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Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 6-9 | Placing Reinforcing Bars.pdf |
TABLE OF CONTENTS CHAPTER 1: SAFETY PRECAUTIO NS........................................ 1-1 CHAPTER 2: INTRODUCTl O N...................................................... 2-1 CHAPTER 3: CONCRETE AND REINFORCED CONCRETE-DEFINITIONS................................................................................. 3-1 CHAPTER 4: REINFORCED CONCRETE BUILDING CONSTRUCTl O N........................................................................... 4-1 Wallt and Wall F--. gs......................................... ______... 4-1 Col. rnn Foo Cio9 ·-···---··-·······-············-·········-···················4-2 Grade Belli TI& ···---···-----······-···········-·····.... ___......... _........... 2 Pile Fc\. lndallons.. _________ _ __________ _ 4--3 Deep Piers 0t Open Caissons......................,.. _..,...,... ____ ________,,. _4-J Comblntd Footlr,gs_·--·-·"· 4-4 F<Junda UOO Ma1S or Raft Fcoings ___________ 4-4 Slab-8o Bm Ancl-G~dof Floor Sysioms............-·········-·········-·········-······· 4-5 One-Way Joist Floor Systems___ _ _ ______... 4-5 Sorod Slab Floor SY,:em............................................................................... 4-6 Flot Slab floor$-···-······-····............... _.......... _.......... _....... 4-7 AM Plat&Aoor Sy&t. ams ______________ 4.. 7 W8l1le Slab Floor Sy Slems ·········································-·····---- 4-3 Ardle S. S-and Oomos ______----·······4-3 Bo and Tonl<o ·-····················-·········· '"" Post-Tensioned Concrete Consouc:lion --········--··········-········-·····4-10 Taft. Up Conl::rele Conrtruction...... ·-··········.... ··-···................................... ··-·-···. 4-11 CHAPTERS : BRIDGE CONSTRUC TION...................................... 5-1 viii Conorm Roinfo,dng St NI lns Ot<M Placing Reinforcement Bars Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 6 REINFORCING STEEL-PURPOSE AND LOCATION IN CONCRETE................................................. 6-1 -······--·····················-···· ···--·····-···································-···· 6-1 Longiludlnal Rofnl OICOmllnt rn Simple 8eam·····-·······--··-----8-4 Stlm. l>s In--------···-···········-··········-········-··6-4 Ro;,,_. _ In C-. UOua lleom··-············-········-········---········8~ Reinfon::ement i'1 Wa&s...,.........-., &,S Roinkl R:emant in F001ings ····-····.......-,..,,.. _,,.,.,,.,,-,.,,,.. ___,,,........... 6--G Shltnkagcand Temperaure-··················----···-···6-8 Con-c>resslon Rolnf"""'""'11 in COiumns~--·········-··········-·········-·· 6-8 Con"lprff. sfon Rclntotoemoot In Beam,, ____,.,.,, __,,,.. ___,,,, __,. ~9 Rem><ting Bors ·-···..... _........ _6-10 Weldld Wn Rll!infcwcorno. n1. _......., __,,..,. "-···.................................. _., S-10 Con01'!e P,coac Uon - ······-··········-··········-···----- 6-10 CHAPTER 7 FA8RICATIZD REINFORCING BARS.......-·········· 7-1 Deformed R8lnl0rcin g Bars _______,,.,., __.,,,. __________ 7-1 Plain 8{k"f;........................... __.,.,,,. _,.,.,... _,,,,..,.................................... 7-1 ROinlorting Bat Si<eo-........ ····-·-·····-·······--7-1 Rolnlofd'l Q ll<n: Tyon Md G,odos o<SIA>el.-..-.-.-.-.-.-.. =-..-...-...-..-.......... 72 Id-lion ol!J<>fo,med Retnlo,dog Bets..-..----------Fabri;:af10n of Rein~ 8al'$..,_........, ___,.,... _,,,,,,................ 7~ Typlcol Bend &lap·--·········--·······-········-·-.....----····---· 7-<! Sp~·-·---.............--··-----·-··--...-. _·..... _. 7-14 Otraeteotufl'WI eo,,.. _.,,......-.,..,... __......................-..................,...,... _, 115 Slandanl Hoolcs. ____ __. _......... _..... _____ __,.... __,7-17 Radio! Prelobl1c:otlon (~ 1011 s,,,. )-......,...-..... ·-··--··-··--..... _.., 720 T°"""nces In Fabflcallon ___--------···--721 OYera J Diameters of Rlwllotcing Sara..-................,.., ______ 7-26 ll<Jr>dlfr G and Togglne----·····-····--...--. 7-28 Marl<t,g Systems __ ···--··---·..----···--·-··....----7-® Plaolng-1ngsa,,-10lhedilion Ix Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 8: UNLOADING, STORING AND HANDLING REINFORCING BARS AT THE JOBSITE...-·-·····-·-··-············· 8-1 o......,....--.........-...................... ·-··----.... ··-····.. ··-·... s-1 SLWface Condklon or e. w......---·---·....................... __..... 8-2 tlo<sw,g......-.........-...... ·-·····-·······-......... _.........................8-3 CHAPTER 9: PLACING DRAWINGS AND BAR LJSTS................. 9·1 Con1ract o,a,,;,,gs.. __................ ____.......-.........-.................... &-1 P1adng D""""9 L......... ·······-·.. ·....--.....-...................... &-2 Placing Ol"a\Wlg& ____, __,_,.,..,,, ___, _______ 9-6 8at LIii,................. _............ _....... _........ _........................ _.........-... 913 CHAPTER 10: BAR SUPPORTS................................................. 10-1 Genam I,..-...............-....,,.,-·-···----· ····--·-······-..............., 10. 1 CHAPTER 11· GOIERAL PRINCIPLES FOR PLACING, SPUCINGAND TYING REINFORCING BARS........................... 11 1 General,,,. __,,,......---······-····-····------··.. .........-......... ·---·· 11-1 Concrete Coller or Protectlon---······----................... _....,,.,.,--···· 11-2 TOKl(ances i DP. 1~-1. ···-······~-......-..,. _-..... 11-3 Spoces...................-... ·.. ·-········.................-..................... _......... _,,_,a 1. a J> S;>lices---······-.......... _..........------.......-.. 11~ _,.., Sf>lic;es.-........-............-..........-........-...........-.........-. 11-23 -Spllces.....------····-......... _........-................. 11-31 ~ Reinforcing Bar$.,... _,,,,..,.,... _,.... _ __...-·········--·-······--.. 11-34 Te YJlre and TOOIS.-..,........-,.....,_...... _.......................-,....,..,_, 11..$4 Genoral Pmoiples of Tyin9 Reinforcing Bats-......-.............-........ ____ 11-39 CHAPTER 12: PLACING REINFORCING BARS IN FOOTINGS, WALLS ANO COLUMNS.......... 12·1 lnc Md Ulll Square o, Rect.,_ Fo Dltr Gs......-............................................. 12 I Conl!nuous Woll Foaling---·.. ·-·..........-··----·.. ··-·· 12-3 Pia caps............... _...........-........ _............................................... _....... 12. i Cowmn Do M!ls..................-........ _... ____.... __.......-.... 12-S eomt,;n8d F<loilngs.............-.........-...... _.........................-.......... _... 1210 M&lor. Raft Slab F°""""1IOO$-,................. ··-·--··.... 12-11 Walla.....,. __.,.,., __,,,,.,··-··---..-............ _,.,.,.. _,__............-.-12-14 Cantilev&r R. elolnl Qg W3lls ______..,,,. __.,.,....,--·······--· 12-20 eou,,ns.... _.. ___...............-........................-... ·----.. 12-22 x Concrotc Reinfordng Steel ln&bu Jte Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 13: PLACING REINFORCING BARS IN FLOORS AND ROOFS............................................................... 13-1 Two-Woy FIii Slal>I--················-······-··· ······-····--······-1312 Two-Way Flat Plat""-----··············--·········-······-·······-13·16 Two-Way Wa~ Slsbs.......,.. _.........................,. __.,,.....-..........-............. 13--18 On&-w,,y S-o n Mata J Ded<s,g...-··········-·······------13-20 s1..-..... ·-·····.............. _................ ____----· 13-22 Blnt, T,nics.,-,cf Grain Elevators..........-·---·"··--·····-·---13'-23 Af<:he:S, Samd-Sh el Roofs. Dome Roofs and Vau1ed Roots...... ___ 13-27 Slobs on Grouod..... _....... __....... _.... _........ _... __...... _ 1W8 CHAPTER 14: PLAC1NG REINFORCING BARS IN POST-TENSIONED FLOOR SYSTEMS...................................... 14-1 General, ,.....-....,----·-------------14-1 Seams..................... ·-········.. ··-···.. ·--·-·········-·"· ···.. ·-···· 14..S 0....Wy Slabs...... _...................--···· ·····-·· 14. 7 ,. _,way s1............-.....................-................................... ·-···......... 1410 Pl~ SGql. J80C::e ror Flat Plate Slab wiih Banded Tendons in One 01..-........ _______________ 1+12 CHAPTER 15: TRANSPORTATION STRUCTURES................... 15-1 -····.. ··-········.-·.. ······-.. ..-·.....-.......-.........-......--15-1 Draw&-gs ··--···········-··---·...-.......-............-,..................... _ 15-1 Bar SUppo<ts-·-----·······-····.. ···-···..--...... _......... _. 15-4 Bar Supports for Hlg~ 811dge Slab Refnfc.,...,. nt ·····-······-·............. 15-S eona..1e Cover.........-...... ·-········-·······-··········-·····--·....... __ 16-7 ear Lilll and Bundling...........-........ _...........-....... __...... _......... _, 15-7 Procedure _____,,.....--·······.............. _......... __........--........... __ 15-8 Pl30ing-roing Bars.. 10th Edillon xi Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 16: HIGHWAY ANO AIRPORT PAVEMENTS 16·1 Cenera L................ 16-1 Con&>uously Rctnlo Rled Conc:teco Pawmenl ___.........-.......................... _.... 16-1 Jointed Re'rdofted Concrete Peve1Tt C111L..,,,,,..-...,,,..... _..,,,,.,... __,,,,,..,. _,,.. 16-$ Plain Conaete Pavement with Weakened Plane or Sa W9d Tr""'ver H Jofnlt...--··········--·········--·········-······---··-···········-···· 18-5 l. Ongltudln al Jalnl S -··--------------... 16-5 Transverse Joinls...............,... _........................................................................ 16-& CHAPTER 17: INSPECT ION OF REINFORCING STEEL........... 17-1 CHAPTER 18: COATED REINFORCING STEEL........................ 18-1 lntrodudio"~---·------------·.. ··-·-1S. 1 Epoxy-Coa!ad Reinforcing Baf S... _______......................... 18· 1 s., &,wo,1$ k M-Epoxy. c.,aled Rew,loltlng Bals........ ·--·····.. ·-··-··---··-···.. 18-S Zn>Coted (Galvanlzed) R-clng Bots..---.. ·--........ __.........-... 1H Epoxy. coated Welded Wire Reinl Ol'CEm El"'----------18-6 APPENDIX A: Metric Reinforcing Bars.......................................... A· 1 GLOSSARY................................................................................... G· 1 INOEX.............................................................................................. 1·1 xii Concrote Renforcing Steel Institute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 4 REINFORCED CONCRETE BUILDING CONSTRUCTION GENERAL Reinforced concrete building construction usually consists of roof and Ooor systems supported by bearing walls and columns. Columns and walls are supp Qrted by found. ltion, of V>1ryi D11 typ<s; each particularly soiled to the soil conditions. It will be helpful lo have a geneo1l knowledge of the dilfereot members that moy be a part of each building. Not all of these are found in every buildll J3. The Arehitect or F. ntineer choo. c;e~ th Me members which work out best for a particular building, from the Slllndpoints of strength and economy. The more commonly used members arc briefly described in Ibis chpu;r. In actual J>12C ti~ many wriations ar~ used. WALLS AND WALL FOOTINGS A bea. cicg wall is supponed b a continuous wall footing, which is usua:Jy twk~ ;i:, wide:; as the thickness of the wall but wider+ if necessary, to :..,xcad tho load from the wall 10 ~,c bearing soil. foundation w11lls = olso used.. reraining walls to withstand earth pressure for oonstruction belo..v ground. When poor soil bearing conditions make it necessary, wall footings may be supported by piles ot caissons IO support the load further down to firm ooil or bed roclc. Figure 4-1 shows a typical wall footing. Plac■,g Reinforcing Bart-10th Edition 4-1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
SLAB-BEAM-AND-GIRDER FLOOR SYSTEMS In this floor system, sholvn in Fig. 4-7, lhe slabs, beams and girders m cas1 at,he same time. A beam o. nd a girder ue similar in func:tion c,i:cepl that 11 gilder usually is larger and more heavily reinforced because it is designed ID suppon lhe IO&d lrom the beams dial li'amo into i L The beams around the ou,. ide ci!!ll'!' of the floor arc called spandrcl IH:m> or merely spandrds. ndrof (Edgo or E'xtor1or) Bo Rec:uingufar Extettor Column Fig. 47 Slab-Beam-and-Girder Floor System The bouorn or a slab, beam or girder is called a soffit. O,amf<r strips (bev eled edgea) are onen used in the fom,s to avoid sharp concrete edges 1b11t might tend to bre2k off. Tliecona'Ole for columns is usually ploud tos10pal lhcundcrsid coftbelow cstsupported beam orgi,d<.-rin the floor above. An intemil of several hours to a day or more is allowed for initial curcoftbe conctctc in the column berorc proceeding with placing the concrete in the floor. ONE-WAY JOIST FLOOR SYSTEMS The ODt>-way joist floor sysrein shown in Fig. 4-8 is,11pported b Y beams and onlunms. The. 6gun: also shows the use ofbolh rectangular exterior and round interior columns. Rein. forced concrete joist floor systems consist of a series of ribs, similar to small beains, wilh a lop slab, all of '"1lich.,.. pillced at one time wilh dw: supporting beams. The jois1sare usually formed b Y S1l!Ddan:1 invated meial oriibetglassfonns which fonn the side and soffit of adjacent joists and the bottom of Uie slab. The forms Plridr Q Relnhxoirl V 8'n-10!h Edition 4-5 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 6-9 | Placing Reinforcing Bars.pdf |
CHAPTERS REINFORCING STEEL-PURPOSE AND LOCATION IN CONCRETE GENERAL As previously explained in Chapter 3~ coccrctc is strong in (:. c. >mprt;s!iion, b Lt relatively_ weak in tension and st:car. Generally, wher~~r ren~1on i~ cue. ~L. the concrete is rcinforc. cd,vith rt;info Tt;mg ::. 1cel Quillily control of both concrete and reinforcing stttl is important to dem on=e to the Engineer or Architect that the spcci Jied design requirements a. re met. The compn::$$ \Vc strength or the ooricrete is verified by taking test eylindc,s as per ~,e Americai, Society for Tu;ting and Matc:rials (AS'llvl). Standard plasnc colds arc used which f Oml the concrete in:o res: cylinders 6 msaics in Ui. wnctcr 11nd 12 1m:~es hi&h After 7 to 28 da)'!; c,f caring, these cyl indmm, placed in a lnboraiory testing m,ehine and crushed in eompn:ssion, with g. wge readings take. non the machine to determine the crushing load. for example, where 3,000 psi concrclc is specified, the eylicd CJ1 afler 28 days should break at about 90,000 pounds load,.. shown in Fill· 6-1. P90,000 lb. Arta=i28. 27 in. 2 P--90,000 lb. Sid. Test Cylinclor 90000 ~3,110psl Fig. 6·1 Test Cylinders of Plain Concrete Placlng Allnforct,g Bors-1 0th fdillon 6-1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
,, ( ~ is a mon:: complc. ~ force lbm !'. implc lctllion or comprc~s Iun A com mon example is a bolted !ap joint fn steel plates., produc~ what is called sin2le shear. In reinforced concrete, this is best illustrated by a loaded col wnn corbel. Both oxmplcs of sln&fc: shear arc shown in Fig. &-2. Bolted Joint-Single Shear Shear on this face Load Column Column Corbel E!o. 6-2 Exom~ of Single Shoar If a $et of books were carried horiwntal ly as shown in Fig. &-3, they would ha,.., to be squee:ied tighdy togelber or they would tlip and fall. In a beam, cach imaginary vertical slice. (as in the car. e <,fa single book) with a load on t Op tends CO slip down, due to what is called vertical shear. Sot of Books Concrote Beam Fig, 6-3 EX'!ffi PIO of Vertical Shear As shown in Fig. 6-4, if """'111 boards= laid fiat across two supporu and load ed. they will bend downward bul will also slip along each olhc:r horizontally. The hori2ootal slippoge is caused by a force known as borlw11tal shear. In the case ofboords, if nails, screws, or lag bolts are installed vertically, they will lt$ist the hori>ooltol shc:ar. l1>o b Ollds will ~>on act as a single w1it, and thus be s:tiffu. Loads ¥ 1111111,1 f Seit of Boards Support Support Fig. 6-4 Example of Horlzontat Shear 6-2 COnavlo Aclnforoit,g Slool lnotltl M Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 6-9 | Placing Reinforcing Bars.pdf |
n a loaded beam or s Jab both vc1 liwl and hori1. ontal shear are prcsent..lrul the net result of the 1wo fo~ is cctlled beam shear. !1\ era-ck resulting from these forces can occur near the support and exte;xls upward and oul\. \'3. «l at ~c of awro:iumately to the top. These forces are also p~1l m an elevated slab. _p1rt,cu a y around t Le perimele1 o W. t)t)Ortmg Cl)lumn~ and the combined result is called punching shear, as shown in Fig,. 6-5 --Punching Shear Beam Sh&ar Fig. 6-5 Shear Tension in rcinfoteed concrete can be caused by bending or shear, by dry ing shrinkage after the OOll CCete hardens, and by temperature changes. An exrunple of hooding tension is shown in Fig. 6-6. As "' beam i loaded, "'1· sion cracks will likely appear ai lhe bottom of the beam. They will develop rapidly in an unreinforced concrete beam with the each appearing near mid~ spon. Unreinforced concrete is weak in tension and will fail suddenly without warnuig shortly after the fust crack appears. LOocl$ ------------Ten11on Cracks Beam deflects under load Fl_g. ~ lension in a Boam Steel pnwides reinfon:emcot 10 lheconcrete where iensle forces exist lhat the coo en.-tc cannot resisl. The following discussion will ill USlrate the location in OOIICltlc mcmbcr1 where reinforcing steel can be most eflbctivdy u,;ed to resist tension. Ploct,g Roinforc:a,g Bara-100, E<ilion 6-,3 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 6-9 | Placing Reinforcing Bars.pdf |
( LONGITUDINAL REINFORCEMENT IN SIMPLE BEAMS Simple beams (also simple slabs,joisis, and girders) supponing loads usumc the dellceled shape as shown in Fig. 6-7. loads Longitud inal Steel loaded Member Deflected Sl\ope Fig. 5.. 7 Simplo Beam The top of the beam is in compression (pushing tog<:lber action) and the bot tom ill in tem,ion (pulling apart action). so lo11gitudinn1 reinforcing 5teel is located near the bottom to prevent failure of tbe concrete in tension. STIRRUPS IN BEAMS When a beam deflects under a loac\ shear stre SSes are al~o presen L es1~'t the d1agpnal tecsion, small U-sbaped ot closed-shape reinforcing baxs called stirrups a. re used and arc placed venienlly across the beom. Waft Load. son Bam Stirrups Possible shear cracks at ab OUt 4S0 angle Fig. 6-8 Stirrups in a Beam ti wan Because shear is usually at a max..imum near the support and decreases toward mid-i;pon, the stirrups llt C mor,, closely spaced near lhc support and spaced increasingly tiuther aparl towanl mid-span, as shown in Fig. 6-8. Concrete is able to rcsisl some shear thus stirrups arc occasionally omiacd near mid-span. Welded wire reinforcement cages can also be used instead of reinfordng bar stirrups to resist shear stresses. 6-4 Concre<e Re;nforang Steel lnoti Me Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
REINFORCEMENT IN CONTINUOUS BEAMS Contlnoous Bwns {or Sllibs) which cxrend o Y<r more than enc span, dttlocc down wan! bet\\-supports and bave reve,sed airvature ave, each mterior sup port, as il IUSlrn... S in l'ig. ~9. This require. s tension ~info,cing steel in Ille bottom of the beam between supports and in the top of the beam OYer the suppons. Loods ~JJ,. li Mbt_ Suppons-fr"" ;i====-i Loadld0!$ml>O( Oeftecfe. d Shape Flg. 6-9 Tw-o-Span Continuous Be. am e. uuile,u Beam. < (or Slabs) !o<>ded at the_top dell..:, downward. In t J,e tanlilev<r (or CM:Crumg). reinforcing bars mus, be placed,n lhe top_ The. o;e bars must b~ cxu,-nc. IOO b. ai:k inro tho matn sp:10 wbe~r possible. otne:rwi~ they mu~ be S<CUrcly ;u,chol'\.-d by bending or hoo~into an outsi<k beam brcolumn igun,: 6ilfil1ow1; ine,rnmple uf a (li101ilcvcr 6C1Wt. Loaded Member ~Top ~Cn lflver Deflected Shape Fig. 6-10 Cantilever Beam REINFORCE MENT IN WALLS Walls, braced a! the top and bottom by floor slabs and looded with horizontal pressure3 on lhc outside face, deftect inward, as mown in Fig. ~ 11. Wall$ re quite reinforcing bars or welded wire reinforcement on the tnside race where lhere is tension. Sometimes, whca spcc;ified by the Engineer, roinforcina bars may be required oround the outside top comer. Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
SHRINKAGE ANO TEMPERATURE REINFORCEMENT 1ensioo stresses in concrete can be caused by rapidly changing temperatures or when the curing pl OCC:$il or the concrete hu been 11CCclcratcd, which causes shrialaige as the concn:lc hardens. Reioforcerneot is needed to hold the re ulling cracks ti&hlly IO(;elhcr. A aood exnmple is a reinfo,-ced concrett high way pave Jneot. IJ\ continuously reinforced con. crete pavcmect, longitudinal reinforcement eliminates the need for cross.. jolnts. The initial drying shrink nge and temperature cycling can ca. use crooking at regular intervals. The re. inforcement is designed to hold those cracks tightly together so the pavement essentially. i. tts a$ on uncr.,cka J 1lub. The roof slabs of rclnfor:o;d ~ocrctc buildings arc subject to-wide tcmpcrz turc ch. 1n~,1:$ well ~ 1;. unc1tt_c: ~hnnk,agc. floor,b 1101 u-. u;_illy subjeciccl to wide tc:mpt:t<1ture. cl1anges, a1e. !bo sut,-jec L h'> shiin Joge. Jt is 8t1)c::rit 11111c1iu to pl. 1cc re,nforchis it. eel in slab. $ 11 right. uia!es-to ch..: ml WJ stress resic,tjng steel. m provide for tht"SC mc!ucru°st. n::5;Scs. This rcmforucrm;nl is refea«i to as te:mperntnr-c. and shri. ol~ge-Sh~el i:lml rntt)' OI-' <lesi_plated oa d. rawm_g:. as T &. S )tccl. lt1 reinforoed <:oncrete-~val. 4, tc1npcrarurc and shri~c-rcinfo~mcm is U$ed. 1t rtgh1. mglcs: ~o the main stcd ror Lhc :,Jtni: _purpu:. c. Oflen in \\'8JI constructio~ temperature and shrinkage reinforcem~r1t may be placerl hori zontally,and vcrtic~dly i. n u wall face for 1empemrure And shnnkn,se pur(''i Me$ only, even though thal face of lbe wall does nol resist any other tension forces. COMPRESSION REINFORCEMENT IN COLUMNS While 100 main pul'J)OSt t0r tt,l\forclng ~eel in oo. ncrete is to resist tension fore~ it is also used to resist compression fon. :es.. The mosl \.-Ommon ll S-e of rcinforciqg s1ttl to resist co1~s:sion forces is in colunrns.. If concrete alone were used, ihe size of column required would he so lalge th3I it would be im prnctic:al and add considerable weight to the stlllcturc. Bccawc rcinfon:in. a bars arc about twenry times stronger than a. n equivalent area of concrete, they are used to resist pan or the column load. The concrute and reinforcing $!eel work together and Ille resulting column is smaller in size and lighter 111 weight. &-8 CQncrul Refnfon:ing S&eel lo&tituut Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
In continuous beams (those which ha YC more than two supports), the com pression in conetete is sometimes high in the bottom near a support. For this reason. and for the structural integrity requirements of the Building Code, some bottom n:inforcing bars arc extended and spliced with the bars in an adjoccnt span. REINFORCING BARS Reinforcing bats are available in different grades (see next chapter). Each grade has distinctive sirength properties. Then: arc parts of a structure where one grade may be used to bctcer advantaic than another. Therefore, the grades are identified on fhe struclwlll drawin~ Each grade rn,s wllat is known as specified yield strength and tensile strength. Yield strength is the load limit to which the steel will $!retch ond rerurn to its original length, much fbe same as stretching a rubber band. Tensile strength is the lod limit al which the steel breaks. WELDED WIRE REINFORCEMENT Welded wire reinforcemen t (plain or deformed) is made from wld-drawn wite. Shccls, rolls and ""i"" benl from shcc:IS an, spocirlcd in various yield sirengrhs. Welded wire reinforcement LS available in various widtl\., and lengths. CONCRETE PROTECT ION To protect reinforcement agaill St fire, corrosion or exposure to weather it m\l St have a mioimutn cover of oonc:retc. The minimum concrete oc,yu ls specified in building codes and shown on the structural drawings. The con crete cover is measured from the exttrior face of the concrm to lhe o UISide of the reinforcement. ln corrosive environments, such as chemical storage and manufacturing facilities. wutewfttcr treatment plants, st:rucrures exposed to seawater, bridges and parking struetures exposed to de. icing salts, additional concrete cover-may be required. This is usually specified on the structural d. rawinas. ln many instunccs, coated reinforcement is used as n corrosion pro1oction sysu,m for chose types of sttuciurcs. For more information on coated reinforcing steel, see Chapter 18. 6-10 Conc<Ole Reln Jorolng Sleel lnstih Ae Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
/ J l Table 7-1 ASTM Standard Roinforcing B;us Nominal Dimensions Bar Size Area. in. 2 Weight, Iba/It Oiamotor, fn. #3 0. 11 0. 3711 0. 375 114 0. 20 0. 668 0. 500 #5 0. 31, 04a o. ois 1/fi 0. 44 1. 502 0. 750 #7 0. 60 2. 044 0. 875 #8 0. 79 2. 670 1. 000 #9 1,00 3,400 1. 128 #10 127 4. 303 1270 #11 1. 56 5. 313 1. 410 #14 2. 25 7. 65 1. 693 #18 4. 00 13,60 2257 #20 4. 91 16. 69 2. 500 REINFORCING BARS: TYPES AND GRADES OF STEEL Rcinfon:ing ban in the United Stales arc rce<lily a Y1U1able in two ditlcrent types of stccl: carboo-s!Cel and low-alloy s<eel, These tw0 type$ of ste<I vruy in yield strcugth, tensile strength, pen:entnse of elong;,tion, bend test requirtme,us. and chemical composition. The pa:nicular grade (minimum yield strength) ofsttcl is a very important factor in the design of rcinfon:od concn:<c truc<urcs. Tb specific llf'l<le required for dillen:nt members ofa reinforred concrete structure will be stated in the project Specifications or on the structural drawings. 7-2 Concrola Re~ Stael lnsli!ula Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
( IDENTIFICATION OF DEFORMED REINFORCING BARS With the diffetent iypes. grades, and sizes ""i. lable. it is necessary 10 provide sonle means of bar identification. 11tc AS IM spcc:if,c:cuions rc~3t c~f..h llar P~cer roll olll O the r<info~ o) A lotter or symbol to show the Producer's mill, b) A number corrc,oponding to the size numbe, of the bar, c) A &ymbol or nwlcing 10 indicate the type of reinforcing stool, and c J) Gnldc mad, as shown in fig. 7-2, to de$ignare Grades 60, 75, 80, 100 and 120. The grade ma,k for Grade 60 may be eitbor the number "60" [4] or Ont (I) sing. le line. When 1. 1 single lioc is med to designate Orade 60, il is small~ and bctwcc-o th¢ two main nos which are on opposite sides of all USA4nade reinforcing bars. Similarly, the grode maiic for Grade 7S may be either the numbcr''7Snor two (2) grade lines. Grade marks for Grades 80, JOO and 120 are as hown in Fis, 7-2. If grade lin-.--s arc used, they m. USI be continued at 102Sl 5 deformation spaces. No~ marl< is required for Grodes 40 and 50. Bar identificatio n maiks may also be orienlfd to read horizontally (at 90-to cho. !ic illuscrared in Fig. 7-2). 7-4 cone,.. Roinlorefng Stool tn Slilule Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
H s Typo of Stool a... C1l'OOll(Al,I I) w..... ~~70lf) $$...-~"'9551 R,_,,Ral~ l..--Re~ A.-,-. iw. l MN) CL.,. ~Clwn't~,OM) CM.-~O! Rllli<,\~ cs-~Clu'«rba(A1"36) Grade Martt or Line s.. a. bflt DIIOw Minimum Yield Designation Grade of steel Grade Mark Grade Line" 40 blank no Unes 50 blank no lines 60 60 111na 75 75 2lines 80 80 3llnes 100 100 ore (A615) 4 Knes (A615) 100 100 (A1035) 3 lfnes (A1035) 120 120 4linos for s. talnles Hteel (A955) reinfordn& ba~ c:r 60-, for c;,,s.. "'... "Gnldt lints must be at lc~t 5 dcformiilltion S))a Ct'S long.. Fig. 7-2 Reinforcing Bar Markings The lronworl<er should verify these marking., to be certain the correct type$, gmdcs, and,iu:s :are being placed in the locations where tlw,y :are intended. If there is any doub~ the lronworkc, should check with the Foreman. PIO<:r G Reonlorolng Bots-10lh Edition 7-5 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 6-9 | Placing Reinforcing Bars.pdf |
SPIRALS Spirals arc used in spjra JJ. Y-rcinforccd coluptns_, piers, and pjles_,,m C arc made ~rormcd bars, Ql.. plain om r Wirt tie, I 10 a spcc,fied diarne1cr~ hape-;mllhtr to 1h01 Qf. 1 <. oiled spnn.,g. TI1e sp,adng of 1he bnr or wire is illl ponanr and spacers are sometimes provided co hold this spacing (known a. ~ tbc pitch), The spacers also serve to provide sufficient stiffiless to the spiral to keep it in alignment while being =ed. II i usually a steel channel or angle punched with a series of"lips" to hold the spiral turns to the proper pitch, as depicted in Fig. 7-4. Each Fabricator SCICCIS lhc shape of spacer best S<Jilod 10 the purp OSCJ to provide the required stiffness. Pitch Pitch Pitch Fig. 7-4 ~pie. al Spiral Spacers i. : r:n~u ~ ha rcgu1r"t"d the u,;,e of spira ~pacers for the pmject ut hat ro? sp~Cili«i the munhcr 4)ij;l)l Cerc; required.,Jable 7-3 " v _ tbe mrnimum number of spacers reqwreafor the s,ze of sptraf and diame:er ofspirall Table 7-3 Minimum Number of Spacets Spiral Bar or Wiro Sjzo Spiral Core Minimum Numbor Diameter, In. of Spacers #3or 318 in. Less than 20 2-20 lo 30 3 114 or 1 /2 In. Moro than 30 4 #Sor 5/8 in. 24 or lass 3 l#l or '3/4 in. More lhan24 4 Where only two spacers are used, Ibey are placed on opposite sides of the spi ral. When ma<e lhan two spacers are used, 1he addilionnl ones may be placod 7-14 Con<nf AI Relnf OO<:ircl Steol lnslill Jte Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6-9 | Placing Reinforcing Bars.pdf |
djocen1 ID lhc 1wo or bundled loose wilb lhc spiral for :lltac:llmcnt at 1hejob site. a,:ing the S{). 'tcers on oppostle sides of1he :spinal penmb the spird. l to be; ship J!Cd flat or '·coll. !l)sed," reqmrin~ space for <torage and shipmen L At the jobsi1c, the,pirals arc opened, and the spacers shifted so lhcy ore about equally spaced 8JOUl!d the pcrimctcroflhe spiral. Some spirals, because of their sma{I diameter, can:10< be collapsed. They are p_pcd with the sp3ccr:-mounted and ace Tahle 7-4 show:-the rnuumum <fo,meter or a collapsible spol, rc Jatcd 10 the spiral size. Spirals that include spacers are called assembled spirals. In some cases such as piles, piers or columns where the pitch is lo. rge or where lhc bar or wire diameter is quite small, or where the spir. 11 can be accurately spaced and tied to longitudinal reinforcing bars, spirals may be furnished hem into coi Is to the specified diameter and the propet numbcl-of turns without spacers. These an: known as unassembled spirals. iable 7-4 Mm1mum Splr. 11 Outside Diameters Minimum Outs,ide Diameter, in. Spiral Bar or Wire Slz:e Which Can Be Of Collapsible Formed Spiral #3 or 318 in. 8 18 #4 or 1/2 in. 10 18 #5 or 518 ln. 15 30 1#6 or 314 in. 24 30 OFFSET COLUMN BARS Offset column bars, ns ~hown in Fig. 1·S, arc bent'° the u1:,,per part, which projects beyond the ftoor abow, will fl! inside the vertical bars in the column above. The comer bars in a column need ID have a larger offiset than the bars along the sides, but for simplified fabrication and placing, a U offset bends in n column arc made using the latgest oflsct. Placlr,g FIMfon,tr Q Bn-100, Edition 7-15 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 6-9 | Placing Reinforcing Bars.pdf |
or 1hc General Con1ro C10<. The U50 or the cnne or hoist is dependent on ar rangements made in advance by the lronwortcer foreman. Fig. 8-1 Rninforcing Bars Stored at Jobsite When tl1e reinforcing bor. ! arc unloaded to the storage area, it i important that the location of the ami be selccte(l for eosy access by tt UCk and rehan dlina of the but to the area of placement in the sttucture. Normally, mai,ght reinforcing bars are stored by si,,:s and by knglhs within one bar size so that easy identification is possible. Bent reinforcing bars are similarly stored and the tags ofbodi straight an<l benl bars are kept at the same end for easy idcn· tification. S1imaps, column liet and spirnls l1J'C usually stored in one aiu wi1h lhe tags kept plainly visible. Figure 8-1 shows reinforcing bars stored at a jobsite. Tags should be all in one direction and at 1he same end of the bundle to avoid wall:ina bclt and forth, up and down the bundles. When a bundle is opened and some of the rcinforeing bars are removed, tl1e bar wilh the tag. Jiould remain with lhc bundle. If possible, the figure indicat ing 1he original 10101 number of n:inrorcing bars should be crossed out and new figure inserted indicating the remaiojng number of bars. SURFACE CONDITION OF BARS The surface condition of reinforcing bars may affi:ct the ability of the bars IO bond to the concrete. The mo. in fact O<S that may decrease bond are the pres coc:c of mill scale, rus1,. oil and mud. 8-2 Conci<>to Rolnlon:lr,g SIMI lnllituto Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 6-9 | Placing Reinforcing Bars.pdf |
Mill scale occurs ti the time the reinforcing bars m manufactun:d (rolled) and resulrs from cooling the hot meal. Loose rus, ar. d scale is usua ly re moved when the bars are handled and loodcd in the fabric.-. ating shop_, or in ll!ll®d!!Jg_;irul honil)mg at tho. J®'il JC Thtli Jiill_ni>t <!illl><le """"~ the bars ls normal and docs noc have an harmful dl"tt. :l on hor. d! Rust improves bond because ru~t increases the roughness of the surface. Only when the height of deformations or the weight of tbc reinforcing bars is,... duccd below tho minimum would rust bo considered harmful, os per ASTM requirements. Reinforcing bars: with rust or mill scale or a oombinatioo of both are considered to he occ:eplllblc without clconing or brushing, provided d1. at the minimum dimensions. including height of defomu11iom, and weight of a cleaned sample arc not Jc,s than ASTM specilicatioo requirements. Reinfon::ing bars should be wiloaded 311d stored in such a manuer that they will be lccpt free of mud. Arry mud coating on tho hors should be washed ol T before they arc placcd. Oc. casiona lly, reinforcing bars become covered with machine oil or grease. which mus, be removed before p L:tcing. Removal may be done by wiping with solvcllls. Sometimes in oiling forms, a slight ovco:spray of form oil gets on the reinforcing bars. Oil prcscnl on the ban; in <1uanlities sullicicnl IO decrease bond must be~ before placing.,,,.,,,ieto. HOISTING Power equipment is normally required co raise or 10"tt reinforcing bars from one level to another or to bridge obs12cles that prevent the hors from being carried mnnunlly. The typo of hoisting cquipmont will depend on: I) The size of the projec~ 2) Whether in a coog,cstcd area or an open :uea; and 3) Th<o height oflhe strucrore. l'ho moot commonly used types of hoisting equipment ore illustrated in Fig. 8-2. Tower cranes should also be included wi1h a note that m many areas NCCCO (National Commission for the Certificat ion of Crane Operators) cer tifications arc nccdcd for crane signo. lina and rigging. Placil1g Relnf O<Cll>g Baro-10th Edition 8--3 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6-9 | Placing Reinforcing Bars.pdf |
When hoi$ting bundles or n:infon:iog ban roughly 30 feet or longer, depend ing on the bar size (smaller bars flex more), it may be necessary to use a spn,a<ler beam,.. hown in Fig. 8-3, so tho n:inforcing bars will not bend excessily. A,prcad<r bc.,m allow, thc 1011d 10 be lifted vcmcully wllhout inducmgahori,. ootal fortt io!Qtbe bunclleofbi= Thcl<:ogtb ortb-der bnm,h<>uld be or lew onc-ll>lf l11e kn_gd, of th< rcmfo,. :,ng \Nm'i 111 tho bundle. The 1>n:adcr beam should be an OSHA or State-approved lifting device, witl\ the lood rating clearly p OOled on tho spreader beam. Fig. 8-J Crano, Chokors ond Spreodor Boam When bundles of rcinfon:ing bani are being hoisted, a taa lino shall be used unless its use creates an unsafe condition (OSHA, Pari 1926, Section 1926. 150J(g)(6)(iii)). A lag line is to be attached IO one or both ends of tho bundle for the purpose of guiding the lood as it is hois!Zd. Co11W:Oliooal rope is most commonly used for this purpose. Safe hoisting requires a skilled op enitor hanclli111 the power equipmen The crane opc,. 10r normally ta Jces di rections from the anlhorizcd signal person Ii) means of hand signals. Then: ""'o standord set of hand sign,1s thut arc ob. <CM:d by all crane opcrat Ot'S (see Fig, 8-4). On some projects, a radio headset is used to relay directions t0 the crane operator. Placing Rolnlon: Bani-10th Edition 8-7 Saf~ty Kool<S WUh Gatn J Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 10 BAR SUPPORTS GENERAL Bar supports are imended to maintain L'le location of the reinforcing bars durt l. 11_,g 1hc coocre1e pl. xcmont They 11Jso ensure proper conercte CO¥Ct is provided ovc-r the rcinforocmcnt and proper design depth is achieved. Concn:le oovcr is very imporn<nt in concrete oomlruclion bc<;ause it provides a minimum outet dimension of conaeie for corrooion pro-ion and 6,eproofmg for the embed ded reinforcing steel. The height of a bar support is lakcn as the distance from the bottom of the leg, sand plate, or runner wire to the underside oflhc rciafor,:ing bar when lhc bar is p,-operty positioned on lhe suppon. A variation or plus or minus 1/8 inch from the specified oomioal height is a nom,al constro Clion IOletance. 81r )uppqrt:t.-re mtcndcd to S\lpport tht rcmforcin. steel and norrn.. l con SLru1,:uon lo$ and, w maints!ll th..:. li~cnl or the rcinforc:. Dg i,~cl.. Bar supports are uot intended to support hoses for concrete pumps, runways for coocrete bug Kies or similar loads. The lrooworker should follow the placing drawings and schedules for plu ing bar supports. Minimum petformance requirements for bar supports can be fowid in ANSI/CRSI RB4. 1 Standard for Supports for 1<,i11forcem,n1 Used in Concreie. If a Contractor or a reinforcing bar placing Sub-Contrae l Or wants bar supports furnished for special conditions, special arrangements must be made 10 ootain them. When b:ir support$ are furnished by a J'abrical Or as part or Ibo coo tract, pla,:. ing drawings should identify bar supports in two w,rys. l11e required place ment and location of bar supports should be graphically shown through the use of schematic placing diagrams and/or typical details. The r<quirod bar suppons should also be called out with a note that indicates the quantity provided, nominal height, type of support. spacing and possibly the location which enables the Ironworker to readily select the proper bar sup1>0ru for placing in the proper locations (Examples : 200 LP of2" BB placed as shown in Lypical beam elevation, 450 PCS of 4 1/2" IHC @48" Each Way, 50 10" IHC@48" in drop panels only, etc. ). Placing Reinforcing 81,.-1 0th &fltion 1 0-1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 6-9 | Placing Reinforcing Bars.pdf |
Bar supports may be made of Slccl wire, pn,cut concre1e, or cornposiu, mate rial. Illustrations of wlre bor supports, prcco Sl concrcic blocks, and composite bar supports are presented in Tables I 0-1, I 0-2, aod 10-3, respecli>dy. For moo, in formation on bar supports, see Chapter 3 of CRSI\ Manual q/Standani Practice. Table 10-1 Typical Types and Sizes of Wire Reinforcement Supports ... IOI. Id IMIO!lf 1U. Ul1M tx:■' IMl......,. 1. WITMIW,,.,... ffl'lt M. lil ZH.,-~to ~·--~<l::£-~A-""-'·'"-2..,--. ~~ ll'll!O't.,,_.,)11'1-r, '-,..... 1-. n Qlfl UIH-~~ e.-w,_...-IC. n ~......... K1,1~H~., 11,:11:l2 °"" <fl,hcitha....-o-... ic.,,.,., ·'-l__~ ~ __ ;,l,J....... '"...,... Tr71-~"°'s-...._,... n M. P,~t;i,. _.........,".......,..-C:4--OC....... ·-~--.. /-,~~ua..a. ·-he,...,...,,,,....... """"'.. r.-r "' JJ\1 nn lfd"M;i111t¥ tl01Skla¥ntt-\\:J..-.... "';.,., --/111 ""Obll'-:ll O 11111......,. _-.....------""""., ~--~-oi,. __A--... :..-,,~ Nl C..htlllll)S. i WI. ' '-. ....--~~... ~... ~-IN "''°"" 141n.... ao/t Nf,,I-tl. U. l1'1a. ~"',~~-.,_.... ~ ~tl. '-11..-~-~-~-!,(... _ K,1,1)l,l...,J.,, hftlllllll!!lt On........ ~~ _.. ,... 1i1,--,......-v--·--....... ·-----· ~........... 1ol'~IN1'0-"""'-.. ~-----a.,........ tr!Mlltt WI..... -"--"......... a-. :1....,,....................... 10-2 Concrete Relnfon:ing Slee! 1.-ute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 6-9 | Placing Reinforcing Bars.pdf |
\ Table 10-3 T pica! Types and Sizes of Plastic Relnforcemenl Supports-BAI !rft AT 11. LUSTAAID......----" IA--.... I It---~---_, ~---.....--~ n ~......... ..,.. ' H,0,,~ ·-...., A fl, ".............. a-\I... -,... A.. _...... I, /--.... ~~,... _-...... l_,. ..,.....-_....-... ----·-~....-..,ier~~--..,t!Qi;o W... M--~0t~tlollfcl hc,II,.-......-..............,................. 1 G-4 Concre M R<linfordng Stool lnstiluto mot A """"""" ·---e.-....,...... _--~........... _........ _. __,....--........ c. nt,i9t.........-o,t,....... IW "·" ~--------.,__, .....,. ag,:i,~r--.-U-'18......... ~.......-.,-.-~~-fldlll"1............ fi11"6bo,;;;11t~!i111 tllll Oo111"1~--..,_ Gtntn1Jt...-a1~n~.,..i'I-· '"'".,.-h.-.,_...,.._~, u,.,-~lol Nla.. f Ol~h. Wlllf ~"'"'----...,., ··. :::'~_,..,,-~--...-~.. -f«hcl&oc O;;,,d....SU:--. ~ l~1'5-~"'""'...,. ·-2"·,.,..,... ~.._.....,.._,.,...-U,t'f"""""'~, IK\tf,C-~..Sll M!Uonul... ~ l4■ ~~...,. _,.... ~,_. «,el "'~-1,;. ibb bclarffl!H W....-..........----.-c--r--.............--,., lllld Oll!llle-lll'Jlllb~,,_....-o. ntrn,..,.,,.. 11111'1""9 ~.,,,-·...,..,....... _..... _,__,.......,. «om,,&c,ta,,;t,fl~..... c,an""1................ ~---.... o. n.,.., ____ I;...,.....,. -·-,io,,..,..... __,. a_..... ~--~-Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
( l CONCRETE COVER OR PROTECTION The proper amoont of concrete co. <:r on the,:einforoing bars is very importmt The Enginca specifics the amount of concrete protection for each J)IUt of the stt Ucturc and bases the design on these cover rcquircmc n1S, laking into consid, enition the requirements of building codes, fin: hazards, possibility of corro sion, and e,cposure to weather. 11/2"100!Jl$idtof m #Cthfll.,l2". II IIQttll'IJltt-¾.. #$611'1dwt¼ ".....,,. 1¼ (b) Walls 1% ld) Beams 3/. "~3/,"....,,.. ~)Jltabs" (~ts" -11Ct-. UBuildi.. Codo~"lll<Slnlcoa mt Co1""'°(ACt3tl-t,~ Soetloo 20. 5. t. l. t. Coocrctc oowu illustnitod we fot sl3bs « joists nee: exposed to~ or in 001t11Ct 'With pund. For 114 and #18 bm in slab$ or joists. the rccpnd concrccc CO¥Cr° is I1/2 inc:ks. fig, 11-1 Minimum Concrete Covo,.. 11-2 concne Rainforct,g Stoot tn Slitute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
Where not spcci~fotlowing nun,murn concttrc cover (o~b,1de of ~ face of concrete) stould be obs«ved· J. inches at sides where coocrctc is cast ag_afost the ground and on bottoms of footmi S or other 1>rinc1pol ~trucrural mcmbtrs where conl.-rctc is pt. ccd on S!l!\Uld. (f!&. ll;l(all ~-2 inches for bars larger man #5, where concrete surfaces, after removal of fonns, will be cxp__Q$td to 1he weather or be in contuct with the ~ and l1/2incbc>for#Sbarsandsma Ccr. (fig. lm(b)) G. I1/2 1o<:hes 10 ouisideofties alld spirals in col WMs. (Fill, 11-l(c)) ~. LS mchcs lo nearest re orcmg bars on the top_, bottom beams and girce,s. (Fig. 11-l(d)) Ii, 1,jnc)) for. tt. Uond sma:Jcrbars on Jop, boltl!m an. d sides ofji,is. i,,, and. l!l1 ~ and bouom o :,labs where t:on\.-rctc ~ur 11<..Q ar~ not e,. pcx;cd dircctl to me ground o; t(1e w-..a,ber and I1/2 ui&hes fo, #14 and ~I~ bar$. (fig<. 11-l(e)and ll-l(f)) 6, V. mch from In< <cs or. II walls no. 1_9p()Scd duclli)' 10 the Jl[Oundof tho 11. 'fathor for #I J and smalle< bar,, and I1/2 inches for #14 aod #18 bats;. ffill-JJ. JQI)) TOLERANCES IN PLACEMENT ( ;cncnal II Js,mportnnt that re Ln or<:mg baf S be placat rut<l held rn posili~ shown on die placing drawir. gs. The strength of any remforced C:O!Krel¢ swctural member can Ge affected by the improper poo1tiomng of the reinforcuig b>!J. ~ cxmnpk:, lowcnna; lh,; lop bars or ruising; the hottom bars by 1/2 mch more chan l,pec m a-me cep s a&ooiifd reduce its oa cany,. og !;,!p>Clt)' by _ per cent Barsupp Ort S, si,a,:,ed ac:cordiag to industry practice for placing bar supports, should be suffi<:ient to position the reinfon:ing bats as required. Unless otherwise noted, reinforcing bars should be plaoed within the following construction tolmnces (AO 117}: I. Tolc:ranco fa< the clear dlsiance to formed soffit., hoold be-1/4 inch, and the tolonnco for concrete cow:r should not exceed minus ooe-third of the mioinnun concrete caver required on the project drawings or in the project specifications. Placing Reinforcing Bara-10th Ecltion 11-3 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
( 2. Tolerance for d>e loogjtudinal localion of bend., arod ends of reinforcing bars should be ±2 inches, excq,c at discontinuous ends of strucrural mem bers where the tolerance should be ± I inch. 3. As long as the tocal number of reinforcing bars n,quired is maintained, a reasonable tolerance in spacing individual bars is J. 3 inches, except where openings, inserts, and embedded items might require some additional shiflina of bars. 4. Tolerance for lap splice lengths should be-I inch. 5. Tolerance for embedded leog U, should be-I inch fot-/l'J lbrough #11 bors, and-2 inches for #14 and #18 bars. 6. Tolerance on the vertical placa:m:nt of reinforcing bors: a. :tl/4 io. (mernb«depth s 4 in. ) b. ±3/4 in. (member depth >4 in.,~ 12 in. ) c. :ti in. (member depth> 12 in. ) 7. Tnlemnce nn the clearance he N'!en reinforcing, ha. rs; one-quartet spte:1-fied dist>nce, not to exceed ±I in. 'fbese reasonabk toler:i. nc:es are a JIO\\-ecl to permit economical reinforcing bar placing one:! still meet the Engineer's dc,ign roquircmcnis. Toler= in the fabrication of reinforcing b<l!s are covered in Chapler 6 of this book. uhc cxoct posuioning. ofl Qn. gitudinal rcinf QJ9Qg bars ii-~rally not critical to the strength of the >truc-tural member; lhcrcforc, the placin_g tolcrancies are not as restrictive as those shown for concrete cover, For example, in ooutinuous beams, the botl Om bars roay be specified to extend 6 inches irll O suppcrting col umns ot each end of the beams. Voriarions in the sheared lengrh ofd,e bars, rho center-to-oenrer discanc:es between cotumns, and rhe form dimensions. make a larger longitudinal tolennce necessa,y. A tolerance of, 2 inches $hoold be suf fic-ent, as shown in Fig. 11 l. 11-4 c:cnc,a Relnf Ofdng Sleel lnlh Me Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 6-9 | Placing Reinforcing Bars.pdf |
Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
( ... LEuct Spacing Not Ct11lcol Total Number of Bars 1s VERY ffl PC)rtant Fig. 11-4 Bars ln Slabs and Wallo As loog as the totll number of rcinfurcing btil S specified is maintained, a rea SON1ble tolerance in spacing individual bars is,t J inches, except where open ings, inscr18, or cmbcdcled items, might require some additional shifting of bars. Where reinfun::ing bars ue spaced in ~labs or walls in Yi inch increments im1Cad of whole inches, the """"' result is obcained by alternating the next smaller and the next larger inch. For example, 121/2-inch spacing equivalent is obrained by alternating the bar spacings 12 inches, 13 inches, 12 inches. 13 inches, and so oo. Lateral Spacing of liars in Joist', Bttm J and Girders. Thc ACI Building C~ Sp«ifies the minimum amount of OOll<retecovcrovcr slimrj,s, ties and od>e< rein fon:inj: bars, as well as thc minimwn clear ~ bel....,.., bars. The American Ass«iation of $rate Higl!way and TJ1111>,x,rtation Officials (AASHTO) estab lishes the minimum amouot of coo=ecove r "'"' reinfotcing bars in bridges. In either case. the Engineer should ddetmi11e whether or not che minimum concrete Ct M< or spacing would req,,i,,o a second or third layer of reinfon:ing ban. A certain amount of wiring of reinfon;iog bais lo bar supp Ol1S and lo stirrups and ties will be required to keep the longitudinal bars r=onablystraigh t, parallel, and at the proper latcrnl spocir1g. lley()tld that, additional tying is UMCcessary; When beams or girders wi1h many reinforcing h3JS are S1l Jll>ORed by columns that are heavily r<inforce<I, it is some<imes helpful to make a fulhi. zcd template for such intcrscctions to hold the oohmm vertical bars in such a position that the beam bars will later pass around the column bas satisfactorily. When these bars cross at dgbr angles, it is acccpiablc for them to be in contact wi01 each other. l. ocatlnn of First and La5t Bar. If neither the p acin~wm~ nor the Engi.. """"'s typical det2ils show where lbe first and last reinfordn_g bars;. a run are to J,,c pla~ i1. (s n:. @. mmcrull&Uiat the spa~ shown m Figs. l-5 through ITTfbe loll 11-6 concrece Aeinf~ Stoel lnctiluto Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
<D \.-...,. 11~ @ rnr; ~..... ~ . '·:",'; *' j Jttr~. ::· ... j ·,J~~-c. Hl3A$Sll'Ull'la) @ w··--.., ,J-~~ d t., -. GAS~IR> ·im~·-·· ~--,. f Fig. 11-15 One-Way Slab Main Flexural Reinfon;ing Bar5 11-14 Cc,ncnte Reinron;lng S<oel- Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
G) ··. i _,_--...-,-,i..... _,,,,,,_.._......... ~---......-......i,,,,. Fig. 11-16 One-Way Slab Shrinkage and Temperature Reinforcing Bars Plac;1111 Reinforeing a..-10th Edllon 11-15 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
, I Cbrificatio n of Field Bending as 0ppo Jed to Field Rca Ugnment : Field Bending-The. first initial bcod in a bar. Field Realignment-T o altc:r the angle or existing position of a bar. When it is necessary to field bend or field realign bars the followil1g item should be reviewed: I. Engineer's approval 2. Safety concerns due to J>O"'iblc breakage of~ 3. Safety concerns due to improper use of equipmen t Field Ot1tlng or Reinforcing Bars. Various means are used to cul rcinfon:ing bars at the jobsile. The smaller size bars, #'3 to 115, can usually be cut with boll cuncrs. All bar sizes ca1\ be au with an abrnsive S3W or by ftame-curting mch a$ u,ing an oxy-aa:,ylcne ton:b. fllmw. cutting of epoxy-c03ted reinforcing bars is not recommended. Any damaged bar =tings must bc r,:ptir,:d. Reprding Oam<>cutt ing. l C3U ha\. : sbown that u,y effect of ftame-cuning is localized 10 lbe end-cut surfaces. Only a very short distance, approximately 3/16 inch, from tbe llan>e-<UI eacls is alfected. From the te SIS it was concluded that flame-cuning had no adverse elfec,s. SPLICES* Reinforced concrete structures ar e gc,,cnlly designed so lhat the scpmtc parts act as a single unit, making it necessary to properly locate construction joints and provide continuity in the reinforcement through the joints. Just as it is im PQ6-sible to place all the concme at one time, it is aloo impossible to p<CMde full laigth continuoos reinforcing bars in most structures because of manufacturing, fabrication,or t Jan Sportation limj1. a1jons. Because splices i. o reinforcement can not be avoided, it is ncca.,ary for tl,e Engineer to provide fo,-prope,1y designed splices, a J\d to identify their lengths and locations on the slf1ld1Jfal drawings. Some knowlt<li;<: of rcinf0r1;ing bar lenglh liir Jia,'ons mey t,,; h<lrful, I. !!irs_arc_ocd,nanly_$!!Xl(C(I in !>![l"Ql>t lengi!i$1 2. Lengths ewer 60 fee: m allllar ~ while net ordi~~ be ob\oin. <d Ill' speci<I &. "nlllll-<:. l!J<. 11!. 11-18 C<>ncnto Reinforot,g Steol lnsd OAo Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
Q111:§+ Fig. 11-18 Maxfm1. 111 Olmonslon-8undles of Bent Bars for Truck Oelive,y Trucking regulations in various states and cities often limit the maximwn lcmgth and width of reinforcing bars (see Fig. 11-18). Sometimes long,:r lengths can be shipped by rail or wate L Bending dimensions ofu:n govem the length that cam be tr. tnsported. f1actic. al con'-tr UClit)n limitation~ Otl (em orc1ne_bar ~ensch~ n':. a. <;! 3. l"o be con sidered cxce11t for slabs on grow,!'!, '. ong lengths of horizontal oors p19. i0!;!i!!g far beyond roquirtd con. structio. n joints arc g_cncrally un<lcsintbk. A 1:>pli. :c ai or n~ ct 1. :on. strui. :1100 ju int c, preferable Vertical bar lcnglhs in columns and walls are more severely res,ricted. In multi-&OI)' construction, column bars arc often one sta<y in height Howcva, with heavily rcinfonx:d col Wllll S and Slauc,cd locati Oll of splices, vertical bors can extend two stories in heigl,L In ltigh ws Us, vertical bars exiending fu U height are sometimes difficult to hold in position and may need to be spliced at one or more locations, either to su. it the Contn1ctnn concrete pl>Cing ni,ention. nr die location of the col Ull'UClion joints as determined by the 1:ngineer. Splices are Jw. attd, at construction joints belwec::n footing} ~ml <. :olur;ms or wrill!i. :wcc:11 oolumnl) bel C"M· and ab Q\c a floor, QC bct'-'tten \\<Jlls ;1nd floo. Reinforcing bars project lhrough the oonstruction joint and are spliced with other bars either by lap splices, or mechanica l or welded splices. In general, spliocs occur where the "1ruclural drawin& permit or where shown in typical structunl details. Jn vt:71:Jcal c:onsfr\letion, lb: erection of fon:ns prior to plac:ng_ reluforcement (i~mc~ in wall~ hould be co01'd1nattd witll lhe n::111 rc. ement,;plice tionoi., to provide a proper nlc. !n S of bracm,s rc:mforcieme ru as,1. ~11 as a n to place reinforcement withir. the concrere cover and construcuon tolerances. (~uns1rucllilli J o. in!uu:. p... Q. U. r ~Wan. : fl5)ffl\. J)ly locatcd..)yhcg $J>htcl>___Q_CS:U"" 10 the honzont,al or vertical ~-Splices at slab and beam construction JOIUL~ are generally gu Jded more by dcs,i;n n::quircmcn L 'll Tho Contnclor should take this into account during the Placing Reinforcing Bara-10th Edtion 11-19, Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 6-9 | Placing Reinforcing Bars.pdf |
\ fonni Qg or excavation operations in order to allow the Ironworker to propeny and efficiently p. lace the reinforcing steel. Bolll ""'WO spbcc<I, u,uolly by lapp11111, wlicn used uh Orizenlal bani on wolls, M1,pcr,1ure 1111d shnok.,ge bars in,labs, or v,,rtical bars extending through bori70!1Ull construel100 Jou,t S-in high walls Md piers. The location and type of splices are shown on the placing drawings. No subsl;. wtion in type or locatioo should bc IUldc witbout proper audl Ority ond specific lnstroetloos u to npplicatioo. The r-rce typcsof spliccurc() lap,(b)medwucal. and (c Jwelded. lbeseare u'1drfi-sc:d in thc-followmg secitons. LAP SPLICES TIM: lcolflh of a lnp splice varies with contrctc Mrtoglh, type of conc;rcto, die yield strengib (grade) of Ibo mnforcing ba J:s, bar size, bar spacing, concrdc cover, and the quantity ot' ties or sin'lll'S-Lap splice lengths a,,; al Wll)'S shown on placing drawings and wm be found either in the details, lap llhm, or in the genen>l notes. Some typical lap splice details are s'-n in rig. 11-19; Olhcr. s are dlown elsewhere in thi J cluptcr. Due 10 clooe spacing of reinforcing ban, it is not always poss,ble to provide lap splices. In-co.-especially on large sitt bll,s. the lengd1 of o lap Splice might be sufficient to mw: another type of splice more economical. Lap splic i J!i of #14 and #18 bors is not pcrmitwd by tbe ACI Building Code, c:xccpt in con,p,:<ssion and only to #11 aod smaller bars, which neeessita~ making some type of mechanical or welded splice. The l'. ngineer may specify a parlicur.. type of mechanical splice, bw more often, !he contract documents will provide a choice of types to die Conttlletor. The Fabricator will ncod ID know the type sclccud so that proper end pn,parntion of the reinforcing bars can be made in I. be shop, ifrcquircd. Also, lbc Fabri CSIOr will need to show lap splice details on lhe placing dnwings for use by tho lroowooi<ers. 11-20 Concrete R001foroing Steellnt1ilulo Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 6-9 | Placing Reinforcing Bars.pdf |
Footing Dowtts.-L:tp Spfice to vel'tk. a J wan Bat'I T t.-l Me.-tl,1"..... (Of C......\~..,,.. ___ ~U i,Spliee (Preferred),-·w'" ,_ I '-~ n,a,lfootlrle~ Lap Splice-Horlzo nl I Wd Bars, l. Ongll Udl nel Footing 8at S & Oow~I Non,C. ontac;t Lap SPk Joist Cou1ruc1ron~Temperat u,. Relnfotcemo nt U. slng Wekled Wire Reinforcem Ht fig. 11-19 l.,op Splices Placing Reinf O<Cing Bari-10th Edi Uon 11-21 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
MECHANICAL SPLICES There are two ga,aal types of proprielal)I mecbanical splices: (a) those used to ttansfer te,ision and/or compression forces, and (b) end-bearing splices used for compression-only rcquircmenls. Brief descriptions and illu,,118lions of some commercially available propriewy mccbanical splices follow. Steel-FIiled Coupling Sleeve The s!ed-lillod COUpling slee,oc (see Fig, 11-21) is a mechanical splice in v. mch moltco melal or "metallic grout" inte,iocks the groo,a inside Ibo splice slcc>c with the defom. toons on the reinfo,clng bar. A crucible is auochcd to the side of the sleere by use of a pouring basin aligned with a tap bole. The orucib!o conlains a filler metll which is ignited, becomes mollco and Dows into the slcew and around the baa, ccmplcicly filling lhe space. The clamps hotdi11g the 1-in position ood the cn,cil,le are remc,,'ed and reused. Bars may have shear cut or 6,me cut ends, but a bar-end check must be made by the Fabric3tor prior to shipmen1. Special details permit USC.. cod mcbor,; or coon<Clioo to Sll'\ICtuml SIOCI memberi. F,g. 11-21 Steel-Filled Coupling Sleeve Ploolng lloo,lordig Bon-10Ch Edftlol'1 11-23 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 6-9 | Placing Reinforcing Bars.pdf |
11 is 11()( inrendcd Iha! n:infon:ing bm saw-cul for tension mechanical splices meet the above AC! Building Code lolcrances for cod-bearing (compression) splices for maximum deviation and gop, Refer to manu&crun:r of tension-compressio n mcdwrical spliccs for maxi mwn end deviation of shear cut or fl-I reinforcitlg bar ends 10 cnsun: adequate dlfead engagement in couplers or adequate leng,th of bar deformations in s J..,..,..typc splices. Tab!e 11-1 lists the maximum gap and n=imum end deviation for /#J to #18 bars. Table 11-1 Maximum Gap and End Devla Uon Bar Sl. ze Apgrox.. Max. IP, 1n. A~x. Max. End ;evlation, In. 118 3,184 1/32 #9 1/16 1/32 #10 1/16 1/32 #11 5184 1/32 #14 3/32 3/84 #18 1/8 1/16 WELDED SPLICES In genenl field "~lded sl1!i!:l;s of reinforcing bars are of two '. )lpes: W la;, splices and (I:,) bllll_Si!li~;, Welded lap splices are recommended only for #6 bars: or smaller. Indirect welded lap splices, using a "back-up" plate, may also be used. In either case, it is nects Sary for the Engineer to consider the bar ccccnlricity in tho design. See various lypcs of welded splices in Fig. 11-36. P!oclng Re;nlorcing Ban-10th E<ltlon 11-31 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
There are several lypes of welded bult splices, some dirccl and otbtrn indim:t which use angles, plres or sleeves. The direct splices a,c illu<1n11cd in Fig. I I 36 and require special cutting or sawing oftbe bar ends. Direel butt joiol T_ypc:s (I) and (2) ore nonnally used in horizonial position and lypes (3) and (4) in vtrlical position. The double-bevel gmo,e weld (lype4) is commonly 11sed for coilann v,:rtical ba,s, An indirect butt splice with splice plate or angle is also shown in Fig. I 1-36. Thc ACI Building Code requir,s thal all,..,ldingshouldconfonnll:JAWS 01. 4, '"Sctu Ctural Wdding Codl.---Reinforc~eel:' of the American Welding ~ ciety. The Welding Code, in tum, rcqutrcs the Contractor to prepare a wrinen welding proccdw-e,pec Jftcotion (WPS) fcr thc welded spliccs. lnformotion on the s-pccific n:quiremenl of a WPS is described in Ora pier 6 and Annex A of Ute Welding Code. Ficrd we Cling o er sin rc. mforcmg bars "lac. :k" ¥-d Jin. Go ··~t" welding) sbouldoc avoided. Simply star<ing a spa. 1' against a bar, "taclci Qg" gn a cglumn !k. Qr !Jiruikagc temperature bar or an_y ~mila, oner(itioo tbat c;Qo~ illc-.,:,;_. higb hea1 a1 one pom? o II b,. 1r crc3lts whal !..'i c:il16d a ··notc N' effcc:~ IC1,1~ h..,c $hown th. at this c-. an n;::d U(. ~ the strength of a bar to 35 or 40 perce.,t of it~ o.-i£,t nal capacity. The cbcmie11I properties or reinforcing bats, except for low-elloy tccl bu, (ASTM A706), can vary considerably. To produce good welds it is o¢e¢>..sary; (a) to have mill le,Creports on the bars, including the chemical propei. tie>,. {b) proper sclcctmn ofelec<rocles ha'i(,·d on ti~ rep. Q,~_(,c J_qy__alificd v~lde. G...-aod (d) careful a<lhcrona: <o weldm_g pioctdurc spc:t. ificauonsi In precast concrete c. ons1ruc:1ion, welded splices are almost a!,vays nece:ssa,yl l'ro COSI concteto membo,s are usually cast wilh projecting bars or plates ll1d lhese projections are CQnneaed from member lo member by butt-welded or lap-wcldcd splices. Placing Rmlorcing 811'1-100, Edtlon 11-33 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
I ! HEADED REINFORCING BARS An alternate, effective way to fttlly aaclior or dev<:lop reinfuccing bars in ten sion within n:latively sh<xt cmbedment lenglhs is to use headed reinforcing bars nithc-r 1llan bars wilh stru1dord hooks. Headed bars consist ofa nut orplatc, h2ving eid,er a row,d, elliptical or l<dangular shape, attached to tbc cod(s) of the bar. Attlclunent of the bead to tbc bar is aocomplishcd by welding. thread ing. cold swaamg. or shear screw. Another con Jitplration of a headed bar is a bor with an integrally-forged bead. Sec rig. 11-37. Since headed reinforcing bars are intended to replace bars with standard end hooks, the benefits of such an nnchoragc,ystcm arc to rcdllcc cmbcdment and simplify bar placement Headed bm were fust used in the constmction ofrein forad concrete offshore oil platforms. Usage ofhcaded bars bas been <Xtended to bridge and building comlruction. Fig. 11-37 Headed Reinforcing Bars TIE WIRE AND TOOLS Canylng Tie Wire. Allhous), the pnctice of carrying rio wire wries somewhat in dilfcrent regions= the country, rie wire is usually available in 3 to 4 pound coils. TI>e coils are readily placed in a tie wire boldc:r or n,c J especially desil!)>ed for this p W])OOO. The reel is su,pcnded from tbc lronworlcer \ belt for easy acces sibility and use. Figure 11-38 shows an lron\\Ollett eying bm in a slab. Size of Tie \Vtn. Wire used for tying_ reinf<. lrting °b<tt:S 1s usua y. o. : or ~~ son. annea led \\1re l. n some cases. a heavier No. IS or No. 14 gauge tiowirc(or2 wins, doubled,of either No. l61/2or No. 16 gauge)may be used,vi= tying bars in heavily-reinforad caissons or walls to maintain tbc proper position of the n,inforcing bani. 11-J4 eonc..t. Rolofordog SIMI ntitute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
Fig. 11-38 Tying Reinfon:ing Bars Twes or Ties. \la. "10US lypes of oes are ll'rod,vhcn sccunng remforcing bars. Much of lhctying is doru: oo fla~ horizontal funnl'l>lk1>11<b'"' ffoor sl. t,, S<;v cral of the mosl oommon lypcs ofltes an: tllustratcd 1n r,_g. 11-19 ~od di,;cnbtd as ronows: ...... Fig, 11~9 Typos of Ties at Reinforcing Bar ln«,rsec1ions Plac;ng Reo1forcing e....-,oth Edmon 11-35 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 6-9 | Placing Reinforcing Bars.pdf |
I \ Detnil A. The Snop oc Sini:Je Tie is normally 11s,:d JO 6a1, hori1. oc11. 1J w Qlt to secure Ulc rcwforcing 6irs i. n position agn!nst dl. $,J>!. 3cdn&IL due to \lo'Ork docc bx_olhcr trades and during concrete placement This is a very simple tie, aoo is wrapped once a:rouod the two crossing. b:!ts in d1agorul m. unn with 1M two ""e cods on lop. The witcs arc then twisted together with a pair ofptim until they arc tis),11gain:,1 lhc bars. The wire is then cut with pliers and the "'1ds adjll Slild sufficiently to prev<:nt them from protruding through the concrete sur faces. This type of tie is ai. o used when tying bart in cni S$00$, al times using No. IS gauge wire. The snap or single tie may be mdc $l<Ongcr by doubling che wire nlber than using !he heavier gauge wire. TI,e de would then be called a double snap ti<> or single tic-<loublc wire. betan ll. 11,e Wrap and Sn,p TIC isoormally usi:d when tying wall rcinfon:c mom, holding !he bars securely in position.., that neithet the hori:o:oosal nor lb<: vertical bl!B can shift during the consm,ction pmc:e« or dwing conc,,,re pla<e mc-o L This tic can also be used to prevent the bent bor ends of either hori1. onta1 or vcttic11l brs from twistin 110111 of position. The tie is made by wrapping the wire I1/2 times around the-ical or horizolllal bar, and then diogo,ully around the inreroecting bar, completing the tie in the same manner as a snap tie (single tie). nciail (;, The SAddlc <,t· uu Tic is more complicated tb4n the lint two do scribed, but is fav-Ored in ce,tain geog,aphical regions of the COllntry. This typo of tic is commonly used for sccuring oolwnn des to vertie41 comer bars, beam stirrups to \ongiltldinal oomc:r bars and securing template bars for walls, col umn and slab6-The wires pass halfway around one of the bars on each side of the crossing bar, tben are hfought squarely around the crossing bar, then up and around the first bar where they are twismd as sliown. A wrap and snap tie or a saddle ric is often \IScd to tic the reinforccmau in wall cwuins that the lroowodccr may climb oo during the installation process. 1)tta Jt 0. 'Ilic Wrap arid Saddfl! Tic is sin,U. ar ro cho saddle de except that lhe wire is wrapped I1/2 times around the first bar; dten oompleled as described for 1ho saddle lie. This type of tic con be u. l Od 10 secure hevy mars thnl ore lilb:d by crane and for securing column ties to wttical bars where !here is a heavy load on the ties. 11-36 Concrete Re"11orcif1V &eel lnotitute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
Ootail Th~ Fi'"""' t:ii;M ·ne is often wrcd in place of tho saddle tie and snap and wrap tie. Howew,r, Ole figure eight tie does not olfe,· the holding strength of the saddle tie. The figure eight tie can also be tied using an additional wrap arowid ooc bar to iocruse the holding strength (simibr to a wrap and snap or wmp and saddle tic). Step 1 S~p2 Step3 Fig. 11-40 Nail Head Tie In oddition, a Nail Ht11d Tie (fig. I I-40) is used when nails arc used os spread ers IO bold wall bars away from the fonns. The wire is wi->PJ,ed once around tile nail bead, then around the ootsido bar of the wall mat, drawing the oor securely againsl the nail bead by twi Sling the ends of the wire. Tools. The tools and equipme,,, usually c:amed by the Ironwodu:, an, as fol lows. All safety equipment mus1 be ANSI approved. Reference Oiapter 7 for additional safety requirements and best practices. I. Hud hat 2. Worlc b OOIS with ankle support, maintained in good condition 3. Safety glasses (provided by employee or Contractor) 4. Ear plugs or protection (provided by Contractor and worn when required) S. GI°""" made ori.. o,er or other appropriate maierial Placing FWnforcing Bin-10th Edition 11--'. 17 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 6-9 | Placing Reinforcing Bars.pdf |
Plan View of Top of F-ooting Im----Plan View of Bottom of Foo Ung Stal'ldn 0t Spedal Suppoct Bv Support SI de Elevation of Footing I ! ·--~-' I. Fig. 12-11 Combined Footing Bars MAT OR RAFT SLAB FOUNDATIONS Sometimes a sin&I slab of reinforced concrete is used underneath all of the columns or walls of a structure, tudng die place of individual column footing> or continuous wall footing:,. 'l'he slab lhiclcness wries widely, dq,cnding on soil condirioos and die loads to be supported, but is usually in the range of I to 5 fcc L The thiclcncs$ could go up to 10 or 15 fec L Geaertilly, a rail slab is reinforced wilb a ma~of reinforcing ban; in twodir,aion<: &he boltom bars berng locate<! 3 mches :1bovc 1h~-ruhsrq{or 101. :d 9111b with d sunllar nut of iop reinforcing sittl locaied 2 inches below the top of the slab. 1n cm!er to. i..,w tho reinfurang bars more clearly, tho placing drawings may show bottom mat bars on one plan view and top mat bars on anodier. The placing draw inss will give tho number of pieces, siz. e, length, and spacing of tlxsc b31$. Often the reinforcing bars may not run the full length of the slab, in which case tbe beginning and end of each lino of reinf01<ing bars will be shown on ihe placing Plocing Relnlortiflg ao,--10lh Edmon 12-11 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
( dmwinp, Where rcinf Ol<ina bars an, laj> spliced to mab upa CXJ11tin UOUJ line of reinforcemen~ the 11umber or 011Crlapping bars of each length is shown. II is ibc r,:spomibility of the General CM=nr to pcv,,ide a linn le-vol subgnldc in acconluncc with the struclllllll drawings and within colen,nces Speeilied in tho conttact documeo1s. Aller the sul>gradc is leveled and prepored ready for n,in. forccmen L inslallation the IO\\u mat rdnrorcing bars will be pl-In lhee,«:a,..-tion. A second layer of aoss bars rests directly on the liist layer and the two layers are tied,ogether as nocessn,y for smbility. Unk$s the number ofbor rie loeatinos is specified in the contract documeots, it is not ~ to tic e--:cry bar intersec- tion or O\en 1111,mar,, in!er,octions, Only enougll Lyin& snould be done 10 ensure llm L Ibo reinforcing bars will remain in place until ~ with oon C<de. A,; a ,::eneml rule, """l' barsbo<,ld be tied in al least three pb,:cs in its len,::th. llars up to 116 should be tied m ut1ers,aions a, teas, every 4 or S feel, wi1h the distance gn,dually im:reascd for larger bats; #10 or fl! I bars shoold be lied every 7 or 8 reet, h is desirable 10 tic n:inforcing bars nc:ir meir ends nd near tl>e '""'" edge oflhemat, where displacement ismorelikclylooccur; The bottom layer of reinforcing bars may be supported on 01mcrc10 blow (similar to small footings) oron chaiis with sand plates. In order :o support 1he IOJ) Jaye, of bat$. special sup POrts d~-d to rail on lhe bottom loyer are wood. Anolhe<,ype of bar support is a dowel block, which can be used m support bolh the bottom and top bar IAyers. Bar Sll Jlll O"-' for fowldalion mm are illll Slnlltd in Fig. 12-12-Soppons me usually Sjl(lcod three to five fccc oo ccmcr in each c1irecoon dependinn on 11\e weight oflhe layer or n:inforcing b3rs being suppoocd. The !clocrion of,ype and method or st Wort depend< on d1e so,1 bearina capacity, the si,i:, lcn;ifl,, a Dd spacing of the ro inforaing bru:s, mid the Placing Scllcomn,aorllchoice u Ille,n051 ellicient method. For SCl Jl)Ol1 of <ep bars in slabs or 4 fee, !hick 0< less, iml Mdual bar suppons made of wire or hcn1 bars are generally p~ }:('If U. ~ or found,111c1'1 m~d~ over,1 feet l'lick,_ cbc design of a support S)-'Srenl for top S!eel is d)e r0$ponsibility of die Coil lractor. The rcinfor,:ing bur supplier orp!occr COIIOO( design the ~on system b to lack of kno..tcdg,: of mginc:cring design requiremerus and oomrol of oonsiruc lion loods. fn additioo, Iha,) ore mll DCIOU> vllriadiais of ios~,llatioo mcdiods mak ing it difficu!L. for the Supplic:r l O e,;limak. The n:inf oo:ing bor supplier will quo,e lhe SUpp0f1 systan based on lbc CUstomt<\/ Buyer~ design. In addition, there arc numerous llllrillions in lhe Plactt~ requimnerus making it ditncull for the Supplia IO esairoare. Therefore, estimating, delailing O< lilmisbing these mataials is no, a 12-12 Concrete Relnlcrelng Stccl Institute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
normal industty practice, llllless by special arranganc:nt with lb<: Ocneral Q,ntmo. mror Plocet Unleos og JCC<I to between ihe Buyer and 010 Seller, ihcse materials will not be inoludcd in tho Supplier's bid. CL Fig. 12-12 Bar Supports for Foundation Mats N'Glf:t! l'lain Ccnau e Skd AI. Pl:utic Clair willh Base Plazc: lf CP-An inl,tiv~... a. 5h et.... 11ti _.-. i pfoto l'o, MMI ~ CUCIJ-Ccainucm-bigh cbait q,per. Coolinuom ru:nncr'Witts p COYidc for su;,port otrlowtr mat of roinfcwcirlg ban. Sun. de. ~. \J'll!in Jo,,·~ hl!Ullh'knk'd-,ordet11h 1ho I l11e,.....,,~ 1,1D l!'!M:r n'la,l--r,rb..,. _ lknd Shapes J2S-, 126. and Jlt. Dow. tel Block-A prec. 1$l block wilh holt f Ot" 14 dowel bar. SVil~e for $up POrt of bo(h eop stlll ~ macs of~i:itfordna tm.. Rt(IOl'I\~ l}r~ (9r~Jbr,l,he t1n Qtalctiwknc:w;; I. 2 rm or~ Plain Cooctei. e Blocks, AB-Pla&ic Qain; v.-idl Base~. CHOJ. Sla00-«1 us~ #4 ban. « dowel bkld:s (\¥clttm Slal Cs only). 2 V.,1tlllha. 1 :' f~MJupl PA f~I ~uillll,..f~ ),11,'1 3, Moce Ihm, feet-83r $1. ff Od S arc pne,ally not (umi5hcd o. «piby special armt1gena,cnt. Placing Reoll""'"'9 Ba,s-101h Edition 12-13 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
\ WALLS Basement walls are teinfo,ced in eilber one or both &ees. The rcinfom:mem usually couslsls of wnical and hori:rontal ban IO form a mat or cuiwn. The larger, more closely-spaced bars may bo ei Uier wnical or horiton1al, depending on the design. The')' arc usually placed nearer to U,e sarfuce or face of the wall. The smaller and more widely-spaced lio (or lem J>Cra!Ure and mrinlalg,:) b:m cross die main reinforcing bars at right angles and are farther from lhe face of the wall. In some lh. in w>lls, a single CUJUln of smaller lo bars, widely-spced temperature and shrinkage bars may be used bolb,"7tically and horimntally, end placed in the cenier of the wall,a,shown in Fig. 12-13. After the oontinuoos wall fnotina has been consuucted, with vertical dowels project ing, formwori< is erecled and secun,ly bmc:ed for only one face of the wall. The project ing d<lwcl:.. ottlinanly of the same sii. e and Spacing as lhc vertical ba J-.,, may be tied,o 1he,,:nic-,1 bar do-. "cls. Oi,o hon7. 011ca br,. r-is,,e Q. 10 the ve. rt1ttl b,:u..c lt) k~p theui plmnb and a, the required Fig. 12·13 One Cunaln o1Wall Bars,pro"&· Then thcou. :r hon zontal bm are placed. Th horizonul and vertical bars r-hould b< 1..-l i;ecun>ly ~... h other 01,utli<;icmtl)I frequent ime. rva Ts to m:tke a rigid cum. in. ·111t--t1lltnhe. r of 1ic S tequ1~wi ll {lc pend on the sire and spacini J)f reinrorcing bar<,_ but <here sl>ould "91 be f.,..,, lhan three ties to a. ny one 1>3. 'r, and, 1n any c:3. Si:, th~ Ile"~ sh(lll:J not be-spaced more than 4 to 6 feel apart in oi!hcr dirn:lior. 12-14 Concnrte-ing Sb,el ln&blu!e Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 6-9 | Placing Reinforcing Bars.pdf |
Relcrcnce is made IO Fig. 13-1 in cnrrying oul o,e following mp. by-step plac ing seq,ience for deep, heavily reinforced beam., that cannot be prea,semb!ed: Step 1-Bm ~f'li (two rows minimum) are sel loogii..dinal ly on the beam soffit fonn, or individual suppons a. re SJ>llced :'It 5 feel on center ma~i, mum. See Fig. 13-2. Benm bolsters may either be a continuous length (run) or in 2'-6" lengths (min. ) with 5'-0" gap (max. ) bc™XD them. Forpc6t-tcn. sioocd beams. bcom bollla S ore usually continuo,,s. s,J s '!'"'I I S11 1. J_l J I I I I J~-j,_.._ BEAN ELEVATION OE. AM BOLSTER Ll &J BEAM ELEVATION INDIVIDUAi. S1JPPORT$ 70F=FM JTll'llll U'I ~-~ a. t"PORTEDffl OW,O fl MEI)~ 111THSUPPO,rra,. 9JCHJ. 3 A....... W OF 2 PUNSOfr. Vta. 'GTH60FIIEAM ICUTt RIMJICIDU)~ All"4'MAA'NF. ll(NUT01it00N IIICMOUAl......anl~ SMI\IP$ AI..O-..WOl,IUM SEC110NYY } Fig. 13·2 Bar Supports for Bottom Bors in Beam, or Girdors Step 2-Stirrup s ""' plaocd with tho ctos:ed end down, locatal opposite layoot marla made along the forms from Sjl OCUl8,1 taken 6om the beam schedule. The stirrups will,.,,, on the beam bolsters. Tho measurement of stirrup spoc:ing usually star1s liom the futt of o,e co Jmnn or wall. Special care should be used in locatiilg stirrups 1111d ties in spandrel beams. 11,ese beams may be S\lbjoct to wealherif1g so ii is ~t tlw the spccifcd concrcle CO<'CI' be provided over the reinfon:cment Placlng Aelnfon:lng 9a,. _ 100, Edition 13-3 \ ) Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
Form tics, nchon, lnse. ns and otht. r items., nae directly related to reinforcing bar placing, Clll be in. slallcd before oc after the bars are placed. Such install rioos may be tbe worl< of olher trades. Cooperation of the lrooworker Supervi sor and his workers with the supervisors and wodc. crs in the other trades is nec """"Y for the orderly inm!lation oran such materials, and to avoid disloc:otion of the cein. fun:mlen t. Bar UJ>J)Orts. Be. cm,md,m,lcr reinf Of Cing bar.. must be adequ. uely supp Qr!cd IJl the formu Q_~enl dbpbcc::mc:n1. by concrc:c placemcm or hy ~ Frcquen Oy, beam bars are placed in rwo or rnore layers and «:q Uire bar separa tora IO be pllccd between the layers at a mioimumof5'-0". JOISTS Joist bars an: placed after all beam reinforcement is in plaoc in 1he beana that suppon the joisls. Figure 13-6 shows typical bar suppot'IS used in <mo-w. iy joist construction. ,~use rcinf'on:cd concrete JOISts USU3Uy havt tv. t') hnuorn reir\lorcmg_bars, a jofs: ch:tfr i-t made wi1h a lop wire formed with ootches or saddles. JQ_juppo_n the nvo bars and rest on either two or 1tmx; supporting legs. s. dependi"8--0fl the ~. zcrec1ed fhc ch. air IS abou1 1/, inch IIOIT°""-T than 1~w 1dth 3. ltd, is furnished ai a oornp ete unit requiring no,~Id tutting, Jobl chairs arc place~ beginning I foottrom die edge of each support and al intcrmeclio tc spa;;,ings as c o:ie lo. 5 foe~ maxuuum sp:;iclng a. 'i possible. lbe long bottom bar is Chen placed on the joist chairs, by threading between beam stirrups and under lop beam ba JS if neccos,uy. The long bottom bar must project into ti. : supports at each end, u called for on lhc pl Jlcina t!r.,winp and within proper construction rolcrances. 13-6 Co11C1111o Relnfo,,:t,g Stool lnalltulo Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 6-9 | Placing Reinforcing Bars.pdf |
.. CONTINUOUS BAR ON BAR aw RS C 3'-0-o. c. OR UPPER JOIST Cl-WR <r (. vi 4 ·. ()" 1-r. vl MAX C,.,AX) :r-O"o. c. ~1.. ('13) ~ SECTION A-A JOIST ELEVATION NOTES: l. ff ERJOCST Qt AIR ~ ALTERNATE SECTION A-A I, Har SIQIOf U fl. IC a,,::IICdll Y not pn:widcd for tcq,,mn. t!'Hh~ wetded WW'II ttln(o. ctmclllit or mofcn'ffl. g baff in ~.._ joist $!3M. It is reen,mn,cndt. d dm ~m J)Cl'. ltl. ft ti«rs be bed. Sid spsood with t O b3t S ceotercd on &111::rnate l'OW$ o( f~ i. e.. about 4 '..-2" ro 6'. fl" oo ccntcr at ri2i>t~to ~ ban. 2, Top~ ;iire n{lmwty "'l'l'°''ed tilht1 by ban oa iadividl W du, or by upper-joi11 Cha. US. J, Fbr n11>way joa11 comaucd(II!. (....nk. slubd).-bu,-tlff'()lt J in lh,11-itt one d!teetloe a!l 1~w:lbt be m~le the $,11Me at (Of otre,,wuy CO!ICRte joist ~on. Ba,. supports 1~-ot quiml ia the dbl..-n:k :iogks :as~ ba,s are SIJll C!Ortcd on me bottom b. m Mll'ling in the &st dircccioll. cu:cpc: COp ban in tbe middk $tripi; may need to be-.,ported Fig. 13-6 Bar Sul!l'Qll!l_ for Joists Ibe short bottom bar is placed on (he same chairs,. iongside :l:e straight long ~ Top lw are Iha, plaocd and cxlend<d the required dislllnee into tho adja cent SJl'II"I, nd where p0ssiblo. tied to top beam \>al$ or stirrup tie bars. The top bars are held in position by S-JPport ix!!!_(usua llx. 1/9) nd irul'vicl1. il bilr ch,i1rs (~milar to high cluu~ bul lim1tcxl tu I¾ mches ma. ximuin l·eight)l The bor chair. : rest on the top of i!ii)Ol>l orms. Thero are some cases wl,e,e the top slab is not thick enough, after allowing for O,e concreie cx,,er and the diam<lcr of Ibo top n:inforcina b. us, to provide space undernca!h for a,upport bar and bar chair. A special upper joist chair is then used which is supponoo on the joist form but bent down to suspend the bars in position. In some cases, especially for the two-way waffle slabs, some improvising may be necessary by the Detailer to show a suitable me:tns for this top,uppott. For example, it might be advisable for the support Im and bar chair to be used and lhe top reinforcing bars pic:la:d up and tied Wldt:mc,ilh the SUpp Ort bars by tie wires. See Fig. 13-7. Plamg Rolnlorclng 8'rs-101h Edition 13-7 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 6-9 | Placing Reinforcing Bars.pdf |
\_'§~~'--. c..,,, Fig. 137 Su,Qportin9 Top Bats in a Joist Some joists may be doubl and even iriplo tho strutdr<I joist width and hvc eitber double or triple the amounts of reinforcing bars or petbap S a smaller number ofla,ger sized bars. Because joist chair. ; :uc made to SUPt)()rt IWO rein forcing bars oc,ly, it may bo necessary IO place two or JJOS$ibly tht<e 5UCh chahs in line with each other actn5S the width of Che joist lo accommod te Ille proper number of bars. Di. s-l Til. mrlon jl)S lso u1. lletl conhnuou. " header J01~t.., or bridging ri~~ ex. tend c. ontinu OUS!Y lbt:: full Je Q"'g_ffior~ ar tight angle. '> l O the 1rn1t11 job:ts and are toe same deillh as thejoi~IS, Distn"'bution n"bs are used for the longer joist spans to brace the joists lotenlly. Thefe is no lilce<I rule to tbo number of rib< used, but the Engineer will generally u. se one at mid-span for spans between 18 and 24 feet, and two at the third points for longer spans. Reinforcing bars in these ribs are shown on the placing drawing., and usually coosist of one or perhaps h\'o lop and bortorn straight bars, lnp spliced as necessary. The bottom bridging bars will lay across the bottom joist bars and tile Wp bars are tied IO the temperature Sleet in the joist slab. tmperatu~ ttlnfort:~menr is placed a J\cc JO~~ !iolccvcs, and conduit S are installed anc inspec<ed. h may C-011S1st oi etther reinf Ol'-'ing bars or welded ~ «'. linforccmcnt. If reinforcing bars are use4, they a~ p Ltced o. n top of all 01hr bnrs, wllh suppon bars un<kn:. :ath them p~!le) 10 the J,Oisl ba. Tern.. pernture bars are spaced according to the placing drawi11gs. lap splioed into contin110us liocs and cxtcndcd into edge beams or walls and hooked only wh..-. ~-When small siz. od reinforcing ban are required. care in placing is neces sary IO mairuain straight bar lines. 1 H Concn,t,a Aelnro,c;ng St Nt tnstilutt Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9 | Placing Reinforcing Bars.pdf |
,,_. q"P$plb \ I \ I See Placing Draw"1g for uo Splk:e Lengtfhs of Tem,:,. raturt Ban or W~ Wiro ~nfol'comont F g. 13-8 Joist Construction Temperatur-o Reinforcement Welded wire reinforoement (see Fig. 13-8), where used, is also typically placed on the outer most layer of bots. Ahhougll it may consist of equal sii. od and spaced wires in both directions, the welded wire reinfoo:::. e,nen1 sornetimes has: larger, mo,e closdy spaced wires in one direction. These run the length of the welded wire reinfon:emcot and arc placc<I aero.. the joils. Wc:ldtd wire re,. inforo,ment in sheeis must be placed in spocilic localiu:ns. \'\\:ldcd wire rein forcement must be kept in proper position and be level before placing concn:te. Wc:ldcxl wire reinforcement may have IO be cut to fit aod should extend, aod perhaps bend down into, !he spondrcl or edge beam. Wben placing welded wire reinforcemen t, the specified side and end bps should be observed. Welded wire reinforcemen t sbould be secured to supports to avo:d displaoement. Undcrflour duct syttcms. C':3rr)'lrl. S elect. neat wiri11. S,. 1R: pt ACt. '<. I 00 ~mum... p. :iru> 1 or Sp<cial hcadc:rs after beam rcin:orcarem ls pla,:ed but bef0< joist ~ a,e placed lt is necessary to M'. Xl<-. id 1ll= duels, placing die rciororcing hors °""' or under the di. ICU as roquirod without mo,,ing the duels from 1heir set position. ONE-WAY SLABS Main ninforw:nent usually consists of alternating loog and short bottom and lop bars. This reinforcemeot eocteods in one direction bctwccn supports. Tem perotun: bars arc placed at right angles to the inoin rein. forcing bol'll. Bar Supports. The bottom n:inforcing bm in slabs are supporred by slab bol Sltr S. Sfndard stock !cng;h:; of <lal!_PQWm ~ ~ o<..l. O... fl:c J ~Jl]l)~ one lcn. &th of~lab bol"tcr L'-U. ~ m asmglc hnc. _il i~ :;ugg. c. i,. 1ed lh3t the end legs be locked logetbcr !o prevent a MP th~ht all OI' a bottom_bar to fall lo the slab soffi1 form, as shown in Fig. 13-9. P1a,:t,g RM11o"'"1g Batt-10th Edili On 13-9 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 6-9 | Placing Reinforcing Bars.pdf |
Fig. 13~ Lapped Slab Bolsters wi-the slab panel length is such that whole r;tock lengths of sfab bolstets do 1101 work out, a pert of the bolster lenglh mu. <t be cut in the field and reiaintd for 11se in compleons another line to P""""' a shonage and waste. ~o OJ. !......~ ime:,. __yf hohlers are placed not m<'!le than 6 me le.-:l tom t e h Jge ut tlk; supplfl1112,be. i:n or wnli. If additional Jinest'll'erequirect. lhcyshoul d be placed equally distant from each other and the outside lines, as close to 4 feet maximum sp3Cing as po$Sil,lc. Then lbe lll8in slab ba<S are placed at the speci fied spacin&-U)n& bouo,n t,a,s extend in<o the end,rupporu. The top reinforcing bats in slabs are held in position either by supporl bats and individual high chairs or by continuous high chaixs. The lines of these supports an: placed at 4 feet maximum spacing with an =hang of about 1 f001 from the outside lines of suppons <o Ille end of die top bars. Where more than two lines are required, they are placed a., described for slab bolsters. Industry pr""~ lice is <o 11loce #4 support ban on individual bigb chairs, which arc "i>"<td 3 feet on center. Unless olllcrwisc indicated on the placing dnlwings, support bars need not be lap spliced the same as tanpcrature bats but may be butted O< even a small space left bctwcca two lengths. Contin UOU$ high chairs have a 51l"ais)1t 1op wire with lcp spaced 8 inches on center. They are furnished in mnd. vd loagths and lap spliced in the same way as slab bolsters. Figure 13-10 shows t)'J)ical bar supports used for one-way slabs. 13-10 Cona9to Rcinfod,g Stoel lnllllute Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 15 TRANSPORTATION STRUCTURES GENERAL Tran,;ponation slructures include bridges. box cul YC<1S, and smaller drainage structures. The mon: common types ofbridaes are the slab bri~, 1hc simple beam bridge, the rigid frame. the arch, and o,e bo, girder. The pi. acing of reinforcing_ steel io transpor-. ation ~t\lrcs is cry ~imilar to the procedures outlined for building con. urut:1!01b..&g\Jrc 15-1 ~OWll> rcm J ing bar> bcin&J)kccd in U!!i!lgc dock. Transporlalion str UCIUre S are usually inore massive due IO heavier loading and d-. eir exposure to a corrosive enviro~ mcnt might require a greater amount of concrete cover on the n:inforccme:nt. Fig. 1S-1 Erecting a Bridge Deck DRAWINGS In building construction, it is necessary for the various trades 10 work from architectura l, ~"tn. lcturalf mechanical, and placing drawings. Transporta tion stn1c1Ur CS are usually built from one set of drawings, because very few archi recrural and mechanica l features are in"'lvcd. Most state mmsportation de partments have standard drawings for their commonly used bridges, culvens, ond smaller drainage stroclurcs. Pio~ Reinforcing Baro-1011> Edition 15-1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 6-9 | Placing Reinforcing Bars.pdf |
CHAPTER 16 HIGHWAY AND AIRPORT PAVEMENTS GENERAL Differences in design or concmc pavements among the transportation age cies of the Stntes:, Counties and Municir,ali1'i~ involve thickness; joint types and spacing; and the amount of reinforcing steel and its 1111Dg Cmc nt in the pavement. The thickness of a highway or airport pavement clcp<.,1ds on the sub~ support, strength of the COl1CICt C, the frequency and weight of wheel loads for the design life ofdle pavement, and type ofsubbasc. Thie~ for m<><kr: le; \'OJumo concrete street~ u..~ '. lr)' om 7 10 1 O inch~, whale, hi 1 v,4 P-Avemcnb rnngwom 8 to 15 mchcs. I-or airport pavemen ts,, lhiclrne~~se. ~.. ar from 1:fiiiches for lightairplall(:-; to over?:4 inches 'orhca,.,y-<rtltyw idc4>ody tii l~c Concrete hig_hw. :i. ys are ui;ually comaructcd in rnu11iplc lanes of 12 feet; with 24 feet being a smndard paving width for tntersta,e highways. Air ports are paved in multiples of 12. 5 to 25 feet. 11,e width of paveme,!!S..!l)r airports is usoa[Jy J50 f<,-cl..(or nmways and /'J feet for taxiway5 ~ncret vcmcnc:s: may be d1v1ded into t1. fcc ~ pc:,. : J. Coutinuousl)' reinforced concrete pavement {CRCP) 2, ~led rci?iforc:cd concrete pnvemcnl (JRC:P) . Plain <. :Om:rctc ~emcru (I;CP) wlth weake~mill Je or saw OO trdn:> verse JOinls., CONTINUOUSLY REINFORCED CONCRETE PAVEMENT In continuously reinforced concrete pavement (CRCP), longitudinal rcin Jon: iog ba B in the range of 0. SS to 0. 90% of die pavement's cross-sectional area, are used continuously to hold tight random transve,se cracks that form due to concrete shrinkage ond environmental fiic1or.. Usually #S to /fl bars are placed on tr\\nsverse 114 bars supported by chairs, unless tube feeding is used, and no chaiis are required. Each loogitudinal reinforcing !>. Ir must be able to develop its full yield strength load from end to end of the pavement with full strength at each line Plac:.,g Reo>tordng Bara-1 0th Edition 1 6--1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 6-9 | Placing Reinforcing Bars.pdf |
Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 6-9 | Placing Reinforcing Bars.pdf |
Table A-2 (PYCS lhe nominal dimension., for the twelve standard sius or de formed bars-#1 0 lo #64. The nominal dimensions ofa deformed bar (in cluding defonnations) are equivalent to thooc or a plain bar having the same wei&J,t per foot as U,e deformed bar. Steel mills produce reinfmcing bars to meet tl\e requirements or the ASTM specifications. The specification s require madcings for bar size designations od for strength levels (grwcs of steel). See Chapter 7 for a discussion of 1hc rcquin:d marl<ings. Slrellglh levels or grades of Steel are the minimum yield strengths. The metric grades of steel arc expressed in units of "Megapas cals", abbreviated ai. MPa. Grade 420, for ex. ample, means a minimum yield stn:ngth of 420 MJa. The value 420 MPa is equivnle,11 to 60,900 pounds per square inch. Grade 420 hors are the metric counterpart of Grade 60 bars. Table A-2 ASTM Standard Reinforcing Bars Bar Size Nominal Dimensions Deslg~Uon Area, in. 2 Weight, lb/ft Dlameler, in. #10 0. 11 0. 376 0. 375 #13 0. 20 0. 668 0. 500 #16 0. 31 1. 043 0. 625 #19 0. 44 1. 502 0. 750 #22 0. 60 2. 044 0. 875 #25 0. 79 2. 670 1. 000 #29 1. 00 SAOO 1. 128 1132 1. 27 4. 303 1. 270 #36 1. 56 5. 313 1. 410 ~ 2. 25 7. 66 1. 693 #57 4. 00 13. 60 2. 257 #84 4. 91 16. 69 2. 500 A-2 Coll Cfll O _,orc;,,g Steel,n.._ Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 6-9 | Placing Reinforcing Bars.pdf |
Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6-9 | Placing Reinforcing Bars.pdf |
Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 6-9 | Placing Reinforcing Bars.pdf |