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