TEMP STRUCTURES CM 420
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43230 Temporary Structures Wall Form Design Part I K 5520 Temporary Structures Tempomry Struciures Wal Form Design Part I l Ms 31116103 c o BEARING OR CRUSH NG Bearmg suesses Compresslon Perpendlcular to the Gram Allowable suesses for compresslm perpendlcuar m me gram Yemvbrafy Sirumura varlous specles and grades oflumber These allowable suesses may be modl ed onereased lfbom orme followlng amena are saus ed Beanng ls applled 3 lrvdwes or more from the end orme mem s Beanng lenglh ls less man s wanes When crl e la are met me allowable suesses are modl ed by the followmg factor Wand Fur mund w hers assume 1 ls equal m the dlameter urwasw crw z Wu c o rempwy swam Bearing or Crushing To check for a bearing failure crushing of wood bers divide ihe imposed load by he area of contact an compare his determined actual bearing sites to he allowable bearin sites If allowable bearing sites a failure resulis Professor Kamran M Nemati Winter Quarter 2007 W129 Temporary Structures wuswv as Wall Form Des 9quot WASHINGTON DESIGN nr EDLLIMN amass Wand mmbas smjenadmmw cmuzs m tmuzsmn 0312M came 912m me MW Dwayne cm mm m gemm m Mmum mum mum mam 2 ampbexmxx Luann mind Mme m mg man mm mm We maemum a M c the slmdemess Ra 2 am u m quotzed m m endemexx nun the mu cm W be the m dammed bvuxmg the ammo y the mom Fzze Fm wood membem dezmol exceed 5n m v c the slmdemess Ra m M uwng exzmv e Wm mm the me mm erdemexx mum x mm mm WWW lt0nlm hngendemevam K m meessur Kamran M Nemau wmr Quarry 2mm 2 W129 Temporary Structures Wall Form Des gn a the slmderness Raliu Emu m2 uan s mbaced m bum dwmmswms n 5 move that me swmmmess mu m we navmwface mm mm at V we mum wee mbacad and 7 fuut hung m2 mudth swmmmess mm mm be 55 0va ED and mum wuud run he Damned vmm mmmnm hrgev membev ezhm uddmmz New hmquot v WA I 66 2 c the We ammqu Mm mm H z a m v slmdemess Ra Evacad Cdmm c Dex mfamxfa m ng Mum mm u mg ml of z n W my WWW Mbnled meessur Kamran M Nemau wmr Quarry 2mm Wall Form Design Part I Temporary Structures 1 a f g lki Wall Form Design Example I STEP 1 FIND PRESSURE The concrete used for this u project satisfied the conditionsquot of Table 54 quot Using Table 54 for R 3 fthr and T 60 F the minimum pressure for design Is Temporary Structures P 600 psf Then the depth of the hydrostatic load zone for a concrete with a unit weight of 150 pcf is l liesa 10 C 0 Temporary Structures Wall Form Design Example The diagram of lateral pressure on wall form is shown here 14quot If M39 i I i A l quot 7quot 3 WEI13 HEEL 11 C 0 Temporary Structures Wall Form Design Example STEP 2 SHEATHING 4x8 sheets of plywood will be used Use plywood the quotstrong Wayquot face grain parallel to PlyWood span Design for Uniformly spaced supports at lft centertocenter I CHECK BENDING Consider a 12in wide strip of plywood For continuous beams more than three supports the following equation is used 2 1095 E Weii i 5 635 W 12 Professor Kamran M Nemati Winter Quarter 2007 4 IJNI39EEEF 7T QIF Clquot Tem po ra ry Stru ctu res Him I I F TDH Wall Form Design Part I l Te m po ra ry Stru ctu res Wall Form Design Example From Table 42 the bending stress for plywood is 1545 psi TABLE 42 REPRESENTATIVE BASE DESIGN STRESSES PSI NORMAL LOAD DURATION VISUALLY GRADED DIMENSION LUMBER AT 19 PERCENT MOISTURE AND PLYWOOD USED WET Derived from recommendations 39of the American Forest amp Paper Association Reference 43l and from recommendations of the American Plywood Association Reference 48 39 Extreme fiber Compression Compression Horizontal Modulus of bending stress 39 L to grain 39 to grain shear Fv elasticity SPEClES AND GRADE V Fl F c n to grain E PLYWOOD SHEATHING USED WET Plyform 39 V Bearing on 39 g v 39 j B B Class 1 Grade stress level 32 1545 face 210 V 57 1500000 NOTE Size adjustments apply to all base bending stresses and compression parallel to the grain except Southern Pine The size adjustments are 39 already included in Southern Pine bending stresses andcornpression parallel to grain in accordance with Reference 4339This makes Southern Pine seem relatively stronger in bending andrcompression Consult Table 428 and Chapter 6 tor details of size adjustments Plywood stresses include an experience factor of 13 recommended by the American Plywood Association Value for rolling shear in the plane of the plies see page 69 for design formula Modulus of elasticity may be increased 10 percent if shear deflection is computed separately from bending deflection 1 When size adjusted bending stress is less than or equal to 1150 psi no moisture adjustment is required 1 Whensize adjusted compression II is less than or equal to 750 psi no moisture adjustment is required The problem states that the forms will be used only once singleuse form the bending stress must be multiplied by an adjustment factor of 125 for short term loading Hence the allowgbk stress f 2125 x1545 E 1930 psi HI i y t 1Iii 1112 1 g 312 TEN 13 C 0 Temporary Structu res Wall Form Design Example From Table 43 the section modulus S for 34in plvwood is 0412 in3 TABLE 43 EFFECTIVE SECTION PROPERTIES FOR PLYWOOD 12IN WIDTHS FACE PLIES OF DIFFERENT SPECIES FROM INNER PLIES ectiv sanded thicke 12in width used with face 12in width used with Approximate ply Mini ness for grain parallel to span face grain perpendicular to span weight lb wood mum shear 2 number ri es Area for Moment Effective Rolling Area for Moment Effective Rolling ness of layers 9 tensron of inertia section shear tension of inertia section shear 4 8 mg and com I modulus constant and com I modulus constant x per m eXtenor pression S IbQ pression S IbQ Sheet Sq ft glue in2 in 1 in3 in2 in2 in4 in3 in2 14 3 0267 0996 0008 0059 2010 0348 0001 0009 2019 26 08 3 0288 1307 0027 0125 3088 0626 0002 0023 3510 35 11 12 3 0425 1 947 0077 0236 4466 1240 0009 0087 2752 48 15 5a 5 0550 2475 I 39 0 39 5 3 39 1528 0027 0164 3119 58 18 gt GA 5 681 2884 w 2081 0063 0285 4079 70 22 7A 7 0586 2942 0278 8 I 2651 0104 0394 5078 83 26 1 7 0817 3721 0423 0664 8882 3163 0185 0591 7031 96 30 113 7 0836 3854 0548 0820 9883 3180 0271 0744 8428 106 33 Use listed 8 value in bending calculations and use I only in deflection calculations Properties taken from March 1985 edition of Reference 48 can be used for all sanded Group I plywoods lF BB PLYFORM GRADE OF PLYWOOD IS USED SLIGHTLY HIGHER VALUES FROM REFERENCE 4 9 CAN BE USED FOR DESIGN 39 w loading of the beam for a 1ft wide strip of plywood is i 600 psf 6001b1f In 14 C 0 Temporary Structu res Wall Form Design Example Substituting in the equation I 1095 E W 19300412 I 1095 21095x133 1261 in I W 39 ii in l39 Til Wormtil tiattw 15 Professor Kamran M Nemati Winter Quarter 2007 5 Mam Temporary Structures Wall Form Des gn Wall rum Design Exanple W mm 2 m wdxhafv wmd mm M a mmmumwenmn 1 arm n m mmg oz lheviuexfonmdu u DFe xnuhinv mm unbe mm s smmm md Ya e u mm as name e mm Wm in We PM w humquot s m m Lm 71m memmmm i in m m WEE m Wanda 152nm a r w vI m c Wall rum De gnExanple pm VAN n mka a mumvi gm be mm m be r 57 pm mm mm mum by 25 R haHevm mm mmquot m zumme mum my 711w imam mm mm my z c Wall rum Design Exanple w Fva the shave a m atmns the smaHest va ue Dhlamed rm us 12 51m 022an meanmq that he was CANNOY he mated aw mm than 12 51 mg avavt Yhe sheets 5mm have M suvvmt at me mm Yhevefme an Equaksvamnq Df studs at 127 mg same a mndmans meessur Kamran M Nemau wmr Quarry 2mm Tem ora Structures u N i v r n x i r v o p N WWASHINGTON Ground Freellng lllesllll39m39rm Ground Freezing Gmqu Frem IGmundlreezingls usajlnrgr mil niunne n gain W mm unn d n slat Typilzlry z mwnf reeze in lhe snil md heal my man a p u s we plats veniezlly 9y s mmdlhrnugh muss ranzlahiy mdngnus In a grnundwau lrnm wdls Fnlmahnn in a new all Gmqu heming vllhemhe mull tarmuzlum males 32 T in my waerimhe snil pureslumsln iue Thm unhu milling pmceeds wllh annular grnundwau in lhe nnrslrmles ie ly md zsaumed smd lm emple zmiwvs Excellent slmnglh at an a lew degmvs helnwlhelleeling palm Furl a darn n Mlhe lamuaure pmducvs nnly miginzl lncmase in sitequot h wllh days hnwwmlhe gmund wall is rmleculzl39y hands a least in pm In lhe snil panicles Prnfessnr Kamran M New Wmmr Quartz 2007 Temporary Structures z x r L7 J Ground Freezing Temporary Structures Ground Freezing The design of a frozen earth barrier is governed by the thermal properties ofthe underlying soils and related response to the freezing system Formation of frozen earth barrier develops at different rates depending on the thermal and hydraulic properties ratum Typically rock and coarsegrained soils freeze faster than clays and silts 3 Temporary Structures Ground Freez ing When soft clay is cooled to the freezing point some portion of its pore water begins to freeze and clay begins to stiffen lfthe temperature is further reduced more of the pore water freezes and the strength of the clay markedly increases When designing frozen earth structures in clay it may be necessary to provide for substantially lower temperatures to achieve the required streng hs A temperature of 20 F may be adequate in sands whereas temperatures as low as 20 F may be required in soft clay Ground Freezing Referring to the gure on slide 1 the frozen earth rst forms in the shape of a vertical cylinders surrounding the freezepipes As cylinders gradually enlarge they intersect forming a continuous wall Professor Kamran M Nemati Winter Quarter 2007 j39uruinangitr gr iiiPAS H l H GTUH Temporary Structures Ground Freezing Temporary Structures Ground Freezing If the heat extraction is continued at a high rate the thickness of the frozen wall will expand with time Once the wall has achieved its design thickness the freeze plant is operated at a reduced rate to remove the heat flowing toward the wall to maintain the condition Temporary Structures Freezing Equipment and Methods The most common freezing method is by circulating brine a strong saline solution as of calcium chloride Chilled brine is pumped down a drop tube to the bottom of the freeze pipe and flows up the pipe drawing heat from the soil tumquot Liul39 39 L Portable i twin 60 ton brine refrigeratio FEW quotW n unit h I pulpEl 1quot r l damn 1 H s 7 420 Temporary Structures Freezing Equipment and Methods The liquid nitrogen LNZ process has been applied successfully to ground freezing The cost per unit of heat extracted is much higher than with circulated brine Nevertheless for small short term projects particularly in emergencies the method can occasionally be competitive Because of the Typical LN2 extremely low system forground L 2 freezing temperature freezing with LN2 is rapid and high strengths of frozen clay can be achieved Professor Kamran M Nemati Winter Quarter 2007 3 Temporary Structures 1 ql qtg Ground Freezing Temporary Structures Freezing Applications The freezing method is remarkably versatile and with ingenuity it can be adapted to a great many project conditions The penetration of a freeze does not vary greatly with permeability so it is much more effective as a cutoff than grout In stratified soils cutoff by freezing encounters fewer problems than drainage by dewatering Freezing can perform the dual function of water cutoff and earth support eliminating sheeting and bracing Temporary Structures Freezing Applications The opposite figure shows a circular excavation supported by a freezewall Circular excavation support by a freezewall Sbgd E E a ng wgtSec on 0 420 Temporary Structures Freezing Applications Figure below shows an excavation supported by gravity retaining wall of frozen earth A combination of vertical and inclined freezepipes is typical to achieve the shape illustrated Freezepipes Note in both cases the freezeball toes into an impermeable clay layer u lt I39 o v0 III quot3939 quot3939DI39 quot 39 l quot below the proposed subgrade N Professor Kamran M Nemati Winter Quarter 2007 4 Temporary Structures Ground Freezing Ground Freezi ng 1 Assembhng freeze p pes W V g 2 nstaHaunn nf freeze p pes l 39 a Appheanen nf freeze Wm ne ectrnmcaHy nnthEd refugeratmn want tuman stmnuns UNIVEHSITY CF rWASH INGTON Ground Freezi ng tuman stmnuns 5 Excavaunn qunng nmp amn nf freeze We 6 Cnnstrucnnn Bf nncrete hner Onmemmp eted refugeraunn can be shut dawn Professor Kamran M Nemati Wimer Quaner 2007 Temporary Structures Shoring and Scaffolding I 520 Temporary Structures Tempomry mctures 0 Yemvorafy Slrumura Sho ng In multiston work The shoring which supporls freshly placed concrete is necessarily supported by lower oors which may not yet have attained their their full strength and which may not have been designed to carry loads as great as those imposed during conslruction Construction Loads may exceed design loads by an appreciable amou Rgficmndy a Kebeile AC 1 Wmuucm e 53 pp 172971733 C 0 Yemporary Slrumura Sho ng Therefore shoring must be provided for enough floors to develop the ee e capacity to support the imposed loads without excessive stress or deflection Whether permanent shores or reshores are used at the several required lower floor levels depends on job plans for reused of materials as well as the rate of strength gain in the structure Wm Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures Shoring and Scaffolding I shoring There are several types of adjustable individual shores The simplest of these is based on c o yempwy Simme Sho ng A portable jacking tool is used to make vertical adjustments Metal shore jack ttings are available to t over the end of 4x4 or 6x6 wood shore thus transforming the piece oflumber into an adjustable shore These devics are capable of varying the shore height as much 12 in Ramada C 0 rempurary rmwa Sho n A number of patented shoring systems have been developed with adjustable legs which eliminate cutting close fitting and edging zws Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures u N v v 7 a s I v o p WWASH INGTON Shorlng and Scaffoldan ScaffoldType Shoring I When tubular steel frame scaffolding was rst introduced it was de 39gned to support the relatively light loads involved in getting workers to the work a I Later contractors began to try out the scaffolding as a support for formwork because of the apparent advantages of its modular assembly and sy t m o jacks for leveling and adjusting elevations Timings 9 ysmpwy strum ScaffoIdType Shoring End frams assembled with diagonal braces to form typical s u a horing tower mu u was lllrl 5quot mm 4m Mm mei39ilk o v C 0 Yemporery Skumura Scaffolding Scaffolding has been used for 5000 years to provide access areas for building and decorating structures taller than people who workon hem Walkthroughtype frames used by masons Wm x Professor Kamran M Nemati Winter Quarter 2007 gnaw Sharing and Sca nlding Temporary Strucmres s a g r y I WKS39H INGTODTJ Scaffolding The Word Sca ddmg refers to any rawsed p atform or ramp u d for mgress and egress for pedesman movement andor me passage of 3 s Smoe me mwd719205 me oomoeptof Wmn me zkform or cast damp was Jnuocuced 1 mm m c Scaffolding were deve oped for her hghter Wewght and speedwer oonsuucuon sumg as sme butms m yonermrd m onenams wegnt Because o he ngner mma cost a ummum s resmcted mosdyto susgended Liatforms c Scaffolding sense Dam unskrmmns mmmw 5 Was m Staffdd have iamuf4 snau be mpame m supwmng wmtfa ue at m mp v Wm m vemverrem munuv me D he mpma vt ivcm me wad svess m we mash axudance Wm azwmue B39qxnaav39v amaxg and Vamzes ofessor Kamran M Nemau Wnter Quarter 2007 1420 Temporary Structures Sharing and Sca nlding Scaffolding r Dzslm made 1quot gimme m cm me we me mmquot mete my New we deem me e ewe eemeeemum r n 5n wwmmm wwngbad M Ruck Andrwzlem vexmded m m exzeed m we Mendexmbedzx zw wvgto bnddzvlvx39zndvhxlerx39mk ukwy nnylnmy 7s memmm Mme me Fa pew e 2nd Aaed New men dumbed wo wvg m werequot m M m ffolding newquot me I Thzevatms assLmE umfuvm mad dwsmbunnn matams seame was must Efren mnsm Bf e4 n s mumtant m vemembev that the OSHA meme m em Dasunrm m the Dnstvumun and use m nmspeemeauv enemeeye staffd e sDDhcan c Tube and Coupler scaffolds ITubeand uqu seamds aveassemmed imm s en H22 b2 m svucmva e ems Imanumhs m e 4 mmnse imm avmnd a mha snhd suppmt 39 weh awmmmhsu ewuvk D atfuvms and m umme vansvevse hmmnm mnnemnns between me pests the umva dwemv bemw the beavevs and pmme mgm me staffu d ofessor Kamran M Nemau Wnter Quarter 2007 Ff 9 12 Temporary Structures Shoring and Scaffolding Tube and Coupler Scaffolds These three elements are usually connected with standard or fixed couplers which provide a 90 connection in two places The three structure WW1 UNIVERSITY OF W NASI llNGTON C o Yemporery Slrumura Tube and Coupler Scaffolds The basic asstmbly and components of tube and L uplcl mu mm 9 M L E Di a l w m w u c 17 my meme Tube and Coupler Scaffolds Diagonal bracing is used to stiffen the s rucmre as necssaw r 39 the longitudinal direction Bracing is generally connected in the posts wit a justablequot 39 elquot couplers which have the facility of adjusting a full 360 Diagonal bracing should alw in ays be attached to th posts as closely as practical to the node points formed by the runner earer connections Wm Professor Kamran M Nemati Winter Quarter 2007 Sharing and Scaffolding Temporary Structures and Coupler ScaffOIdS Another important structural element is the building tie which connects the scaffold to the wall or structure and is needed to provide rigidity and anchorage of the scaffold in the transverse direction Scaffolds need to be laterally supported otherwise they are unstable because of their heighttowidth ratio and have low strength to resist wind and other lateral lfi lill lrquot if Temporary Structures LJNIlHE z l T Ell l w nimsriiw mw Tube and Coupler Scaffolds b Window reveal tube ill Ill gg ii ii Y A in 394 3 g 39 39 i i i t 539 f i W JAEEHNETDH N forces Wisix iluillcrft itll 19 C 0 Temporary Structures Tube and Coupler Scaffolds Methods of stabilizing a a Wall tie and anchorage quotquotquot quot Buttto wall CrossbraCe Wi 39 i l illlifgfl il 20 C 0 Temporary Structures Methods of stabilizing against a building cant d 21 Professor Kamran M Nemati Winter Quarter 2007 at Shoring and Scaffolding U Temporary Structures x I Tube and Coupler Scaffolds I Methods of stabilizing against a building canfd c Reveal between 7 pilasters WNWlimit c o remparsry structure Tube and Coupler Scaffolds Ap p I ic atio n Tube and coupler scaffolds can be assembled in numerous ways because of the flexibility of their assemny dimensions in the horizontal and vertical planes Unlike sectional frame scaffolds they are not restricted by ame id in e ansverse direction by brace length in the longitudinal direction or by frame height in the vertical direction Consequently they are preferred for access to workplaces having irregular dimens39o contours eg churches old auditoriums etc myrrh z m x D o remwy mue Tube and Coupler Scaffolds BaSIc Configuration s follows l nener D E m g o Q 5 1 1 Dub 9 d these are used for access to yertlcal surf Constructlol39l alteratlol39ls Or ELI ace They conslst freoetltlye parrsof posts along the length connected by earens and runne i Also called all n wall scaffolds these are used for tne constructlon of masmr walls They conslst of angle posts 3 to 5 feet awa from the wall surface spaced at regular or yarylng lnteryals along the wall The dfferent feature of tnls type of scaffold ls that tne lnslde ends o e earer are suooor e a on I rses n the wall belng bullt lnstead of tne lnslde DOSE r s y 20 or ll Wall Scaffolds aces for N E Professor Kamran M Nemati Winter Quarter 2007 432x Temporary Structures Shoring and Scaffolding I jibeand Coupler Scaffolds Basic Configuration requtred be t for access to cethngs or for spectahzed load support reqmremene not 5 V g F i i39 l An apphcabon of tower scaffolds is to provtde statr access to to unusual structures such as coohng towers M mm c o vemwsry swam Sectional Scaffolding e construction principle of sectional scaffolding is shown be ow mummy c o rempersry structure Sectional Scaffolding The most common material used in the fabrication of steel frames is 1 SISins 0D tubing with a wall thickness tw and 0105 in The most common grade of steel used for this purpose is AISI designation A1050 a highcarbon alloy having a minimum yield stress of 50000 psi with a corresponding ultimate stress of over 75000 si The higher carbon steel is generally preferred because iis lower ductility and greater rigidity make it more resistant to damaging and bending of the members and because it has greater strength Wmmcm 27 Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures Excavations and Excavation Supports L7 7 C 015 Excavations and Excavation Supports V m 520 Temporary Structures c aa vmwy armoure Excavation and Excavation Supports In many constructionjobs deep excavations must be made before the structure can be built When excavations have the potent39 I to endanger lives or adjacent ro ertles bracing to support the soil must be designed The Occupational Safety and Health Act OSHA requires that all trenches exceeding 5 feet in depth be shored In large construction areas excavation walls may e s oped instead of providl g t tural support l C o Yemporary Structura Slope Failure Mechanisms Rotational Slump in homogeneous clay Professor Kamran M Nemati Winter Quarter 2007 quotSW432quot Temporary Structures u N 5 v s p 5 l w r o e tiWWASll l NGTON Excavations and Excavation Supports S pe Stability hg orces r sol weight downslope forces causing instability Resi g orces 39 39 opposlte direction resisting forces Mechanism of failure When driving forces exceed the resisting forces rauur on y ul 39 39 lllulllelll R FS Dnvmg Fumes If FS 5 1 the slope will fail I If FS gt 1 the slope is theoretically stable The usual FS required is hetween13 and 153 Fillmore Yempurary Strumura C Slope Stability Confd To Es illl ate the factor of safety for a slope the following he soll and water proflle 2 The klhema cs of potentlal slope fallure l The strength and welght of sells and he proposed slope geometry This estimate is for holll ogeneou materials Stability number is de ned as Professor Kamran M Nemati Winter Quarter 2007 GM 51 Tem porary Structu res E cavations and Excavation Supports Slo From the graph m 455 N Ifthe cut described above is sulesszz g nu EMU 455 2412 par and muons iw Yemvurafy Strumura C 0 Slope Stab ty Cont39d uvaERSlTY or lWWASH l NGTON nu Clay Cut Slope with Vertical Sids vwrw P39wm Sml Somph ciao mum is Vuyxvft lt sun lt s 5qu S ri nu 25 em Erin vi innn eznn n man in em Su mnnemnn i rz man Vuym nun mun men n m a an a mu The slope failures are probable in shallow excavations only for very soft to medium homogeneous clays By flattening the slope angle from 90 to 45 significant improvemen in the factor of safety for a sl fa given height can be achieved 7 C Slope Protection Temporary slope protection should he provided to prevent sloughing of soilm aterials into the excavation the slope To prevent slope erosion in rainstorms spray on particles on the surface prevent changes In moisture content on the surface of the slope to maintain stability Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures r 3361100 F 39 i J Excavations and Excavation Supports Shallow Trenches Crosstrench bracing are used in utility trench va ions intermittent sheeting and bracing Trench Shielding continuous sheeting and bracing C 0 Tempnrzry Siruciures Shallow Trenches Crosstrench bracing are used in utility trench excavations Power race System Thai i xin39o39x c 0 Tmme summ Deep Cuts Excavation depths exceeding 10 to 20 ft require specialized planning for support Lateral earth pressure is proportional to the vertical pressure As a cut is made the soil at the face tend to expand and move into the cut area If a support is placed against the excavation surface to prevent the soil movement then the preexcavation stress is maintained Wn39u39i39iixi o Professor Kamran M Nemati Winter Quarter 2007 45M 45219 Temporary Structures 39 L 39 I Excavations and Excavation Supports Excavation Support Methods Soldier beam and lagging 39 39 riven o a depth slig ly elowthe final excava ion Their spacing is in the order of6 to 10 feet so that available tim er can be used for agging The lagging timber which is slightly shorter than the spacing but on the order of2 to 4 in thick are 39 39 uie front flan e 39 39 as excavation proceeds Some hand excavation is usually required to get the lagging into the place so delel seem c o vempwy meme Excavation Support Methods Soldier beam and lagging Soldier piles are installed with conventional piledriving equipment or in augured holes The horizontal sheeting or lagging is installed behind the flange closest to t xcavation inside The sheeting can be installed on the inside face oft e ront ange and held In place by various methods such as clips welded studs or bars etc Willa 3 c ii vempwy Simme Soldier Beam and Laggin The soldier pile and laggin o s inappropri r perfectly cohesionless soil For cohesionless soils sheeting must be used Professor Kamran M Nemati Winter Quarter 2007 QM 333 Temporary Structures u N l v s a s I r v o F WWASl l I NGTON Excavations and Excavation Supports The soldier beam and lagging retaining wall Temp mry Struclu ms c 0 Soldier Beam and Lagging WY Soldier beam and lagging retaining wall Closeup of soldier beam and lagging C 0 Tempnrzry Structurvs Soil Nailing Soil Nailing is an insitu reinforcing of the soil while It is excavated from the top down An array of soil nails which are passive inclusions are installed in a grid that functions to create a stable mass of soil This mass of reinforced soil functions to retain the less stable material behind it In the right soil conditions soil nailing is a rapid and economical means of constructing excavation support systems and retaining walls Professor Kamran M Nemati Winter Quarter 2007 45M 43 Excavations and Excavation Supports Tem porary Structu res Soil Na ng In many applicatians sail nailing can be the least disruptive way ta canstruct a retaining wall ng re uires an unusual amaunt dwark craftsmans 39 nd geatechnical knawledge ta canstruct The typical canstructian sequence begins with the excavatian af a shallaw cut Then shatcrete is applie tat e face cf the cut and sail nails are drilled and grauted This sequence is t en epeated untI subgrade is reached UNIVERSl39Y 0F KWVWKSlHNGTON c o Tehpwy Strumura cehshueneh evah undElEmund labuvaluw anhe uc aevheweh Teeuhee tempuvaw shehhe eh allluuv smes enhe exemneh ThemTevaheesTenhe shunnuwasspewe e enumuvelhanplusuvmm suheTheh The excavalmn dEplhvaned um me sneer andWas cunslmcled m culhmal suneehsmheevsmsaheveTavsaheeehseeTavevsa s Tlhgvaveland AppvmlmalelvN El suuaveleelulaveawassml ahee B w es W eelTim a Temporary emewe Sall Nai ng Examples charliewa in Washnylon stare Invarsity Pullman WA T a T r The mu deep excavalmn at lhls she was made m 5mm have slmhllv clavEV shl wnh 51mm peheuaheh Teslslancesvangmglmm15in o5 The 5m had a he 513quot e 1 es l sTehevznnp dalllcllunangl ulZEde e AlunecumEVDHhESlE alwu 51w huhaummnumwasmealemehvel Ehmdl hhaheewau The muvemenlvvas lesslhan n 3 mchesallhelace enhe mm lesslhan n 2 Thehes at 18 leelbehmd lhewall ahe lesslhan n1 mchesal aeTeel behmdlhewall msmlnallswevedeslunedlusupp lheexcavalmn zn Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures 39 k 39 VI Excavations and Excavation Supports Soil N ng Examples The Barman Center UC n r eWChemmal amen u m ch upm 57122 deep The un cunssed u175 c quot51 u n msmule rammed an excavahun m suunaumgam shmcvele quotd25 uvu nan s Wuuld have mle eved erh u n u mum seclmnwasshuvedwrlh1Dmlsulpevmanenlsmlna s A permane shulcvele lacmg was mslaHed m quotmm mm shuwvu mam wmch was gaw el edwlenweeks Yemporary Strumura c Excavation Bracing appropriate called waleris placed against the soil support to waler across the excavation zz Yemvorary Structura c Excavation Bracing Cont39d I For y 39 39 39 The su ort for the rakers driven piles or footings are installed at the bottom of the excavati WM an snowi m mt m n Mam L em mm m mm 3211 T31 quotWM Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures Excavations and Excavation Supports Temporary Structures Excavation Bracing Cont d LJHINHEHEIMT Ell I IMAEHIHGTDN Construction of the soil support and removal of the remainder of the excavation then begins Compared to crosslot bracing in raker bracing system the central portion of the work area is relativelyuncluttered 39 quot Wale g Raker r t Limit of first 1 U o o I 3 quotquotng in o o I 39 quotQ a r39 v I 39 39 a 0 va39 fJ m LE i i H I excavation U 51 3 r Temporary 2 q ma 39 foundahon M m I i I ii p 3 WE I i39i WASHIHEQTDM 24 C 0 Temporary Structu res Excavation Bracing Cont d Rbr ing 5 C 0 Temporary Structures Tleback Systems Tiebacks or anchors are structural system which acts in tension and receives its support in earth or rock The system consists of the earth or rock which provides the ultimate support for the system A tension member or tendon which transfers the load from the soilretention system to the earth or rock A stressing unit which engages the tendon permits the tendon to be stressed and allows the load to be maintained in the tendon Wiw lllmg dm 26 Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures Excavations and Excavation Supports Temporary Structures Tieback Systems E J 7 WASHING IHll9ilquotEFl5TT Earth anchors are usually installed at an angle of 10 to 20 down from horizontal If the acceptable soil is not encountered at these levels it is necessary to change the angle to engage the proper soil stratum Ground surface Sfressing Bond ee Unil 39 2009 Assamed surface of f lt S dinq wedge 39 10 m 20 V Sou Sheeting Grouf or Transfer Tendon 39 moferial Excavofion b rode Su 9 f W Wiriai tzlwcmm 27 C 0 Temporary Structures Tieback Systems Anchors or tiebacks eliminate obstructions in the excavation inherent in rakers or struts ell beyond any They consist of rods that nw potential failure surface into firm undisturbed soil or rock Some tiebacks are made with high tensile cables grouted into rock and prestressed against a wale and othersrutilizing ordinary steel rod or reinforcing steel lif iailil c39ngm 28 C 0 Temporary Structures Tiebacks Tieback systems are generally very successful in preventing movements of the excavation walls Usually the excavation wall is left in place after the permanent construction inside the braced excavation is complete Its is often used as the back form for the permanent basement of the structure Tiebacks if left in place are always cut to relieve tension when the permanent structure can safely carry the load 1 39 sci l Kiltmmiatdm Professor Kamran M Nemati Winter Quarter 2007 10 Temporary Structures 39 x w J E cavat39ons and Excavat39on Supports Mars Phoenix AI les mrmm n Tleback Examp T Wu Rissance r rhrs rsa 4mm 2 uedbackexcavauun The hsurrac materrar mvuuehwmchWematuvexcavauunWasm aHed cursrsed urzsreet ur medrumdersetu dense sardsard maveL urderrarr bvvevv dense sand EYEVE and names 60 The 60 cumamed a WEE percentage UV cubmesupm 18 rrchesrr drarheter Thetub cursrsted urszruuu square enershurrrd and uebacks r Nrmv 2n Yemvorafy structure mlts assouated WIt supports 0 Movement The opposite gure was developed from data gathered m on ahumherorhraced 39 Q m lt 3 E o xarh Ie You want to estirh atethe settlemeht15 ft from the bracing wall of ado rt e avatioh in soft clay C GLOSSARY OF TERMS waler Hurrzurtar trrhher used tu hum cruse sheetrrrg rrr pusr rurr Laggmg Lengths ufsawn hardwuudtrrhher p anks used tu suppurtthe srdes war and tu prevent rhaterrar rrurh thuse races fang rrrtu the excavatmn The term rs arsu sumetrrhes used when rererrrrrgtu the ayeruf puhrrg huards durrrg the same duty rrr trerrches The aggmg rs suppurted rrrturrr by Warmngs regs caps sets urframes as apphcahre See arsu ames heruw Lathes 1 25 tn 1 5 metres rung used tu suppurtthe srde WaHs arrd ruur rrr dnves arrd suppurted rrr turrr by Wahngs regs ur caps as apphcahre strut Hardwuud trrhher usuaHy hurrzurrtar rrr cumpressrurr resrstrrrgthrust ur pressure rrurh the race ur races urarr excavatmn soldrer Vertrcar uprrghthardwuudtrmher usedrur suppumng a trerrch warh tamer thethrustrrurh hurrzurrtar Waers arrd suppurted b struts Wmsm lt w39 32 Professor Kamran M Nemati Winter Quarter 2007 If KI Tem porary Structu res Construction Dewatering memsnm Construction Dewatering of th soil WWW rm The purpose of construction dewatering is to environment in such a way as to permit the structure to be constructed in the dmquot Dewatering means the separation of water from the soilquot or perha e particular construction prob em completely quot T control of ground water and even the improvement of physical properties of soil Yemvoraystruaura Construction Dewatering ps taking the water out o concepts like predrainage of M420 Dewatering CAIS I Excavation from W I lfthe site is on land the sthcture is built in place I lfthe site is offshore the struct osi ion reduce the frictional surrounding ground Add weight Eentonite clay slurry is injected atthe soilstmcture interface etting is used in cohesionless soils Wu omm m Yemvoraystruaura SONS ithin the permanent structure ure is floated into Professor Karnran M Nemati Winter Quarter 200 EM 219 Tem porary Structu res ag Construction Dewatering I CAISSONS Conj d During unwatering a caisson in cohesioniess soils the upward flow from the surrounding groundwater induces a quickcondition which results in loss of strength at the bottom of excava ion To prevent quick condition the head difference caus39n n w should be kep caissons should not be used in the vicinity ofexisting l l structures tha can e damaged due to loss of ground v from beneath their 5 l J roundations Permeability and Seepage w ofWater in Soil Soils quot 39 a which water can flow from points of high energy to points of low energy It is necessary to estimate the quantity of u derground seepage for investigating problems involving the pumping of water for underground construction and makin sta y alysis fearth dams and earth ret ng structures that are subjected to seepage forces 39Wxx mn xi ink cM42o ramparsysmaurs ermeability Test Constant Head Test ASTM D2434 collected In a given time period t Then Q 9 Apparent velocity of the ow 2 7mmth Professor Karnran M Nemati Winter Quarter 200 2 CM 430 Temporary structu res Construction Dewalering Pcnnzabib39zy my In ms Dirty purlsum a gnu sumrm mm mm may munum saxmm ls V meiwzmvam y Mm 5 mm mm m L Pcnnzabib39zycomw 29 gt QvA2 gt know PM L v 1a z a g Him summr k m v Mug ochnnzability for Vivian soil W Mum mm m mm a m mm m n ml by m w m an x mm 1 Ahquot le meessm Kammn M Neman Wm Quarter 2007 Temporary Structures W U if is H5 ear 9 F l tilearn i M mw Construction Dewaterlng Temporary Structures Example for the Constant Head Test For a constant head laboratory permeability test on a fine sand the following values are given Length of specimen 10 in Diameter of specimen 25 in Head difference 18 in Water collected in 2 minutes 0031 in3 I Determine a Hydraulic conductivity k of the soil inlmin b Discharge velocity kQL 0 03110 HA 182522 b vkz390175gtlt102O315gtlt102 inmin will W I I itquotf 0175 gtlt102 in min Temporary Structures Permeability in the Field by Pumping from Wells In the field the average hydraulic conductivity of a soil deposit in the direction of flow can be determined by performing pumping tests from the well 2 2 72 kH2 H1 Original groundwater q Steady state pumping rate R level 2 I Ground surface 2 1 g I 0 39 39 dp p pql l 4 39 u quot 39 I 4 5 v e v 39 u o I I 39 p I I w v I 0 r 1 d a y I a u I I 39 4 O l n Q I 39 l e 39A n r I 39 K 39 I 39 39 39 1 Z 1 39 I h 39 39 f 39 vi 139 l u 4 s a o r I Groundwater level r 39 I x k t n a v v 39 39 r l 39 4 durlngpumpmg l 2 2 t I 39 L 39 39 I 39 a r39 4 39 H I V 2 quot 3939 l 39 quot quot 39 vV gt Q s b 39 A 8 H 0 quot 2 I 39 39 39 Pumped weir77quot radius of influence Temporary Structures k Determined from Pumping Tests 10000 39 5000 For D10 03 mm k 2000x10394 cmsec 02 cmsec 0quotIquotH151A H1185 I o 3939Fc105 ti EES39 quotESez i7 ORi Coefficient of permeability x 1039quot4 emsec 005 01 v 02 03 05 10 20 00 Effective grain size of stratum mm war I m lures 11 Professor Kamran M Nemati Winter Quarter 2007 4 1919 Tem porary Structu res Construction Dewatering o la Consider the case of p umping from a well in an unconfined permeable la er under ain by an impermeable stratum Given q 26 mein H 157llatR 1oon H2180llatR2200 Calculate the hydraulic conductivity in mm of the permeab e layer n Wu wlu ms UNlVERSlYY 0F rW ASI l INGTON Dewatering Methods Wellpoints pipe at the surface cons i u e a wellpoint system 39Wxx vmmtk CM42o remwaymw Dewatering Methods Wellpoints Effective lifts of 15 fl are quite common at sea 39 39 Iifk ran Imml be increased to as nuch as 25 ll 7mm w m Professor Karnran M Nemati 0 Winter Quarter 20 7 Temporary Structures Construction Dewatering Wellpoint header linef 3192 L Q of pump suction39 T Temporary Structures Dewatering Methods Wellpoints Wellpoint h w I f w Orlgmal water level Atmospheric pressure Wellpoint Predrained water level Suc39 on Normal 15h 5m h Practical maximum 22ft I m hPiezometer llNl39r FR5lquotT39 Cquot l Wi t llll lm l l 15 r Temporary Structures Dewatering Methods Wellpoints I T T T T T T T T l i 39 i l l i l a J lquot i 5 l r L 16 420 Temporary Structures Dewatering Methods Wellpoints N 1 39 I 39 j ne 39 Normal weter level elevation 4 sand 39 39 Loose fine sand Elevation M l 39 53212 ll 39 Predrained water level lt Elevation 18 I u V 3 medium sand V R N j trace silt L 1 Multistage wellpoint system 39 m m aura 17 Professor Kamran M Nemati Winter Quarter 2007 P m 1429 2 Tremie Concrete Temporary Structures II Tremie 7 I W5quot H I NGTODF c Iremie Euncrete underwamr cmaem p aw an mporbant ro e m me cmsuucuon venous e emenB m oompom acnon a e to me pmng m me fooung m x c Iremie Euncrete Mix Hg sump concrete wmw set retarders SmaHer aggregate sues Fourrhour Wor a My Deswgned for p acement under wamr Ma uerme p pe Drawn me Nemau m Quamxl m W129 TemporaryStructures a WASHINGTON Trem Concrete Iremle Euncrete Wm Strumlzl tirem 5 mm ewe ci36quotm2x m m sass as We TaaT aggegae WweTgH fme mat 5m mm a the ADM anal Woe n WWW magma PaIIaalu ASrMsls Type NoTF mn bxVd39 c Iremle uncrete Warmm Ma n oz n os Wham Wtfarkadlmnglc wxmDvefenb vu T aka dthmev oahmamumhmm Ar mm mm Ughasthmath mm ame Yo mam eumg The to m W W whammy weth h the We a 55nn 7 mm m 2 2a dav 1 Wm Rwoulunzx veofs n ma x hamav mum M T Vope vphmd mad 9w mme egegahm and mum m a c Placemml ul Tremie Euncrete The uTaeahent Bf name mnueta Ts u 10 12h we The we may be samahaT tut JDTMS shaqu be ahead and bdtad wnh sum baa gasket sa 5 m DTEEntanv WV Taakaee Bf wane The name we must have suf ment wau dezs sa that n reeanvev buwam when anntv meessax Kamnn M Nemau sze Quarter 2mm 2 CM 67291 Temporary Structures ru I v s a s I v v o F i WASI IINGTON Tremle Concrete Placement of Tremie Concrete I Install a steel plate on the bottom end with a soft rubber gasket The plate is tied with twine to the pipe c o vempwy Slrumura Tremie Pipe Eakngimme mg in eulian lhezmlvxlavi mm 2 m mm mm in mm mm pixmvenlm m mm mm mm be mm m 04 x c o vempwy Slrumura Transition of the pipeline from vertical to horizontal a Professor Kamran M Nemati Winter Quaner 2007 3 ii Temporary Structures 1i Ugll n f slj f OF Tremie Concrete r ASllINGTON rm39 3 39 Tremie Concrete Application Tremie concrete procedures was used to repair damage to a reef in the Florida Keys caused by vessel impact I The impact site was located in six to ten feet of water off Miami in a region 0 t e reef frequented by sightseeing boats and recreational divers The ship impact destroyed the living surface 0 t e reef over an area of approximately 50ft by 70ft forming a shallow crater in the reef Diver Places underwater tremie concrete etween reef unils and bottom Bottom of ge can been seen just a few feet above the diver39s head 39 l39rriic o C u Placement of Tremie Concrete Tremie pipe on the bottom All connections tight Notches in bottom of pipe Place rabbit in top of tremie pipe Keep minimum 50 feet into concrete Keep tremie tied down with stout ropes Wmiriiicfm v n C C Placement of Tremie Concrete The placement is started by placing the sealed pipe on the bottom and then partially filling it with the tremie concrete mix When tremie has been filled to a reasonable distance distance required to overcome the frictional head 12 m above the balancing head of fresh concrete versus surrounding liquid the pipe is raised 150 mm allowing the concrete to flow out The lower end of the pipe is kept embedded in fresh concrete but no deeper than where the concrete has taken the initial set with retarder to prevent the initial set the depth of embedment comes less sensitive Which Kmml 12 Professor Kamran M Nemati Winter Quarter 2007 4 Wi Tremie Concrete Temporary Structures W aigf h 39 x 39 J Placement of Tremie Concrete The tip of the tremie pipe should always be immersed about 1 m as a minimum so as to prevent water in ow into the pipe The ow of concrete should be smooth consistent with the rate at which ooncrete can be delivered into the hopper at the top The method of delivery should provide relatively even feed to the hopper rather than large batches being suddenly ump When large aras are to be oovered multiple tremie pipes should be used The distanoe tremie can ow without exoessive segregation is between 6 and 20 m Wx sr 1i mm c u IMWHW 51mm Placement of Tremie Concrete Till xlilN o j Tem porary Structures I Tremie Concrete App ca ons l i i r rir rk d Professor Kamran M Nemati Winter Quarter 2007 lumneFesl r QF 1 Temporary Structures Temporary Structures er Pile Tremie Concrete SPTC is used for very difficult conditions in soft ground with a high water table Soldier piles are are set in predrilled holes and the space between flanges of adjacent soldier piles is excavated and filled with bentonite slurry Reinforcement is lowered into the trenches and tremie concrete is placed As tremie concrete displaces the slurry it is collected and recycled for future use The final product is a continuous concrete wall beneath the ground surface prior to excavation After completion of the wall excavation and interior bracing can begin WEalED mjm 16 C 0 Temporary Structures Soldier Pile Tremie Concrete Reinforcing steel Tremie tube n25 39 j r Previous section Steel wide flange section in predrilled holes Writififfj id 17 C 0 Temporary Structures SI u rry Tre nch Typical free hanging mechanical clamshell for slurry trench excavation r Li EM my gr WH ASHDJIZSDM Professor Kamran M Nemati Winter Quarter 2007 6 32 Temporary Structures Tremie Concrete a Soldier Pile Tremie Concrete M i r T eehanging mechanical Ni l39ERSIY EJF I l WA SHINGTO c n c u Slurry Trench Method Cont d Used in cases of troublesome dewatering and excavation support problems It involves constructing an impervious barrier beneath the ground surface The excavated material is replaced with heavy clay slurry the lateral pressure from the slurry Will keep the trench open V 21 leix r ri xxliox Professor Kamran M Nemati Winter Quarter 2007 cm 63 Tremie Concrete Temporary Structures ak1 r Slurry Trench Method Cont39d I After the excavation is completed concrete placement follows using tremie ooncrete method from bottom to the top of excavation I As tremie concrete displaces the slurry it is collected and recycled for future use I When the concrete is cured site is enclosed within a rigid impervious barrier I This method has been employed to depths exceeding 200 feet Wags c o ramparary swam Slurry Trench Diaphragm Walls In recent veal39s the slurry trencn metnod nas been successfullv developed to deal We partlcularlv troublesome dewaterlng and excavatlm supper problems beneath the ground surface Temporary Skinning c g Slurry Trench Diaphragm Walls W Professor Kamran M Nemati Winter Quaner 2007 Temporary Structures 1 Eag ig Slab Form Design 20 Temporary Structures Temporary Structures Slab Form Design LJNIl39u39EREIl T l39 ill l l meal l l NGTGN C 0 Temporary Structu res Slab Formwork L She hing 39 quotquotquot StringENE Shore 5 q Parts of wpical slab formwork I a a i n F 39 3 3 Wile E l 3 I271 20 2 C 0 Temporary Structu res Slab Formwork Design Steps Step 1 Estimate design loads Step 2 Sheathing thickness and spacing of its supports joist spacing Step 3 Joist size and spacing of supports stringer spacing Step 4 Stringer size and span shore spacing Step 5 Shore design to support stringers Step 6 Check bearing stresses step 7 Design lateral bracing Wu l E Ii Z a a 3 Professor Kamran M Nemati Winter Quarter 2007 1 quotumnvEHEI l r a l e ailimam I NGTE JH Tem porary Structures Temporary Stru ctu res Slabform Example Design forms to support a flat slab floor 8 in thick of normal weight concrete using construction grade Douglas Fir Larch forming members and steel shoring Ceiling height is 8 ft and bays are 15x15 ft Since forms will have continuing reuse do not adjust base design values for short term load k A I ib lt Ainch plywood I aw um 30 3 30 30 I 7 I 7 l 7 tan 39 a u WHI Still i 4 C 0 Temporary Structu res Slab form Design Example I STEP 1 ESTIMATE LOADS Dead load concrete and rebar 8 in 12 inftX 150 pcf 100 psf Minimum construction live load on forms 50 psf refer to lecture 1 Weight of forms estimated 8 psf Total form design load 100 50 8 158 psf I a a 5 Y a j39 i WH39AEEELNQ TIDEZ C 0 Temporary Structu res Slab form Design Example I STEP 2 SHEATHING DESIGN Assuming 34in form grade plywood sheathing from Tables 4 2 and 4 3 Fb 1545 psi FS 57 psi E 1500000 psi 5 0412 in3 I 0197 in4 IbQ 6762 in2 1ija im w Professor Kamran M Nemati Winter Quarter 2007 a 1412 Slab Form De Temporary Structures n CHECK BEND W47 Summngmm eon c m 4qu mm mm 2 lrfmhmde mp ufp kuud m w aewluaaunsapsrxl my amp mm m 158 SBlblf v WKs d FaA my meessur Kamran M Nemau wmr Quarry 2mm Temporary Structures Slab Form Design W Temporary Structu res Lay 139 I Slab form Design Example CHECK ROLLING SHEAR For design purposes consider a 1foot wide strip of plywood Then VQ 3 119 since Vmax 06wL so FsV QO6WLgtltg or b b i Substituting in above equation 2 F5 x E 57 x 6762 40 ft or 48 inches 06w Q 06 x 1 58 WWA FIEEIit jiit39if39i 10 C 0 Temporary Structures Slab form Design Example From the above calculations I 208 in governs Meaning that joist supports CANNOT be more than 208 inches apart HOWEVER in order to select the span we must consider the size of the plywood sheets and equal spacing of supports In this case 5 equal spaces of 192 inches on an 8ft wide plywood sheet will be appropriate I ELF f0 1 1 C 0 Temporary Structures Slab form Design Example I STEP 3 JOIST SIZE AND SPACING OF STRINGERS TO SUPPORT THE JOISTS Check 2X4 construction grade DouglasFirLarch as joist forms are used repeatedly so there is no shortterm load adjustment From Table 42 F 1000 psi and FV 95 psi and should be adjusted for horizontal shear by a factor Of E Z Z TABLE 42 REPRESENTATIVE BASE DESIGN STRESSES PSI NORMAL LOAD DURATION VISUALLY GRADED DIMENSION LUMBER AT 19 PERCENT MOISTURE AND PLYWOOD USED WET Derived from recommendations of the American Forest amp Paper Association Reference 43 and from recommendations of the American Plywood Association Reference 48 Extreme ber Compression Compression Horizontal Modulus of bending stress I to grain to grain shea elasticity SPECIES AND GRADE F F a II to 9 E DOUGLAS FIRLARCH I I I I a i No 2 24 in thick 2 in and wider 625 1300 39 1600000 II 11quotng k E I Construction 24 in thick 24 in wide 1000 625 1600 1500000 12 Professor Kamran M Nemati Winter Quarter 2007 IJNIIEEEFIEII IT Ell I was I I HETDH 9mm Temporary Structures Wgsvm ag Slab Form Design Slab lurm Design Example mtgmam answth T i ngsqu m 12 Ime Yzb e us my mm M s 25 m 1 35m 2nd 2 as m c 39W m 551nv5 mum 2mm w 253 mzm n m wanna n v w v in x W mm m mnzmm sham mas immua in a unfum v ma a cmnmcus team 2 vwnnvx253 Linn 525 9033717253 2 km A o L 45339x12m 595mmes 12 meessur Kamran M Nemau wmr Quarry 2mm 41211 Temporary Structures x s r Slab Form Design I WAS39HINGKDDIG Campanng the three spans a m ated abqu I aa 1 nches gnvems Cunsnenng 15x15 feet bays and 35 mm spamng s a reamnabb number Ms meanst at the mung Bf ha Y 5X36 1803nche 715ml 4 mamaswow ramN a quot xixIn quot39 11 Y w M Dmmmm m m M 1 Vw Wm meessur Kamran M Nemau wmr Quarry 2mm 9174129 Temporary Structures Wgsvamig Slab Form Design Slab lurm Design Example Ithm me aha2 takuanms 1 42 5 m um Meannu that smngevs CHNNOT be mule wowgvaz m am an sdan an mmensmns Bf m2 bsv IThe 15a mycmwdbemmmnms any space was nhes Jar5 as 3 a lajgyabb span cm 5 r is c warmth2W we m check me pumbhwofuxmg 2 deevev mngem e 3x5 w my H mm the hurewaung in mm H Wm have we Wu max beryer m 2 3x5 membev Fuv54 3xsfmm Yzbk n a lnnnpf2nd L a m mm H m F mum WT m m mvsxsm smm W MT m 45m wvm mm m w 3x5 mm W W Me the mm 5 mm Dzze c arm 5 SHORE DESK smngev m and 2mm 2mm meed hymn waned 45 vth 2pm meessur Kamran M Nemau wmr Quarry 2mm 7 Slab Form Design Temporary Structures l Slab form Design Example Schematic design an sis imam e 1923 Ei39 h 7 l i Eagle u 4x11 shores El Elf em l 39n m I I I a u mi f t E l M KIWI Temporary Structu res 22 IJNI EFingT ll l tilins llH T N Slab form Design Example Refer to Table 711 for wood shoring material Both 3x4 and 4x4 are more than adequate to carry 1778 lbs for an effective length of 8 ft C 0 Temporary Structu res sa gt gr Slab form Design Example Step 6 Check Bearing Stresses Bearing should be checked where stringers bear on shores and where joists bear on stringers Stringers bearing on shore Assume the head piece of the adjustable steel shore is 1112x3 58quot The 3x6 stringer is actually 212 in thick Bearing Area Ii Mia 24 quot39 w f39 quotF39 quot39 J IF quot Lillilu illIiquot g z r sa l Niall5395Lllg 1 tL quotfquotm C 0 Temporary Structu res Professor Kamran M Nemati Winter Quarter 2007 174320 Temporary Structures txglfl 1 g Slab Form Design J Slab form Design Example Ifthe headpiece is placed parallel to the stringer baring area is 2 2x11 2 or 2875 in2 Bearing strss will be total shore load 1778 S 62 ps1 beanng area 2875 This is well below the base Fa Which is obtained from Table 42 the value of compression L in grain Fa for No 2 2x4 Douglas FirLarch is 625 psi c o vampwy swam Slab form Design Example Joist bearing on skin ers Tne two members are 1V2 and 2V2 H v Wide Contact beanng area 2mm 3 75 Z Average load transmitted byjolst to smnger is lost soacmg gtlt Joist span gtlt fonn load x x1587581b 12 12 75811 202 3 75 in2 ps39 Bearing at this point is also low relative l e 625 psi base value for FM W Professor Kamran M Nemati Winter Quarter 2007
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