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