Kombinasi Beban KOMBINASI MOMEN Kontrol Tegangan Beban Atap genteng keramik BA . Beban Gording BG . Beban Bracing Ikatan Angin BB

19 Pembebanan Beban mati qD Berat gording Channel 200x75x20x3,2 = 9,27 kgm Berat atap = 50 kgm 2 x 1,299 m = 64,95 kgm Berat trackstang 10 x 9,27 = 0,927 kgm + q tot = 75,147 kgm Beban hidup qL Pekerja di tengah bentang P = 100 kg Air hujan qR = 40 – 0,8 x a x Lc = 40 – 0,8 x 30 x 1,299 = 20,784 kgm Beban angin qA = 25 kgm 2 Koefisien angin tekan ct = 0,02 x a – 0,4 = 0,02 x 30 – 0,4 = 0,2 Koefisien angin hisap ch = – 0,4 Beban angin tekan = 0,2 x 25 x 1,299 = 6,495 kgm Beban angin hisap = -0,4 x 25 x 1,299 = -12,99 kgm

b. Kombinasi Beban

Gambar 4.2 Arah Gaya pada Gording Profil C 200x75x20x3,2 • Beban Mati qD = 75,147 kgm qDx = 75,147 x sin 30 o = 37,574 kgm qDy = 75,147 x cos 30 o = 65,079 kgm • Beban Hidup P = 100 kg Px = 100 x sin 30 o = 50 kg Py = 100 x cos 30 o = 86,602 kg q x C200.75.20.3,2 y 20 qL = 20,784 kgm qLx = 20,784 x sin 30 o = 10,392 kgm qLy = 20,784 x cos 30 o = 17,999 kgm • Beban Angin qA = qAy = 6,495 kgm

c. KOMBINASI MOMEN

Mx = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × + × l Px l q q Lx Dx 6 , 1 4 1 6 , 1 2 , 1 8 1 2 = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × + × × 4 50 6 , 1 4 1 4 392 , 10 6 , 1 574 , 37 2 , 1 8 1 2 = 203,433 kgm = 20 343,3 kgcm My 1 = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × + × l Py l q q Ly Dy 6 , 1 4 1 6 , 1 2 , 1 8 1 2 = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × + × × 4 86,602 6 , 1 4 1 4 999 , 7 1 6 , 1 079 , 65 2 , 1 8 1 2 = 352,3496 kgm = 35 234,96 kgcm My2 = ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × + × × 2 2 5 , q 2 , 1 8 1 l q Ly Dy + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × × 2 5 , 4 1 l Py + ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × 2 2 3 , 1 8 1 l q Ay = ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × + × × 2 2 4 999 , 7 1 5 , 079 , 65 2 , 1 8 1 + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × × 2 4 86,602 5 , 4 1 + ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × × 2 2 4 495 , 6 3 , 1 8 1 = 69,4194 kgm = 6 941,94 kgcm Dari kombinasi 1 2 dipilih My max yaitu My1 = 35 234,96 kgcm 21

d. Kontrol Tegangan

BJ 37 fy = 2400 kgcm 2 f = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ 1 , 72 234,96 35 8 , 16 343,3 20 Wx My Wy Mx = 1699,606 kgcm 2 1210.910 Syarat, f ≤ fy 1699,606 kgcm 2 ≤ 2400 kgcm 2 ………… Oke

e. Kontrol Lendutan

Keterangan :Pemasangan trackkstang antar gording pada tengah bentang gording, memberikan kekakuan tambahan padanya terhadap sumbu y. Gambar 4.3. Lendutan gording δ ijin = 400 240 1 240 1 × = × L = 1,667 cm 450 450 3,2 3,2 22 Sumbu X δ X = ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ × × × + ⎪⎭ ⎪ ⎬ ⎫ ⎪⎩ ⎪ ⎨ ⎧ × × + × 3 4 48 1 384 5 l I Es Px l I Es q q y y Lx Dx = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × ⋅ × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × ⋅ + × − 3 6 4 6 2 400 5 , 87 10 2 50 48 1 400 5 , 87 10 . 2 10 392 , 10 574 , 37 384 5 = 1,2945cm Sumbu Y δ Y = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × + × 3 4 2 48 1 2 384 5 l I Es Py l I Es q q x x Ly Dy = ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × × + ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ × × ⋅ + × − 3 6 4 6 2 200 721 10 . 2 602 , 86 48 1 200 721 10 . 2 10 999 , 17 079 , 65 384 5 = 0,022 cm δ = 2 2 2 2 022 , 2945 , 1 + = + y x δ δ δ = 1,2946 cm ≤ δ ijin = 1,667 cm…………..Oke

4.1.3. PERHITUNGAN STRUKTUR REDESAIN KUDA-KUDA Perhitungan Struktur Redesain Kuda-Kuda Utama

1. Data Perencanaan o Bentang kuda-kuda : 18,00 m o Jarak kuda-kuda bentang gording Lk : 4,00 m o Jarak gording Lc : 1,299 m o Sudut kemiringan atap a : 30° o Penutup atap genteng keramik + usuk + reng : 50 kgm 2 o Plafond + penggantung : 18 kgm o Beban angin : 25 kgm o Beban hidup : 100 kgm 23 o Beban air hujan = 40-0,8×a×Lc : 20,784 kgm o Berat gording profil C 200.75.20.3,2 : 9,27 kgm o Tegangan leleh baja fy : 2400 kg cm 2 S17 S47 S61 S46 S60 S45 S59 S44 S58 S43 S57 S42 S56 S41 S55 S40 S32 S31 S30 S29 S28 S27 S26 S25 S16 S15 S14 S13 S12 S11 S10 S37 S50 S36 S49 S35 S48 S34 S33 S24 S38 S23 S8 S9 S18 S19 S20 S21 S22 S1 S2 S3 S4 S5 S6 S7 S39 S51 S52 S53 S54 Gambar 4.4 . No. Frame Kuda – Kuda Utama F E D C B A Z Y X W V U T S R G F E D C B A O N M L K J H P Q I Gambar 4.5 . No. Joint Kuda – Kuda Utama BEBAN MATI 24

a. Beban Atap genteng keramik BA .

BA = q x Lk x Lc = 50 x 4,00 x 1,299 = 259,8 kg. Berat atap dilimpahkan ke tiap buhul bagian atas konstruksi yaitu : bA = bQ = 259,8 2 = 129,9 kg bR = bS = bT= bU = bV = bW = bX= bY = bZ = bA’= bB’ = bC’ = bD’= b E’ = b F’ = 259,8 kg. Keterangan : b = buhul joint

b. Beban Gording BG .

BG = q x Lk= 9,27 x 4,00 = 37,08 kg Beban gording dilimpahkan ke tiap buhul bagian atas konstruksi yaitu : bA = bS = bU = bW = bY = bA’ = bC’ = bE’ = bQ = 37,08 kg

c. Beban Bracing Ikatan Angin BB

Braching menggunakan baja ø18 mm Beban Bracing = A . γbaja = . . . 4 1 2 D π γbaja = 7850 . 018 , . 14 . 3 . 4 1 = 1,996 kgm γbaja = 7850 kgm 3 Panjang Bracing = 2 2 598 , 2 , 4 + = 4,7696 m BRACING Gambar 4. 6 . Bracing Keterangan : Tinjau jarak antar kuda-kuda max = 4,00 m Beban bracing pada buhul joint : 1,299 m 4,00 m 1,299 m 25 bA, bQ = 12 x 4,7696 m x 1,996 kgm = 4,76 kg. bS, bU, bW, bY, bA’,bC’, bE’ = 4,7696 m x 1,996 kgm = 9,520 kg.

d. Beban Angin