The document provides calculations for the boiler foundation of a daerator (38-D-101) as part of the Cilacap Crude Oil Tank project in Cilacap, Central Java, Indonesia. It includes modeling of the structure, material properties, load assumptions including dead load, live load, wind load, and seismic load. Load combinations are considered for analysis. Reinforcement design is also addressed. The calculations are performed according to various codes and standards for concrete and steel structures.

1. PERTAMINA UP. IV CILACAP REKAYASA BARATA
LEMBAR PERHITUNGAN BOILER FOUNDATION
(DAERATOR 38-D-101)
PROYEK : CILACAP CRUDE OIL TANK
KLIEN : PERTAMINA UP IV CILACAP
LOKASI : CILACAP, JAWA TENGAH
NO. DOK. REK : CCT–00–A0–CS–005R
NO. DOK. PTM : 242–C-420-010
NO. PEK. : 07-1701
1 RE-ISSUED FOR APPROVAL
0 ISSUED FOR APPROVAL 6/09/ 2007 HYT/GS NIEL/AV SR
REV URAIAN TANGGAL DIBUAT DIPERIKSA DISETUJUI
PT. Rekayasa Industri

2. PEK. NO.: 07-1701 REV
LEMBAR PERHITUNGAN BOILER FOUNDATION 1
NO. DOK. PTM : 242–C-420-010
(DAERATOR 38-D-101) NO. DOK. REK : CCT-00-A0-CS-010 R
TANGGAL OLEH DIPRS DISTJ
10 Mar 08
LEMBAR RIWAYAT REVISI
No. Rev Tanggal Uraian
0 27 Agustus 2007 ISSUED FOR APPROVAL
1 10 Maret 2008 RE-ISSUED FOR APPROVAL
DAFTAR DISTRIBUSI
Internal Engineering (by EDO): Internal REKAYASA (by EDO): External CONTRACTOR (by Transmittal)
Civil Lead Eng. 1 Copy Project Manager 1 Copy Pertamina UP-IV 1 Copy
Electrical Lead Eng. 1 Copy Deputy Project Manager 1 Copy For Approval
Instrument Lead Eng. 1 Copy Procurement Manager 1 Copy For Review
Mechanical Lead Eng. 1 Copy Project Control Manager 1 Copy For Info.
Piping Lead Eng. 1 Copy Construction Manager 1 Copy
Process Lead Eng. 1 Copy QA/QC Manager 1 Copy
Engineering Manager 1 Copy
PT. Rekayasa Industri

3. DAFTAR ISI
1. UMUM
1.1 Gambaran Struktur 3
1.2 Desain Filosofi 3
1.3 Satuan Ukuran 3
1.4 Program Komputer yang digunakan dalam Analisa Desain 3
1.5 Code dan Standar
1.5.1 Code & Standar Umum 3
1.5.2 Code & Standar Khusus 3
1.6 Material yang digunakan dan tegangan ijin 4
2. PEMODELAN
2.1 Model struktur & perspektif 5
2.2 Properti & Panjang Batang Struktur 6
2.3 Penomoran Batang 7
3. DATA PEMBEBANAN
3.1 Beban Mati (Dead Load) 8
3.2 Beban Hidup (Live Load) 8
3.3 Beban Equipment (Equipment Load) 8
3.4 Beban Angin (Wind Load) 8
3.5 Beban Gempa (Seimic Load) 10
3.6 Kombinasi Pembebanan 13
4. DESAIN ANALISA
4.1 Desain Baja 13
5. DESAIN PONDASI
5.1 Pemeriksaan Reaksi Tiang Terhadap Kapasitas Tiang Pancang 14
5.2 Penulangan 19
LAMPIRAN
- Gambar
- Data Equipment
Page 2

4. 1. UMUM
1.1 GAMBARAN STRUKTUR
Proyek : CILACAP CRUDE OIL TANK
Klien : PT. PERTAMINA
Lokasi : Cilacap, Central Java
Fasilitas : Platform Deaerator
Jenis Struktur : - Struktur beton bertulang untuk pondasi
- Struktur baja untuk plat form
1.2 DESAIN FILOSOFI
Tujuan dari perhitungan ini untuk melakukan verifikasi integritas struktural, kekuatan, dan
stabilitas.
Karena baja dan beton yang digunakan sebagai material, struktural desain disesuaikan dengan
working stress methode untuk struktur baja dari AISC dan the ultimate strength methode untuk
beton dari American Concrete Institute (ACI).
1.3 SATUAN PENGUKURAN
Satuan pengukuran dalam desain menggunakan metric system.
1.4 PROGRAM KOMPUTER YANG DIGUNAKAN DALAM DESAIN ANALISA
Program Komputer yang digunakan dalam desain analisa, adalah :
- Staad Pro
- Math Cad
- MS-Excel
1.5 CODE DAN STANDAR
1.5.1 Codes & Standar Umum
- ACI 318 - 2002
"American Concrete Institute"
Building Code Requirement for Structural Concrete
- ACI 315
"Standard Practice for Detailing Reinforced Concrete Reinforcement"
Page 3

5. - UBC 1997 Edition "Uniform Building Code"
- SNI-03-1727-1989
Tata cara perencanaan Pembebanan untuk bangunan gedung
- AISC 2005 ASD Series
Requirement for Steel Structure
1.5.2 Codes dan Standar Khusus
- Spesifikasi Perencanaan untuk Sipil dan Struktur
- Laporan Penyelidikan Tanah dan Studi Pondasi Untuk Pembangunan 2 (Dua) Tanki Crude
dan Perhitungan Pondasi Pompa 014P101/102 oleh PT SOFOCO
1.6 MATERIAL YANG DIGUNAKAN DAN TEGANGAN IJIN
−2
Kuat tekan beton : fc := 280 ⋅ kg ⋅ cm
−2
Tegangan leleh dari baja : fy := 4000 ⋅ kg ⋅ cm : (Ulir)
− 2 ( Polos)
fy1 := 2400 ⋅ kg ⋅ cm
−3
Berat unit beton : γc := 2400 ⋅ kg ⋅ m
−3
Berat unit baja : γs := 7850 ⋅ kg ⋅ m
−3
Berat unit tanah urug : γsoil := 1700 ⋅ kg ⋅ m
Daya dukung tanah
Dari laporan penyelidikan tanah
−2
Qall := 5 ⋅ tonne ⋅ m
Page 4

6. 2. PEMODELAN
2.1 MODEL STRUKTUR dan PERSPEKTIF
Page 5

7. 2.2 PROPERTY & PANJANG BATANG STRUKTUR
Page 6

8. 2.3 PENOMORAN BATANG
Page 7

9. 3. DATA PEMBEBANAN
3.1 BEBAN MATI (DL)
- DL beban sendiri --> by Staad Pro
- DL grating --> 35 kg/m2
- DL handrail --> 2x3.24 kg/m (pipa dia. 32 mm)
3.2 BEBAN HIDUP (LL)
- LL --> (265 kg/m2)
3.3 BEBAN EQUIPMENT (E)
Kondisi empty & operating(E1) E1 := 8.3325tonne
3.4 BEBAN ANGIN (W)
Beban angin harus dihitung sesuai dengan rumus yang diberikan didalam UBC 1997, chapter 16
P = Ce x Cq x qs x Iw
Dimana, Ce = koefisien gust factor berdasarkan ketinggian struktur berdasarkan
table 16-G UBC 1997
Cq = koefisien tekanan pada struktur berdasarkan tabel 16-H UBC 1997
Iw = faktor keutamaan struktur pada tabel 16-K UBC 1997
qs = tekanan angin pada standar ketinggian 33 feet berdasarkan table
16-F UBC 1997
W = Beban angin rencana (kg/m2)
Page 8

10. 904 914
1591
2810
1219
1219 3493
Luas area equipment ( X ) a1 := 1.219m ⋅ 2.81m
Luas area equipment ( Z ) a2 := ( 3.493m ⋅ 1.219 m ) + ( 1.591m ⋅ 0.914 m )
Jarak antara titik berat equipm. dg support Lev := 1200mm
Jarak antar support Lh := 2032mm
Jarak antar baut pada support Lb := 914mm
Ce := 1.24 Co := 1.37
−2
qs := 80 ⋅ kg ⋅ m Cq2 := 0.8
Cq1 := 1 Iw := 1.15
-2
W1 := Ce ⋅ qs ⋅ Cq1 ⋅ Iw W1 = 114.08 kg m ( diberikan pada struktur )
-2
W2 := Ce ⋅ qs ⋅ Cq2 ⋅ Iw W2 = 91.264 kg m
Untuk Vessel luas area dikalikan faktor pengali (Co)
Pw1h := W2 ⋅ a1 ⋅ Co Pw1h = 428.282 kg (X)
Mpw1h := Pw1h ⋅ Lev Mpw1h = 513.939 kg m
Mpw1h
Pw1v := Pw1v = 126.461 kg (X)
2 ⋅ Lh
Pw2h := W2 ⋅ a2 ⋅ Co Pw2h = 714.199 kg (Z)
Mpw2h := Pw2h ⋅ Lev Mpw2h = 857.038 kg m
Mpw2h
Pw2v := Pw2v = 468.839 kg (Z) ( diberikan pada support equipment )
2 ⋅ Lb
Page 9

11. Mpw1h Mpw2h
Pw1h Pw2h
Lev Lev
BY1 BY1 BY1
Lh Lb
Pw1h Pw1h Pw2h Pw2h
3.5 BEBAN GEMPA (V)
Beban gempa untuk setiap fasilitas harus dihitung berdasarkan rumus yang tercantum dalam UBC
1997, chapter 16
Total gaya geser dasar rencana ditentukan dengan rumus berikut :
V = Cv I W
RT
Total gaya geser dasar rencana tidak boleh lebih dari :
Vmax = 2.5 Ca I W
R
Total gaya geser dasar rencana tidak boleh kurang dari :
Vmin = 0.11 Ca I W
Dimana, V : Total gaya horizontal atau geser pada dasar
Ca : Koefisien gempa dasar, table 16-Q UBC 1997
Cv : Koefisien gempa dasar, table 16-R UBC 1997
I : Faktor keutamaan/importance factor, table 16-K UBC 1997
R : Numerical Coeffiicient yang mewakili kapasitas daktilitas dari
system yang menahan beban lateral, table 16-N & table 16-P
UBC 1997
T : Periode getar alami struktur
W : Total Beban mati, beban hidup yang dikurangi, beban pipa dan
beban mesin/peralatan
Page 10

12. Ketentuan yang berlaku untuk proyek ini adalah sebagai berikut :
1. Seismic Risk Zone 3 ( Z = 0.3)
2. Important factor I = 1.25 untuk semua struktur
3. Profile tanah adalah tipe tanah lunak (Soft Soil Profile SE, UBC 1997)
4. Periode Getar struktur, T dihitung berdasarkan rumus berikut :
T = Ct (hn)3/4
Dimana Ct = 0.0835 untuk steel moment resisting frames
Ct = 0.0731 untuk reinforced concrete moment resisting
frames dan eccentrically braced frames
Ct = 0.0488 untuk bangunan-bangunan lain
hn = ketinggian struktur yang ditinjau (m)
3
4
T := 0.0731 ⋅ 9.5 T = 0.396
Dari tabel UBC didapat :
I := 1.25 Cv := 0.84
Ca := 0.36 R := 5.6
Gaya geser yang diperoleh =
I I Vmin := 0.11 ⋅ Ca ⋅ I W
W
V := Cv ⋅ W Vmax := 4 ⋅ 2.5 ⋅ Ca ⋅
R ⋅T R
Vmax = 0.804 Vmin = 0.05 W
V = 0.474 W W
Karena V>Vmax maka V yang digunakan adalah V=0.201 W
Beban gempa akibat DL+0.5 LL dihitung dengan StaadPro dan didistribusikan ke sambungan kolom
dan beam
Beban gempa untuk equipment dihitung berdasarkan rumus dalam UBC 1997, chapter 1632
I ⎛ hx ⎞
Veh := ap ⋅ Ca ⋅ ⋅⎜1 + 3 Wed
R ⎝ hr ⎠
Page 11

13. Wed : Equipment weight
ap : Structure Component Amplification Factor, varies from 1~2.5
hx : element elevation respect to grade
hr : structure roof elevation respect to grade
Berdasar data yang diperoleh diambil :
ap := 2.5 (maksimum)
Wed := E1
hx := 9.5 ⋅ m
hr := 9.5m + 2.18m
I ⎛ hx ⎞
Veh := ap ⋅ Ca ⋅ ⋅⎜1 + 3 ⋅ Wed
R ⎝ hr ⎠
Berat Equipment Wed = 8.332 tonne
Beban gempa rencana Veh = 5758.467 kg ( diberikan pada support )
Mve1h := Veh ⋅ Lev Mve1h = 6910.161 kg m
Mve1h
Pw1v := Pw1v = 1700.335 kg (X)
2 ⋅ Lh
Mve1h
Pw2v := Pw2v = 3780.175 kg (Z)
2 ⋅ Lb
Mve1h Mve1h
Veh Veh
Lev Lev
BY1 BY1 BY1
Lh Lb
Pw1v Pw1v Pw2v Pw2v
Page 12

14. 3.6 KOMBINASI PEMBEBANAN
Untuk desain stabilitas pondasi dan Untuk desain penulangan
steel structure
1.4DL+1.4E(1)
DL+E(1)
0.9DL+0.9E(1)+1.3WX
0.75DL+0.75E(1)+0.75WX
0.9DL+0.9E(1)+1.3WZ
0.75DL+0.75E(1)+0.75WZ
0.9DL+0.9E(1)+1.43VX
0.75DL+0.75E(1)+0.75VX
0.9DL+0.9E(1)+1.43VZ
0.75DL+0.75E(1)+0.75VZ
1.4DL+1.4E(1)+1.7LL
DL+LL+E(1)
1.05DL+1.275LL+1.05E(1)+1.275WX
0.75DL+0.75LL+0.75E(1)+0.75WX
1.05DL+1.275LL+1.05E(1)+1.275WZ
0.75DL+0.75LL+0.75E(1)+0.75WZ
1.05DL+1.275LL+1.05E(1)+1.4VX
0.75DL+0.75LL+0.75E(1)+0.75VX
1.05DL+1.275LL+1.05E(1)+1.4VZ
0.75DL+0.75LL+0.75E(1)+0.75VZ
Page 13

15. 4 DESAIN ANALISA
4.1 DESAIN BAJA
Desain baja menggunakan analisa dengan STAADPro berdasar AISC Series
Hasil :
( 1.33) ⋅ 950 cm
- horisontal displ. maksimum = 1.5 cm (join 15)arah X < δall := δall = 6.317 cm ( ok)
200
( 1.33) ⋅ 270 cm
- vertikal displ. maksimum = 0.228 cm (join 17)arah X < δall := δall = 1.796 cm ( ok)
200
- rasio maksimum = 0.33 (member 1) >> kolom
0.332 (member 29)>>balok
0.741 (member 66)>>bracing
Page 14

16. 5. DESAIN PONDASI
Dimensi Pondasi :
Lebar pondasi : bf := 1.1m
Panjang pondasi : df := 1.1m
Panjang pedestal : bp := 0.45m
Lebar pedestal : dp := 0.30m
Tinggi pondasi : hf := 0.45m
Tinggi pedestal : hp := 0.6m
Tinggi tanah diatas pondasi : hs := 0.3m
Total tinggi pondasi : h := hf + hp h = 1.05 m
Lebar grade beam : bg := 250mm
Tinggi grade beam : dg := 450mm
Bentang grade beam : Lg1 := 4860mm
Lg2 := 2700mm
Berat pondasi : Wf := γc ⋅ ( bf ⋅ df ⋅ hf + bp ⋅ dp ⋅ hp) Wf = 1501.2 kg
Berat tanah diatas pondasi : Ws := γsoil ⋅ ( bf ⋅ df − bp ⋅ dp) ⋅ hs Ws = 548.25 kg
Berat grade beam : Wg := γc ⋅ bg ⋅ dg ⋅ 0.5 ⋅ ( Lg1 + Lg2) Wg = 1020.6 kg
Berat pondasi : D := Wf + Ws + Wg D = 3070.05 kg
bp
hp
bp hs
bg dp df
dg hf
bf
bf
Page 15

17. 5.1 Pemeriksaan Reaksi Tiang Terhadap Kapasitas Tiang Pancang
A. Pemeriksaan kapasitas axial
Gaya tekan yang diijinkan (Pall) :
Pall1 := 40tonne (dari data vendor)
Pall2 := 45tonne (dari laporan geoteknik)
Dipakai : Pall := min ( Pall1 , Pall2)
Gaya tekan maksimum : (dari output STAADPro untuk Load comb pondasi)
Fy := 4340kg
Total vertical load : VL := Fy + D VL = 7.41 tonne
⎛ VL ⎞
Jumlah tiang yg diperlukan : Σn := ⎜ Σn = 0.185
⎝ Pall ⎠
Jumlah pile yg diambil : Σn := 1
Dimensi tiang pancang ( triangular ) : S := 320 ⋅ mm
S
luas penampang pile Apl := ⋅ [ S ⋅ ( sin ( 60 ⋅ deg ) ) ]
2
4Apl
ekivalensi diameter Dia1 := Dia1 = 237.605 mm
π
⎛ S ⎞
⎜ 2
Dia2 := 2 ⎜
⎝ sin ( 60 ⋅ deg ) ⎠ Dia2 = 369.504 mm
Dia := max ( Dia1 , Dia2) Dia = 369.504 mm
Jarak minimum ke tepi pondasi : semin := 1.2 ⋅ Dia semin = 0.443 m
VL
Pv := Pv = 7.41 tonne
Σn
Status = "OK Pv<Pall"
Page 16

18. Gaya tarik yang diijinkan (Pall) :
Pall := 6.41tonne (dari data vendor)
Pall := 15tonne (dari laporan geoteknik)
Dipakai Pall:6.41tonne
Gaya tarik yang terjadi : (dari output STAADPro untuk Load comb pondasi)
Fyt := −1.285 ⋅ tonne
Pvt := D − Fy
Pvt = −1269.95 kg
Status = "OK Pvt<Pall"
B. Pemeriksaan Reaksi Tiang Terhadap Kapasitas Lateral
Diameter of pile : Dia = 369.504 mm
Jumlah total tiang : Σnt := 8
Gaya lateral yang diijinkan (Hall) :
Hall := 2.25tonne (dari laporan geoteknik)
Gaya lateral maksimum yang terjadi : (dari output STAADPro untuk Load comb pondasi)
Fz := 623kg
Hmax := Fz
Hmax = 0.623 tonne
Status = "OK Hmax<Hall"
Page 17

19. C. Pemeriksaan pile head treatment
Pile cut off harus berjarak 75 mm sampai 100 dari bawah pilecap (M.J. Tomlinson).
Panjang tendon/tulangan untuk menyatukan tiang dan pile cap untuk praktis digunakan
40d ( d = pc-wire diameter ).
pc wire
Pile beton yang dipotong
40d H = beban horisontal
h = 75 mm
Jarak PCO dari bawah pondasi d = 19 mm pco := 75mm
Dari data vendor d = 19 mm
Panjang pc wire = 40 x 19 = 760 mm
Check terhadap concrete bearing pressure
−2
Compressive concrete strength untuk pile cap : fc := 280 ⋅ kg ⋅ cm
−2
Allowable bearing pressure : fcb := 0.33 ⋅ fc fcb = 92.4 kg ⋅ cm
Bearing force : H/A < fcb
Dimana : A = bearing area = ( Dia x h )
Dia = diameter pile
Hmax = maximum horizontal load
h := 10cm
A := Dia ⋅ h
Hmax −2
= 1.686 kg ⋅ cm Hmax/A < fcb Status OK
A
Status = "OK Hmax/A < fc"
Page 18

20. 5.2 Penulangan
A Penulangan Pile cap
Pemodelan struktur dengan asumsi pile cap menahan beban axial
dp
GL
.
q
L
q
df
Beban aksial maksimum dari output Staadpro untuk load comb penulangan :
Fyr := 7356kg
1.4D + Fyr −1
Beban : qu := qu = 10.595 tonne ⋅ m
bf
L := 0.5 ⋅ ( df − dp)
Penulangan pile cap :
qu 2
Ultimate momen : Mult := ⋅L Mult = 0.848 tonne ⋅ m
2
Luas selimut beton dc := 7.5 ⋅ cm
1
Diameter tulangan rdia := 1.3 ⋅ cm Tinggi efektif d := hf − dc − ⋅ rdia
2
Beban per lebar pondasi df = 1.1 m d = 0.369 m
Page 19

21. Perhitungan :
ρmin := 0.0018
Mult −2
Rn := Rn = 0.63 kg cm
2
0.9 ⋅ df ⋅ d
0.85 ⋅ fc ⎛ 2 ⋅ Rn ⎞
ρ := ⋅⎜1 − 1− ρ = 0.00016
fy ⎝ 0.85 ⋅ fc ⎠
ρtop := ρmin if ρ ≤ ρmin
ρ if ρmin < ρ
ρtop = 0.0018
ρbot := ρtop
2
Asbot := ρbot ⋅ df ⋅ hf Asbot = 8.91 cm
Dicoba: D-13 @ 150
rd := 1.3cm s := 15cm
(
Asteel := 0.25 ⋅ π ⋅ rd ⋅
2 ) df
s
Asteel = 9.734 cm
2
Digunakan D-13 @ 150
Status = "Asteel > Asbot, Rebar . OK"
Page 20

22. B Punching Shear
Dia+d
Dia
d hf
pco
Tinggi pondasi : hf = 0.45 m
concrete cover : dc := 75 ⋅ mm
rebar dia: dr := 13 ⋅ mm
Tinggi Efektif : d := hf − pco d = 0.375 m
Vpu := ( 1.4)Pall
Punching shear : Vpu = 21 tonne
Vpu
Vpn := Vpn = 24.706 tonne
0.85
Perimeter length : bo := π ⋅ ( Dia + d) bo = 2.339 m
0.5 −1
Vpc := 1.06 ⋅ fc ⋅ bo ⋅ d ⋅ kg ⋅ cm Vpc = 155.573 tonne
Allowable Punching Shear :
Status = "Vpc > Vpn ----> PUNCHING SHEAR OK"
Page 21

23. C Penulangan Grade Beam
Panjang grade beam : Lgg := 4.86m
-1
Berat grade beam : Wgg := γc ⋅ bg ⋅ dg Wgg = 270 kg m
-1
Berat tanah diatas grade beam : Wsg := γsoil ⋅ bg ⋅ hs Wsg = 127.5 kg m
-1
Beban merata grade beam : qp := 1.4( Wgg + Wsg) qp = 556.5 kg m
1 2
Mg1 := ⋅ qp ⋅ Lgg Mg1 = 1095.359 kg m
12
Multg := Mg1
Multg = 1095.359 kg m
Luas selimut beton dc := 7.5 ⋅ cm Diameter tulangan rdia := 1.3 ⋅ cm
Beban per meter lebar bg = 0.25 m
1
Tinggi efektif d := dg − dc − ⋅ rdia d = 0.369 m
2
Perhitungan :
ρmin := 0.0035
Multg −2
Rn := Rn = 3.585 kg cm
2
0.9 ⋅ bg ⋅ d
0.85 ⋅ fc ⎛ 2 ⋅ Rn ⎞
ρ := ⋅⎜1 − 1− ρ = 0.0009
fy ⎝ 0.85 ⋅ fc ⎠
ρtop := ρmin if ρ ≤ ρmin
ρ if ρmin < ρ
ρtop = 0.0035
ρbot := ρtop
Page 22

24. 2
Asbot := ρbot ⋅ bg ⋅ d Asbot = 3.2244 cm
Dicoba: 3 D-13
n := 3
rd := 1.3cm
(
Asteel := 0.25 ⋅ π ⋅ rd ⋅ n
2 ) Asteel = 3.982 cm
2
Digunakan 3 D13 ( top & bottom )
Status = "Asteel > Asbot, Rebar . OK"
Tulangan geser
Kuat tekan beton : fc1 := 28 MPa
Tegangan leleh baja : fy1 := 240 MPa
Tulangan sengkang : rdg := 10mm
Tinggi efektif : d = 0.369 m
φs := 0.75
qp ⋅ Lgg
Vult := Vult = 1352.295 kg
2
Vult := 3895.5N
fc1
φVc := φs ⋅ ⋅ bg ⋅ d φVc = 60934.96 N
6
Status := "No Shear Reinforcement required" if Vult < 0.5 ⋅ φVc
"Only Minimum Shear Reinforcement" if 0.5 ⋅ φVc < Vult < φVc
"Shear Reinforcement Needed" if Vult > φVc
Status = "No Shear Reinforcement required"
d d
smax := if < 600mm smax = 184.25 mm
2 2
d
600mm if > 600mm
2
Digunakan
φ 10 @ 100 Pada ujung grade beam
φ 10 @ 150 Pada tengah grade beam
Page 23