porous don,t cont ibute to the pormeability of corcrete where a the capillary cavities depends on the w/o ratio. This is one of the maio fictors coDtributitrg ol iniluetrcing permeability of clncrete.

6. Explain in detail the

different methods ofrepair.

The vadous methods aie available for carrying out the sfuctural repain to a distressed stnicture. The basic methods, which coird be used singly or in

csnbination more than one me briefly described iii the following subsecfion. For detailed speci6cation and step wise sequence ofoperation. Repairs using mortars:

) )

Mortar repairs are the most common form of repairs being resorted into the field without knowing the limitations such repair in skuctural rehabi I itati on/stren gthening. A variety ofmortars are available for carrying out repairs ofstructures, these are explained with their limitation and areas of Erplication in the following subsection.

Portland cement mortars:

! ! ) ! !

if

Structural repa s with Portland cement mortars shall be made only specifically approved by the engineer-in-charge. Approvat for hand applied,cement mortar repairs will be given only for very small repair areas, not assqciated with critical performance oftie sEucture. When approved, Portland iement mortar may be used for repairing defects on exposed, new concrete surfaces only. Such repairs are applied only if the defects are small and are too wide for dry pack and too shallow for concrete replacement and only if the repairs can be completed within 24hours of removing the forms. Portland cement mortar shall not be used for repairs to old or existing concrete or for repairs that extent to or below the first layer ofreiltrorcing steel-

! F

)

Portland cement mortar shall consist ofordinary portland cement gBde 43, clean water and clean graded sand. The proportion ofPortland cement and sand shall preferably be intd the same proportion as used in the preparation ofparent concrete, All materials ofmortar mixture and their application techniques shall be in accordance with relevant specifi cations.

tg,

?. Explain in detail the diffeient materiats used in Rehabilitation and retrofitting methods:

) ! F

) !

Polymer modified cement mortars are used for repairs on old hardened concrete for repairing defects on exposed concreie surface dnly. For large repairs area with thickness in excess of 50mm, concrete, as repair material, is a better option. For thicker applications, over larger areas, it is desirable to use appropriate reinforcing mesh fxed with U-nails. These shall use polymers hdrnixed in specified proportions, based on selection criterion. Other materials shall be same as in Portland cement mortars stated above. Howevel these shall follow the given relevant specifications, ifspecified.

Epory mortars:

F

! ) !

These mortars consist ofresin, hardener and silica sand and axe applied over an epoxy bonding coat over old hardened concrete surface. These mortars attain strength in few hours, these modars have very high strength and are abrasion resistant, water resistant and can be used in few

millimeters thickness overlays. these are used for repairs at location$ where it is dimcult to use epoxy bonded concrete, depth ofrepair is less than 40mm or repair areas are small(less than 0. I sq.m) and few in numbers. When depth of repair exceeds 15mm but it is less than 40mm, the buildup of patch repair over large areas shall be in layers using appropriate reinforcing mesh fixed with U-nails or shear keys

Dry pack and epoxy bonded dry pack:

! )

Dry pack repair technique is application ofdry cement sand mix. It consists of cement and clean sand (in proportion I :2.5) with just enough water to be able to form a ball by hand. It is immediately packed into place before the bond coat as dried or cured, with suitably shaped hardwood dowel and hammer in 8 to l0nim thick layers.

B. XXPT.ATN

ABOUT RX}IABITATION AND RT,TROFTITING METUODS,

Tbt.decision lo or replace a shuctue or its componelt ca b€ takeo @ry & -repair eo'uiderarion of likely service rife of rhe strucbre is astabrishrd bas€d otr &e t rrmicrl &

mrnical

evaluatioo. Once a decisioD. bosed on pretiminary invesigatioos! is ta&ea b carry ilrc rryirs, proper diagnosis, idenritrcation & extenr of distress in ;uctnral mertb€rg h O 3'ti bc correctly assessed. A detailul methodology should be developd whicn snDr d bcludc

rydlable

l. Z

Methods of .epair & Repair materials repaE ltraregy can be adopte4 kerping the objective in view. This drall bc baserl m 1 Emhratioq atrd available altematiye mdbods ofrepair A rnaterial. priority should be assig"d to Repair of stru€tEral defecfs to eDsure safety ofthe structure and 2. Protectiotr ofthe structure from ffrrther deterioration. Tte selected method ofrepair should achieve oae or more of the following objeetives Reiostate the stnrctural integrity of the llt€mber by rc.storing or incrwing its seqtt & stiftre.ss. hevent the ingress of distress lromotitrg agents such as moishrrc, chtryides ad qtoa dioide to improve dwability. Maintaining the aesheticJappeaace ofconcrete surface. Rqlair Opaioos: Daeding upo-n lhe specific condition of deteriomted shoctures, the opfun of fnc r4eir Ek hods could be otre or more ofthe following: Grouting & crack repair Patch repair Reptacement ofstructually !,!Eak corfiete Replac€med of $palled, and/o dehiruted corcrete Replac€med ofcarbomfed corcrtte srmuoding $eel reioforcemeat Cleaning and passivating the corroded steel reinforcoent Concrete overlays with nomEl, Iow or highly fluid concrete, laten modified cocre& & corrosion protectiotr such as jacheting Cenhal Design OrganizatioD

Try

l.

o

.

.

o . . . . o o .

lHormance Requiremetrts of Repair S)rsteDs:

. . . . r o

Strength, Serviceability aod DEabihty Protection of steel Botrd with parcnf sur&ce

Dinensiooalstability Resistancc to enviromedalh' fuduced dmge Ece of application appoanuce illortaIrce f.ctors to be considered for stlection of repiir mc&od5: . Type and exteot ofdistrcss .

. . .

Locatioo of dishess Eovironmentalexposrre Ayailability ofskil

tl

. . .

Availability oftims and occess for rcpairs

Appearance Cost Repair Stagc: Concrete removal and surface Fixing suitablc formwork Bonding/Passivating coat and rcpair application

. . o

preparation

a

Concrete remoyal and surfrce preparation: Prior to prcparation of coucrete surfaces, exposed reinforcement should be iospected for access clearance, qoss-s@tional area and location. Refuforcing bars must bc ftrthei exposed if the remaining concrete is de-bonded from the rcinforcing steel. Removal must be continued to completely expose the bar if more than half of a reinforcing bar perimeter has been exposed. For completely exposed rcinforcing bars, a miaimum averuge clea.ao"e of 25mm oi nominal maximum size of aggregate plus 5mm, whichever is geater, must be provided between tbe reinforcing bar and surmunding concrete. A struct'rar engineer should be consulted if the crosssectional axea of an individual bar has been reduced by tS-percent or more or if two adjacetrt ba," have been reduced by lO percent or more. Out-of-plani aud loose reinforcement should be secucd in its design locotion. Ifthe damage is due to corrosion, a suitable coating may be considered after rcmoyal oftotal rust Fop ils suface t9 protect the exposed reinlorcing ste;I. Final inspection of rhe preparcd arca including remedying any deficieocies should be iompteted just prior to batching -tne repalr material.

Form work: If repais are required on vertical or oyerhead surfaces and if the repair materiat is likely to mg formwork will be required. Prior to installing forms, the cotrcrete surface must be inspecled fi any surface contours that could result in air being happed dudng conoete placement or pumping. If afu is slightly to get happe4 concrete mirst be^removed t chringe the contour, or velt tubes must be installed. Formwork should be secured to the concreti with expansion anchors of standatd makes, etc. Installed fiom anchors should be pretested for slippage. Perfomred foam gaskets or casl-in-place foam may be required to provide a watertighi seal betw€€n tbe cooqete and form surfaces.

Applying bonding coat and repair application: These shall be qut as per the .epair methodysystem selected based on engineering ' -carried judgment considering various options available as under: . Filling ofcracks with cement and/ or resign based grout . lnjecting $out into a mass ofdry aggegate . Poured corcrete

. . . . . .

Pre-packed concrete Dry packing Sprayed concrete (shotqete) Repair and strengthening methodV system be in three $oups Materials Methods &system

gr : 9.Diecuss verious types of

repoir strotegies ofRCC boiktiry. fNoy/dcc

20lll

Cracks including micro cracks down !o a width of 5 microns. Upon curing, the repir resin bonds the tactur;d and fissured matrix in to a monolithic structural member ofexceedingly high shength. Padial vacuum

qeation

aud introduction

o0ftE,air resin are achived by mafutaining vacuom with the poting devices in the ftachrre or surfoce being repaired connected lo the , vacuuE Source. The partial vacuum pressure are, thus apnlied hy the enclosed sys&rn . lhe Epair resins are inhoduced , while maaintaining the negative pressures, to 6ll the major crack& intercormected cmcks & voids and micro cracks. The concrete matrix, including the voids with io the fracture, is impegnated with the repair resin materials. the method ian alsro be nade icaqble to stone fi masoDruy shuctures.

q

The adEotage lies in Eoisture evacwation alotrg with any deletedou$ gas6s and or ma&dals ftom the concrcte matrk ofthe wall iacttrre u/all surfacos. ih" diTing proc.€ss caD be moniiored by usi[g itr-line hydrcdeters installed in "oo"ra" the special vacuum tuling Therracuum proccss offels the following advaltagqs over gessure injuction methods. Repain can be copmpleted in a relatively shorter pedod oiti-e rr,ith oo suoihc€ to the quatity oithe repair. The repairs should be cost etrective. Efficietrt and complete filling ofexistini ftaetnes, idotcoD[ected ftactues and voids artd tbe complete filling of micro frac;cs.Total absence of If,EssuE pockets enswos and faciliaes deeper i'11 oofre[frir rcsin. Evacuation ofmoistue Aom lb€ iderior conqete m;trix ofthe frachrre.No possible eitenuation ofthe darnage due to absenca ofapplied Fessues.Ability to intoduce a ultra-low viscosity materials into the facture areas. Improved bonding due to lack of afu bubbles mrmatly assosiated wirh lov, viscosity, tow specifc Sravity rcpair rcsins.Continued conosion ofreinforcement would be significantly tliminished because ofthe evacuations of, and sealing out of moishrrc fiom the tre;ted cohcrete mallic Using methyl methacrytaae (MMA) Io thJ vacuum system, the requircmeots is of imprcgnaling concrete with a mahyl methacrylate {MMA) based monomer catalyst system foliowedly insitu polyrnerization ofthe monomet by heat. MMA is tow viscosity high strength material zuitable for vacuum injection processes Its yiscosity is 5-l5cps with sup€rior physical Foperties, flexibility and srrp€dor bo{ding ard wEtting properties.

.

Using erpanding vinyl esaer get : These are low viscosity gelg which are water soluble acrylic oonomers. Tlre gel is used , 6r injectioo ald sealiag ofjoints aDd cracks agaius water leaks. Due to its ultra low viscosity, it has a very low Ilow resista.oce and is able !o permeale iq to the smallest hair liDe cracks aod cqillaries. Thus, it s€ats them reliably and permanently. When it contact vrilh waler, it sv,ells to dotrb.le its_ volumc while retainiog its shape. This process is purely physical and reversible. As a rE$lt of thil uDique property, the material will retain its selfhealing property even when in a dry codition. Thr,se process€s involve udque materials ald hence nEis speciiis advice anrt close qervisioo in their field applications.

Rchabilitation anrl rctroliathg methods: ' Thin polymer overlays:. ' do" are *i to improve the abrasion rcsi$ance and creating water prooling bariers on It is th" t"rf;;; ;d ;J ; a protittive couting. Th"se are applied in tess than I o.mm thickness' q"iJ ruitutf" fo, i-p-iring surface characteristics aad also it aot as protective coating' It gen'erally comprises of . . ODe coat ofptim€r . One or more co&ts of seolart. .f"ff consist of vinyl ester resh, initiator and-promoter' Each coat of sealant m" pti-* titanium of same material as it tire primer but with the addition ofsilica filter' shalfconsist"""i dioxide

pipeot

and carbon black pigment.

Thin epory -'ff,Jr"overlay:

--

to improve the abmsion resistance and creating water ptoofing/protective. and orotavi are apptJ in z-3mm thickness' It generally comprises ofresin Tt it "porv g# it ,n*iiru"t". trt* polvmer overlavs' There are several tlpes of "outinn. Th;;ilg,h suit different performance requrements' Epory ovedays requirc ""AfZUfJt" "p."y-.t*f"v piotectir" coatir,g in e*posed locations subjected to ultra violet exposure'

*"G"a

ilff;..

Resin/polymer moditied cemeut sturry injectiotr: different th" ;"., pret atent te"hniqua used for repairing cracks is by^ injection -of material for injection typu. of-*.toiat J"p"riang upon the na'ture of the defect' The selection of the fimctions that i!ir;r.tii"lo"grt *:d"*"tioing ofthe poperty ofthat repat material andqacking is properly iiis imperative that the-cause of p".rorm. lo-all ;;h "ases, "-;;;r otnerwise, the selection ofmatedal could b€ totatly faulty' aeterminea,

---'d;f

ffii"

r{i.

rloLATJ Tm n/potlt llgcn or

ranrrrruxcr

(ApwMAy 2010)

MAINTNANCEIAIECOBK Basics ofmaintenance on conqete structue is that lhe stluctule is adequately mfitained perfomanc.e_is^^always above tho reqoir"a f"r"r aGnj it" ,"rrii"iiiE. uorrurr", rdrce concreE xi used m ddtarent stmcture such as building dang bridgg etc. lvhich perform

$ch tlat its

erder difercnt cnvirounental c.ondilions, it is not possiblet hy down-idiatical performance ..it€rion for all struchfes. fierelore, in the maintenance part of tt tSCe th" Dairtcnanc€ action is classified into four diferent categorios specified " as fofl;wsi "poin"diorL Category A: Prevention maiotenanoe - tho maintenance to preve the appearanc! ofvisible dolerioratiolt on the structure during tbe service life. Category B: Corrective maihtenarce - the maitrlenance in which, appropriate cour[er measures should be taken afte. degradation aipea.ance ofthe structureshas;ppeared. Caregory C: Observational maintorance - tht maintcnance oarricd out primilily on the basis of visual iospection without any direct measEes and permits certain deterioration of the rtucfures. Citegory r): Non-inspection riaintenance - the maintenance applied to the sEuctures in which the direct ir$?eotion is diffcult or practically impossibfeil Ue car.ieA out. su"a erground shucfures. Cdtical structures such as dams and nuolear power plants haying a long service life or dructu es situated itr ha$h environment may be classified into tie high; maintenanc€ calegory. Similarly, criteria for classirying structues into other maintenanci cateeories need t de developed. It should b€ pointed out that certaiD structurcs in wbich anv -maiatenaace rtion is very diflicult to carried out may be categorized separately. .

E

*

MANruNANCT.EIBAIEGL For fulfilling the rational and reliable mainlenanc€ activities in order to keep the Frfomance ofshucture alwa)as above its rcquircd level, it is necessarv to eyaluate the time_ dqerdent degradatioh process ofthe performance ofshucture during ihe life, with adequate ,.liability .However, since the performaoce degradation oannot be ilways Gctly trrlalied lbsed oo the curent mginecring level. It should be vo.ified hdirectly considedng a flrture dlterioration condition expected by using the dete.ioralion evaluate m6del. Hirq it h Eedless to say that the periodio inspectio, results are indispensable for evaluating the Fformance of strucnrre. The oveEll process mentioftd above are surely canied out on the tasis of the" maiotenaDce stratggy". Namely, the maintena-oce Srateglr comprehensively aDcompass " inspection "," estimation of dete oiation level and mLs", "evaluation of I.rformance ofst uctue ",,'rcmedial actions n arld 'recording". Of coursq'the combination efthes€ steps dilfers to the different maintenaacs category, cinsidering the ofthe structnilq L?ads to the third parti€s, and environmenlal conditioDs.

.l

tss4cIIQN stn:ctures should be be taken' d"t"l;;-th.;rgh i*p"ction. obviouslriiuniesirabte signs of deterioration .oai1 so seleoted carefully i.spection items;orded an. tools uied should be pafi of JSCE th" d;sit"d in information car be obtain accurately ,In the maintenance of inspection method ux-d and &'eqLroroy aDd timing -..in.ation -on the basis of the catelories insPection" as "initial ins?ection" "Monitoring"' "'routine inspeaio-n" ."extraordinary inspection"' and

Occuredce of detedoration and

/ or change in its performance of

I*"ii"*ti.,It". ;;i

','ffi#;Tu;ifi;"i;;

tt-

:";;i;;;;;";'"detaited

Theinitialinspectioniscarriedoutbefo'ethestrucfureisputintotheoperatiooafter

objecrive of initial *.of",i"i' .t l6r"*ction or of '"pui'l itt*gtn"ningio work.The record any deviations from the

in.ha,ri^n

i.

tie *ort tr ti" i,itiJ

escential is to comDile

re-cords,

$ruotuto , .dd to pr.parcd documont rehich "t"tt action' Therofore in certain oase in the absenc€ *t" firtur€ maintenancr u" *u""i"a datq any inspcction may deem to be the initial inspeotior'

Hffiiil;i.;il,to-uritr' tli" "ri-?*" Ilpt"rJ..fv

f-

to be caried out to while the structure is in service, routine and regular inspections need is carried out inspection a"t"r*i* *i"iiit J"ailed insp€ctlon is required oi not' ThL routine intervals. such as daily' certain ;;;;;ti"; basis without.ating -y si""in" efforgo,tatusing appropriate tools at regular rtii. n;g.,lar inspeciio;'; be carrie.d ill rirv i, to be used and the inte.,als. such as once in a v"* "*i"t-tooti .n JJ u" decided on the basis of such factors as likelv ;;;;ilof deterioratio!, envkolrnental conditions, importarce of the structuro

i.i -dffiii il;#;""r",i.

*;;;;it;;

classification of the maintenance aotion'

l'"

'------' 1. I

!

t , !

I

t6.\ tb1

44"4^ r?".

a-ll

4-

.,1 -r^ ha a, t

flai.c

9w.8rr-

*44

jbaaelo-.a.udo

-nun ,*^ouX. tgoA os.Lt. pl-.t

dt r"r^N;rt^t

X 7te/'J4F+\t

r*'_*:# .o-!-\n'

€f",,^-eX.s "*.L "tatwon *^A 7u ctt *s db-tpta ,rarur^Ss
darh;rr"a

I

,""*,u

,),,!t . b

cu> ],oc'AA a-ve

-i*e

p^.L,|r,r.",

vt;\ - D,-l-^-&",

fl.EJ-

l'*;L,h-"'t X E+,-*rl oS

vetn-ett'>

t

{p P'l* L'}"" H'iEd t3).'

jR.a;aoJ+"- r1?irJ

-TL i

&'

{o" l'^'l"n''

.,'.*. -re{) *"'1"') a"'i)o

,...

ana ..^,a.^uri(q VLv ,rd *+^l; "-. 1ln^ - lL! 'Ylv^t

ao\;,ft

'j,-f


rl @hr

I

Gv)

wr d-L{

&^z n?,tz -..oyd tuVX '$*-* o'ar2'-'

l"s &"- ,1t- 2-{', ;-y"t *A .* <)

Gncr*r,

YoiA

^-^-"4

yr".n Jo o.A "of l

J./.e:b-Vt.

lL ,o,3"-* )o o.&

,L", t*.,!a P,or-A^,.

a" tt{-

.t -.ll -a 8o. ,

,'-,,.l*i-L r-

cl.^,,.)

(Laerz-.le 2

rao;"- IL,,* 1 u",'b i

-

c^-)

-

'tr,l'^

.1.,,oo1f,,ou.A -

o

sl,--.-1t+

IJ re^"LV

lL-

fl--1

u?Lbt

-

o-ts

>

+

1*L" 1L;'2 ASTrl ;D

JS.

ts,- r t-\a i-. ;- Jei'.-";
*

.r T1 '.r.f-un,

s{ I

-Ll-y P".*.-

I

Ku""a 4,-*-,.

]t

.:

Y.-A"l,f t1 cYi..= .,^) oJ. 4 G-"e,.|. ,

i.^)

b)

)

dBda."

/^jL

.

*ta< .

o G,Lr.(ele,-lir Cl'lo-"+..;4;ro ol) aq,.o <1"+.: a1 *,,*?" \.,. e) G.,.L.-^Ir* P..) ; e--".r" 4) Ho,z*..ru

G.rlz^l

-

r-- r-L"- A T{
l--

..lJlV-L\r.*, ?'-'x^l /g d;ch'** c'an L /Yha ?,,

tt,4v"-3+L

4n ,ob..

c\c.uta%

n!as-.z

I ro.. .^ ;

1-' l- '^1.r, Le I +,e, : 1E

. 'e-.a, -,'^:

r.,r-o

. :,-

L-frL--k-.E"- -* b. +?l ^z*t-.,n-'*. 9,1: l,:

'

/

li* r-------zn-tzl

-..-7v_-

-/,//

,/,//

' tt;l %Hul l:-*t ,/,// b/i ,///

l$'-1,//,/l i |

xV/-fr n,*, *"... .*.t(

lo Jr ao .r

6s,

f/.a

-*t

*//,/

xV/ 4'e,

i -tL --#-\ cl^,a-;-, |L/^", (^o.rO I V tyb

,/ ,/,/

// ,/

a. A-." G-c'.t 61>.,,tr-.J ruar;.,*t.

li

lrr@ I 1."- lll!4

c 1,,*tI 4

l'l! i-,

.<

Ku*a *L-t--

X

1,,*

r! l,*/.2

.tt

,o ,, 4

I I

r.

c;-..<.-tz c,,-

roitt'

Lbs.-tr3 at;V.-?-d .74-.,dl Av*'.,..-. rciY'*"r"t' Cl t

-rL t* q "h."t Io ..n ^ *." tr*' v-"l"Ji I .8"-6ta-"t VL..k""-tL $,"+ *f+ q

V,la;t

f,*.2

iL.--dL

o-rt,^.;d -'''

I I I

i l

i

I,l {

,.9

,t

.l

L.r.,-.- ,u'a'\ G-,-r"r-.-.ltz

y.-a*) *d*,-^d"

aq/;f'Y *" -

a:a \ *

*;r*;'-ua g.-"^-* + "rl"*at'-* o7. h-"". ,, c.,.;a-,^LL T+ rry'^h

16- a"-tG- - 6-o'l' o't" q i;l ""''''' Jr. t -l i- tss ' +cr'oa t-;ia - R..o,,,n',l.Ali"- 4Q ?iY" Brs - 133'1 Po't ] ParFs, As-rrr c s'iz-rr, I

I

TL

t\_ YuG-

x

n ln

h'^

ffz

x1p.^

f io."-. ''*" 6'-'*+')

.'-,r"v o^-Q;.a -fu ':; zol-d r'*^ . .3L^. e+-^--"."-

^.

-ra*-'.-x'-'t

8"4*-

C<.rtu4:l

.{.*;v

---r

E-

.-

.

)

o.d

G,-6tua*t ^w, .:\-e.i4^-*A-"- -Jt-*

^*+l

&.-,.2"*-. ;bl.,z,,tc

;{

zt^t.

tat \vc

cnlqbt-a I

LJL.. L,

h -:( t-!)/ll)+t\ EA.

ct

- a{l):.

)

e["^hdh,

rl-

r-, I

r-

1->

1L Vct";\ u) c)e*"*"";--

U7 f'f"rl-

h'o

a-o Ul+n-4!:,nL f-t,'. i^

-{

G.tc1*e

-

'ol--a^_

;! zLar- .gtB-''-.."- c,.<7

;-

.t'.+t6 .l

@'

-tt^-

p+t-.

o .?--T AZ L* - l'-,,.-a.. -lI* c--i:"V' 41r,+' ;va:ic'h'o o,-L. J- e-oLol" .1+-.38

A-nto *v-.V t

r->*dL);-!)

'42^t|""'he l,.ui ' -tr.-

a.{,r+

t

I

-- tu--,1"2 ,. ;-y-A Lt l,- .a

.

\

..("-rr.a,--l vit..h*-.*

fP

1e! anz.

!

/_ oS, 1\src'de'

-,a

,

arco,,nt't-l

Co^cr-L. Akt'-l--*

A^dr'

.#a.-" 'q ^,*-l*, (2.*^r c*l^t , ..^*n .t*czqa.r*t q)o

.1:

t, ^" z,'t, -

E^.-a,r* +-* *

')i& 1 tL-

'tt-' 'ul 1 tr* 7'.^'"it *,z*iV a^A 41d., ' t: c;"* E-' tl"S""u' -It" f,L u^*U o qL'an't'4

?-dtr-,'t') -{ t- F't fu a' o.d t:bAf Cv) *, c;lc-laL/

.Ir, *y.^_*Z n;y;u

z)ccac-i y*V

I

ad'

"'l*'.Q

V -- L6'

1* ?*.nL',c'rt'

'|.*,o).u c",o d kD rlo 6t, hll.

i1

t ,-+l 4-

L Lr-

'-^6i 1

tr*

'a'( &^.-J

aryba^lt--

d' d*za,ar-.ri)LJa

O .t \l_ ca-cc,l" -r .)) 'nazo3o t1

a,-er-te

tu

-s-ttr-1"-tr-

qy"\ 4 -* .lL )o a-6ott'2.

4l faitL

val' '!^ r,o

1

.+

C-."e...-l-c

-

'cta;kc *o"d-l,'i

n 9*

c,

u=te_

U.l-,;L, >

;

-tg.-

h.

!,..t

4 Zi-.a *u !^Sit, Y* ,1,- *5 ^L.rI eL " 7axe.d

,Z dl,,* +l

'a"'--;8,.

'c;nA

cL

'3

/' 1 I#

*^,,."-'- ;*.

(*

-)L-d-

t6d,4l

are^\

'fr^2"

r-vtt d

\.A^.e6 2.1h \wo-',x.A .Q;

-

.

r ;-

.c."L-.:"

Lt-