CARA MENDESAIN PENULANGAN TANGGA Contoh hasil analisa dari ETABS didapat : Pada pelat tangga : M11 = -311,6979 Kgm = -3116979 Nmm M22 = -1582,6438 Kgm = -15826438 Nmm Pada bordes : M11 = -879,6493 Kgm = -8796493 Nmm M22 = 1863,7989 Kgm = 18637989 Nmm Tebal pelat t = 15 cm = 150 mm PADA PELAT TANGGA ARAH 1-1 d = 150 -25 = 125 mm As = 86,58 mm2 As min = 0,0020 x b x d = 0,0020 x 1000 x 125 = 250 mm2 250 mm2 > 86,58 mm2 Maka As perlu = 250 mm2 Pakai tulangan diameter 8 mm A = ¼ x Î x d2 = ¼ x Î x 82 = 50,265 mm2 A = 50,265 x 5 = 253,125 mm2 Jarak tulangan 1000/5 = 200 mm maka Ø8-200 mm a = 4,765 ØMn = Øx As x fy x (d-a/2) = 0,8 x 253,125 x 400 x (125-(4,765/2)) = 9932017,5 Nmm ØMn > Mu 9932017,5 Nmm > 3116979 Nmm …………..(OK) Maka dipakai tulangan pembagi Ø8-200 (arah pendek) ARAH 2-2 d = 150 -25 = 125 mm As = 439,62 mm2 As min = 0,0020 x b x d = 0,0020 x 2500 x 125 = 625 mm2 625 mm2 > 439,62 mm2 Maka As perlu = 625