10. Berat tabel dan kapasitas keran = 8 + 25 = 33 ton

RA=1,6(33.18.519.5

+ 152

)

=1,6(31,31+7,5)

¿1,6(38,807)

= 62,09 ton

Impak 10 % = 6,209

68,299 ton+¿

Tinjau balok keran bentang : 5 meter

R1 = 68.299 x 1,625

5 = 22,197 ton

R2 = 68.29 x 3,375

5 = 46,1 ton

Akibat beban hidup

Momen max di a = R1 x (2.5 – 0,875)

= 22,197 x (2,5 – 0,875) = 36,07 ton.m

Momen max di b = R2 x (1,625 – 1,75)

= 46,102 x (1,625 – 1,75)

= - 5,76 ton.m

Akibat Beban Mati

Berat Sendiri Rel = 30 kg/m

Berat Sendiri Keran = 150 kg/m

Total : 30 kg/m + 150 kg/m = 180 kg/m

MDL = 1,2 . 18

(180) . (5) . (2) = 675 Kg.m = 0,675 ton.m

Momen Total :

Mux = 41,48 ton.m + 0,675 = 41,155 ton.m = 421,55 Kn.m

Momen akibat gaya melintang

12

. 1

15. (33). (1,6) = 1,76 ton

Muy = 1,76

34,145 x 36,07 = 1,859 ton.m = 18,59 kN.m

WF = 400 x 400 x 13 x 21

i. Fun = MuxSx

+ MuySy

– 421,55 x106

3330 x103 + 18,59x 106

1120 x 103 = 143,189

0,9 x 240 = 216 => 143,189 < 216

Pemeriksaan terhadap tekuk torsi

ii. Lp = 790√ ty

x ry = 790√240

x 101 = 5150,4 mm

X1 = 20633,56 MPa

X2 = 3,30374 . 10-4 mm4/ N2

Lb = 18,983 mm

Maka, 5 < 5,150

Lb < Lp = Bentang Pendek

Mn = Mp

Periksa Penampang

b2tf

x 400

2x 21 = 9,524 < 10,97

htw

= 27,54 < 108, 44

Mr = Sx (Fx – Fr) = 3330 x 103 (240 – 70) = 566,1 kN.m

Mp = 2x . Fy = 3600 x 13 x 103. (240) = 864,03 kN.m

Mn = Cb . (Mr + Mp – Mr) x ¿))

= 845,73 kN.m < Mp (= 864,03 kNm)

∅b . Mn = 0,9 x 845,73 = 761,157 kN m < Mux = 421,155

Jadi, WF 400x400x13x21 dapat dipakai sebagai balok untuk keran tersebut.