TEMP STRUCTURES CM 420
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1 432 Temporary Structures Formwork for Concrete CTTITWASIIINdTON 5520 Temporary Structures Temporary Structures Formwork For Concrete 1 WSVTTT 31116103 c o Tempwy Mme CM 420 Temporary Structures The rst part ofCM 420 MT oeaT wnh the mate a s memoos and teehthues assooateo wnh temporary suuhctures uuhzed Tn venous construcuon operauons suc as concrete formwork conshuchon major emphase Wm be pTaeeo oh concrete formwork eohsouehoh Coverw vg deta ed oeSTgh anaWsTs of oom vernca and hohzohtax umber formwork systems c o Tempeery meme CM 420 Temporary Structures There Wm be two mToterm exams and three omzzee szzed Wm be gwm mmughnut the quane someones unawrmunced The rst Exam M be gwen semnd Una oh Thursday Ma Grading System The course w A H h the foHowmg WeTghB 25 fur humewurk ass gnmEnE 15 fur three qmzzes 3U fur 21h mwdtam exam AH exams Wm be dosed book on Tuesday Februay Tu and the mh am mm Professor Kamran M Nemati Winter Quarter 2007 QM 43250 Temporary Structures Formwork for Concrete CTTITWASIiINdTON CM 420 Temporary Structures Recommended Textbooks Hur M K Formwork for Concrete 6th edition American Concrete Institute Detroit Michigan 1995 Ratay Robert T Handbook of Temporary Structures in Construction 2nd edition McGraw Hill New York 1996 WW1 C o Yemporery Structura CM 420 Temporary Structures Class Web Site is located at httpcou rseswashingtoneducm420 c o YMWW Wm Formwork for Concrete Formwork development has paralleled the growth of concrete const uct39o throughout the 20th century The increasing acc plance of concrete as a major constr cu39on material presents the form builder 3 new range of problems in the development ofappr 39 t sheathing materials and maintenance of rigid tolerances Wimi i Professor Kamran M Nemati Winter Quarter 2007 Li M Ii ls E E 5 T 391quot D P W l l I TilSTEM Temporary Structures crete Tem po ra ry Stru ctu res Formwork for Concrete Formwork is a classic temporary structure in the sense that g7 l it is erected quickly highly loaded for a few hours during the concrete placement g a and within a few days ErrWolers r Wood forms Wire snap ties disassembled for future use El Also classic in their temporary a nature are the connections braces tie anchorages and adjustment devices which forms need W 1 vquot 39l llj ii ill at ll Ill 1i Aikli tita 7 C 0 Temporary Structures Formwork for Concrete The term quot Temporary Strumresquot may not fully imply the temporary since some forms tie hardware and accessories are used hundreds of times which necessitates high durabiliw and maintainability characteristics and design that maximizes productiviw Unlike conventional structures the formwork disassembly characteristics are severely restricted by concrete bond rigidity and shrinkage which not only restricts access to the formwork structure but causes residual loads that have to be released to allow stripping from the concrete which initiates disassembly I m Ei lfl t iiI IJIEai 8 C 0 Temporary Structures Formwork for Concrete Lumber was once the predominant form material but developments in the use of plywood metal plastics and other materials together with the increasing use of specialized accessories have changed the picture Formwork was formerly built in place used once and wrecked Because of high labor costs in the US the trend today is toward increasing prefabrication assembly in large units erection by mechanical means such as flying forms into place by crane and continuing reuse of the forms V I E ii in ii 5 E if E Etieiilillfiiilti isi 9 Professor Kamran M Nemati Winter Quarter 2007 3 CM 63290 Temporary Structures Formwork for Concrete UNIVfRSIWY OF WVVAS H I N GTON Formwork for Concrete or Wood ve 5L5 steel formwor o odularpane formri isownconnecting hardware and goo for extensive reuse were realized Bviioiiiimsfor quot quot commerciallv and used in the field g v v i A A 1909 construction scene shows the rst application of steel form street paving c o remwsy same Formwork for Concrete dular panei forming l5 the norm All i c o rempaery simme Objectives of Form Building Forms mold the concrete to desired size and shape and control its position and alignment But formwork is more than a mold it is a temporary structure that supports ils own wei the 39eshly placed concr ta construction live loads including materials equipment and per onnel Professor Kamran M Nemati Winter Quarter 2007 M429 Temporary8tructures a Formwork for concrete WASHINGTON Easm enemas m imm mum ave m2 fdd cum 7 yn mm a mug quotmm mm m dmermm y mg m 59w n m m mm m m mm Amduve WWW mg m mm mm m MWmaummmm CmDEvanm 2rd mdnanm banem mans mmmam the mmm ave mazsaw m 3mm mesa ma s Emmy u 2 mm mm mm Famwuvk m mum up w 5n Demenl y the mm 2 mm m 9 made Wm m dex gmng 2nd b quot73quot x m the zmludov hde m a WWW mm 1 WW mmmg mzhlyov Xzfely gt c s me And mm 9mm bezmx 2rd my mum mum e emenl dEDend on zzzuzle mmmm the Farquot m Am m mm m3 9M md n We d WEKMWW W a m mmmg mhm quot1 Wm mm m m M M m M m mm m WWW m m m the Wm M mummy mu m we g a me nd 3mm m mm meessur Kamran M Nemau wmr Quarry 2mm CTWWASHlNdTON 6330 Temporary Structures Formwork for Concrete Causes of Formwork Fallure Formwork tarlures are cause of manv accro ts and tarlures that occur ourrng concrete constructron whlch usuallv happen when fresh concrete rs perng placeo Generallv some unexpected event causes one member to tarl then othens pecome overloaded or mrsalrgneo and the entrre tormwnk gr cture collapses Formwork collapse causes rnjuries loss ofllf pe damage an E g 7 construction delays 5quot t Wounm n c rehearsry rumura Causes of Formwork Failure The main causes of formwork failure are 1 Improper stripping and shore removal 2 Inadequate bracing 3 Vibrati 4 Unstab not plum 5 Inadequate oontrol of ooncrete placemen Lack of attention to formwork details Loolrno onlhe orouno useo as a base rora 7 on e soil under mudsillsquot shoring Muusrll A planh rramer orsmall shore or poslrrrrormhor rehearsry Strumura c 0 Causes ofFailul39e Improper Stripping and Share Rem val Premature strrpprng of forms premature remwal of Shores and careless Dractlces ln rershorlng can produce catastrophrc resulmr for E e menl bulldlng e supporleu pylloorsmays a 2 old or older Fallule occurreu on lhe24lh lluul whele llwas shoreu lolhe 5rdayruld 23m lloor The marinaded 23m lloorlarleu m shear arounu one ormore columns lllggellng a collapselhal cameo lhluugh lhe enlrre helgm ollhe bulldlng Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures WU I v r a 5 v r o F Formwork for Concrete WASl39llNGTON Causes of Failure Inadequate Bracing The more fre uent causes of formwork failure however are other effects that induce lateral force components or induce displacement of supporting members Inadequate cross bracing and horizontal bracing ofshores is one of the factors most frequently involve in formwork accidents dollars had been spent on diagonal bracing for the formwork support asllM u39 w u Ianrmrzrystruclures Causes of Failure Inadequate Bracing Use of Diagonal Bracing High shon39ng with heavy load at the top is vulnerable to eccentric or lateral loading Diagonal braclng improves the stabrlrty ofsuch a structure as do guys or struts to solid ground or competed structures Ill ll le i Mimi Zn Ianrnrzly Structures quot Causes of Failure Inadequate Bracing The main exhibition oor of the New York Coliseum oollapse when ooncrete was being place Forn39s for the oor slab were supported on two tiers of shores Case study New Vork Coliseum orrnwork collapse where rap39d delivery of concr e forces at the top of high shoring Professor Kamran M Nemati Winter Quarter 2007 7 we Temporary Structures Wu r3 a E a 5 l 1 v o F Formwork for Concrete WAblllNGTQN Causes of Failure Inadequate Bracing Use of Diagonal Bracing Case study New York Coliseum Increased diagonal bracing was added to all remaining shoring following partial collapse of formwok g c Causes of Failure Inadequate Bracing Use of Diagonal Bracing When a failure occurs at one part inadequate bracing may permit the collapse to extend to a large portion of the structure and multiply the damage Suppose a worker accidentally rams or wheelbarrow into some vertical shores and dislodges a couple of them This may set up a chain of reaction that brings down the entire oor One major objective of bracing is to prevent such a minor accident or failure from becoming a disaster 39frl mgdggstxw 23 c Causes of Failure Vibration Forms sometimes collapse when their supporting shores or jacks are displaced by vibration caused by passing traffic movement of workers and equipment on the formwork the effect of vibrating concrete to consolidate it Diagonal bracing can help prevent failure duerto vibration lf 39 lmvfo 39 Professor Kamran M Nemati Winter Quarter 2007 8 M4129Temporarystructures a Formwork for concrete WASHINGTON EzusesoIF um mung mm Mudsllls sham m awakde be 22k m 2 2 m2mw2zm 2ndzmxlmdedwzH mm 222 magma youndthm mmmmm 2 mm Aegmmdmmlbe 2mg mamthe mm mm euhng Animudsm mmlmlvexl r 5 mm M be meant m mm 2 wath max uwahng the NM 22 o FzIIure mam2 mm 039 outlet Flammmk blen Vuxuexlhzl u 2 ul em m mg 2 2m Wm 22 ufmnmw go enhz mm md m m mzvprudul mm mam 2m mam mm L formwufx 39n x 22 o FzIIure thk autumnquot m rumwuk Details awhth r222 mmmm may mum Km dffererre m zxxemb vdeh m2v f Tu oa mm mm uzdng mm w mm 22 mde 22 mm rmth a Mu thgHen me 0 n deuce mew hnnng myde m Mme mm 272 meessur Kamran M Nemau wmr Quarry 2mm 9 I 439 Formwork for con Planning fur Sale Temporary Structures crele OSHAOltwvzhomSzfehzn e Mmmmnhon reguzhu Immue AG yem veau men Kim M d He ne Amman made endzl we m k uwad 9mg 2rd Rethng Rememnp e Mhled z m P39epan ngneey 2nd Hindu rung 2nd mdmung Ydeume n 2 FummkSDea ahm W 2rd oa Dd y mu d be in mm 2nd lnXDe v Wex s39 ri meessur Kamran M Nemau n w car Quarry 2mm Temporary Structures T U 2quot 39i 2539 quotT P F WHEN I Hill Hiqu Form Materials and Accessories v 2 7 1 2 A L I y 0 l l 139 Temporary Structures Temporary Structures Form Materials and Accessories LJI39iJll u39EREITT ll in wawnwnmw C 0 Temporary Structures Form Materials and Accessories Practically all formwork jobs require some lumber Local supplier will advise what material and sizes are in stock or promptly obtainable and the designer or builder can proceed accordingly Southern yellow ine and Douglas fir sometimes calle Oregon pine are widely used In structural concrete form They are easily worked and are the strongest in the softwood group Both hold nails well and are durable They are used in sheathing studs and wales l I nullJ ETE Wmasialw39iiisttw 2 C 0 Temporary Structures Form Materials and Accessories ll II I l u f ii I N 0 if 39 quot 1 r I 39 Jugquot j 3 H L 095 I I V b 6 ll U X n 39 I quotLiiilgi 5 I 0 39 U d S Footing a a Plate Typical wall form with components identified Plywood sheathing is more common than board sheathing material Wiriaifaii915133 3 Professor Kamran M Nemati Winter Quarter 2007 1 Temporary Structures W u 4 It E 5 it F I Tiau illinif w Form Materials and Accessories Temporary Structures Form Materials and Accessories F t n 1 n I 1 It i 39 39 l 39 g N w 13 E 31 V WALE quot 39 a I i g g I a 2 3 5 55 9 5 S v I 7 LE Wales provide points at stud support WA I 7 a a j Parts of typical wall formwOrk Wilhelmiihide 4 C 0 Temporary Structures Ties A concrete form tie is a tensile unit adapted to holding concrete forms secure against the lateral pressure of unhardened concrete A wide variety of readymade ties with safe load ratings ranging from 1000 lb to more than 50000 lb are used today They consist of internal tension unit and external holding device and are manufactured in two basic types Continuous single member Internal disconnecting type i113iillrif Wuxxalalmatch 5 0 Temporary Structures I quot Wedge or Tie Hold Desin Varies wmer Seal Optional J II IIquot u v if WASHER SPREADER CRIMPED FOR BREAK BACK I Washer End Optional Some commonly available Single quotma aata aomAY member ties 39 D LTAPER TIE TO BE WITHDRAWN 1quot J n i STRAP TIE USED WITH PANELS 7 Av LOOP END TIE USED WITH PANELS V 39 El Lll Hi pi r39 i I E III martiniMicah 6 Professor Kamran M Nemati Winter Quarter 2007 2 Gil7 Temporary Structures W xg Form Materials and Accessories J Continuous Single Member Ties Continuous single member in which the tensile uni i a single piece and a special holding 39 39 aging the tensile unit against the exterior of the form e single member dlstance some are cut flush with the concrete sur ace Wu r wn c o vempwy swam Internal disconnecting Type Ties Internal disconnecting type in which the tensile unit has an inner pa 39 th rt WIth r aded connections to removable external members which make up the rest of the tensile unit The generally remain in the concrete Wumftik o v yempm same T Ies The two types of tying devices are identified commercially by various descr39 ti names such as form clamps coil ties rod clamps snap ties etc Except for taper ties the continuous single member type is generally used for lighter loads ranging up to about 5000 lb sa The internal disconnecting type of t39 39 available for light or medium loads but finds ils greatest application under hea ier construction loads up to about 70000 lb Wit Professor Kamran M Nemati Winter Quarter 2007 Temporary Structures Form Materials and Accessories V willquot l M She hing 5 f doile R Slringer7gt Shore 5 4 Parts of typical slab formwork 39 El 1 El 3 i 3 ii Ulla l a l m TEEa If Temporary Structures Fo m Materials and Accessories 10 IJHIMFHEI T DP l WASHI 3 ETD H Lumber Finish and Sizes finished concrete I 39 claim Fifi Wat1 l a l zine C 0 Temporary Structu res Lumber which has been surfaced in a planing machine to attain smoothness of surface and uniformity of size is called dressed lumber The surfacing may be on one side 15 one edge S1E two sides SZS two edges S2E or combination of sides and edges SlSlE SISZE SZSlE or on all four sides S4S Dressed lumber is generally used for formwork because it is easier to handle and work but rough sawn boards and timbers may be used in bracing and shoring or as a form surfacing material to secure a special texture effect in the 11 Lumber Finish and Sizes and dry lumber 3l2 gt Specified actual size of a 22 2x4 for different moisture contents and finishes Essasq Rough 19 Percent Moisture I w BL is i it 7 3 q i W132 213 l 2 I NE 13in S48 l9 Percent Moisture l 916 C 0 Temporary Structu res Minimum sizes of both rough and dressed lumber are specified by the American Softwood Lumber Standards PS 2070 It changes the dimensions to equate green Lumber is commonly referred to by its nominal size Minimum sizes for green lumber are selected so that as moisture is lost it becomes the same size as dry lumber llt3 slice a I S48 More Than l9 Percent Moisture 12 Professor Kamran M Nemati Winter Quarter 2007 als and Accessories Temporary Structures Table 41B shows actual dimensions and cross section properties of American Standard lumber at 19 percent moisture content must always be used for dedgn Values of Table 41B can be safely used with either dry or green lumber LuiJJEu39 t 1 itiatzlztfirzttw Actual not nominal sizes 2 a Temporary Structures Form Materials and Accessories TABLE 41B PROPERTIES OF AMERICAN STANDARD BOARD PLANK DIMENSION AND TIMBER SIZES COMMONLY USED FOR FORM CONSTRUCTION Based on data supplied by the National Forest amp Paper Association x I 1 X I X 4X13 the neutraI axis c1 ff x x j i Area of section Moment of inertia Section modulus Nominal Amerpan Standard 5 i 39 39n Board A roximate SlZe Inches bxd q nquot m I 39 p13 SIze 39 390 39 A bd I boa12 S bola6 feet per weIght lb per inches 848quot at 197 A linear toot linear ft for use bxd max39mum mo39Sture of piece in form design Rough 84 Rough S48 Rough S48 4x1 3 zx 317 262 020 012 046 033 033 06 6x1 5 2x34 492 412 031 019 072 052 050 10 8x1 7x34 645 544 041 025 094 068 067 13 10x1 9394x34 820 694 052 032 1 20 087 083 17 12x1 11X 995 844 063 039 145 105 100 20 4X1 31X1 408 350 043 029 076 058 042 09 6x114 5 2x1 633 550 068 i 046 119 092 063 13 8X1 A 7X1 830 725 087 060 156 121 083 18 10x1 A 91 1055 925 111 077 198 154 104 23 12x1 A 11X1 1280 1125 135 094 240 187 125 27 X1 V2 312114 498 437 078 057 114 091 050 10 687 122 089 39 1 77 143 075 17 906 160 118 232 7 189 100 22 0x1 l 2 9 Ax1 4 1289 1156 203 150 295 241 125 28 12X1V2 11x1 4 1564 1406 246 183 358 293 150 34 4x2 3 2x1 2 589 525 130 098 1 60 131 067 1 6x2 5 2x1 2 914 825 201 155 248 206 100 20 8X2 71V2 1198 1 087 264 204 325 272 133 26 10x2 9112 1523 1387 335 260 413 347 167 34 12x2 11X1V2 1848 1687 407 316 501 421 200 41 2x4 1 2X3 2 589 525 645 536 356 306 067 13 2X6 1 2X5 2 914 825 2410 2080 857 756 100 20 2XB 1392x7 1198 1087 5432 4763 1473 1314 133 26 1 2X10 1 2x9 1523 1387 1 1158 9893 2380 21 39 167 34 2x12 1 V2x11 4 1848 1687 19931 17797 3504 3164 200 41 3x4 2 2x3 2 952 875 1042 898 575 510 100 21 3x6 2 2x5 2 1477 1375 3893 3466 1384 1260 150 34 3x8 2 2X7 1936 1812 8774 7939 2380 2190 200 44 3x10 212x9 2461 2312 18024 16489 3845 3565 250 56 3x12 272X11 x 4 2986 2812 321 96 29663 5661 5273 300 68 4X4 3V2X3 l 1314 1225 1439 1250 794 715 133 30 4X6 3 2x5 2 2039 1925 5376 4853 1912 1765 200 47 4X8 3 2X7 4 2673 2538 121 17 1 1115 3286 3066 267 62 4X10 3V2X939A I 3398 3238 24891 23084 5310 4991 350 79 6x3 5 2x2 2 1477 1375 848 716 646 573 150 33 6x4 5V2XSV2 2039 1925 2233 1965 1232 1 123 200 47 6X6 512x5392 3164 3025 8343 7626 2966 2773 300 74 6X8 5 x7 2 4289 41 25 20781 39 19336 5451 5156 400 100 8x8 712x7392 5814 5625 281 69 26367 7389 7031 533 137 Rough dry si2es are 118 in larger both dimensions Based on a unit dry weight of 35 lb per cu ft Actual weights vary depending on species and moisture contents At 15 percent moisture content the unit weight 01 Douglas FirvLarch is 3411 per cu ftand that of Southern Pine is 37 lb per cu ftThe other species commonly used in formwork in North America weigh less 13 IaJP Illl39siFFi l39T 111P 1415111111371 C 0 Design for formwork is based on the allowable or working stresses Allowable stress depends on so many factors including the species of wood grade cross section moisture content and load duration 1 111slziaozmi TABLE 4 2 REPRESENTATIVE BASE DESIGN STRESSES PSI NORMAL LOAD DURATION Form Materials and Accessories Temporary Structures 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 1 to grain to grain shear FV elasticity SPECIES AND GRADE b c a ii to grain E DOUGLAS FlR LARCH No 2 24 in thick 2 in and wider 875 625 1300 95 1600000 Construction 24 in thick 24 in wide 1000 625 1600 95 1500000 DOUGLAS FIRSOUTH No 2 24 in thick 2 in and wider 825 520 1300 90 1200000 Construction 24 in thick 24 in wide 925 520 1550 90 1200000 SOUTHERN PINE sizeadjusted values No2 24 in thick 24 in Wide 1500 565 1650 90 1600000 No 2 24 in thick 56 in wide 1250 565 1600 90 39 1600000 No 2 2 4 in thick 8 in wide 1200 565 1550 90 1600000 Construction 24 in thick 4 in wide 1100 565 1800 100 1500000 SPRUCEPlNEFIR 39 No 2 24 in thick 2 in and wider 875 425 1100 70 1400000 Construction 2 4 in thick 4 in wide 975 425 1350 70 1300000 HEMFIR N0 2 24 in thick 2 in and wider 850 405 1250 75 1300000 Construction 24 in thick 24 in wide 975 405 1500 75 1300000 ADJUSTMENT FACTOR FOR MOISTURE CONTENT ABOVE 19 0851 067 081 097 09 ADJUSTMENT FACTOR FOR MAXIMUM LOAD DURATION 7 DAYS OR LESS 125 125 125 Temperature OTHER APPLICABLE ADJUSTMENT Sizel Fiat Use T T r T r FACTORS FOR LUMBER Beam Stability Bearing Area Size Shear Stress Temperature 7 and Repetitive Column Stability Member PLYWOOD SHEATHING USED WET Plyform Bearing on B B Class 1 Grade stress level S2 1545 face 210 57 1500000 NOTE39 Size adjustments apply to all base bending stresses and compression parallel to the grain except Southern Pine The size adjustments are already Included In Southern Pine bending stresses and compression parallel to grain in accordance with Reference 43 This makes Southern Pine seem relatively stronger In bending and compression Consult Table 42B and Chapter 6 for 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 6 9 for design formula Modulus of elasticity may be increased 10 percent it shear de ection 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 When srze adjusted compression H is less than or equal to 750 psi no moisture adjustment is required Table 42 shows base design values for several species of wood in common use for formwork14 C 0 duration of load Feta El A I39gln EdgarRI Adjustment for Load Duration For form work materials with limited reuse ACI 347 permits design using allowable stresses for temporary structures or for temporary loads on permanent structures In case of lumber this is interpreted to mean the 25 percent working stress increase adjustment factor of 125 shown in Table 42 for 7 days or less Temporary Struc jlll39ill139siEF5lWT 13F T ora Structures e emp ry 139 WASHIHETDH Form Materials and Accessories Temporary Structu res Adjustment factors for size and Flat Use Size Factor Except for Southern Pine the No 1 and No 2 lumber frequently used for formwork is subject to stress adjustment based on member size use Table 4 2B Flat use factor When dimension lumber 2 to 4 in thick is loaded on the wide face the base value of bending stress can be multiplied by adjustment factors shown in Table 42B TABLE 423 SIZE AND FLAT USE ADJUSTMENT FACTORS FOR BENDING STRESS AND COMPRESSION PARALLEL TO THE GRAIN FOR NO 1 AND no2 DIMENSION LUMBER BENDING STRESS ADJUSTMENT MULTIPLIER ADJUSTMENT FACTOR WEDm OF Size Factor Flat Use Factor FOR COMPRESSION LUMBER PARALLEL TO GRAIN 2 and 3 m 4 in thick 2 and 3 In 4 In thick thick thick 39 2 and 3 in 15 15 100 115 4 in 15 15 110 100 115 Sin 14 14 110 105 110 Sin 173 13 115 105 110 8 in 12 13 115 105 105 min 11 12 120 110 100 12in 10 11 39 120 110 100 14 inand wider 09 10 120 110 090 l m l 1 V r Cquot i Wales 1 E l LET 1 aw 16 C 0 Temporary Structures Form Materials and Accessories Engineered Wood Products Plywood Plywood is widely used for job built forms and prefabricated form panel systems Plywood is a flat panel made of a number of thin sheets of wood A single sheet in the panel may be referred to as a ply or layeh A layer may consist of a single ply or it may be two or more plies laminated together with their grain direction parallel l I 39 a E i u I 39I I E l 51305 17 C 0 Temporary Structures I M t 39 d A 39es Ta ble 43 shows the effective section pro pe rtles for plywood TABLE 43 EFFECTIVE SECTION PROPERTIES FOR PLYWOOD 12IN WIDTHS FACE PLIES OF DIFFERENT SPECIES FROM INNER PLIES Effective A sanded thick 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 53m tension of inertia section shear tension of inertia section shear in exterigr and com I modulus constant and com I modulus constant 48 per 39 lue pressron S IbQ pression IbQ s eet Sq ft 9 in2 in4 in3 in2 in2 in4 M in3 in2 1A 3 0267 0996 0008 0059 2010 0348 0001 0009 2019 26 0 8 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 V5a 5 0550 2475 0129 0339 5824 1528 0027 0164 3119 58 18 3A 5 0568 2884 0197 0412 6762 2081 0063 0285 4079 70 22 7A 7 0586 2942 0278 0515 8050 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 49 CAN BE USED FOR DESIGN 39 V 39 LE i 4 r 39 Ti 391 I 139139939 I l If 3 2151 7 s 18 Professor Kamran M Nemati Winter Quarter 2007 LJMI39EEFFQEIT U 39 WT A51 l I HGTDH Temporary Structures Form Materials and Accessories Temporary Structures Form Materials and Accessories PIyWOOd Plywood at the bottom face grain parallel to span is used the strong way With face grain perpendicular to the span direction the specimen at the top is used the weak Plywood Used The Strong Way way quotWmfaili t 19 C 0 Temporary Structures Vertical Loads Vertical loads on formwork include The weight of reinforced concrete The weight of forms themselves dead load The live loads imposed during the construction process material storage personnel and equipment The concrete weighs 150 pcf it will place a load on the forms of 125 psf for each inch of slab thickness Le a 6inch slab would produce a dead load of 125gtlt6 75 psf neglecting the weight of the form I t L I ll 5 H uquot i W i E l iii Elk 1H 20 C 0 Temporary Structures Vertical Loads ACI Committee 347 recommends that both vertical supports and horizontal framing components of formwork should be designed for a minimum live load of 50 psf of horizontal projection to provide for weight of personnel runways screeds and other equipment When motorized carts are used the minimum should be 75 psf Regardless of slab thickness the minimum design value for combined dead and live loads should be 100 psf or 125 psf if motorized carts are used I Lmin9quoti Wii395lElTiJEIIL IH 21 Professor Kamran M Nemati Winter Quarter 2007 7 IJHIl39u39F ggl DIE Temporary Structures w W El W T w 1 teaser i I H ET f 1 Form Materials and Accessories l l L I 31 2 5 l1 4 Jr S777 1 5 7 l 2 7 quot 1 J y f h 1 39A lt Hi 1 Ve rt Temporary Structures 7 1E 3951 IFJEV B crete crew 11 l 31 quot in e h l ii i39l Live load including power bug y and the con A minimum live load of 75 psf is recommended for design where power buggies are used W 1113 1392 1 4 22 C 0 Temporary Structu res I v FORMWORK FOR CONCRETE r I TABLE 51 VERTICAL LOAD FOR DESIGN OF SLAB FORMS PSF Includes weight of concrete and reinforcement plus construction live load of 50 psf formwork weight not included I I able 539 1 SI IOWS TYPICAL JOIST SLAB CONSTRUCTION Weights and dimensions vary slightly from one system manufacturer to another Weights calculated for a 412 in slab thickness above the form F Joist 30in Wide forms 53in wide forms 66 in wide forms orm depth in W1dth cvc spacmg design cc spacing design cc spacing of design cc spacing design m of joists in load psf of joists in load psf joists in load psf of joists in loadpsf I I 6 26 132 36 125 10 5 25 135 35 127 I 6 26 139 36 130 5 25 142 35 132 12 6 26 147 36 135 8 28 155 38 142 5 35 137 14 6 36 141 72 124 8 38 149 74 l 128 6 36 147 39 59 131 72 127 16 7 37 151 60 134 73 129 8 38 156 61 137 74 132 6 36 159 59 139 72 133 20 7 37 165 60 142 73 136 8 38 170 61 146 74 139 varying thickness using minimum live TYPICAL WAFFLE TYPE TWOWAY JOIST SYSTEMS quot in Weights and dimensions vary 4 quot 5quot slightly from one system manufacturer to another SOLID SLAB CONSTRUCTION SIZE OF PAN FORM IN Weight psf for 4V2 in slab Slab 100 lb per cu 125 lb per cu 150 lb per cu Depth Overall plan Void plan above form 0 a O S n Thickness It concrete ft concrete ft concrete of pan I 3 100 I 100 100 24x24 19x19 153 4 100 100 100 8 30x30 24x24 146 5 100 102 113 36x36 30x30 142 I I 6 100 113 125 24x24 19X19 162 I I e I I I I 7 108 123 138 10 30x30 24x24 160 8 117 134 150 36x36 30x30 152 9 125 144 163 24x24 3919x19 178 I 10 133 154 175 12 30x30 24a24 172 11 142 165 188 36x36 30x30 164 e O r m W I C m a y 12 150 175 200 AC1 347 recommends a minimum of 100 psf for form 24x24 19x19 190 esi n 39 d g 30x30 24x24 186 14 36x36 30x30 171 g 48x48 41x41 169 e a e 60x60 52x52 159 Information on slab weights for other form srzes can be 36x36 soxao 181 developed from data providedby form manufacturers For an 16 48x48 1 41x41 175 increase or decrease of 1 inch in slab thickness above form 60 3960 57 3952 168 simply add or subtract 125 psf from tabulated values for k A e e I normal weight concr t 36x36 30x30 207 20 48x48 41x41 196 39 60x60 52x52 187 48x48 41x41 218 g 60x60 52x52 207 1111 55 f Ll 3915lzllli395iiILWZei 23 C 0 Temporary Structu res Vertical Loads When slab form members are continuous over several supporting shores dumping concrete on one span of the form member may cause uplift of the form in other spans Forms must me designed to hold together under such conditions If form members are not secured to resist this uplift they should be built as a simple pan Fresh Concrete Produces Upward Movement Here Here Unless Forms and Shores quot Ax ore Joined Securely and 391 1 Attached to Base Support 39 I j 39 tit ii i F i Weaslzmc trite 24 Professor Kamran M Nemati Winter Quarter 2007 8 917429 Temporary Structures v r x s 7 Form Materials and Accessories V WKSHING I ODN Loads mused bv ivesh curneta suamst WaH a mum imms um ivtm me DvavW mad m a hmmnm s ab fum The em Faced Emulate b eves muaan v kg a mu pmmum a hvdus39an uessuve mans ataaHv an mavemca ms 5 ataa pvessue s mmDavaHe m M mud head W cmueta 5 mm M hemmmn the new vemwed in ms n a set mm s mB me Dfmamm turnete at me berm m we fum beams m hymen and ad m ess than mu E F Macenmt cenpeamve m curneta mm H y a m v deors quotluluq mm quotmm m Form We ght channel m Atnhun Yemvenlum 2mmer the m hm Omen2mka meessur Kamran M Nemeu wmer Quarry 2mm CM Temporary Structures 1 U f I v F R 5 I T Y 0 r WAS TINGTON Form Materlals and Accessories EQUATIONS USED IN CALCULATIONS OF THE SAFE SUPPORT ACING IN RDRMWORK DESIGN xnumsxnm C o Temporary Sirumura Form Design When the material for formwork have been chosen and the anticipated loading estimated a form should be 399 strong enough to carry the anticipated loads safely and stiffenough to hold its shape under full load At the same time the builder or contractor wants to keep costs down by not overbuilding the form C Form Design Refer to class handouts for wall and slab form design Farmalt m mm Professor Kamran M Nemati Winter Quarter 2007 s 743230 Temporary Structures Wall Form Design Part II 5520 Temporary Structures Temporary Structures Wall Form Design Part II l WASH 1510 CTTITWASIIINdTON c o vempwy swam Wall Form Design Example Continued Design forms for 14 ft high wall to be concreted at the rate of 3 ft per hour internally vibrated ume the mix is ma e wi Type I cement 3 o n i 3 1quot n 3 5 m Slump is 4 in T e rms will be used ony m 39 39 PHI Form gade plywood sheaihing 3 in thick is available in 4 x 8ft sheels and 4500 coil ties are on hand Framing lumber of No 2 Douglas FirLarch is to be purchased as required Rama 2 Yemvorery Slrumura C 0 Last session we di 1 Determined the prssure on the form 2 Used 4 x 8 sheets of 34quot thick plywood for sheathing in strong way 3 designed for stud spacing of l OC 31 Checked for Bending 32 Checked for Deflection 33 Checked for Rolling Shear 4 Stud spacing of 12inch OC was veri ed Wm Professor Kamran M Nemati Winter Quarter 2007 Wall Form Design Part II Temporary Structures Wales support the studs 1n l M IE M I In yerHum g 45 m L f 5 iii l in wwwmawadm i f I L on I i WWI3915 l l a C TIE3 Temporary Structures Wall Form Design Example STEP 3 STUD SIZE and SPACING OF WALES IJNIl39EEEREITTQF l IAFAEHIHGTDH Wall Form Design Example pressure of 600 pSf Design for 2X4 S45 studs Find the maximum Span that can support a lateral Equivalent uniform load w iS the max lateral pressure times the stud Spacing C 0 Temporary Structures Hence 600 psf X 12 in 12 inft w stud 600 lblf bending deflection and Shear I w K i II I a WERE3915 l E I C TIDE Studs can be considered as continuous beams subjected to uniform loading Like the previous set of calculations check for allowable Span for Wall Form Design Example CHECK BENDING this value Should be adjusted of the American Plywood Association Reference 48 Assume using No 2 Douglas FirLarch studs From Table 42 the extreme fiber bending streSS Fb iS 875 pSi However C 0 Temporary Structures 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 Extreme ber Compression Compression Horizontal Modulus of bending stress L to grain to grain shear Fv elasticity SPECIES AND GRADE F Fe 9 l to grain E DOUGLAS FlRLARCH No 2 24 in thick 2 in and wider 625 1300 Construction 24 in thick 24 in wide 10 625 1600 quot Lu 395 1 WW I I I NC TLTL M Professor Kamran M Nemati Winter Quarter 2007 Wall Form Design Part II Temporary Structures Temporary Structu res fwl M II Form Design Example The first adjustment factor is the shortterm loading factorof 125 The second adjustment factor is the size factorobtained from Table 4 28 which is 15 Therefore I F 875 psix125gtlt15 1640 psi I W131 uIEl Ei L I fa Temporary Structu res C 0 Wall Form Design Example The values of section modulus S for 2x4 S48 No 2 Douglas FirLarch can be obtained from Table 413 as 306 in3 TABLE 41B PROPERTIES OF AMERICAN STANDARD BOARD PLANK DIMENSION AND TIMBER SIZES COMMONLY USED FOR FORM CONSTRUCTION I h M I A r I v39 I WEEK 11 l E I 3quot ELquot 0 Based on data supplied by he National Forest amp Paper Association 39 1 7 x d X X is the neutral axis A F x d1 x x l 1 b lrb l nb American St d d VArea olsyec lion Moment o f inertia Sedionmsodulus Nominal inche sq in In In B d Approx1m te Size 343 at 19 A bd I baquot12 S baa6 leet per weighl lb per Inches m mum m St linear loot Inear It Ior use bXd f 09 in form desi nquot Rough S43 Rough 43 Rough 543 p 9 2x4 589 525 645 356 3 06 067 1 3 2x6 1 2x5 2 914 825 2410 200 857 100 2 0 ZXB 1392X7 4 1198 1087 5432 4763 I 1473 1314 133 2 6 2x10 1 Ax9 4 1523 1387 11158 9893 2380 2139 167 3 4 2x12 1V2X11 A 1848 1687 19931 17797 3504 3164 200 4 1 8 Temporary Structu res C 0 beam is Wall Form Design Example The allowable stud span as a continuous 110951FLS w 110951M 2317111 600 gt E 51 39 4 397 LINE39EEEFJEITT UP 1 tttaSHINETUN Professor Kamran M Nemati Winter Quarter 2007 M 41 Wall Form Des gn rt II Temporary Structures v WKs w an zumue de ezhm u 6 mm um mm mm m m mm H 6 dex y u mum x nnnnn w 2nd m We a the vz m M a E a s the mmenlt mmzfon 1525 m rm n rm C m 5m FW n e n 2How2b e mmumg my y Shin m a c Wall rum Design Exanple Hanzanta Shea Myustment meessur Kamran M Nemau wmr Quarry 2mm CW7 4 Temporary Structures gxg Wall Form Design Part II 39 Wall Form Design Example SPACING OF THE WALES From the stud spans calculated above the shortest span is based on bending which is 317 inches This means the wales which are the stud supports CANNOT be spaced more than 317 inches apart this span can be increased near the top since in the top 4 it the pressure decreases linearly from 600 psf to 0 The top and bottom wales are often set utll ft from top and bottom of wall forms Mira C o Temporary Structura Wall Form Design Example Place wales 12 inches from both top and bottom of the wall form Then 1439 r 139 r 139 12 ft or 144 inches remains for spacing the other wales which can be no more than 317 inches apart Set them at 30 in except one span at 24 in smaller spans at the bottom We place the smaller span near the bottom of the form where theoretically a higher pressure could occur Wm lir39v C Wall Form Design Example soquot 25quot Wh m ik n u39 Professor Kamran M Nemati Winter Quarter 2007 l Temporary Structures Wakigvfl Wall Form Design Part II n mum mg n 7 n ulnwvvlyna lt 7 m 7514115 w I m n kmquot A Wa zs39mmpil y C g vempwymme Wall Form Design Example STEPS 4 amp 5 TIE DESIGN WALE SIZE and TIE SPACING From the pressure diagram the equivalent uniform load per lineal foot of wale is determined to be 1500 lbf The problem statement indicates that 4500lb coil tis are available andmwvill be use I r 5 r Wumnik o v C o Yemporary Slrumura Wall Form Design Example S EPS 4 amp 5 TIE DESIGN WALE SIZE and TIE SPACING cm With the maximum load per lineal foot of wale being 1500 lbs then the maximum u39e spacing is Tie capacity 7 45001b 7 7 7 3 a gd 150701bft FF Professor Kamran M Nemati Winter Quarter 2007 91714129 Temporary Structures W g Wall Form Design Part II CHECK EENDIMS mm 02de Comm be sn mm than wpa w Tnm h bung dex gned n w uYheveFae Iris E o HECK ammm ms mum s ass n the Exvsne be Thazfuv m2 vaquwad 55mm mudu us acumen w linux32 2n c Wall rum Design Exanple In avdev m avmd dnqu af hmhevi may mmmarwuse nu 2memhevwa e Sathe vequwed 52mm madn us af 9 55 n 5 rm w memhas nerennq m Yah e Ha dauh e 2X45 Wm we d a 52mm madums af 2x as m 5 12 n I thh 5 955 m 9 55 n I and theyefme nut accepta e cnemnq the m We sue M m vesu t m 2gtltSIEIIEIZEHn3gtQEEw whwh sansnes the 52mm madums vqu 5 n A n m meessur Kamran M Nemau antar Quarry 2mm IJNH E39FFE IlITQF Temporary Structures 1 WA HHHFTDN Wall Form Design Part II t J Temporary Structures Wal Form Design Example I CHECK SHEAR To check the horizontal shear for the double 3x4 wales use the horizontal shear stress formula for a uniformly loaded continuous beam 09WL 2d Theyare w 2d or exactly the fV 13 331761 fV bd 12 same formulas From Table 413 the value of bd for a 3x4 member can be obtained as 875 in2 or simply 25 X35 875 in2 09x1500 2x35 z x 3 7714gtlt242 186 1 238 1gtOK fV 2x875 12 j p lt p Therefore the stress in the double 3x4 members meets the requirements The value of the adjusted allowable shear stress of 238 psi was calculated before refer to page 20ofvt e handout WEAR l l b 1 1m 22 C 0 Temporary Structures Wall Form Design Example I STEP 6 BEARING CHECK Check 1 bearing of the studs on wales and 2 bearing between the tie washer or tie holders and wales From Table 42 the value of compression Perpendicular to grain Fa for No 2 2x4 Douglas FirLarch is 625 psi 23 I neuillgrufi WEE3915 I E l KC EDIE C 0 Temporary Structures Wall Form Design Example 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 L to grain to grain shear FV elasticity SPECIES AND GRADE Fb Fcl 6 l to grain E DOUGLAS FIRLARCH No 2 24 in thick 2 in and wider 875 1300 95 1600000 Construction 24 in thick 24 in wide 1000 6 5 1600 95 1500000 From page 13 of the handout the multiplying factors for indicated lengths of bearing on small area plates and washers are shown below 35 Length Of 12 1 1 12 2 3 4 6 0r bearing in more Factor 1 79 1 37 1 25 1 19 1 13 1 09 1 00 1131092 111 W 1321 11 quot30731 24 Professor Kamran M Nemati Winter Quarter 2007 9174129 Temporary Structures Wgsvamv Wall Form Design Part II ma Assumea mnrsmavenewasha am we beavm ayes s 3quotZ r VARYzquot 12 z 7 2 53 9 53 m 1 The and beam mass 5 mm aim 1W7P ltE4PS w J m x WE Yhe beam 5125 between wa es an be aku ated as 2 mm X 5 Laad tvansfev m the web 7 A the 5 sum shave ma he aw the web x the aheva the 5m spamquot u mnygxmmnnm r y unn x zmwlt625vyantlt meessur Kamran M Nemau wmr Quarry 2mm Wall Form Design Part II Temporary Structures Wa I 4x8ft 34 thick plywood sheathing 3 12 insquare tie washer I it u ii ll 3 d E int JE iilHEZii lTH 2x4 848 No 2 Douglas Fir Larch studs 12in OC 4500lb coil ties with 3ft spacing Double 3x4 V Temporary Structures lwales 28 AMI39EEE I l39l Ell l nesmmmm Wall Form Design Example Bracing for Lateral Loads minimum 20 psf wind loading prescribed by local code gives a value larger than the 100 lbft minimum established by ACI Committee 347 Consider the necessary bracing for a wall form 14 ft high above grade in an area where the local building code specifies a I Table 57 page 6 of the handout indicated that 140 lb per lineal foot should be used for design of bracing since the wind force C 0 Temporary Structu res 1 l i l i i F nquot I Us l a l is t IBEX 29 C 0 Temporary Structu res B g f L t I L d 39Unb IADLI DI IVIINIIVIUIVI LnlanL I CING FOR DESIGN OF WALL FORM BRA ps 30 90 6 45 30 60 75 120 8 r r r 100 100 100 100 15077 10 100 100 100 125 180 1 100 100 120 150 gt 210 1 105 00 140 quot 175 240 6 120 C100 160 200 270 18 39 135 00 180 225 300 39 20 150 100 200 250 L 39 150 h 22 or more 75 h 50 h 100 h 125 r 7 Walls below grade JMENT 7 8ft or less quot BRACE TO MAlNTAIN ALIGI my known 100 psf minimum or bracerfor 39 More than 8 ft lateral forces which are gree eq W scribedb ed 39 design grea y quot 2 ills 39 fl l 1 islimaw 30 Professor Kamran M Nemati Winter Quarter 2007 10 mam Temporary structures Wall Form Des rt II l Wex s39l liil d li Bracing lur Lateral Luads strut aaang Ween lml bunny n Vumded elan enea lolzkgellmvzlemlona empremm load lnen en ale nae bnzlng mzv re uxed mnea enneenene a ellhev ena n l mung eneagt lo lnnxmll zzmmuhl ea neneenal rune lo lne lvu bnzlng c Bracing lur Lateral Luads strut aaan rr Ween hymn n elaenea l m reel bdrm lne lee erlne wall lne buzlng nael l AWMorel an e onlbpev luzdzwhed thelw me e c Bracing lur Lateral Luads strut Elam a Hv lne hommlzl bnzlng nene 2 reel nan lne Aw oflhe wall We hzvl to be 27 l ne We n Dul x reel nan lne wall Lee lne Malloryth belwun nae er lne vlghl lmngle lo nna lne lne lengln or We and load l mun any meessur Kamran M Nematl Wlnter Quarter 2mm 41211 Temporary Structures Wall Form Design Part II I WASHINGTON Bracing lur Lateral Luads am am 3 r 2 mg M y 12TE39 1usn 5r k 4 IRKmltmPRsKmnml 3x 3nhwtmwm a e a c Bracing lur Lateral Luads mm are spam evav a at 3WD me wau mm wen 232m we must be tamed by each brace a emace m cm Hume me swam Eftmremms na s etc must be madea uuam in me cmsrm aad m x meessnr Kamran M Nemau wmer Quarry 2mm
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