Perencanaan balok Analisa Portal Akibat Beban Gempa
Profil W 14 x 176 Dimana : Ag = 51,8 in
2
E = 29000 r
x
= 6,43 in G = 11200
r
y
= 4,02 in J = 26,5 in
4
Sx = 281 in
3
F
R
= 10 Ksi untuk baja gilig Cw = 40500 in
6
Zx = 320 in
3
Iy = 838 in
4
Efek Balok Lb = 236,16 in
Lp = 4,02
36 300
r Fy
300
y
= 201 in
= 16,75 ft
X
1
=
2 .
. .
A J
G E
Sx
=
2 51,8
20026,5 2900011
281 π
= 5275,992
X
2
=
2
. 4
j G
Sx I
Cw
y
=
2
,5 1120026
281 838
440500
= 1,733 x 10
-4
Lr =
2
Fr X2.Fy
1 1
Fr Fy
ry.X1
=
2 4
10 1,733x10
1 1
10 36
5,992 4,02527
= 1156,129 in = 96,344 ft
maka Lp Lb Lr Mencari nilai Cb :
Cb = 1,75 + 1,05
2
1 M
M + 0,3
2
2 1
M M
= 1,75 + 1,05
548,771 384,269
+ 0,3
2
548,771 384,269
= 2,51
Cb =
2 1
4 ,
6 ,
1 m
m
=
548,771 384,269
0,4 0,6
1 = 3,1
Cb =
C B
A MAX
MAX
M M
M M
M .
3 .
4 .
3 5
, 2
. 5
, 12
= 2,33
3.270,221 4.34,477
3.262,944 1
2,5548,77 8,771
12,5.54
2,3
Dipakai Cb = 1 Mp = F
Y
.
X
= 36 . 320 = 11520 kip.in = 960 kip.ft M
r
= Fy-F
r
. S
X
= 36-10 . 281 = 7306 kip.in = 608,83 kip.ft M
n
= C
b
L L
L L
M -
M -
M [
P r
P b
r P
P
= 1
75 ,
16 96,344
75 ,
16 68
, 9
1 608,83
960 960
= 939,837 kip.ft
dipakai Mn = Mp M
n
= 0,9 x 960 kip.ft M
n
= 864 kip.ft = 10368 kip in
Efek kolom 4,02
1255,84 y
r KL
= 63,64
c
= E
Fy r
KL
x
.
2
=
29000 π
36 ,64
3 6
2
= 0,714 Fcr
= 0,658
2 c
.Fy
= 29,081 Pn
= Ag. Fcr = 51,8 . 29,081
= 1506,403
c
Pn =
c
. Pn = 0,85 . 1506,403
= 1280,441 kip maka
c
Pn Pu
1280,441 kip 24,238 kip Pn
Pu
c
0.2
1280,441 24,238
0.2 0,0189 0,2
Syarat : 1
Mn Mu
n 2
Pu
P 1
10368 6585,252
2.1280,441 24,238
0,645 1…………………….memenuhi
Kontrol Penampang Kompak Tekuk Badan
36 640
0,830 15,22
Fy 640
tw d
= 18,337 106,667
Penampang Kompak Tekuk Sayap
36 65
2.1,310 15,650
Fy 65
2.tf bf
= 5,973 10,833
Penampang Kompak Kontrol terhadap Geser
Vu = 53,352 kips
337 ,
8 1
tw h
59 Maka :
ФVn = 0,6 x fy x d x tw = 0,6 x 36 x 15,22 x 0,830 = 272,864 kips ФVn Vu 272,864 kips 53,352 kips
Kontrol Defleksi
∆maks = 360
L =
360 68
, 19
= 0,05467 ft = 0,1389 in ∆
= Ix
E L
q .
. .
384 4
4
=
2140 .
29000 68
, 19
. 3248
, 1
. 384
4
4
= 0,0000459 ft = 0,0005508 in ∆ = 0,0005508 int ∆maks = 0,7104 in