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by: Ibrahim Crona


Ibrahim Crona
GPA 3.9


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Class Notes
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This 14 page Class Notes was uploaded by Ibrahim Crona on Wednesday September 9, 2015. The Class Notes belongs to CM 420 at University of Washington taught by Staff in Fall. Since its upload, it has received 37 views. For similar materials see /class/192189/cm-420-university-of-washington in Construction Management at University of Washington.




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Date Created: 09/09/15
r3130 Cofferdams Temporary Structures W ag if Cofferdams Tem pprary tructu res c o remparsry Strumura Cofferdams A cafferdam is a temporary structure designed to keep water andor sail out of the excava an in which a bridge pier or other structure is built Standard Handbook of Heavy Construction maniacs C 0 Yemvurary Strumura C offerd ams water md soil so as m permit dewatering and construction of the permaient facility structure in the dr A cofferdam involves the inmrac on of the structure soil and wamr The loads imposed include the hydrostatic forces of the water as well as the dynamic forces due m curren an waves Because oofferdams ae typically constructed under adverse conditions in a maine environment and becaise signi caitdeforma ons of elemenE may occur at various stages of construction it is dif cult m mahtain close mlerances Ample provisions must e made for deviations in dimensions so that the mished W structure may be construcmd according m plm X i Z Professor Kamran M Nemati Winter Quarter 2007 1 W129 Cofferdams Temporary Structures Eullerdams Yhe We Weed m we zoKudzm Avuduve by zmxlvuzhun Eamvmenl 2nd wenhun mun be d g m zmmdeve buth dunn Aszhon y the Mum 2m dunng eeneemeum uflhe Avudure er Remwz e the zoKudzm mun he dznned 2nd exezuled wuh the me degvee y ave 2 u m 2 2 en 2 Azgerb r zge 22 we men We vemuvz m we Devmznenl eemme mun 2km mrmdeved n AM renew heel We extendmg be w me Devmznenl Avuduve 2ye uRen m uffznd e m a2ee me thew mam v M2 me meme 0 Idhzenl to me lure w 4 Eullerdams In Mum emeemm 22km 2 Dznmoml emeem me mm m be expeeee m the M2quot mew 2nd mu2pee mmee mmne me hem e we mm 2 meme 2e2 Wm afzdequae nee My 24 mmquot 2m 2enm 2e2kpy2emeeen zhepzn M Wee 2m EEPS39E M me v WA I 66 C Eullerdams IIypEs ulcu erdam narated EanhrTyp2 mmber Cnb DnuberWaH2d Sheet PHE C2Hu ar meessur Kamran M Neman wma Quarter 2mm 12a Cofferdams Temporary Structures Eullerdams uBraoed Cofferdams mm 0va mm we mm m imm a hm ammd m2 Excavanmswa me hm 5 men bated m we mde xncam 5 damaged wmanw used in budge was m smuuwwaca aur 35mm v Ms39 i d c Eullerdams uuuemam Des39gn Eunsiderah39uns mm wan 4 Wm faces an meme emem mm 3 93wa sgamstvemca may lcE M Mr Annie Ezrlh and Passve mh Prvsmres m x ms ages ofCofferd m a Excavanm 2rd msvumm m puny c Eullerda Advam AMW svmues m mwse vespumbmtv aha mans mm mfessnr Kamran M Neman wma Quarter 2mm Temporary Structures gxg 39 k 1 Cofferdams Cofferdams Items needed for installation Pie driving hammer Vibratary or Impact Crane of sufficient size Stee sheet piles are typically used Hpies andor wideflange beams for wales and stringers uBarges may be required C o Yemporery Slrumura Cofferdams TYPES OF IMPOSED LOADS Hydrostatic pressure The maxlmum probable helght oumlde the cofferdam cofferdam urlng vanous Stages of co strucnon h to be consldered These result h the Hetdeslg pressure shown below Mama th rams on pamaw dewatend comment m Wamm c Cofferdams TYPES OF IMPOSED L Forces due to Soil Loads The soils impose forces both locally on forces are additive to the hydrostatic forces Local forces are a major component of the lateral force on Sheetpile walls causing bending in the Sheets bending in the wals and axial comprssion in uis Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures 394 2 399quot 555 E F l tilnatal l I NGTL JH Cofferdams Temporary Structures Co erdams TYPES OF IMPOSED LOADS Forces due to Soil Loads Cont d V Active quot pressure Soft mud l Z 1 Net Passive e e J Dr SSUr j pressure Sand 2 C 0 Temporary Structures Cofferdams TYPES OF IMPOSED LOADS Current Forces on Structure With a typical cofferdam the current force consists not only the force acting on the normal projection of the cofferdam but also on the drag force acting along the Sides With flat Sheet piles the latter may be relatively small whereas with zpiles it may be substantial since the current will be forming eddies behind each indentation of profile as Shown below C 0 Temporary Structures Cofferdams TYPES OF IMPOSED LOADS Wave forces Waves acting on a cofferdam are usually the result of local winds acting over a restricted fetch and hence are of Short wavelength and limited to height Waves can also be produced by passing boats and Ships especially in a restricted waterway Waits liliingm ta 14 Professor Kamran M Nemati Winter Quarter 2007 5 ark14m Temporary Structures v M39s z d fw C offe rd E III s Eullerdams me e men ewe eee wees a two AWE e Que exa kd We expansm m 2 Maser q dw hemw wmem new we mu w an m hszeenuxed quot12m 2nd Meme en the gen We were the 22 duels meme n2 Nada Awe Amduve 2ye uRen um 2 mm m a Nnnn bHlofzmhd 2ye2 Eullerdams was ur mmsm Laws 525mm Luz meee We not been namz Wzmmdeved m em 9 Aemvouw Meme m we Dan Fm vuvhvge WWW 2nd deep 2mm m h ngxe Xm aHvzdue 2ye2e eeme evz uzhun hde be Devfovmed mammal lua meee 2ye the We uxquvzzmed w mmm mn Eamvmenl Wm ung de the Mum 2nd szdmg on M We the zzhon y wzvu me 2e c Eullerdams swur Seem y the mm mm a 2an 2mg the whim we the um tomu wvvenlx mm emenee m wzvlvduzed wvvenl Some aim we eem 2m meme e eee Me Deemed when meee em Me zded emewenw AVUV pnmzz New Li Drumung My e to depmu 2 mum ofzvuxhed vudlt a hemv 3 a el Aware eepmeueuee New e m by 2 mzurexx of hev We mew u we new n the meessur Kamran M Neman wma Quarter 2mm 6 VTHNH39I EREIUT QF f w was H I H GTDH Temporary Structures Cofferdams Q Q 39 it l 1 ll 347139 Z 39 lr g Temporary Structures Cofferdams Cofferdam Components Sheet piling Bracing frame Concrete seal Bearing piles Wis39Ix i iiQJriicquotfi 18 C 0 Temporary Structures Cofferdams The typical cofferdam such as a bridge pier consists of sheet piles set around a bracing frame and driven into the soil sufficiently far to develop vertical and lateral support and to cut off the flow of soil and in some cases the flow of water 391 d Q 339 Structural bracing I 59 51 frame I Sheet piles quotWW A AW L r E22221 W hslimcgmx 19 C 0 Temporary Structures Cofferdams Install Wale and Strut System for Framework Template e u quot x M39sHES V r r 39 quot 139 quot 1 3 i T 1 V 1 77 I It i I r M L r WHIP 4 Wiscactiimcrzmg 20 Professor Kamran M Nemati Winter Quarter 2007 7 Cofferdams Temporary Structures Cofferda ms The structure inside may be founded directly on rock or firm soil or may require pile foundations In the latter the cofferdam In order to dewater the cofferdam the bottom must be stable and able to resist hydrostatic uplift Placement of an underwater concrete seal course is the fastest and most common method ail i W1 39J l liquot if ii Te m po ra ry Stru ctu res case these generally extend well below 21 39I imrue agl r a ElliFEE ill I H ETDN Cofferda ms An underwater concrete seal course may then be placed prior to dewatering in order to seal off the water resist its pressure and also to act as a slab to brace against the inward movement of the sheet piles in order to mobilize their resistance to uplift under the hydrostatic pressure l M Structural bracing frame 4 rr H ll pile In 0 H p Concrete seal course h Ll k Bearing piles Witfailthan l l l L l C 0 Temporary Structu res 22 Cofferdams Construction Sequence For a typical cofferdam such as for a bridge pier the construction procedure follow the listed pattern 1 Predredge to remove soil or soft sediments and level the area of the cofferdam I ill 132245 l l scarta C 0 Temporary Structu res 23 Professor Kamran M Nemati Winter Quarter 2007 77lJNI WFFlEITTDF 139 illf lll I NGTDH Temporary Structures C o ff e rd a m s Temporary Structures Cofferdams Construction Sequence 2 Drive temporary support piles 3 Temporarily erect bracing frame on the support piles Y gr 1 i ll than i a l aquot r my 24 C 0 Temporary Structures Cofferdams Construction Sequence 4 Set steel sheet piles starting at all four corners and meeting at the center of each side 5 Drive sheet piles to grade 6 Block between bracing frame and sheets and provide ties for sheet piles at the top as necessary v i 1 quot a M M nial 25 C 0 Temporary Structures Cofferdams Construction Sequence 7 Excavate inside the grade or slightly below grade while leaving the cofferdam full of water v 1 E v se Wm i ii L 26 Professor Kamran M Nemati Winter Quarter 2007 9 l 4 El Tl IEJNI VFFa l w ThieSHIHCITEN Temporary Structures Cofferdams Temporary Structures K 5i Fl H l f l 1 5 ll 14 2 l V g My 1 j 1 9 r 39 39 4 H 1 m l q 1 55 7j 47 l l A 1 r y M 1217 x pwm M rs r g lv s l Cofferdams Construction Sequence 8 Drive bearing piles 9 Place rock fill as a leveling and support COUI SE if E w m e I I lh 27 mil H F i I vi l a l r g rm Temporary Structures 0 0 Cofferdams Construction Sequence 10 Place tremie concrete seal 28 Le d Ci W93 l I iii Ti f39i Temporary Structures 0 0 Cofferdams Construction Sequence Tremie concrete seal 263322 107 Z i I P le r1 t H4 e v l LBVGl l 1 E M 1r r 29 i 11 39fz I my I ll 5 i ILwl5lalr aa12 Professor Kamran M Nemati Winter Quarter 2007 Cofferdams Temporary Structures Temporary Structures Cofferdams Construction Sequence Lag Tremie concrete seal 77s 3 imth Slope 116ToiziO Loi ronce N x Tremie concrete i 39 7 El H Ii 5H1 I i Lil HT EllE HGTGH 12 Dewater 13 Construct new structure 39Z aim Blocking or 4L in 5i i Wiixg inmrcintt 30 C 0 Temporary Structures Cofferdams Construction Sequence 11 Check blocking between bracing and sheets bockfill 39 Wi ii ii 31 C 0 Temporary Structures Cofferda ms Cofferdam for the Sidney Lanier Bridge Oregon WW imE 32 Professor Kamran M Nemati Winter Quarter 2007 11 031 63290 Cofferdams Temporary Structures ak1 Cofferdams Construction Sequence 13 Consh39uct new sh39ucture 14 Flood cofferdam c o vemwsry swede Cofferdams Construction Sequence 15 Remove sheet piles 16 Remove bracing 17 Backfill Wll39ds39x39xiic c o Yemvurary rumura Cofferdams Traditional Sheet Pile Shapes l Larsonl u Type U Used fur lntermedlate m deep Used fur appllcatmns slmllar Wall eensmeuen in z 7 Type w Flat I Straight Type SA 5 Arch shaped s lightweight Used fur lled cell cunstructlu Used fur shalluvvervv ll eunstrumun 35 Professor Kamran M Nemati Winter Quarter 2007 5M5 Temporary Structures WU N l v e a s r r o F 1 WASHINGTON Cofferdams n Cofferdams Typical types of interlocks fd l Ball amp Socket BS Single Jaw SJ Double Jaw DJ amp Hook amp Grip HG Double Hook DH Thumb amp nger three point contact TF Wx u39l l Refs 36 c Cofferdams Braced Cofferdam Construction Insta Wale and Strut System for Framework Template c Cofferdams Braced Cofferdam Construction lnslall Wale and Strut System for Framework Template Cont d Professor Kamran M Nemati Winter Quarter 2007 13 12a Cofferdams m Wm Temporary Structures c Eullerdams nus fa mmnmu sheet ales 5mm s m zorlndov mm not dnwvg 2 mm mm than m u engh before dnwv the lament We uum 0 mm mm madmpm mm m m m mam Wm gmmuy aux the mm mm out ufp umb n mHy mu m the We mm m x v Ms39 i d f2 snr Kamran M Neman a Quarter 2mm


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