Question

2-You are given the task of designing a simply supported one-way slab, with a 13 feet span. The slab supports a live load of 200 psf. Use fc=3,000 psi, fy=60,000 psi. Provide a sketch of your design.

Answer 1

Giren one-way simply supported slab span L = 13 feet. Live load = 200 PSF fo= 3000 psi fy = 60000 psi Design one coay sab :- Son:- step o i slab thickness :ch acc. to ACI code 9.5 table gesca L = 13X12 = 7.8" 2020 psf tory h=8" & d=9" max factored moment (mu) :- self weight of slab (s/W) = 8 x 150 = 100 Wu= 42 (s/w) + 1.6LL 21,2x100 + 1.6x200 Wu= 440 psf to rect for 1 feet width of nab, mu= Wul² = 0.44 X13² = 9.295 k-feet 3 min. required deel rato Prod :- 3 Sreq = ossfli-si-emo o reball 4 = 0.85x3 4x9.2958 12 1.7X0.9 X 3 2 Xg? Treg= 0.00218 Area of steel required :- Ast req = Greg y byd = 0.00218 x 12 x 9 = 0.235 102 Try # 6 bars . Area of bars = 0.3 in2 Spacing = 12XA = 12 x 0.3 = 15.32 in. Area Try #6 bars spaced at 15 inch 0.235 -

As design = 12 * 0.3 = 0.45 in 2 > Area hence ox. ddest=h-cover-halt bar dia. = 8 - 0.75 -0 Acc. to ACI code 7.7.2 does = 7" - ok min=3JFT 2=0.88" © steel ratio check- 8 = true - trives on = 0.00419 200 ACS code 10.5 - fy fy Z 3 J3000 > 200 60000 60coo Smin = 0.00273 > 0.0033 solmin - hence ok ③ Depth of whitney stress block :- a = has the recite = 055*3X123 Omn= 0 Asfy(d-) = 0.9x0.4560 (9-0) ē 208.008 Kin = 17.33 K-feet > mu hence ok secondan sein forcement - emin = 0.00273 - ACE Code 7.12.2.1 Ash = fmin xbxh = 0.00273x12x8 = 0.26 1'n 2 try #6 bars sn= 12xA3 = 12x0.3 = 13.84 in S 0.26 - prouide # 6 bars spaced @ 13". - nci code 7.12.2.2

Distribution bars; main bars. section -- - petails of main bar along this line d Details of Distribution bard . along this line. - - - - - - ----- - plan