LIST OF EQUIPM ENT / MACHINERIES ......................................................................................... ......................................................................................... 3
6.
PROCEDURES FOR F OR SITE SIT E COMPOUND SET UP ......................................................................... ........................................................................... 4 6.1
PRE-START IN!ESTIATION " SUR!EY SUR! EY ....................................................................... 4
6.4
LOCATION OF SITE .......................................................................................................... ............................................................................................................ 4
6.5
SCOPE OF #OR$ ........................................................................ .............................................................................................................. ...................................... 5
LIST OF EQUIPM ENT / MACHINERIES ......................................................................................... ......................................................................................... 3
6.
PROCEDURES FOR F OR SITE SIT E COMPOUND SET UP ......................................................................... ........................................................................... 4 6.1
PRE-START IN!ESTIATION " SUR!EY SUR! EY ....................................................................... 4
6.4
LOCATION OF SITE .......................................................................................................... ............................................................................................................ 4
6.5
SCOPE OF #OR$ ........................................................................ .............................................................................................................. ...................................... 5
FABRICATION OF SHEET PILES ON SITE SIT E ....................................................................13 .6.1 S(+ S( + P*/S )*N+*N, A2R*A+*)N A2R*A+*)N ............................................................... ............................................................... 1" .6. )RNR P*/ A2R*A+*)N ................................................................................ ................................................................................1% .6." + APRD P*/ A2R*A+*)N .............................................................................. 1%
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1. INTRODUCTION +he statement is s78mitted here for the 97r9ose of 8etter 7nderstanding to the client as to ho: the different elements of the 9ro;ect :ill 8e e gi!ing an idea of the methods> 9roced7res> safet= meas7res and 9r7dent techni?7es that :ill 8e ado9ted for s7ccessf7l com9letion of the :orks. Ser!ing as a :orking doc7ment> the method statement shall identif= the res9onsi8ilities of the contractor and its staff and also ens7re that ?7alit= of :orks meet the standard s9ecification. s9ecification. (S/ onstr7ctor Pte /td has 8een a:arded to :ork on the *m9ro!ement to 2edok anal ontract 1 for 79grading and :idening e contractor is re?7ired r e?7ired to constr7ct a tem9orar= flo: di!ersion to deal :ith intense storms from 79stream d7ring constr7ction. arth Retaining Steel Str7ct7res RSSB :ill 8e installed to form the flo: di!ersion canal in a99ro the e
3. PURPOSE +he 97r9ose of this method statement is to o7tline 9roced7res and methodolog= for installation of sheet 9iles 8= ado9ting silent 9iling methods.
4. REFERENCE DOCUMETNS A. 2. . D. . . ,. (.
Working Proced7res Proced7res of of Normal CPress *n Method Working Proced7res Proced7res of of Normal CWater etting etting Method Sheet Piling Plan Plan s78;ected s78;ected to re!ision re!ision in lengthB lengthB Silent Piler Machine Model )100 atalog7e Silent Piler Machine Model Model SA100 atalog7e Silent Piler Machine Model SA150 atalog7e /ifting Plan Mill ertificates ertificates & actor= actor= Prod7ction Prod7ction ertificates ertificates
5. LIST OF EQUIPMENT / MACHINERIES A. S7r!e=ing +otal Stations
Method Statement & Risk Assessment of Sheet Piling Works
All :orks :ill onl= 8e allo:ed to commence 79on a99ro!al of the 9ermit-to-:ork 8= (S/.
6.2 DAILY TOOL BOX MEETIN
Dail= tool8o< meeting shall 8e cond7cted 9rior dail= commencement of :ork> 8riefing and highlighting on all ;o8 sco9es and haEards in!ol!ed to all site 9ersonnel.
6.3 PRE-START IN!ESTIATION " SUR!EY
Prior to commencement of site :orks> an e :hich :ill 8e maintained as constr7ction record. 6.4 LOCATION OF SITE
+he 9ro;ect site is located at the eastern 9art of Singa9ore> ast oast Park:a= and the Sea.
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6.5 SCOPE OF #OR$
+he sco9e of :ork for constr7cting tem9orar= flo: di!ersion canal as 9lanned in stage 1 of flo: di!ersion scheme is s7mmariEed as follo:sF a. Setting o7t and location markings 8. *nstallation of sheet 9ilings and constr7ction of marine cofferdam cells c. om9letion sheet 9iling :orks and cofferdam cells
6.6 ORANISATION CHART
+he tentati!e :ork sched7le for :orks in this MS as f ollo:sF
HSL CONSTRUCTOR PTE LTD
CONSTRUCTION MANAER
+an Soo Peng AMF '%'1 0$&"B
+o o!ersee all :orks relating to the constr7ction site.
#SH COORDINATOR
M7hammad (airiEam AMF 6$11 &"60B +o monitor and ad!ise all (SR matters relating to the constr7ction site.
SUPER!ISOR
SUPER!ISOR
Sel!am Pra87 AMF 61$% &&0&B
/o: hie: Siang AMF '5$ &%%1B
+o s79er!ise all :orks in S*+ are in accordance to s9ecifications and to ens7re a safe> health= and en!ironment friendl= :ork area
+o s79er!ise all :orks in :orksho9 are in accordance to s9ecifications and to ens7re a safe> health= and en!ironment friendl= :ork area
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6.% SITE PROCEDURES " METHODOLOY
Prior to the 8eginning of :ork> contractor shall locate the 9osition of :ork 8= esta8lishing and marking the sheet 9ilings. +he sheet 9ilings> 9art of RSS str7ct7res shall 8e constr7cted in accordance :ith the details on the 9lans and all :ork shall 8e 9erformed in a :orkmanlike manner satisfactor= to Professional ngineer. ollo: 79 the com9letion of sheet 9iling insertions> gro7nd monitoring de!ices :ill 8e installed to monitor and control ma;or gro7nd mo!ement in the !icinit= of site. ,ro7nd monitoring de!ices shall 8e installed and cali8rated 9ro9erl= 8efore starting of e site clearance> ca8le detection and 7tilit= di!ersion# 9rotection to 8e carried o7t along sheet 9ile alignment according to all a!aila8le information. +rial trenches to 8e carried o7t 8= main contractor to confirm the location of the e metal hoarding and safet= nets shall 8e erected and installed aro7nd the !acant land :here it is t o 8e carried o7t 8= main contractor> if necessar=. c. ertificate All o9erators> :elders shall carr= rele!ant certificates#licenses d7ring the :ork. /ike:ise> all lifting o9eration related certifications shall 8e s78mitted 9rior to :ork commencement. d. Sign8oards All installation :orks :ill 8e carried o7t :ithin the hoarded :orking com9o7nd area> therefore sign 8oards for traffic control and 9edestrian are needed to install 8= main contractor> if necessar=. Working area shall 8e 8arricaded 8= main contractor if the o9eration is in t he 978lic area. or night o9eration> :arning lights shall 8e arranged 8= main contractor. e. Setting o7t Setting o7t of sheet 9ile to 8e cond7cted 8= main contractor s7r!e=or> to set o7t internal :all of the sheet 9iles and the 9osition of each 9ile and to esta8lish +2Ms on site for determining the c7t-off le!els of sheet 9iles.
6.& INSTALLATION METHOD OF SHEET PILIN
+his :orking acti!it= :ill 8e carried o7t 8= o7r a99ointed s78-contractor> Gian (ock. on!entionall=> sheet 9iles ha!e 8een !i8rated or 9o7nded into the gro7nd. (o:e!er> s7ch method ine!ita8l= generates e silent 9ilers :ill 8e introd7ced to 7tilise 9ress-in force the setting criteria of 9ile is set as ma :hiche!er come firstB and h=dra7licall= ;ack in 9iles into gro7nd. ,enerall=> normal CPress *n Method :ill 8e a99lied. Where!er there
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is enco7ntering of diffic7lt soil conditions> a7 :ater ;etting method can 8e 7tiliEed as means to significantl= im9ro!e 9rod7cti!it= and cost> as :ell as o9timiEing the sheet 9ile section re?7ired.
6.&.1 HOISTIN OF SHEET PILES
(oisting of Sheet 9iles for installation 8= ra:ler crane. a. /ifting crane shall 8e selected> 8ased on the :eight of the mem8ers to 8e lifted. ra:ler crane shall 8e certified 8= P according to the actor= Act of Singa9ore. 8. Working access and area shall 8e good and :ide eno7gh for this t=9e of :ork incl7ding s:ing o9eration. c. /ifting s79er!isor shall 8e assigned for the o9eration. Riggers> signalman and etc. shall 8e :ell organiEed. +he= shall 8e instr7cted clearl= for the o9eration. d. ra:ler crane shall 9ark at the 9re-determined 9ositions. Sheet 9iles la= do:n area shall 8e selected at the earl= stage. e. ns7re the shackle has a !alid /, certificate iss7ed 8= A#PB 8efore 7sed. f.
+he ma
g. (andle it caref7ll= & slot into the 9re-c7t center hole diameter 50mm at the to9 of sheet 9iles. 100mm from the to9 of sheet 9ilesB h. P7sh the shackle into 9re-c7t center hole referred to item gB. i.
Rigger man :ill ens7re the shackle f7ll= tightens.
;.
+he :hole lifting o9erations sho7ld 8e s79er!ised 8= lifting s79er!isor.
k. )nce the sheet 9ile has inserted to the silent 9iler ch7ck 8= crane and 9ress in at least "#% length of sheet 9iles into the gro7nd> silent 9iler o9erator :ill confirm and ens7re e!er=thing is in order 8efore gi!ing instr7ction to the trigger man to release the shackle. +he shackle m7st 8e reacha8le 8= a man height. l.
Re9eat it again for ne
6.&.2 NORMAL SILENT PILIN METHOD
+he sheet 9iling is started from a reaction stand :hich sim7lates the to9 of sheet 9iles. After 9ositioning the reaction stand !erticall= on 9ro9osed alignment> the initial "-% 9ieces of sheet
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9iles shall 8e 9itched and 9ressed-in 7sing the silent 9iler machine to the re?7ired de9th. o7nter:eights> often in the form of sheet 9iles are 7sed to 9ro!ide an initial reaction force. @9on com9letion installation of initial "-% 9ieces> the co7nter:eights and reaction stand shall 8e remo!ed. +hen> installation for the remaining sheet 9iles shall contin7e.
+he ne the sheet 9ile shall 8e 9ressed-in to the re?7ired de9th. *f necessar=> sheet 9ile shall 8e ;oined 8= :elding to achie!e the re?7ired 9enetration length. (o:e!er> 9rior to com9leting the dri!ing of sheet 9ile> the silent 9iler machine is released from the anchoring 9iles. +hen> the main 8od= of silent 9iler machine is lifted and tra!elled for:ard. +he main 8od= is lo:ered and the feet are clam9ed on the ne
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6.&.3 SILENT PILIN #ITH #ATER (ETTIN METHOD
+his method e dri!ing the steel sheet 9ile into t he soil. After the 9ile is correctl= dri!en into the soil> the :ater ;et is sh7t off> and the ;et 9i9e is e :hich> in t7rn> 9ress7riEes and feeds the :ater thro7gh the :ater s799l= hose and 9i9e line for in;ection from the noEEle.
)n the other hand> the :ater ;et ;ointl= method is intended to facilitate smooth> acc7rate> and damage-free dri!ing of steel sheet 9iles 8= red7cing 9oint resistance> skin friction resistance> and ;oint friction resistance ca7sed 8= dri!ing o9eration :ith the aid of :ater ;et from the :ater ;et 97m9. *n;ection of :ater ;et into sand= soil can ca7se 9ore :ater 9ress7re in soil 9articles to tem9oraril= increase> leading to easil= mo!ing soil 9articles and res7ltant so-called Hli?7efaction.H +his 9henomenon is 7sed to red7ce the 9oint resistance of steel sheet 9ile. *n addition> e hel9ing red7ce the skin friction resistance. 7rthermore> :ashing of sand from the ;oints of alread= dri!en steel sheet 9iles ca7ses eliminated H:edge 9henomenonH of ;oints> leading to red7ced ;oint friction resistance. When the in;ection is interr79ted after com9letion of 9ile dri!ing> the :ater 9ro9agates thro7gh the soil to 9rod7ce so-called :ater-8inding 9henomenon> contri87ting to more consolidated soils than 8efore. +his 9henomenon hel9s sta8iliEe the alread= dri!en steel sheet 9iles> and 9rod7ce 9ro9er reaction forces allo:ing dri!ing of s78se?7ent steel sheet
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9iles. Sometimes it is re9orted that H7se of t he :ater ;et ;ointl= method for dri!ing of steel sheet 9iles can ca7se loosened soils in the s7rro7nding gro7nd and res7ltant ca!ed-in road s7rfaces and#or damaged ho7ses> and th7s the :ater ;et ;ointl= method is ne!er ado9ted.H *n 9ractice> ho:e!er> 9ro9er control of :ater flo: and 9ress7re hel9s 9rod7ce the :ater8inding 9henomenon in the site soils after com9letion of dri!ing> and the soils 8ecome consolidated> ha!ing little effect on the s7rro7nding sites. +his s7ggests that safe> sec7re> and en!ironment-friendl= methods sho7ld 8e selected for dri!ing of steel sheet 9iles> and the :ater ;et ;ointl= method is the most relia8le among the c7rrentl= a!aila8le methods.
6.&.4 !IBRATORY EXCA!ATOR METHOD
D7e to 7n9redicta8le soil condition on site> contractor ma= face diffic7lties in 7sing silent 9iler method. *t co7ld 8e !ar= soil 9rofiles at certain locations :hich im9ose higher resistance to dri!ing stresses and th7s limit the 7sage of silent 9iler method. or s7ch circ7mstance> !i8ro-mo7nted e and allo:ing to easil= dri!e in sheet 9ile. Des9ite of the ad!antages> e dri!er :ill clam9 to the end of sheet 9ile. *t :ill 8e 9itched 79 and !i8rated in 9lace> 7ntil the re?7ired toe le!el is reached. ontractors shall ens7re that !i8ration limits are not e
6.&.5 !IBRATORY HAMMER METHOD
D7e to limitation of !i8ro-mo7nted e !i8rator= hammer :o7ld 8e 7sed to tackle hard gro7nd condition and installation of sheet 9ile length more than 1%m. As of common 9roced7re> sheet 9iles :ill 8e trans9orted and off-load on site at :orking locations.
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+em9orar= frame g7ide 8eam :ill 8e fi :ith a ga9 9ro!ided 8et:een their faces in order to allo: for the 9itching of the sheet 9iles. +hen> !i8rator= hammers cl7tches :ill 9itch the sheet 9ile and lift it 79 8= cra:ler crane. +he sheet 9iles :ill 8e attached a safe line :ith feat7re of release shackle attachment. +hen> it :ill 8e 9itched do:n 8= the !i8ration force of hammer. D7ring the o9eration> contractor has to 8e caref7l and to ens7re that !i8ration limits are not e
6.&.6 EXTRACTION OF SHEET PILES S)*+, M+
+he sheet 9ile e the sheet 9ile is 97lled !erticall= 79:ards. *f necessar=> sheet 9ile shall 8e c7t to facilitate the e 9rior to com9leting the e the silent 9iler machine is released from the anchoring 9iles. +hen> the main 8od= of silent 9iler machine is lifted and tra!elled 8ack:ards. +he main 8od= is lo:ered and the feet are clam9ed on the ne
!)), M+ Sheet 9iles tend to 8e eas= to 8e e !i8rator= hammer :ill 8e 8ro7ght in together :ith cra:ler crane. rane :ill lift the !i8rator= hammer to :ork locations and clam9 the sheet 9ile. )nce 9o:er is generated> !i8ration force ind7ced from hammer :ill red7ce cohesion of soil and start to 97ll o7t sheet 9iles. At the same time> cra:ler crane :ill gentl= ad;7st its 8oom radi7s to 97ll 79 sheet 9iles. +he same o9eration :ill 8e re9eated 7ntil each sheet 9ile is lifted 79. ontractors shall ens7re that !i8ration limits are not e :ill 8e loaded and trans9ort off-site.
Method Statement & Risk Assessment of Sheet Piling Works
Most of the 1m sheet 9iles :ill 8e ;oining on site d7e to trans9ort diffic7lt= for 1m length normal lorr= tr7ck can onl= fit ma total 15 n7m8ers of corner 9iles :ill 8e 9re-fa8ricated 9rior to installation. +he= are es9eciall= needed for shar9 t7rning 9oints in RSS at seaside. D7e to nat7re of :ork> ta9ered 9ile :ill also 8e fa8ricated and installed at e!er= 00 th sheet 9ile. +he 97r9ose of ta9ered 9ile is to ad;7st and ens7re the !ertical alignment of sheet 9iles.
6.'.1 SHEET PILES (OINTIN FABRICATION
9ieces of sheet 9iles :ill 8e selected> lifted and 9laced at designated location for ;ointing in :elds. After 9lacing> lifting gears :ill 8e detached. Welders start to 9re9are and grind one of the edge of sheet 9iles 7ntil it 8ecome 8e!el edge. After that> 8oth ends of sheet 9iles one end :ith normal edge> another end :ith 8e!el edgeB to 8e 97t together> merged and ;ointed as 9er :elding details stated 8elo:.
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Sheet 9ile :ill 8e left for cooling do:n of " ho7rs 8efore lifting. +hen> lifting team :ill rig the sheet 9ile 9ro9erl= and fli9 o!er it. After that> :elding :ill 8e carried o7t at another side of sheet 9ile ;oint. 6.'.2 CORNER PILE FABRICATION
orner 9ile is a s9ecial sheet 9ile to create +-section and form an interlocking element to connect sheet 9iles so that the= can 8e com8ined :ith s9ecial corner 9rofiles. 2efore the start of :ork> nos. of sheet 9iles in length 1m :ill 8e selected and laid 9ro9erl= at fa8rication =ard. irstl=> sheet 9ile :ill 8e c7t into half and left for cooling do:n a8o7t fe: ho7rs. Angle 8ars :ith siEe of 100<100<1mm :ill 8e :elded onto another sheet 9ile at inter!al of ".5m. Welding details of angle 8ar :ith sheet 9ile can 8e referred to attachment F Sheet Pile a8rication Detail. +hen> the half-c7t sheet 9ile is lifted and slotted into 9re-;oint angle 8ars s9acing. +he sheet 9ile alignment :ill 8e ad;7sted so that it is in right 9osition. After:ards> :elders :ill start to :eld and ;oint angle 8ars and sheet 9ile. inall=> fa8ricated sheet 9iles :ill 8e shifted to another storage location :aiting for installation.
6.'.3 TAPERED PILE FABRICATION
*f at an= time the sheet 9ile :all !ertical alignment is tilted and o7t of line of connection slot> contractor :ill 9ro!ide ta9ered 9ile to ins7re s7cceeding 9iles are !ertical. nos. of sheet 9iles :ill 8e selected and laid 9ro9erl= at fa8rication =ard. +he first ste9 of c7tting se?7ence> sheet 9ile :ill 8e c7t along its diagonal line. After it left for cooling do:n for " ho7rs> it :ill 8e lifted and 97t ad;acent to another sheet 9ile. Ne it :ill 8e ad;7sted and confirmed in 9osition 8efore another ;oint :elding 8egins. Welder :ill start to :eld the ;oint at 8oth sides as 9er details in attachment F Sheet Pile a8rication Detail. After
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that> s9lice 9lates :ill 8e :elded to strengthen connection of sheet 9iles. inall=> the fa8ricated sheet 9iles :ill 8e shifted to another storage location for installation. *n!estigation sho7ld 8e carried o7t to re!ie: the ca7se and ens7re there is no Cde-cl7tching of sheet 9iles.
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APPENDIX A ATTACHMENT> LOCATION LAYOUT PLAN
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APPENDIX B ATTACHMENT> CONSTRUCTION DRA#IN
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APPENDIX B ATTACHMENT> CONSTRUCTION DRA#IN
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APPENDIX C ATTACHMENT> SILENT PILER MACHINE MODEL ECO100 CATALOUE
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APPENDIX C ATTACHMENT> SILENT PILER MACHINE MODEL ECO100 CATALOUE
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APPENDIX D ATTACHMENT> SILENT PILER MACHINE MODEL SA100 CATALOUE