This document provides information about the design of a roof structure including: 1. Load calculations for dead loads from roofing materials and live loads from rain and workers. 2. Load factors are applied to calculate design loads. 3. Moment and shear force calculations are performed based on the design loads. 4. Steel I-beam profiles are selected to resist the maximum tensile and compressive forces calculated. 5. The profiles are checked against design strength limits for yielding, ultimate strength, and block shear.

1. Nama : Vicky Wildan Y Dosen Pembimbing : Dr.Nindyawati, S.T., M.T.
NIM : 120523417699
Offering :
A. DATA ATAP
Jenis atap = Genteng
Berat = 50 kg/m²
Plafon = 30 kg/m²
Angin (dari tepi laut, PPI : 22) = 25 kg/m²
Angin Tekan 0,02*α - 0,4*s*Tek.Angin*Jarak.kuda-kuda*jarak Gording = 30.00 kg/m²
Angin Hisap -0,4*s*tek.angin*Jarak.kuda-kuda*jarak Gording = -120.00 kg/m²
B. DATA BAHAN
Tegangan leleh baja (yield stress) fy = 250 MPa BJ41
Tegangan tarik putus (ultimate stress) fu = 410 MPa
Tegangan sisa (residual stress) fr = 70 MPa
Modulus elastik baja (modulus of elasticity) E = 200000 MPa
Angka Poisson (Poisson's ratio) ʋ = 0.3
SNI-03-1729-2002 5.1.3 hal 29
C. DATA PROFIL BAJA
Profil : Double L - Sama Kaki 90x90x10
H = 90 mm
B = 90 mm
t = 10 mm
r1 = 10 mm
r2 = 7 mm
A = 1700 mm²
Ix = 1250000 mm⁴
Iy = 1990000 mm⁴
Sx = Sy = 19500 mm³
rx=ry = 27.1 mm
r-max = 34.2 mm
r-min = 17.4 mm
Berat profil w = 13.3 kg/m
Gambar 1. Profil IWF (PT. Gunung Garuda)
E. DATA KUDA-KUDA
Panjang elemen thd. Sb x L = 11892.30 mm
Momen Maksimum akibat bebn terfaktor Mu = 4101274.6 mm
Momen Pada 1/4 bentang Ma = 1025318.7 mm
Momen ditengah bentang Mb = 4101274.6 mm
Momen Pada 3/4 bentang Mc = 1025318.7 mm
Gaya geser akibat beban terfaktor Vu = 9906.7764 mm
Faktor reduksi kekuatan untuk lentur φb = 0.9 mm
Faktor reduksi kekuatan untuk geser φf = 0.75 mm
F. SECTION PROPERTY
G = E / [ 2 x ( 1 + ʋ ) ] = 76923.077 MPa
h1 = tf + r = 17 mm
h2 = ht - 2 * h1 = 56 mm
h = ht - tf = 80 mm
J = Ʃ*b x t
3
/3] = 2 x 1/3 x bf x tf³ + 1/3 x ( ht - 2 x tf ) x tw³ = 8.33E+04 mm⁴
Iw = Iy x h² / 4 = 3.184E+09 mm⁶
X1 = π / Sx x √ [ E x G x J x A / 2 ] = 1.68E+05 MPa
X2 = 4 x [ Sx / ( G x J ) ]² x Iw / Iy = 5.922E-08 mm²/N²
Zx = tw x ht²/4 + (bf - tw) x ( ht - tf ) x tf = 84250 mm²
Zy = tf x bf²/2 + (ht - 2 x tf) x tw²/4 = 42250 mm²
G = modulus geser Zx = modulus penampang plastis terhadap sb x
J = konstanta puntir torsi Zy = modulus penampang plastis terhadap sb y
Iw = konstanta puntir lengkung X1 = koefisien momen tekuk torsi lateral -1,
h = tinggi bersih badan X2 = koefisien momen tekuk torsi lateral - 2,
Atap
PERHITUNGAN KUDA-KUDA

2. Lebar Q 1600 0.01
(m) (N/m) 16
1 Beban Gording 83.2 N/m 4.00 332.8
Beban Atap 500 N/m² 15.59 649.5191
Berat plafond 300 N/m² 300
1282.319
Beban Sambungan (10%) 10% 1282.319053 128.2319
Beban Aksessories (10%) 10% 128.2319053 12.82319
1423.374
Gambar 2. Beban Mati (Staad Pro 2004)
2.2 BEBAN HIDUP (LIVE LOAD)
Jarak antara gording s = 2 m
Beban air hujan q hujan x s x 10³ = 500 N/m
Beban hidup merata akibat air hujan QLL = 500 N/m
Beban hidup terpusat akibat beban pekerja (PPI:22) 100 Kg PLL = 1000 N
Gambar 3. Beban Hidup(Staad Pro 2004)
2. BEBAN PADA KUDA-KUDA (PPIUG 1983)
0.25 kN/m²
No Material Berat Satuan
Beban hidup akibat beban air hujan diperhitungkan setara dengan beban genangan air setebal
1 inc = 25 mm
q hujan = 0,025 x 10 =
Jumlah
2.1 BEBAN MATI (DEAD LOAD)
Jumlah Total

3. 2.3 BEBAN ANGIN (WIND LOAD)
1 300 N/m²
2 -1200 N/m²
Gambar 4. Angin Tekan dan Angin Hisap(Staad Pro 2004)
3. BEBAN TERFAKTOR (SNI 03-1729-2002 PASAL 6.2.2)
Beban merata Qu = 1,2 x QDL + 1,6 x QLL+ 0,8W = 2748.049 N/m
Beban terpusat Pu = 1,6 x PLL = 1600 N
Sudut miring atap α = 0.480 deg
Beban merata Qu = Qu x 10
-
³ = 2.748 N/m
Beban terpusat Pu = Pu x cos α = 768 N
Angin Tekan
Angin Hisap
Beban Angin Pada Atap
No Jenis Angin Berat Satuan

4. 4. MOMEN DAN GAYA GESER AKIBAT BEBAN TERFAKTOR
Panjang bentang Kuda kuda sumbu lokal L = L1 = 10392.30 mm
Momen akibat beban terfaktor terhadap sumbu lokal Mux = 1/10 x Qux x Lx² + 1/8 x Pux x Lx = 30676590 Nmm
Momen pada 1/4 bentang MA = 3/4*Mux = 23007443 Nmm
Momen di tengah bentang MB = Mux = 30676590 Nmm
Momen pada 3/4 bentang MC = 3/4*Mux = 23007443 Nmm
Gambar 5. Reaksi Perletakan
Perhitungan Gaya Batang
Beam L/C Axial Force N
Tekan (-) Tarik (+)
13 4 -93129.9
4 4 87845
14 4 87267.3
12 4 -82775.3
12 4 -82775.3
27 4 -79383.3
3 4 75333.4
26 4 -72881.1
11 4 -72105.5
18 4 69818
25 4 -65727.3
15 4 63064.2
17 4 62222.1
17 4 62222.1
10 4 -61470.5
24 4 -58571
29 4 54305.1
19 4 -51336.9
5 4 -50821.3
2 4 50750.6
16 4 46273.8
1 4 45449.6
30 4 -18133.2
31 4 -15401.3
32 4 -13208
6 4 12674.3
33 4 -11581.8
34 4 -11561.8
35 4 -10012.7
7 4 8698.7
36 4 -8528
20 4 8275.7
37 4 -7228.3
21 4 5599.8
8 4 4753.7
22 4 3010.2
23 4 -111.5
9 4 100.6
-93129.9 87845
RA 29932.4
RB 26332.4
Nilai Maksimum

5. 5. PERENCANAAN PROFIL
5.1 Batang tarik
Dimensi Profil
Profil Siku 90 x 90 x 10
H = 90 mm
B = 90 mm
t = 10 mm
r1 = 10 mm
r2 = 7 mm
A = 1700 mm²
Ix = 1250000 mm´
Iy = 1990000 mm´
Sx = Sy = 19500 mm³
rx=ry = 27.1 mm
r-max = 34.2 mm
r-min = 17.4 mm
w = 13.3 kg/m
Batang Tarik Maksimum = 87845 N
Panjang Batang Tarik Maks = 2.13 m
фbaut = 12 mm
фlubang SNI 03-1729-2002, Diameter Lubang < 24mm = фbaut + 2mm = 14 mm
Kontrol Kelangsingan Struktur Tarik
Jari Jari Girasi (digunakan r min) r-min = 1.74 cm
Panjang Batang L = 213 cm
Kelangsingan λ = L/r = 122.41 cm
Tahanan Nominal
Batas Leleh Faktor Tahanan (tegangan leleh) φ = 0.9
Batas Leleh Pu = f. fy.Ag = 382500
Periksa Batas Leleh
382500 > 87845 (OK)
Batas Putus
Kondisi Fraktur Faktor Tahanan fraktur) φ = 0.75
Luas Neto An = Ag - фlubang * t atau An<0.85*Ag = 1445 mm2
Koef reduksi U = 1 - x/L = 0.84
Luas Penampang Efektif Ae = U * An = 1212.99 mm
2
Kondisi Putus (Fraktur) Pu = φ*fu*Ae = 372993.2 N
Periksa Kondisi Putus (Fraktur )
372993 > 87845 (OK)
Kontrol Geser Blok (Block Shear )
Luas Neto Akibat Geser (ditinjau 100 mm) Anv = 100*t*2-(фlubang*2) = 1972 mm2
Luas Neto Akibat Tarik (ditinjau 100 mm) Ant = H*t*2-(фlubang*2) = 1772 mm
2
fu . Ant 0.6.Fu.Anv
726520 > 485112
Maka Tn = 0.6*fy*Agv+fu*Ant
Luas Bruto Akibat Geser (ditinjau 100 mm) Agv = 100*t*2 = 2000 mm
2
Tahanan Nominal Tn = 0.6*fy*Agv+fu*Ant = 1026520 mm2
Periksa Batas Leleh
1026520 > 87845 (OK)

6. 5.2 Batang Tekan
Batang Tekan Maksimum = -93129.9 N
Panjang Batang Tarik Maks = 2.39 m
фbaut = 12 mm
фlubang SNI 03-1729-2002, Diameter Lubang < 24mm = фbaut + 2mm = 14 mm
Periksa Kestabilan Elemen
Flens
Syarat λ = b/t ≤ 200/(fy)^0.5
9 < 12.649 (OK)
Web tidak ada syarat untuk profil siku
Kapasitas Profil
Mu = f Mn
Kondisi Tumpuan pada Batang = Sendi - sendi
Faktor Panjang Tekuk k = 1
λ = k*L/r = 88.19
λc = λ/π*fy/E)^0.5 = 0.99
Syarat 0.25 < λc < 1.2
0.25 < 0.99 < 1.2
ω = 1.43/(1.6-0.67λc) = 1.34
Nn = Ag*fcr = Ag*fy/ω = 317766.2 N
Nu/ф*Nn = 0.010174
Syarat 0.010174143 < 1
maka Dimensi Profil Kuat Memikul Beban Terfaktor
SNI 03-1729-2002 (LRFD;62)