Question

AQ4 Design the reinforcement and check the deflection by span-to-depth ratio of the stairs as shown in DWG-04 with the following design information: Design parameters Waist, h = 275 mm Tread = 260 mm Riser= 160 mm Number of Risers, N = 14 Flight horizontal length, L2 = 260 x 14 = 3640 mm Flight width, W = 1250 mm Landing slab thickness = 275 mm (same as waist) Landing clear width, Ln = 1250 mm (same at both ends) Width of support, Sw = 200 mm (same at both ends) fcu = 40 MPa fy = 500 MPa Cover = 25 mm Preferred bar size = 16 mm Density of concrete = 24.5 kN/m3 Allowance for finishes = 1.5 kPa Allowance for handrail/parapet = (assume negligible) Characteristic imposed load = 5.0 kPa

Answer 1

design constant a computation of ly 2 500 MPa Sex 2 uOmpa. Os 0.45 Rumax 700 100+ 0.87 X 500 1x50o = Ruz 0,36 x Nexx Numar (1-0,416 numor) 25.267 17 computation of wading Rean weight wi per horizontal meth for waist seco XIX 1,25x24.5x1000X 1,25 X 24.5 √260²x160² wi a 275 x 1 1000 260 2 275 X1 X 1.25 x24.5 X1000X CF 9888.8 weight we er horizontal meth Rui for steps. We = 160 x 1,25x260 x 2450 = +274 Alm 2450 Nm.

a 9888. s + 0 2 450 Total dead weight in 12.30 kN/m. weight of tinishid 21.5x1.25 kN/m a 1.875 kmln. wright of imposed 5x1.25 lood 2 6.25 kr Total to wart - 12.30 + 1.875 +6.25 2 20.428 KN/m. Factor wade lit X20420T KNI 228.78 Info = 30.64 kNam 2 298 x 3.644 1.25 Moment - wt where to 3.64+1 2+ 200 +1.25 1 3.64 + 2x1.25 +.200 26.34 30.64 x 6.34 2th 5 of kram = 30.64 y 2 153.94 KM. m

14 Design of waist slabe hellers Mu de V Rub 193.6x106 5,267x 1250 2 152.9 mm depth a 180 mm Take over all Etfective depth a 180-25- 8 2 147 win 3 Refforcement Computation of WOOD 0.57Gor 500 4.6 x 153.948.6 4DX 1000 X 1472 IX 147 338011 Not use 16mm Ø bar Astar 1 x 16²2 201.06 waan No it bar required. 1.25x 3380.11 221 vos 201.06 1250 - 59.524 60 mm САС)

Distribution reventer einen Acase 0.12% 160x1200 azuo wina tense spacis of 18 min d bar 120 x 50,3 20 180 350 m