Bab 3 Perencanaan Atap

BAB 3

PERENCANAAN ATAP

3.1Rencana Atap

Gambar 3.1. Rencana Atap

Keterangan :

KU = Kuda-kuda utama G = Gording

KT = Kuda-kuda trapezium N = Nok

SK = Setengah kuda-kuda utama JR = Jurai

3.2Dasar Perencanaan

Secara umum data yang digunakan untuk perhitungan rencana atap adalah sebagai

berikut:

a. Bentuk rangka kuda-kuda : seperti tergambar

b. Jarak antar kuda-kuda : 6 m

c. Kemiringan atap (α) : 33°

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d. Bahan gording : baja profil lip channels in front to front

arrangement ( )

e. Bahan rangka kuda-kuda : baja profil double siku sama kaki ()

f. Bahan penutup atap : metalroof

g. Alat sambung : baut-mur

h. Jarak antar gording : 1,79 m

i. Bentuk atap : limasan

j. Mutu baja profil : BJ-41

σijin = 1666 kg/cm2

σleleh = 2500 kg/cm2 (interpolasi nilai

SNI 03-1729-2002)

Gambar 3.2. Perencanaan Kuda-kuda

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3.3Perencanaan Gording

3.3.1 Perencanaan Pembebanan

Pembebanan berdasarkan PPIUG 1983, sebagai berikut :

a. Berat penutup atap = 25 kg/m2

b. Beban angin = 25 kg/m2

c. Beban hidup (pekerja) = 100 kg

d. Berat penggantung dan plafond = 18 kg/m2

3.3.2 Perhitungan Pembebanan

Kemiringan atap (α) = 33°

Jarak antar gording (s) = 1,78 m

Jarak antar kuda-kuda utama = 6 m

Dicoba menggunakan gording dengan dimensi baja profil tipe lip channels in

front to front arrangement ( ) 150 × 130 × 20 × 3,2 pada perencanaan kuda-

kuda dengan data sebagai berikut:

a. Berat gording = 19,14 kg/m

b. Ix = 664 cm4

c. Iy = 476 cm4

d. h = 150 mm

e. b = 13,0 m

f. ts = 3,2 mm

g. tb = 3,2 mm

h. Zx = 88,6 cm3

i. Zy = 73,2 cm3

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1) Beban Mati (titik)

Berat gording = 19,14 kg/m

Berat plafond = ( 1,5 × 18 ) = 27 kg/m

Berat penutup atap = ( 1,79 × 25 ) = 44,75 kg/m +

q = 90,89 kg/m

qx = q sin α = 90,89 × sin 33 = 49,502 kg/m

qy = q cos α = 90,89 × cos 33 = 76,227 kg/m

Mx1 = ⅛ . qy . L2 = ⅛ × 76,227 × 62 = 343,021 kgm

My1 = ⅛ . qx . L2 = ⅛ × 49,502 × 62 = 222,760 kgm

2) Beban Hidup

P diambil sebesar 100 kg.

Px = P sin α = 100 × sin 26 = 54,464 kg

Py = P cos α = 100 × cos 26 = 83,867 kg

Mx2 = ¼ . Py . L = ¼ × 83,867 × 6 = 125,800 kgm

My2 = ¼ . Px . L = ¼ × 43,837 × 5 = 81,696 kgm

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3) Beban Angin

Beban angin kondisi normal, minimum = 25 kg/m2.

Koefisien kemiringan atap (α) = 33 °

1) Koefisien angin tekan = (0,02α ‒ 0,4) = 0,26

2) Koefisien angin hisap = ‒ 0,4

Beban angin :

1) Angin tekan (W1) = koef. Angin tekan × beban angin × ½ × (s1+s2)

= 0,26 × 25 × ½ × (1,79+1,79) = 11,635 kg/m

2) Angin hisap (W2) = koef. Angin hisap × beban angin × ½ × (s1+s2)

= – 0,4 × 25 × ½ × (1,79+1,79) = – 17,9 kg/m

Beban yang bekerja pada sumbu x, maka hanya ada harga Mx :

1) Mx (tekan) = 1/8 . W1 . L2 = 1/8 × 11,635 × (6)2 = 52,358 kgm

2) Mx (hisap) = 1/8 . W2 . L2 = 1/8 × – 17,9 × (6)2 = – 80,55 kgm

Kombinasi = 1,2D + 1,6L ± 0,8w

1. Mx

Mx (max) = 1,2D + 1,6L + 0,8w

= 1,2(343,020) + 1,6(125,801) + 0,8(52,358) = 654,792 kgm

Mx (min) = 1,2D + 1,6L - 0,8W

= 1,2(343,020) + 1,6(125,801) - 0,8(80,55) = 548,466 kgm

2. My

My (max) = My (min)

= 1,2(222,760) + 1,6(81,696) = 398,026 kgm

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TEKAN HISAP

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Tabel 3.1. Kombinasi Gaya Dalam pada Gording

Momen

Beban

Mati

(kgm)

Beban

Hidup

(kgm)

Beban Angin

(kgm)

Kombinasi

(kgm)

Tekan Hisap Minimum Maksimum

Mx

My

343,021

222,760

125,801

81,696

52,356

-

–80,55

-

654,792

398,026

548,466

398,026

3.3.3 Kontrol Terhadap Tegangan

Kontrol terhadap tegangan Maksimum

Mx = 654,792 kgm = 65479,2 kgcm

My = 398,026 kgm = 39802,6 kgcm.

σ =

=

= 917,523 kg/cm2 < ijin = 1666 kg/cm2

Kontrol terhadap tegangan Minimum

Mx = 548,466 kgm = 54846,6 kgcm.

My = 398,026 kgm = 39802,6 kgcm.

σ =

=

= 823,935 kg/cm2 < ijin = 1666 kg/cm2

3.3.4 Kontrol Terhadap Lendutan

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Dicoba profil : 150 × 130 × 20 × 3,2

E = 2,1 × 106 kg/cm2

Ix = 664 cm4

Iy = 476 cm4

qx = 0,4951 kg/cm

qy = 0,7623 kg/cm

Px = 54,46 kg

Py = 83,87 kg

3,333 cm

Zx =

=

= 1,080984 cm

Zy =

=

= 1,167702 cm

Z =

= 1,591 cm

Z Zijin

1,591 cm 3,333 cm …………… aman !

Jadi, baja profil lip channels in front to front arrangement ( ) dengan

dimensi 150 × 130 × 20 × 3,2 aman dan mampu menerima beban apabila

digunakan untuk gording.

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3.4Perencanaan Jurai

Gambar 3.3. Rangka Batang Jurai

3.4.1 Perhitungan Panjang Batang Jurai

Perhitungan panjang batang selanjutnya disajikan dalam tabel di bawah ini:

Tabel 3.2. Panjang Batang pada JuraiNomor Batang Panjang Batang (m)

1 2,122 2,123 2,124 2,125 2,336 2,337 2,338 2,339 0,9710 2,3311 1,9512 2,88

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13 2,9214 3,6115 3,90

3.4.2 Perhitungan Luasan Jurai

Gambar 3.4. Luasan Atap Jurai

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Panjang l-11 = ½ . 1,79 = 0,895 m

Panjang 1-1’ =1’1” = 0,75

Panjang 2-2’ = 2’-2”= 1,5

Panjang 3-3’ = 3’-3”= 2,25

Panjang 4-4’ = 4’-4”= 3

Panjang Tritis = 1,79 m

Panjang aa’ = 3,75 m Panjang a’a” = 3,75 m

Panjang bb’ = 2,63 m Panjang b’b” = 2,63 m

Panjang cc’ = 1,875 m Panjang c’c” = 1,875 m

Panjang dd’ = 1,13 m Panjang d’d” = 1,13 m

Panjang ee’ = 0,375 m Panjang e’e” = 0,375 m

A1 = (Panjang aa’ + Panjang bb’) × (Panjang tritis + Panjang 1_11)

= (3,75 + 2,63) × (1,79 + 0,895)

= 17,11 m2

A2 = (Panjang bb’ + Panjang cc’) × (Panjang 1_11+ Panjang 1_11)

= (2,63 + 1,875) × (0,895+0,895)

= 8,06 m2

A3 = (Panjang cc’ + Panjang dd’) × (Panjang 1_11+ Panjang 1_11)

= (1,875+ 1,13) × (0,895+0,895)

= 5,37 m2

A4 = (Panjang dd’ + Panjang ee’) × (Panjang 1_11+ Panjang 1_11)

= (1,13+ 0,375) × (0,895+0,895)

= 2,69 m2

A5 = 2 × (½ × Panjang 1_11× Panjang ee’)

= 2 × (1/2 × 0,895 × 0,375)

= 0,34 m2

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Gambar 3.5. Luasan Plafond Jurai

Panjang l-11 = 0,75 m

Panjang 1-1’ =1’1” = 0,75 m

Panjang 2-2’ = 2’-2”= 1,5 m

Panjang 3-3’ = 3’-3”= 2,25 m

Panjang 4-4’ = 4’-4”= 3 m

Panjang Tritis = 1,5 m

Panjang aa’ = 3,75 m Panjang a’a” = 3,75 m

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Panjang bb’ = 2,63 m Panjang b’b” = 2,63 m

Panjang cc’ = 1,875 m Panjang c’c” = 1,875 m

Panjang dd’ = 1,13 m Panjang d’d” = 1,13 m

Panjang ee’ = 0,375 m Panjang e’e” = 0,375 m

A1 = (Panjang aa’ + Panjang bb’) × (Panjang tritis + Panjang 1_11)

= (3,75 + 2,63) × (0,75 + 1,5)

= 14,34 m2

A2 = (Panjang bb’ + Panjang cc’) × (Panjang 1_11+ Panjang 1_11)

= (2,63 + 1,875) × (0,75+0,75)

= 6,75 m2

A3 = (Panjang cc’ + Panjang dd’) × (Panjang 1_11+ Panjang 1_11)

= (1,875+ 1,13) × (0,75+0,75)

= 4,5 m2

A4 = (Panjang dd’ + Panjang ee’) × (Panjang 1_11+ Panjang 1_11)

= (1,13+ 0,375) × (0,75+0,75)

= 2,25 m2

A5 = 2 × (½ × Panjang 1_11× Panjang ee’)

= 2 × (1/2 × 0,75 × 0,375)

= 0,28 m2

3.4.3 Perhitungan Pembebanan Jurai

Data-data pembebanan:

Berat gording = 19,14kg/m

Berat penutup atap = 25 kg/m2

Berat plafond dan penggantung = 18 kg/m2

Berat profil kuda-kuda = 14,18 kg/m

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Gambar 3.6. Pembebanan Jurai Akibat Beban Mati

a. Beban Mati

1) Beban P1

a) Beban Atap = luasan A1 × berat atap

= 17,11 × 25

= 427,68 kg

b) Beban Kuda-kuda = ½ × btg (1 + 5) × berat profil kuda-kuda

= ½ × (2,12 + 2,33) × 14,18

= 31,59 kg

c) Beban Plat Sambung = 30 % × beban kuda-kuda

= 30 % × 31,59

= 9,48 kg

d) Beban Bracing = 10% × beban kuda-kuda

= 10 % × 31,59

= 3,16 kg

e) Beban Gording = Berat profil gording × Panjang gording 4’-4”

= 19,14 × 3

= 114,84 kg

2) Beban P2

a) Beban Gording = berat profil gording × panjang gording 3’-3”

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= 19,14 × 5

= 86,13 kg

b) Beban Atap = luasan A2 × berat atap

= 8,06 × 25

= 201,38 kg

c) Beban Kuda-kuda = ½ × btg (5+ 6+ 9 + 10) × berat profil kuda-kuda

= ½ × (2,33 + 2,33 + 0,97 + 2,33 ) × 14,18

= 56,56 kg

d) Beban Plat Sambung = 30 % × beban kuda-kuda

= 30 % × 56,56

= 16,97 kg

e) Beban Bracing = 10% × beban kuda-kuda

= 10 % × 56,56

= 85,66 kg

3) Beban P3

a) Beban Gording = berat profil gording × panjang gording 2’-2”

= 19,14 × 1,5

= 57,42 kg


= 5,37 × 25

= 134,25 kg

c) Beban Kuda-kuda = ½ × btg (6 + 7 + 11 + 12) × berat profil kuda-kuda

= ½ × (2,33 + 2,33 + 1,95 + 2,88) × 14,18

= 67,33 kg


= 30 % × 67,33

= 20,20 kg


= 10 % × 67,33

= 6,73 kg

4) Beban P4

a) Beban Gording = berat profil gording × (2 × panjang gording 1-1’)

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= 19,14 × (2 × 0,75)

= 28,71 kg


= 2,69 × 25

= 67,13 kg

c) Beban Kuda-kuda = ½ × btg (7 + 8 + 13+14) × berat profil kuda-kuda

= ½ × (2,33 + 2,33 + 2,93 + 3,61) × 14,18

= 79,42 kg


= 30 % × 79,42

= 23,83 kg


= 10 % × 79,42

= 7,94 kg

5) Beban P5


= 0,34 × 25

= 8,39 kg


= ½ × (2,33 + 3,90) × 14,18

= 44,18 kg


= 30 % × 44,18

= 13,25 kg


= 10 % × 44,18

= 4,42 kg

6) Beban P6

a) Beban Plafon = luasan A5 × berat plafon

= 0,28 × 18

= 5,06 kg

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b) Beban Kuda-kuda = ½ × btg (4 + 14 +15) × berat profil kuda-kuda

= ½ × (2,12 + 3,61 + 3,90) × 14,18

= 68,27 kg


= 30 % × 68,27

= 20,48 kg


= 10 % × 68,27

= 6,83 kg

7) Beban P7


= 2,25 × 18

= 40,50 kg

b) Beban Kuda-kuda = ½ × btg (3 +4 + 12+13) × berat profil kuda-kuda

= ½ × (2,12 + 2,12 + 2,88+2,92) × 14,18

= 71,22 kg


= 30 % × 71,22

= 21,37 kg


= 10 % × 71,22

= 7,12 kg

8) Beban P8


= 4,5× 18

= 81 kg

b) Beban Kuda-kuda = ½ × btg (2 + 3+ 10+ 11) × berat profil kuda-kuda

= ½ × (2,12 + 2,33 + 1,95) × 14,18

= 60,44 kg


= 30 % ×60,44

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= 18,13 kg


= 10 % × 60,44

= 6,04 kg

9) Beban P9


= 6,75 × 18

= 121,5 kg

b) Beban Kuda-kuda = ½ × btg (1+ 2 + 9) × berat profil kuda-kuda

= ½ × (2,12+ 2,12 + 0,97) × 14,18

= 36,99 kg


= 30 % × 36,99

= 11,1 kg


= 10 % × 36,99

= 3,07 kg

10) Beban P10


= 14,34 × 18 = 258,19 kg

Tabel 3.3. Rekapitulasi Pembebanan Jurai Beban Beban Beban Beban Plat Beban Beban Jumlah Input

Beban Atap GordingKuda-kuda

Penyambung Bracing Plafond Beban

SAP 2000

(kg) (kg) (kg) (kg) (kg) (kg) (kg) (kg)P1 427,68 114,84 31,59 9,48 3,16 - 586,75 704,4P2 201,38 86,13 56,56 16,97 5,66 - 366,68 367P3 134,25 57,42 67,33 20,20 6,73 - 285,94 286P4 67,13 28,71 79,42 23,83 7,94 - 207,03 208P5 8,39 - 44,18 13,25 4,42 - 70,24 71P6 - - 68,27 20,48 6,83 5,06 100,64 101P7 - - 71,22 21,37 7,12 40,50 140,21 141P8 - - 60,44 18,13 6,04 81,00 165,62 166P9 - - 36,99 11,10 3,70 121,50 173,28 174P10 - - - - - 258,19 258,19 310,8

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b. Beban Hidup

Beban hidup yang bekerja pada P1 = P2 = P3 = P4 = P5 = 100 kg

Input SAP 2000 = 100 × 1,6

= 160 kg

c. Beban Angin

Perhitungan beban angin :

Gambar 3.7. Pembebanan Jurai Akibat Beban Angin


Koefisien angin tekan = 0,02 0,40

= (0,02 × 24,66) – 0,40 = 0, 45

a. W1 = luasan atap A1 × koef. angin tekan × beban angin

= 17,11 × 0,45 × 25 = 193,83 kg

b. W2 = luasan atap A2 × koef. angin tekan × beban angin

= 8,06 × 0,45 × 25 = 91,26 kg

c. W3 = luasan atap A3× koef. angin tekan × beban angin

= 5,37 × 0,45 × 25 = 60,84 kg

d. W4 = luasan atap A4 × koef. angin tekan × beban angin

= 2,69 × 0,45 × 25 = 30,42 kg

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e. W5 = luasan atap A5× koef. angin tekan × beban angin

= 0.34 × 0,45 × 25 = 3,80 kg

Tabel 3.4. Perhitungan Beban Angin pada Jurai

Beban

Angin

Beban

(kg)

Wx

W.Sin

(kg)

Input

SAP

2000

(kg)

Wy

W.Cos

(kg)

Input

SAP

2000

(kg)

W1 193,83 64,70 65 176,15 1041W2 91,26 23,94 24 86,22 614W3 60,84 20,57 21 55,14 502W4 30,42 7,52 8 28,93 397W5 3,80 0,75 1 3,69 235

Dari perhitungan mekanika dengan menggunakan program SAP 2000 diperoleh

gaya batang yang bekerja pada batang jurai kuda-kuda sebagai berikut :

Tabel 3.5. Rekapitulasi Gaya Batang Jurai

BatangKombinasi

Tekan (-) Tarik (+)Kg Kg

1 1362 -2 174,9 -3 - 986,64 - 2099,65 - 1252,66 - 277,67 - 1252,68 1170,9 -9 - 836,710 - 173,711 1400,5 -12 - 1327,413 881,8 -14 1673 -15 65,2 -

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3.4.4 Perhitungan Profil Jurai

a. Perhitungan Profil Batang Tarik

Pmaks. = 2099,6 kg


Fnetto =

Fbruto = 1,15 × Fnetto = 1,15 × 1,26 = 1,45 cm2

Dicoba menggunakan baja profil 50.50.5

F = 2 × 4,8 = 9,6 cm2

F = penampang profil dari table profil baja

Kontrol tegangan yang terjadi :

σ

σ ≤ 0,75σijin

247,43 kg/cm2 ≤ 1249,5 kg/cm2 ………. aman !!

Jadi digunakan profil 50.50.5

b. Perhitungan Profil Batang Tekan

Pmaks = 1673 kg

L = 3,61 m = 361 cm

Dicoba, menggunakan baja profil 50.50.5

F = 2 × 4,8 = 9,6 cm2

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ix = 1,51 cm = 15,1 mm

λ =

λg

= 108,87 cm

λs

Karena λs

> 1,2 maka :

ω = 1,25 × λs2

= 1,25 × (2,21)

2

= 6,11


σ

σ ≤ σijin

1065,13 kg/cm2 ≤ 1666 kg/cm2 ………. aman !!


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3.4.5 Perhitungan Alat Sambung Jurai

a. Batang Tarik

Digunakan alat sambung baut-mur.

Diameter baut (Ø) = 6,35 mm = 0,635 cm (1/4 inches)

Diameter lubang = db + max. 2 mm

= 6,35 + 2

= 8,35 mm

(Ø lubang profil 50.50.5 = 14 mm, Tabel Baja)

Tebal pelat sambung (δ) = 0,625 . d

= 0,625 . 8,35

= 3,97 mm

Menggunakan tebal pelat 4 mm

Tegangan geser yang diijinkan

τ geser = 0,6 . σijin

= 0,6 . 1666

= 999,6 kg/cm2

Tegangan tumpuan yang diijinkan

τ tumpuan = 1,5 . σijin

= 1,5 . 1666

= 2499 kg/cm2

Kekuatan baut

Pgeser = 2 . ¼ . π . d2 . τ geser

= 2 . ¼ . π . (0,635)2 . 999,6

= 633,39 kg

Pdesak = δ . d . τ geser

= 0,8 . 0,635 . 2499

= 1269,49 kg

P yang menentukan adalah Pgeser = 1269,49 kg.

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Perhitungan jumlah baut-mur,

Digunakan : 2 buah baut

Perhitungan jarak antar baut :

3d ≤ S

2

≤ (15t atau max. 200 mm), dimana t = tebal pelat lapis tertipis

dalam sambungan.

Diambil, S2

= 2 . db

= 2 . 6,35

= 12,7 mm = 15 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 6,35

= 9,525 mm = 10 mm

b. Batang Tekan


Diameter baut (Ø) = 6,35 mm = 0,635 cm (1/4 inches)


= 6,35 + 2

= 8,35 mm

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= 0,625 . 8,35

= 3,97 mm




= 0,6 . 1666

= 999,6 kg/cm2



= 1,5 . 1666

= 2499 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (0,635)2 . 999,6

= 633,39 kg


= 0,8 . 0,635 . 2499

= 1269,49 kg




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3d ≤ S

2


dalam sambungan.

Diambil, S2

= 2 . db

= 2 . 6,35

= 12,7 mm = 15 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 6,35

= 9,525 mm = 10 mm

Tabel 3.6. Rekapitulasi Perencanaan Profil JuraiNomorBatang

Dimensi Profil Baut (Inch)

1 50.50.5 2 Ø ¼2 50.50.5 2 Ø ¼3 50.50.5 2 Ø ¼4 50.50.5 2 Ø ¼5 50.50.5 2 Ø ¼6 50.50.5 2 Ø ¼7 50.50.5 2 Ø ¼8 50.50.5 2 Ø ¼9 50.50.5 2 Ø ¼10 50.50.5 2 Ø ¼11 50.50.5 2 Ø ¼12 50.50.5 2 Ø ¼

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13 50.50.5 2 Ø ¼14 50.50.5 2 Ø ¼15 50.50.5 2 Ø ¼

3.5Perencanaan Setengah Kuda-kuda

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Gambar 3.8. Rangka Batang Setengah Kuda-kuda

3.5.1 Perhitungan Panjang Batang Setengah Kuda-kuda


Tabel 3.7. Panjang Batang pada Setengah Kuda-kudaNomor Batang Panjang Batang (m)

1 1,5

2 1,5

3 1,5

4 1,5

5 1,796 1,797 1,798 1,799 0,9710 1,9511 2,9212 3,9013 1,79

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14 2,4615 3,28

3.5.2 Perhitungan Luasan Setengah Kuda-kuda

Gambar 3.9. Luasan Atap Setengah Kuda-kuda

Panjang l-9 = ½ . 1,79 = 0,89 mPanjang l-9 = 2-3 = 3-4 = 4-5 = 5-6 = 6-7 = 7-8 = 8-9 = 0,89 m

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Panjang 1-2 = 1,79 m

Panjang aa’ = 7,5 m

Panjang cc’ = 4,5 m

Panjang ee’ = 3,75 m

Panjang gg’ = 2,25 m

Panjang ii’ = 0,75 m

A1 = Luas aa’c’c

= ½ (aa’+cc’) × (1-2 + 2-3)

= ½ (7,5 +4,5) × (1,79 + 0,89)

= 16,10 m2

A2 = Luas cc’e’e

= ½ (cc’+ee’) × (3-4 + 4-5)

= ½ (4,5 + 3,75) × (0,89+ 0,89)

= 7,38 m2

A3 = Luas ee’g’g

= ½ (ee’+gg’) × (5-6 + 6-7)

= ½ (3,75 + 2,25) × (0,89+ 0,89)

= 5,37 m2

A4 = Luas gg’i'i

= ½ × (gg’+ii’) × (7-8 + 8-9)

= ½ × (2,25 + 0,75) × (0,89+ 0,89)

= 2,68 m2

A5 = Luas ii’jj’

= ½ × ii’ × 11-l

= ½ × 0,75 × 0,75

= 0,28 m2

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Gambar 3.10. Luasan Plafond Setengah Kuda-kuda

Panjang l-9 = ½ . 1,5 = 0,75 m

Panjang l-9 = 2-3 = 3-4 = 4-5 = 5-6 = 6-7 = 7-8 = 8-9 = 0,75 m

Panjang 1-2 = 1,5 m




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= ½ (aa’+cc’) × (1-2 + 2-3)

= ½ (7,5 +4,5) × (1,5 + 0,75)

= 13,5 m2


= ½ (cc’+ee’) × (3-4 + 4-5)

= ½ (4,5 + 3,75) × (0,75 + 0,75)

= 6,19 m2


= ½ (ee’+gg’) × (5-6 + 6-7)

= ½ (3,75 + 2,25) × (0,75 + 0,75 )

= 4,5 m2

A9 = Luas gg’i'i

= ½ × (gg’+ii’) × (7-8 + 8-9)

= ½ × (2,25+ 0,75) × (0,75 + 0,75 )

= 2,25 m2

A10 = Luas kk’m

= ½ × kk’ × 11-l

= ½ × 0,75× 0,75

= 0,28 m2

3.5.3 Perhitungan Pembebanan Setengah Kuda-kuda




A

48



Gambar 3.11. Pembebanan Setengah Kuda-kuda Akibat Beban Mati

a. Beban Mati

1) Beban P1


= 16,10 × 25 = 402,41 kg


= ½ × (1,5 + 1,79) × 14,18

= 23,31 kg


= 30 % × 23,31

= 6,99 kg


= 10 % × 23,31

= 2,33 kg

2) Beban P2

a) Beban Gording = berat profil gording × panjang gording G1

= 19,14 × 4,5= 86,13 kg

A

49


= 7,38 × 25 = 184,44 kg

c) Beban Kuda-kuda = ½ × btg (5 + 6+ 9 + 13) × berat profil kuda-kuda

= ½ × (1,79 + 1,79 + 0,97 + 1,79) × 14,18

= 44,94 kg


= 30 % × 44,94 = 13,48 kg


= 10 % × 44,94

= 4,49 kg

3) Beban P3


= 19,14 × 3 = 57,42 kg


= 5,37 × 26 = 134,14 kg

c) Beban Kuda-kuda = ½ × btg (6 + 7 + 10+ 14) × berat profil kuda-kuda

= ½ × (1,79 + 1,79 + 1,95 + 2,46) × 14,18

= 56,60 kgd) Beban Plat Sambung = 30 % × beban kuda-kuda

= 30 % × 56,60 = 16,98 kg


= 10 % × 56,60

= 5,66 kg4) Beban P4


= 19,14 × 1,5

= 28,71 kgb) Beban Atap = luasan A4 × berat atap

= 2,68 × 25= 67,07 kg

c) Beban Kuda-kuda = ½ × btg (7 + 8 + 11+15) × berat profil kuda-kuda

= ½ × (1,79 + 1,79 + 2,92 + 3,28) × 14,18

A

50

= 69,36 kgd) Beban Plat Sambung = 30 % × beban kuda-kuda

= 30 % × 69,36= 20,81 kg


= 10 % × 69,36= 6,94 kg

5) Beban P5


= 0,28 × 25

= 7,03 kg


= ½ × (1,79 + 3,90) × 14,18

= 40,30 kg


= 30 % × 40,30

= 12,09 kg


= 10 % × 40,30

= 4,03 kg

6) Beban P6

a) Beban Plafon = luasan A6× berat plafon

= 13,5 × 18

= 243 kg

7) Beban P7


= 6,19 × 18

= 111,38 kg

b) Beban Kuda-kuda = ½ × btg (1 + 2 + 9) × berat profil kuda-kuda

= ½ × (1.5 + 1,5 + 0,79) × 14,18

= 28,17 kg


= 30 % × 28,17

= 8,45 kg

A

51


= 10 % × 28,17

= 2,82 kg

8) Beban P8

a) Beban Plafon = luasan A8× berat plafon

= 4,5 × 18

= 81 kg

b) Beban Kuda-kuda = ½ × btg (2 + 3 + 10 + 13) × berat profil kuda-kuda

= ½ × (1,5 + 1,5 + 1,95 + 1,79) × 14,18

= 47,76 kg


= 30 % × 47,76

= 14,33 kg


= 10 % × 47,76

= 4,78 kg

9) Beban P9


= 2,25 × 18

= 40,5 kg


= ½ × (1,5 + 1,5 + 2,92 + 2,46) × 14,18

= 59,41 kg


= 30 % × 59,41

= 17,18 kg


= 10 % × 59,41

= 5,94 kg

10) Beban P10


= 0,28 × 18

A

52

= 5,06 kg


= ½ × (1,5 + 3,90 + 3,28) × 14,18

= 61,54 kg


= 30 % × 61,54

= 18,46kg


= 10 % × 61,54

= 6,15 kg

Tabel 3.8. Rekapitulasi Pembebanan Setengah Kuda-kuda

Beban Beban Atap (kg)

Beban Gording

(kg)

Beban Kuda-kuda

(kg)

Beban Plat

Penyambung (kg)

Beban Bracing

(kg)

Beban Plafond

(kg)

Jumlah Beban (kg)

Input SAP 2000

P1 402,41 - 23,31 6,99 2,33 - 435,05 523,20P2 184,44 86,13 44,94 13,48 4,49 - 333,49 400,80P3 134,14 57,42 56,60 16,98 5,66 - 270,80 325,20P4 67,07 28,71 69,36 20,81 6,94 - 192,88 231,60P5 7,03 - 40,30 12,09 4,03 - 63,45 76,80P6 - - - - - 243 243,00 291,60P7 - - 28,17 8,45 2,82 111,38 150,82 181,20P8 - - 47,76 14,33 4,78 81 147,86 177,60P9 - - 59,41 17,82 5,94 40,5 123,68 148,80P10 - - 61,54 18,46 6,15 5,06 91,22 110,40

b. Beban Hidup

Beban hidup yang bekerja pada P1 = P2 = P3 = P4 = P5 = 100 kg

c. Beban Angin

A

53


Gambar 3.12. Pembebanan Setengah Kuda-kuda Akibat Beban Angin



= (0,02 × 33) – 0,40 = 0,26


= 16,10 × 0,26 × 25

= 104,63 kg


= 7,38 × 0,26 × 25= 47,95 kg


= 5,37 × 0,26 × 25

= 34,88 kgd. W4 = luasan atap A4 × koef. angin tekan × beban angin

= 2,68 × 0,26 × 25

= 17,44 kge. W5 = luasan atap A5× koef. angin tekan × beban angin

= 0,28 × 0,26 × 25

= 1,83 kg

A

54

Tabel 3.9. Perhitungan Beban Angin pada Setengah Kuda-kuda

Beban

Angin

Beban

(kg)

Wx

W.Cos

(kg)

Input

SAP

2000

(kg)

Wy

W.Sin

(kg)

Input

SAP

2000

(kg)

W1 104,63 87,75 70,40 56,98 45,60

W2 47,95 40,22 32,80 26,12 21,60W3 34,88 29,25 24,00 18,99 15,20W4 17,44 14,62 12,00 9,50 8,00W5 1,83 1,53 1,60 1,00 0,80



Tabel 3.10. Rekapitulasi Gaya Batang Setengah Kuda-kuda

BatangKombinasi

Tarik (+) Tekan (-)Kg Kg

1 632,68 -2 632,68 -3 28,2 -4 - 529,45 - 838,266 - 156,667 479,52 -8 1052,97 -9 181,2 -10 570,02 -11 872,82 -12 0 -13 - 720,714 - 913,8515 - 1079,32

3.5.4 Perhitungan Profil Setengah Kuda-kuda

A

55


Pmaks = 1052,97 kgσijin = 1666 kg/cm2

Fnetto =

Fbruto = 1,15 × Fnetto = 1,15 × 0,63

= 0,73 cm2


F = 2 × 4,8

= 9,6 cm2



σ

σ ≤ 0,75σijin

129,04 kg/cm2 ≤ 1249,5 kg/cm2 ………. aman !!



Pmaks= 1079,32 kg

L = 3,28 mm = 328 cm


ix = 1,51 cm

F = 2 × 4,8

= 9,6 cm2

A

56

λ =

λg

= 108,87 cm

λs

Karena λs

> 1,2 maka :

ω = 1,25 × λs2

= 1,25 × (2,00)

2

= 4,99


σ

σ ≤ σijin

560,84 kg/cm2 ≤ 1666 kg/cm2 ………. aman !!


A

57

3.5.5 Perhitungan Alat Sambung Setengah Kuda-kuda

a. Batang Tarik


Diameter baut (Ø) = 6,35 mm (1/4 inches)


= 6,35 + 2

= 8,35 mm



= 0,625 . 6,35

= 3,97 mm




= 0,6 . 1666

= 999,6 kg/cm2



= 1,5 . 1666

= 2499 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (0,635)2 . 999,6

= 633,39 kg

A

58


= 0,8 . 0,635 . 2499

= 1269,49 kg





3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 6,35

= 19,5 mm

= 20 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

A

59

= 1,5 . 6,35

= 9,525 mm

= 10 mm

b. Batang Tekan


Diameter baut (Ø) = 6,35 mm (1/4 inches)


= 6,35 + 2

= 8,35 mm



= 0,625 . 6,35

= 3,97 mm




= 0,6 . 1600

= 960 kg/cm2



= 0,6 . 1666

= 999,6 kg/cm2

A

60



= 1,5 . 1666

= 2499 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (0,635)2 . 999,6

= 633,39 kg


= 0,8 . 0,635 . 2499

= 1269,49 kg





3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 6,35

= 19,5 mm

A

61

= 20 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 6,35

= 9,525 mm

= 10 mm

Tabel 3.11. Rekapitulasi Perencanaan Profil Setengah Kuda-kudaNomorBatang

Dimensi Profil Baut (Inch)

1 50.50.5 2Ø1/42 50.50.5 2Ø1/43 50.50.5 2Ø1/44 50.50.5 2Ø1/45 50.50.5 2Ø1/46 50.50.5 2Ø1/47 50.50.5 2Ø1/48 50.50.5 2Ø1/49 50.50.5 2Ø1/410 50.50.5 2Ø1/411 50.50.5 2Ø1/412 50.50.5 2Ø1/413 50.50.5 2Ø1/414 50.50.5 2Ø1/415 50.50.5 2Ø1/4

A

62

3.6Perencanaan Kuda-kuda Trapesium

Gambar 3.13. Rangka Batang Kuda-kuda Trapesium

3.6.1 Perhitungan Panjang Batang Kuda-kuda Trapesium


Tabel 3.12. Panjang Batang pada Kuda-kuda TrapesiumNomor Batang Panjang Batang (m)

1 2,00

2 2,00

3 2,00

4 2,00

5 2,00

6 2,00

7 2,00

8 2,00

9 2,00

10 2,00

11 2,23

12 2,23

13 2,00

14 2,00

15 2,00

16 2,00

17 2,00

A

63

18 2,00

19 2,23

20 2,23

21 0,9822 1,9523 1,9524 1,9525 1,9526 1,9527 1,9528 1,9529 0,9830 2,2331 2,7932 2,7933 2,7934 2,7935 2,7936 2,7937 2,23

A

64

3.6.2 Perhitungan Luasan Kuda-kuda Trapesium

Gambar 3.14. Luasan Atap Kuda-kuda Trapesium

A

65

Panjang b-c = ½ . 2,23 = 1,115 m

Panjang b-c = c-d = d-e = e-f = 1,115 m

Panjang a-b = 1,34 m




Panjang ff’ = 3,0 m


= ½ (aa’+ cc’) × (a-b + b-c)

= ½ (5,6 + 4,5) × (1,34 + 1,115)

= 12,398 m2


= ½ (cc’+ ee’) × (c-d + d-e)

= ½ (4,5 + 3,5) × (1,115 + 1,115)

= 8,920 m2

A3 = Luas ee’f’f

= ½ (ee’+ ff’) × e-f

= ½ (3,5 + 3) × 1,115

= 3,624 m2

A

66

Gambar 3.15. Luasan Plafond Kuda-kudaTrapesium

A

67

Panjang b-c = ½ . 2,00 = 1,00 m

Panjang b-c = c-d = d-e = e-f = 1,00 m

Panjang a-b = 1,2 m




Panjang ff’ = 3,0 m


= ½ (aa’+ cc’) × (a-b + b-c)

= ½ (5,6 + 4,5) × (1,20 + 1,00)

= 11,110 m2


= ½ (cc’+ ee’) × (c-d + d-e)

= ½ (4,5 + 3,5) × (1,00 + 1,00)

= 8,00 m2

A6 = Luas ee’f’f

= ½ (ee’+ ff’) × e-f

= ½ (3,5 + 3) × 1,00

= 3,250 m2

3.6.3 Perhitungan Pembebanan Kuda-kuda Trapesium






A

68

Gambar 3.16. Pembebanan Kuda-kuda Trapesium Akibat Beban Mati

a. Beban Mati

1) Beban P1 = P11


= 12,398 × 50 = 619,888 kg


= ½ × (2,00 + 2,23) × 26,2

= 55,413 kg


= 30 % × 55,413 = 16,624 kg


= 10 % × 55,413 = 5,541 kg

2) Beban P2 = P10


= 12,3 × 4,0 = 49,2 kg


= 8,920 × 50 = 446 kg

c) Beban Kuda-kuda = ½ × btg (11+12+21+30) × berat profil kuda-kuda

= ½ × (2,23 + 2,23 + 0,98 + 2,23) × 26,2

= 100,477 kg


= 30 % × 100,477 = 30,143 kg


= 10 % × 100,477 = 10,048 kg

A

69

3) Beban P3 = P9


= 12,3 × 3,0 = 36,9 kg


= 3,624 × 50 = 181,188 kg


= ½ × (2,23 + 2,00 + 1,95 + 2,79) × 26,2

= 117,507 kg


= 30 % × 117,507 = 35,252 kg


= 10 % × 117,507 = 11,751 kg

4) Beban P4 = P5 = P7 = P8

a) Beban Kuda-kuda = ½ × btg (13+14+23+32) × berat profil kuda-kuda

= ½ × (2,00 + 2,00 + 1,95 + 2,79) × 26,2

= 114,494 kg

b) Beban Plat Sambung = 30 % × beban kuda-kuda

= 30 % × 114,494 = 34,348 kg

c) Beban Bracing = 10% × beban kuda-kuda

= 10 % × 114,494 = 11,449 kg

5) Beban P6

a) Beban Kuda-kuda = ½ × btg (15+16+25) × berat profil kuda-kuda

= ½ × (2,00 + 2,00 + 1,95) × 26,2

= 77,945 kg


= 30 % × 77,945 = 23,384 kg


= 10 % × 77,945 = 7,794 kg

6) Beban P12 = P22


= 11,110 × 18 = 199,98 kg

A

70

7) Beban P13 = P21


= 8 × 18 = 144 kg


= ½ × (2,00 + 2,00 + 0,98) × 26,2

= 65,238 kg


= 30 % × 65,238 = 19,571 kg


= 10 % × 65,238 = 6,524 kg

8) Beban P14 = P20


= 3,25 × 18 = 58,5 kg


= ½ × (2,00 + 2,00 + 1,95 + 2,23) × 26,2

= 107,158 kg


= 30 % × 107,158 = 32,147 kg


= 10 % × 107,158 = 10,716 kg

9) Beban P15 = P16 = P18 = P19

a) Beban Kuda-kuda = ½ × btg (3 + 4 + 23 + 31) × berat profil kuda-kuda

= ½ × (2,00 + 2,00 + 1,95 + 2,79) × 26,2

= 114,494 kg


= 30 % × 114,494 = 34,348 kg


= 10 % × 114,494 = 11,449 kg

10) Beban P17

a) Beban Kuda-kuda = ½ × btg(5+6+25+33+34) × berat profil kuda-kuda

= ½ × (2,00 + 2,00 + 1,95 + 2,79 + 2,79) × 26,2

= 151,043 kg

A

71


= 30 % × 151,043 = 45,312 kg


= 10 % × 151,043 = 15,104 kg

Tabel 3.13. Rekapitulasi Pembebanan Kuda-kuda Trapesium Beban Beban Beban Beban Plat Beban Beban Jumlah Input

Beban Atap GordingKuda-kuda Penyambung Bracing Plafond Beban

SAP 2000

(kg) (kg) (kg) (kg) (kg) (kg) (kg) (kg)P1=P11 619,888 - 55,413 16,624 5,541 - 697,466 698P2=P10 446 49,2 100,48 30,143 10,048 - 635,868 636P3=P9 181,188 36,9 117,51 35,252 11,751 - 382,597 383P4=P8 - - 114,49 34,348 11,449 - 160,292 161P5=P7 - - 114,49 34,348 11,449 - 160,292 161

P6 - - 77,945 23,384 7,794 - 109,123 110P12=P22 - - - - - 199,98 199,98 200P13=P21 - - 65,238 19,571 6,524 144 235,333 236P14=P20 - - 107,16 32,147 10,716 58,5 208,521 209P15=P19 - - 114,49 34,348 11,449 - 160,292 161P16=P18 - - 114,49 34,348 11,449 - 160,292 161

P17 - - 151,04 45,312 15,104 - 211,460 212

b. Beban Hidup

Beban hidup yang bekerja pada:

P1 = P2 = P3 = P4 = P5 = P6 = P7 = P8 = P9 = P10 = P11 100 kg

A

72

c. Beban Angin


Gambar 3.17. Pembebanan Kuda-kuda Trapesium Akibat Beban Angin



= (0,02 × 26) – 0,40 = 0,12


= 12,398 × 0,12 × 25 = 37,193 kg


= 8,920 × 0,12 × 25 = 26,760 kg


= 3,624 × 0,12 × 25 = 10,871 kg

Koefisien angin hisap = 0,40


= 3,624 × ( 0,40) × 25 = - 36,238 kg


= 8,920 × ( 0,40) × 25 = - 89,200 kg


= 12,398 × ( 0,40) × 25 = - 123,978 kg

Tabel 3.14. Perhitungan Beban Angin pada Kuda-kuda Trapesium

A

73

Beban

Angin

Beban

(kg)

Wx

W.Cos

(kg)

Input

SAP

2000

(kg)

Wy

W.Sin

(kg)

Input

SAP

2000

(kg)

W1 37,193 33,429 34 16,304 17

W2 26,76 24,052 25 11,731 12W3 10,871 9,771 10 4,766 5W4 -36,238 -32,57 -33 -15,886 -16W5 -89,2 -80,172 -81 -39,102 -40W6 -123,978 -111,43 -112 -54,348 -55



Tabel 3.15. Rekapitulasi Gaya Batang Kuda-kuda Trapesium

BatangKombinasi

Tarik (+) Tekan (-)kg kg

1 8547,37 -2 8776,65 -3 8602,23 -4 10689,58 -5 12014,75 -6 12008 -7 10675,9 -8 8581,12 -9 8739,76 -10 8504,61 -11 - 9712,9812 - 9490,4413 - 10588,6614 - 11989,1815 - 12450,4116 - 12450,1517 - 11981,8618 - 10574,4219 - 9504,3920 - 9797,92

A

74

21 - 295,3222 1005,1 -23 - 1627,1524 - 890,825 - 352,7226 - 896,9327 - 1633,4328 996.62 -29 - 295,5330 - 292,1331 2763,86 -32 1756,49 -33 580,75 -34 589,76 -35 1765,3 -36 68,18 -37 - 275,6

3.6.4 Perhitungan Profil Kuda-kuda Trapesium


Pmaks = 12014,75 kg


Fnetto =

Fbruto = 1,15 × Fnetto = 1,15 × 7,509 = 8,636 cm2


F = 2 × 16,7 = 33,40 cm2



A

75

σ

σ ≤ 0,75σijin

423,204 kg/cm2 ≤ 1200 kg/cm2 ………. aman !!



Pmaks= 12450,41 kg

L = 2,00 mm = 200 cm


ix = 2,22 cm

F = 2 × 16,70 = 33,40 cm2

λ =

λg

= 111,016 cm

λs

A

76

Karena 0,25 < λs

< 1,2 maka :

ω

= 1,354


σ

σ ≤ σijin

504,649 kg/cm2 ≤ 1600 kg/cm2 ………. aman !!


3.6.5 Perhitungan Alat Sambung Kuda-kuda Trapesium

a. Batang Tarik


Diameter baut (Ø) = 19,05 mm (¾ inches)


= 19,05 + 1

= 20,05 mm


A

77


= 0,625 . 19,05

= 11,906 mm




= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg

P yang menentukan adalah Pdesak = 4114,800 kg.



A

78


3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

= 28,575 mm = 30 mm

b. Batang Tekan




= 19,05 + 1

= 20,05 mm



= 0,625 . 19,05

= 11,906 mm


A

79



= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg





A

80

3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

= 28,575 mm = 20 mm

Tabel 3.16. Rekapitulasi Perencanaan Profil Kuda-kuda TrapesiumNomor

BatangDimensi Profil Baut (Inch)

1 75.75.12 4 Ø ¾2 75.75.12 4 Ø ¾3 75.75.12 4 Ø ¾4 75.75.12 4 Ø ¾5 75.75.12 4 Ø ¾6 75.75.12 4 Ø ¾7 75.75.12 4 Ø ¾8 75.75.12 4 Ø ¾9 75.75.12 4 Ø ¾10 75.75.12 4 Ø ¾11 75.75.12 4 Ø ¾12 75.75.12 4 Ø ¾13 75.75.12 4 Ø ¾14 75.75.12 4 Ø ¾

A

81

15 75.75.12 4 Ø ¾16 75.75.12 4 Ø ¾17 75.75.12 4 Ø ¾18 75.75.12 4 Ø ¾19 75.75.12 4 Ø ¾20 75.75.12 4 Ø ¾21 75.75.12 4 Ø ¾22 O (t2=10,5 mm) 4 Ø ¾23 75.75.12 4 Ø ¾24 75.75.12 4 Ø ¾25 O (t2=10,5 mm) 4 Ø ¾26 75.75.12 4 Ø ¾27 75.75.12 4 Ø ¾28 O (t2=10,5 mm) 4 Ø ¾29 75.75.12 4 Ø ¾30 75.75.12 4 Ø ¾31 75.75.12 4 Ø ¾32 75.75.12 4 Ø ¾33 75.75.12 4 Ø ¾34 75.75.12 4 Ø ¾35 75.75.12 4 Ø ¾36 75.75.12 4 Ø ¾37 75.75.12 4 Ø ¾

3.7Perencanaan Kuda-kuda Utama A

A

82

Gambar 3.18. Rangka Batang Kuda-kuda Utama A

3.7.1 Perhitungan Panjang Batang Kuda-kuda Utama A


Tabel 3.17. Panjang Batang pada Kuda-kuda Utama ANomor Batang Panjang Batang (m)

1 2,002 2,003 2,004 2,005 2,006 2,007 2,008 2,009 2,0010 2,0011 2,2312 2,2313 2,2314 2,2315 2,2316 2,2317 2,2318 2,23

A

83

19 2,2320 2,2321 0,9822 1,9523 2,9324 3,925 4,8826 3,927 2,9328 1,9529 0,9830 2,2331 2,7932 3,5433 4,3834 4,3835 3,5436 2,7937 2,23

3.7.2 Perhitungan Luasan Kuda-kuda Utama A

A

84

Gambar 3.19. Luasan Atap Kuda-kuda Utama A

Panjang b-c = ½ . 2,23 = 1,115 m

Panjang b-c = c-d = d-e = e-f = f-g = g-h = h-i = i-j = j-k = k-l = 1,115 m

A

85


Panjang aa’ = cc’ = ee’ = ff’ = 5,5 m



Panjang kk’ = 3,0 m

Panjang ll’ = 2,5 m


= aa’ × (a-b + b-c)

= 5,5 × (1,34 + 1,115)

= 13,502 m2


= cc’ × (c-d + d-e)

= 5,5 × (1,115 + 1,115)

= 12,265 m2


= (ee’ × e-f) + (½ (ff’ + gg’) × f-g)

= (5,5 × 1,115) + (½ (5,5 + 5,0) × 1,115)

= 11,986 m2

A4 = Luas gg’i'i

= ½ (gg’+ ii’) × (g-h + h-i)

= ½ (5,0 + 4,0) × (1,115 + 1,115)

= 10,035 m2

A5 = Luas ii’k’k

= ½ (ii’+ kk’) × (i-j + j-k)

A

86

= ½ (4,0+ 3,0) × (1,115 + 1,115)

= 7,805 m2

A6 = Luas kk’l’l

= ½ (kk’+ ll’) × k-l

= ½ (3,0 + 2,5) × 1,115

= 3,066 m2

A

87

Gambar 3.20. Luasan Plafond Kuda-kuda Utama A

Panjang b-c = ½ . 2,0 = 1,0 m


Panjang a-b = 1,2 m

Panjang aa’ = cc’ = ee’ = ff’ = 5,5 m



Panjang kk’ = 3,0 m

Panjang ll’ = 2,5 m


= aa’ × (a-b + b-c)

= 5,5 × (1,2 + 1,0)

= 12,100 m2


= cc’ × (c-d + d-e)

= 5,5 × (1,0 + 1,0)

= 11,000 m2

A

88


= (ee’ × e-f) + (½ (ff’ + gg’) × f-g)

= (5,5 × 1,0) + (½ (5,5 + 5,0) × 1,0)

= 10,750 m2

A10 = Luas gg’i'i

= ½ (gg’+ ii’) × (g-h + h-i)

= ½ (5,0 + 4,0) × (1,0 + 1,0)

= 9,000 m2

A11 = Luas ii’k’k

= ½ (ii’+ kk’) × (i-j + j-k)

= ½ (4,0+ 3,0) × (1,0 + 1,0)

= 7,000 m2

A12 = Luas kk’l’l

= ½ (kk’+ ll’) × k-l

= ½ (3,0 + 2,5) × 1,0

= 2,75 m2

3.7.3 Perhitungan Pembebanan Kuda-kuda Utama A






A

89

Gambar 3.21. Pembebanan Kuda-kuda Utama A Akibat Beban Mati

a. Beban Mati

1) Beban P1 = P11


= 13,503 × 50 = 675,125 kg


= ½ × (2,00 + 2,23) × 35,6

= 75,294 kg


= 30 % × 75,294 = 22,588 kg


= 10 % × 75,294 = 7,529 kg

2) Beban P2 = P10


= 12,3 × 5,5 = 67,65 kg


= 12,265 × 50 = 613,25 kg


= ½ × (2,23 + 2,23 + 0,98 + 2,23) × 35,6

= 136,526 kg


= 30 % × 136,526 = 40,958 kg


= 10 % × 136,526 = 13,652 kg

A

90

3) Beban P3 = P9


= 12,3 × 5,5 = 67,65 kg


= 11,986 × 50 = 599,312 kg


= ½ × (2,23 + 2,23 + 1,95 + 2,79) × 35,6

= 163,760 kg


= 30 % × 163,760 = 49,128 kg


= 10 % × 163,760 = 16,376 kg

4) Beban P4 = P8


= 12,3 × 4,5 = 55,35 kg


= 10,035 × 50 = 501,75 kg


= ½ × (2,23 + 2,23 + 2,93 + 3,54) × 35,6

= 194,554 kg


= 30 % × 194,554 = 58,366 kg


= 10 % × 194,554 = 19,455 kg

5) Beban P5 = P7


= 12,3 × 3,5 = 43,05 kg


= 7,805 × 50 = 390,25 kg


= ½ × (2,23 + 2,23 + 3,9 + 4,38) × 35,6

= 226,772 kg

A

91


= 30 % × 226,772 = 68,032 kg


= 10 % × 226,772 = 22,677 kg

6) Beban P6


= 12,3 × 2,5 = 30,75 kg


= 3,066 × 50 = 153,312 kg

c) Beban Kuda-kuda = ½ × btg (15+16+25) × berat profil kuda-kuda

= ½ × (2,23 + 2,23 + 4,88) × 35,6

= 166,252 kg


= 30 % × 166,252 = 49,876 kg


= 10 % × 166,252 = 16,625 kg

f) Beban Reaksi = (2 × reaksi jurai) + (reaksi setengah kuda-kuda)

= (2 × 2528,14) + 2520,18

= 7576,46 kg

7) Beban P12 = P22


= 12,1 × 18 = 217,8 kg

8) Beban P13 = P21


= 11 × 18 = 198 kg


= ½ × (2 + 2 + 0,98) × 35,6

= 88,644 kg


= 30 % × 88,644 = 26,593 kg


= 10 % × 88,644 = 8,864 kg

A

92

9) Beban P14 = P20


= 10,75 × 18 = 193,5 kg


= ½ × (2 + 2 + 1,95 + 2,23) × 35,6

= 145,604 kg


= 30 % × 145,604 = 43,681 kg


= 10 % × 145,604 = 14,56 kg

10) Beban P15 = P19


= 9 × 18 = 162 kg


= ½ × (2 + 2 + 2,93 + 2,79) × 35,6

= 173,016 kg


= 30 % × 173,016 = 51,904 kg


= 10 % × 173,016 = 17,302 kg

11) Beban P16 = P18


= 7 × 18 = 126 kg


= ½ × (2 + 2 + 3,9 + 3,54) × 35,6

= 203,632 kg


= 30 % × 203,632 = 61,089 kg


= 10 % × 203,632 = 20,363 kg

A

93

12) Beban P17


= 2,75 × 18 = 49,5kg

b) Beban Kuda-kuda = ½ × btg (5+6+25+33+34)× berat profil kuda-kuda

= ½ × (2 + 2 + 4,88 + 4,38 + 4,38) × 35,6

= 313,992 kg


= 30 % × 313,992 = 94,198 kg


= 10 % × 313,992 = 31,399 kg

e) Beban Reaksi = (2 × reaksi jurai) + (reaksi setengah kuda-kuda)

= (2 × 3891,13) + 3680,59

= 11951,94 kg

Tabel 3.18. Rekapitulasi Pembebanan Kuda-kuda Utama A Beban Beban Beban Beban Plat Beban Beban Beban Jumlah Input

Beban AtapGordin

gKuda-kuda

Penyam-bung Bracing Plafond Reaksi Beban

SAP 2000

(kg) (kg) (kg) (kg) (kg) (kg) (kg) (kg) (kg)P1=P11 675,125 - 75,294 22,588 7,529 - - 780,536 781P2=P10 613,25 67,65 136,52 40,958 13,652 - - 872,04 873P3=P9 599,31 67,65 163,76 49,128 16,376 - - 896,22 897P4=P8 501,75 55,35 194,55 58,366 19,455 - - 829,48 830P5= 7 390,25 43,05 226,77 68,032 22,677 - - 750,78 751

P6 153,31 30,75 166,25 49,876 16,625 - 7576,4 7993,3 7994P12=P22 - - - - - 217,8 - 217,8 218P13=P21 - - 88,644 26,593 8,864 198 - 322,10 323P14=P20 - - 145,6 43,681 14,56 193,5 - 397,34 398P15=P19 - - 173,02 51,904 17,302 162 - 404,22 405P16=P18 - - 203,63 61,089 20,363 126 - 411,08 412

P17 - - 313,99 94,198 31,399 49,5 11462,8 11951,9 11952

b. Beban Hidup

A

94


P1 = P2 = P3 = P4 = P5 = P6 = P7 = P8 = P9 = P10 = P11 = 100 kg

c. Beban Angin


Gambar 3.22. Pembebanan Kuda-kuda Utama A Akibat Beban Angin



= (0,02 × 26) – 0,40 = 0,12


= 13,503 × 0,12 × 25 = 40,508 kg


= 12,265 × 0,12 × 25 = 36,795 kg


= 11,986 × 0,12 × 25 = 35,958 kg


= 10,035 × 0,12 × 25 = 30,105 kge. W5 = luasan atap A5 × koef. angin tekan × beban angin

= 7,805 × 0,12 × 25 = 23,415 kg

f. W6 = luasan atap A6× koef. angin tekan × beban angin

= 3,066 × 0,12 × 25 = 9,198 kg

A

95



= 13,503 × ( 0,40) × 25 = - 30,662 kg


= 12,265 × ( 0,40) × 25 = - 78,05 kg

c. W9 = luasan atap A4 × koef. angin tekan × beban angin

= 11,986 × ( 0,40) × 25 = - 100,35 kg


= 10,035 × ( 0,40) × 25 = - 119,863 kg

e. W11 = luasan atap A2 × koef. angin tekan × beban angin

= 7,805 × ( 0,40) × 25 = - 122,65 kg

f. W12 = luasan atap A1 × koef. angin tekan × beban angin

= 3,066 × ( 0,40) × 25 = - 135,025 kg

Tabel 3.19. Perhitungan Beban Angin pada Kuda-kuda Utama A

Beban

Angin

Beban

(kg)

Wx

W.Cos

(kg)

Input

SAP

2000

(kg)

Wy

W.Sin

(kg)

Input

SAP

2000

(kg)

W1 40,508 36,408 37 17,757 18

W2 36,795 33,071 34 16,129 17W3 35,958 32,319 33 15,763 16W4 30,105 27,058 28 13,197 14W5 23,415 21,045 22 10,264 11W6 9,198 8,268 9 4,032 5W7 -30,662 -27,559 -28 -13,442 -14W8 -78,05 -70,151 -71 -34,214 -35W9 -100,35 -90,194 -91 -43,991 -44W10 -119,863 -107,732 -108 -52,544 -53W11 -122,65 -110,237 -111 -53,766 -54W12 -135,025 -121,36 -122 -59,191 -60

A

96



Tabel 3.20. Rekapitulasi Gaya Batang Kuda-kuda Trapesium

BatangKombinasi


1 35284,62 -2 36681,82 -3 38645,02 -4 37083,04 -5 34981,27 -6 34891,68 -7 36891,17 -8 38342,75 -9 36305,22 -10 34893,73 -11 - 39931,4212 - 43154,0113 - 41399,1614 - 39297,8715 - 36766,5516 - 36799,7217 - 39313,5618 - 41403,5319 - 43155,4120 - 39968,0321 - 1979,9222 376,7 -23 1940,4 -24 3438,29 -25 19861,79 -26 3305,29 -27 1841,54 -28 332,77 -29 - 1961,0930 2386,56 -31 - 1912,4832 - 3221,8133 - 2823,0634 - 2634,66

A

97

35 - 3052,7736 - 1767,537 2458,88 -

3.7.4 Perhitungan Profil Kuda-kuda Utama A


Pmaks = 38645,02 kg


Fnetto =

Fbruto = 1,15 × Fnetto = 1,15 × 24,153 = 27,776 cm2


F = 2 × 22,70 = 45,40 cm2



σ

σ ≤ 0,75σijin

1001,426 kg/cm2 ≤ 1200 kg/cm2 ………. aman !!


A

98


Pmaks= 43155,41 kg

L = 2,23 mm = 223 cm


ix = 3,02 cm

F = 2 × 22,70 = 45,40 cm2

λ =

λg

= 111,016 cm

λs

Karena 0,25 < λs

< 1,2 maka :

ω

= 1,238


σ

A

99

σ ≤ σijin

1177,54 kg/cm2 ≤ 1600 kg/cm2 ………. aman !!


3.7.5 Perhitungan Alat Sambung Kuda-kuda Utama A

a. Batang Tarik




= 19,05 + 1

= 20,05 mm



= 0,625 . 19,05

= 11,906 mm




= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

A

100

Kekuatan baut


= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg





3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

A

101

= 28,575 mm = 30 mm

b. Batang Tekan




= 19,05 + 1

= 20,05 mm



= 0,625 . 19,05

A

102

= 11,906 mm




= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg





A

103

3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

= 28,575 mm = 20 mm

Tabel 3.21. Rekapitulasi Perencanaan Profil Kuda-kuda Utama ANomor


1 100.100.12 10 Ø ¾2 100.100.12 10 Ø ¾3 100.100.12 10 Ø ¾4 100.100.12 10 Ø ¾5 100.100.12 10 Ø ¾6 100.100.12 10 Ø ¾7 100.100.12 10 Ø ¾8 100.100.12 10 Ø ¾9 100.100.12 10 Ø ¾10 100.100.12 10 Ø ¾11 100.100.12 12 Ø ¾12 100.100.12 12 Ø ¾13 100.100.12 12 Ø ¾14 100.100.12 12 Ø ¾

A

104

15 100.100.12 12 Ø ¾16 100.100.12 12 Ø ¾17 100.100.12 12 Ø ¾18 100.100.12 12 Ø ¾19 100.100.12 12 Ø ¾20 100.100.12 12 Ø ¾21 100.100.12 12 Ø ¾22 100.100.12 10 Ø ¾23 100.100.12 10 Ø ¾24 100.100.12 10 Ø ¾25 O (t5=165,2 mm) 10 Ø ¾26 100.100.12 10 Ø ¾27 100.100.12 10 Ø ¾28 100.100.12 10 Ø ¾29 100.100.12 12 Ø ¾30 100.100.12 10 Ø ¾31 100.100.12 12 Ø ¾32 100.100.12 12 Ø ¾33 100.100.12 12 Ø ¾34 100.100.12 12 Ø ¾35 100.100.12 12 Ø ¾36 100.100.12 12 Ø ¾37 100.100.12 10 Ø ¾

A

105

3.8Perencanaan Kuda-kuda Utama B

Gambar 3.23. Rangka Batang Kuda-kuda Utama B

3.8.1 Perhitungan Panjang Batang Kuda-kuda Utama B


Tabel 3.22. Panjang Batang pada Kuda-kuda Utama BNomor Batang Panjang Batang (m)

1 2,002 2,003 2,004 2,005 2,006 2,007 2,008 2,009 2,0010 2,0011 2,2312 2,2313 2,2314 2,2315 2,2316 2,23

A

106

17 2,2318 2,2319 2,2320 2,2321 0,9822 1,9523 2,9324 3,925 4,8826 3,927 2,9328 1,9529 0,9830 2,2331 2,7932 3,5433 4,3834 4,3835 3,5436 2,7937 2,23

A

107

3.8.2 Perhitungan Luasan Kuda-kuda Utama B

Gambar 3.24. Luasan Atap Kuda-kuda Utama B

A

108

Panjang b-c = ½ . 2,23 = 1,115 m



Panjang aa’ = cc’ = ee’ = gg’ = ii’ = kk’ = ll’ = 5 m


= aa’ × (a-b + b-c)

= 5 × (1,34 + 1,115)

= 12,275 m2


= cc’ × (c-d + d-e)

= 5 × (1,115 + 1,115)

= 11,15 m2

A2 = A3 = A4 = A5

= 11,15 m2

A6 = Luas kk’l'l

= kk’ × k-l

= 5 × 1,115

= 5,575 m2

A

109

Gambar 3.25. Luasan Plafond Kuda-kuda Utama B

A

110

Panjang b-c = ½ . 2,0 = 1,0 m


Panjang a-b = 1,2 m

Panjang aa’ = cc’ = ee’ = gg’ = ii’ = kk’ = ll’ = 5 m


= aa’ × (a-b + b-c)

= 5 × (1,2 + 1,0)

= 11,0 m2


= cc’ × (c-d + d-e)

= 5 × (1,0 + 1,0)

= 10,0 m2

A8 = A9 = A10 = A11

= 10,0 m2

A10 = Luas kk’l'l

= kk’ × k-l

= 5 × 1,0

= 5,0 m2

3.8.3 Perhitungan Pembebanan Kuda-kuda Utama B






A

111

Gambar 3.26. Pembebanan Kuda-kuda Utama B Akibat Beban Mati

a. Beban Mati

1) Beban P1 = P11


= 12,275 × 50 = 613,75 kg


= ½ × (2,0 + 2,23) × 35,6

= 75,294 kg


= 30 % × 75,294 = 22,588 kg


= 10 % × 75,294 = 7,529 kg

2) Beban P2 = P10


= 12,3 × 5 = 61,5 kg


= 11,15 × 50 = 557,5 kg


= ½ × (2,23 + 2,23 + 0,98 + 2,23) × 35,6

= 136,526 kg


= 30 % × 136,526 = 40,958 kg


= 10 % × 136,526 = 13,652 kg

A

112

3) Beban P3 = P9


= 12,3 × 5 = 61,5 kg


= 11,15 × 50 = 557,5 kg


= ½ × (2,23 + 2,23 + 1,95 + 2,79) × 35,6

= 163,76 kg


= 30 % × 163,76 = 49,128 kg


= 10 % × 163,76 = 16,376 kg

4) Beban P4 = P8


= 12,3 × 5 = 61,5 kg


= 11,15 × 50 = 557,5 kg


= ½ × (2,23 + 2,23 + 2,93 + 3,54) × 35,6

= 194,554 kg


= 30 % × 194,554 = 58,366 kg


= 10 % × 194,554 = 19,455 kg

5) Beban P5 = P7


= 12,3 × 5 = 61,5 kg


= 11,15 × 50 = 557,5 kg


= ½ × (2,23 + 2,23 + 3,9 + 4,38) × 35,6

= 226,772 kg

A

113


= 30 % × 226,772 = 68,032 kg


= 10 % × 226,772 = 22,677 kg

6) Beban P6


= 12,3 × 5 = 61,5 kg


= 5,575 × 50 = 278,75 kg

c) Beban Kuda-kuda = ½ × btg (15+16+25) × berat profil kuda-kuda

= ½ × (2,23 + 2,23 + 4,88) × 35,6

= 166,252 kg


= 30 % × 166,252 = 49,876 kg


= 10 % × 166,252 = 16,625 kg

7) Beban P12 = P22


= 11 × 18 = 198 kg

8) Beban P13 = P21


= 10 × 18 = 180 kg


= ½ × (2,0 + 2,0 + 0,98) × 35,6

= 88,644 kg


= 30 % × 88,644 = 26,593 kg


= 10 % × 88,644 = 8,864 kg

9) Beban P14 = P20


= 10 × 18 = 180 kg

A

114

b) Beban Kuda-kuda = ½ × btg (2+3+22+30) × berat profil kuda-kuda

= ½ × (2 + 2 + 1,95 + 2,23) × 35,6

= 145,604 kg


= 30 % × 145,604 = 43,681 kg


= 10 % × 145,604 = 14,560 kg

10) Beban P15 = P19


= 10 × 18 = 180 kg


= ½ × (2 + 2 + 2,93 + 2,79) × 35,6

= 173,016 kg


= 30 % × 173,016 = 51,904 kg


= 10 % × 173,016 = 17,302 kg

11) Beban P16 = P18


= 10 × 18 = 180 kg


= ½ × (2 + 2 + 3,9 + 3,54) × 35,6

= 203,632 kg


= 30 % × 203,632 = 61,089 kg


= 10 % × 203,632 = 20,363 kg

12) Beban P17


= 5 × 18 = 90 kg

A

115

b) Beban Kuda-kuda = ½ × btg (5+6+25+33+34)× berat profil kuda-kuda

= ½ × (2 + 2 + 4,88 + 4,38 + 4,38) × 35,6

= 313,992 kg


= 30 % × 313,992 = 94,198 kg


= 10 % × 313,992 = 31,399 kg

Tabel 3.23. Rekapitulasi Pembebanan Kuda-kuda Utama B

Beban Beban Beban Beban Plat Beban Beban Jumlah Input

Beban AtapGordin

gKuda-kuda

Penyam-bung Bracing Plafond Beban

SAP 2000

(kg) (kg) (kg) (kg) (kg) (kg) (kg) (kg)P1=P11 613,75 - 75,294 22,588 7,529 - 719,16 720P2=P10 557,5 61,5 136,52 40,958 13,652 - 810,14 811P3=P9 557,5 61,5 163,76 49,128 16,376 - 848,26 849P4=P8 557,5 61,5 194,55 58,366 19,455 - 891,38 892P5=P7 557,5 61,5 226,77 68,032 22,677 - 936,48 937

P6 278,75 61,5 166,25 49,876 16,625 - 573,01 574P12=P22 - - - - - 198 198 198P13=P21 - - 88,644 26,593 8,864 180 304,1 305P14=P20 - - 145,6 43,681 14,56 180 383,84 384P15=P19 - - 173,02 51,904 17,302 180 422,22 423P16=P18 - - 203,63 61,089 20,363 180 465,08 466

P17 - - 313,99 94,198 31,399 90 529,58 530

b. Beban Hidup


P1 = P2 = P3 = P4 = P5 = P6 = P7 = P8 = P9 = P10 = P11 = 100 kg

c. Beban Angin

A

116


Gambar 3.27. Pembebanan Kuda-kuda Utama B Akibat Beban Angin



= (0,02 × 26) – 0,40 = 0,12


= 12,275 × 0,12 × 25 = 36,825 kg


= 11,15 × 0,12 × 25 = 33,45 kg


= 11,15 × 0,12 × 25 = 33,45 kg


= 11,15 × 0,12 × 25 = 33,45 kge. W5 = luasan atap A5 × koef. angin tekan × beban angin

= 11,15 × 0,12 × 25 = 33,45 kg


= 5,575 × 0,12 × 25 = 16,725 kg


A

117


= 5,575 × ( 0,40) × 25 = - 55,75 kg


= 11,15 × ( 0,40) × 25 = - 111,5 kg


= 11,15 × ( 0,40) × 25 = - 111,5 kg


= 11,15 × ( 0,40) × 25 = - 111,5 kg

e. W11 = luasan atap A2 × koef. angin tekan × beban angin

= 11,15 × ( 0,40) × 25 = - 111,5 kg


= 12,275 × ( 0,40) × 25 = - 122,75 kg

Tabel 3.24. Perhitungan Beban Angin pada Kuda-kuda Utama B

Beban

Angin

Beban

(kg)

Wx

W.Cos

(kg)

Input

SAP

2000

(kg)

Wy

W.Sin

(kg)

Input

SAP

2000

(kg)

W1 36,825 33,098 34 16,143 17

W2 33,45 30,064 31 14,664 15W3 33,45 30,064 31 14,664 15W4 33,45 30,064 31 14,664 15W5 33,45 30,064 31 14,664 15W6 16,725 15,032 16 7,332 8W7 -55,75 -50,108 -51 -24,439 -25W8 -111,5 -100,216 -101 -48,878 -49W9 -111,5 -100,216 -101 -48,878 -49W10 -111,5 -100,216 -101 -48,878 -49W11 -111,5 -100,216 -101 -48,878 -49W12 -122,75 -110,327 -111 -53,81 -54



A

118

Tabel 3.25. Rekapitulasi Gaya Batang Kuda-kuda Utama B

BatangKombinasi


1 15922,11 -2 16480,24 -3 16485,44 -4 14728,99 -5 12609,76 -6 12508,1 -7 14523,81 -8 16178,03 -9 16107,28 -10 15533,01 -11 - 18046,8112 - 18500,7413 - 16534,1114 - 14276,9415 - 11840,416 - 11900,3817 - 14340,2118 - 16596,3419 - 18561,0520 - 18139,2221 - 696,3922 939,89 -23 2249,54 -24 3414,34 -25 8272,69 -26 3281,25 -27 2158,08 -28 899,99 -29 - 679,3430 170,43 -31 - 2269,3132 - 3406,2433 - 3866,634 - 3652,3835 - 3235,3836 - 2135,4337 232,94 -

A

119

3.8.4 Perhitungan Profil Kuda-kuda Utama B


Pmaks = 16485,44 kg


Fnetto =

Fbruto = 1,15 × Fnetto = 1,15 × 10,303 = 11,848 cm2


F = 2 × 22,70 = 45,40 cm2



σ

σ ≤ 0,75σijin

427,194 kg/cm2 ≤ 1200 kg/cm2 ………. aman !!



A

120

Pmaks= 18561,05 kg

L = 2,23 mm = 223 cm


ix = 3,02 cm

F = 2 × 22,70 = 45,40 cm2

λ =

λg

= 111,016 cm

λs

Karena 0,25 < λs

< 1,2 maka :

ω

= 1,238


σ

A

121

σ ≤ σijin

506,457 kg/cm2 ≤ 1600 kg/cm2 ………. aman !!


3.8.5 Perhitungan Alat Sambung Kuda-kuda Utama B

a. Batang Tarik




= 19,05 + 1

= 20,05 mm



= 0,625 . 19,05

= 11,906 mm




= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

Kekuatan baut


A

122

= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg





3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

= 28,575 mm = 30 mm

A

123

b. Batang Tekan




= 19,05 + 1

= 20,05 mm



= 0,625 . 19,05

= 11,906 mm




= 0,6 . 1600

= 960 kg/cm2



= 1,5 . 1600

= 2400 kg/cm2

Kekuatan baut


= 2 . ¼ . π . (1,905)2 . 960

= 5469,666 kg


= 0,9 . 1,905 . 2400

= 4114,800 kg

A

124





3d ≤ S

2


dalam sambungan.

Diambil, S2

= 3 . db

= 3 . 19,05

= 47,625 mm = 40 mm

1,5d ≤ S

1

≤ (4t + 100 atau max. 200mm)

Diambil, S1

= 1,5 . db

= 1,5 . 19,05

= 28,575 mm = 20 mm

Tabel 3.26. Rekapitulasi Perencanaan Profil Kuda-kuda Utama BNomor


1 100.100.12 6 Ø ¾

A

125

2 100.100.12 6 Ø ¾3 100.100.12 6 Ø ¾4 100.100.12 6 Ø ¾5 100.100.12 6 Ø ¾6 100.100.12 6 Ø ¾7 100.100.12 6 Ø ¾8 100.100.12 6 Ø ¾9 100.100.12 6 Ø ¾10 100.100.12 6 Ø ¾11 100.100.12 6 Ø ¾12 100.100.12 6 Ø ¾13 100.100.12 6 Ø ¾14 100.100.12 6 Ø ¾15 100.100.12 6 Ø ¾16 100.100.12 6 Ø ¾17 100.100.12 6 Ø ¾18 100.100.12 6 Ø ¾19 100.100.12 6 Ø ¾20 100.100.12 6 Ø ¾21 100.100.12 6 Ø ¾22 100.100.12 6 Ø ¾23 100.100.12 6 Ø ¾24 100.100.12 6 Ø ¾25 100.100.12 6 Ø ¾26 100.100.12 6 Ø ¾27 100.100.12 6 Ø ¾28 100.100.12 6 Ø ¾29 100.100.12 6 Ø ¾30 100.100.12 6 Ø ¾31 100.100.12 6 Ø ¾32 100.100.12 6 Ø ¾33 100.100.12 6 Ø ¾34 100.100.12 6 Ø ¾35 100.100.12 6 Ø ¾36 100.100.12 6 Ø ¾37 100.100.12 6 Ø ¾

A

Bab 3 Perencanaan Atap

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