( 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