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