1. BEBAN RENCANA : Gaya Tekan Gaya Uplift Gaya lateral
68.26 59.50 4.35
Ton Ton Ton
2. DAYA DUKUNG PONDASI TIANG BOR: **** Daya Dukung Tekan Tiang Bor Tunggal: Qc
= (Nc*cu*Ab) + (ca*As) = (9*cu*Ab) + (a cu*As) Ket : cu = undrained shear strength pada ujung tiang bor = qc/15 ca = adhesi rata-rata sepanjang selimut tiang = a cu ult
(kg/cm2) (kg/cm2)
a = koefisien adhesi
cu = undrained shear strength rata-rata sepanjang selimut tiang
(kg/cm2)
Dari data sondir : 2 qc = 250 Kg/cm cu = qc/15 = 16.667 kg/cm2
, Pada Elevasi - 12.00
(pada ujung tiang)
2 qc = 20.0 Kg/cm , (rata-rata qc sepanjang tiang) (undrained shear strength rata-rata sepanjang tiang) cu = qc/15 = 1.33 kg/cm2 = 13.3 ton/m2 ( dari grafik a VS cu diperoleh a = 0.4
Dipakai : Tiang bor f 30 cm 2 Ab = 706.5 cm pf = 94.2 cm As = pf Lpile 2 = 98910 cm Qc
ult
Qc
all
= = = =
,
L
pile
=
10.50
)
m
(9*cu*Ab) + (a cu*As) 105975 + 52752 158727 kg 158.73 ton
= Qc ult/SF = Qc ult/2.5 = 63.491 ton
(tekan)
**** Daya Dukung Tarik Tiang Bor Tunggal: QT
ult
= (ca*As) = (a cu*As)
Ket :
ca = adhesi rata-rata sepanjang selimut tiang = a cu
(kg/cm2) a = koefisien adhesi cu = undraine shear strength rata-rata sepanjang selimut tiang (kg/cm2)
Dari data sondir : 2 qc = 20.0 Kg/cm cu = qc/15 = 1.33 = 13.3
(rata-rata qc sepanjang tiang)
(undrained shear strength rata-rata sepanjang tiang) kg/cm2 ton/m2 ( dari grafik a VS cu diperoleh a = 0.4
Dipakai : Tiang bor f 40 cm 2 Ab = 1256.0 cm pf = 125.6 cm As = pf Lpile 2 = 131880 cm QT
ult
QT
all
= (a cu*As) = 70336 kg = 70.34 ton = QT ult/SF = QT ult/3 = 23.445 ton
(tarik)
,
L
pile
=
10.50
m
)
**** Daya Dukung Lateral Tiang Bor Tunggal: Hall = ( k.f.da ) / b Ket :
Ha k f da
= = = =
Daya dukung mendatar yang diijinkan (kg) Koefisien reaksi lapisan tanah di bawah permukaan dalam arah lateral (Kg/cm3) Diameter tiang (cm) Besarnya pergeseran normal (cm)
b = 4 ( k.f )/4EI E = Modulus elastisitas bahan tiang (Kg/cm2) I = Momen Inersia penampang (cm4) I = 125600 fc'= 189 Ec = 204328 k = 0.50 da = 1.00 b = 0.003736
cm4 kg/cm2 kg/cm2 kg/cm3 cm
Hall = ( k. f. da ) / b = =
5353.2 Kg 5.00 Ton
(lateral)
Daya Dukung Bored pile Group : Jumlah Tiang bor (s) = 3 effisiensi group (x) = {16-(s-1)}/16 = 0.88 jarak antar tiang (m) = jarak ke tepi (n) = Lebar Pondasi (B) =
1.50 0.50 2.50
(Fled formula)
m
m
B
m m m
n Qcompr.total = s (x *Qcomp.tunggal) Qtension total = s (x *Qtension tunggal) Hall total = s (x *Hall)
=
166.66 Ton
=
61.54 Ton
=
13.13 Ton
m
n
3. KEAMANAN TERHADAP UPLIFT/TARIK : Volume Beton (Vb) = {(m+2n)*B*T} - {(msin60)*0.5m*T} + {C*C*(H-T)} 3 = 2.59 m Berat Beton (Wb) = Vb * 2.4 t/m3 = 6.23 Ton 0 Volume Tanah (Vs) = (Berbentuk limas terpancung terbalik dengan sudut 30 ) (D-T) 2 1 2 1 = [{B+( /cos30)} * /3*{(Bcos30)+(D-T)}] - [B * /3Bcos30] - [C*C*(D-T)] m3 = 10.63 Berat tanah (Ws) = Vs * 1.6 t/m3 = 17.00 Ton
Qtension
total
= s (x *Qtension tunggal) = 61.54 Ton (daya dukung tarik bored pile total)
Wtot = = Gaya Uplift =
Wb + Ws + Qtension 84.77 Ton
total
59.50 Ton
<
W
Total
=
84.77
Ton
… (OK)
4. KEAMANAN TERHADAP BEARING / TEKAN : P = Gaya Tekan + Berat Beton (Wb) = 74.49 Ton Qcompr.
total
= s (x *Qcomp.tunggal) = 166.66 Ton (daya dukung tekan bored pile total)
P =
74.49 Ton
<
Qcompr.tot = 166.66 Ton
… (OK)
5. KEAMANAN TERHADAP SLIDING/GESER : d = Koefisien friksi = 0.45 H
all
=
13.13 Ton
(daya dukung lateral bored pile total)
P = Gaya Tekan + Berat Beton (Wb) = 74.49 Ton Gaya Lateral
=
SF
= =
sliding
4.35 Ton (P*d + H all )
/
Lateral
10.72
>
1.5
(OK)
6. PENULANGAN : Mutu Beton : fc' = 18.9 Mpa
(K-225)
Mutu Tulangan : fy = 400 Mpa fys = 240 Mpa
(BJTD40) (BJTP24)
D > 13mm f < 13mm
A. PEDESTAL faktor beban = 1.3 P
tot
= Gaya Tekan + Berat Pedestal = 69.42 Ton
Gaya Tarik =
59.50 Ton
Momen = Lateral*(H-T) = 6.96 Ton.m
Pu = 1.3* Ptot =
90.25
Ton
Tu = 1.3* tarik =
77.35
Ton
Mu = 1.3* Momen =
9.05
Ton.m
Penulangan Utama: C
- Akibat Tekan: C
Pu = 90.25 Ton Pu = f 0.8*(0.85fc'*(Ag-As) + As*fy) {Pu/(0.65*0.8)}-0.85fc'Ag fy - 0.85fc' 2 = -81.37 cm
As = C = 0.55 m Ag = C*C = 0.3025 m2 2 = 3025 cm
As1 - Akibat Tarik:
Tu = Tu =
Asmin = 1%* Ag Asmin =
As =
2 30.25 cm
As2 = - Akibat Momen (bolak-balik): Mu = 9.05
77.35
Ton
f As*fy (Tu/0.7) fy 27.63
cm2
Ton.m
Mu = f Asfy (d-1/2a) Mu = 0.8 Asfy (d-1/2a) Mu = 0.8 Asfy (d-(Asfy/1.7fc'b)) As = Mu /{0.8fy (d-(Asfy/1.7fc'b))} 2 11.64 cm
As3 =
, dimana
a= Asfy/0.85fc'b
As As
Perlu
Perlu
= (
= Max( As min, As1, As2, As3) 2 30.25 cm , digunakan besi : 16 D16 )
D
16
DIAGRAM INTERAKSI PEDESTAL 400
200
100
f Pn
(Ton)
300
0 0
5
10
15
20
25
30
-100
-200
f Mn
(Ton.m)
Penulangan Sengkang: Gaya Lateral =
4.35
Ton
Vu = 1.3* tekan =
5.66
Ton
1.57
cm2
Vc = 1/6 fc'1/2 bd = 19.93 Ton Vs = Vu/f - Vc = -12.39 Ton
(Sengkang minimum) f 10 mm
Dicoba : smin < <
, f = 0.75
Av*fys
/3b
22.84 cm
smin < 1/2 C < 27.50 Sengkang dipakai :
cm f 10 -150
…… Av = 2.1/4. p f2 =
35
B. PELAT PONDASI/PILE CAP C
T B
Lebar Pondasi (B) = 2.50 m Tebal Pondasi (T) = 0.40 m Tebal efektif (d) = T - (selimut beton T= 7cm) = 0.33 m = 33 cm Pedestal (C) = 55 cm Analisa Geser Pons: Teg. geser beton 2 arah :
vc
1
= /3 fc'
= =
1/2
1.449 14.49
MPa Kg/cm2
Luas bidang Geser Pons = 4*(C+d)*d 2 11616 cm
= kuat geser beton : Vc =
= P
tot
vc
*4*(C+d)*d 168332 Kg
= Gaya Tekan + Berat Pedestal = 69.42 Ton
Syarat : Pu
Pu < f Vc Pu < 0.75Vc = 90248 kg
Pu = 1.3* Ptot = =
f Vc
<
=
90.25 90248
126249 Kg
Ton kg
(OK)
Penulangan pile cap: P
tot
=
Luas pile cap (A) =
69.42 Ton 2 4.30 m 2 16.14 Ton/m
qmax = Ptot/A =
qu = 1.3*qmax * B qu = 52.45 Ton/m
faktor beban = 1.3
Mu = 1/2*qu*(1/2B -1/2C)2 Mu = 24.93 Ton.m =
2493086.2 Kg.cm
Mu = f Asfy (d-1/2a) Mu = 0.8 Asfy (d-1/2a)
, dimana
a= Asfy/0.85fc'b
Mu = 0.8 Asfy (d-(Asfy/1.7fc'b)) As = Mu /{0.8fy (d-(Asfy/1.7fc'b))} 2 As = 24.58 cm As
min
= rmin*B*d =
As
perlu
=
16.50 2
24.58 cm (16 D16 - 150 )
, rmin = cm2 ,
0.002
digunakan besi :
D
16
C. TIE BEAM 30 cm
50 cm L
L
tiebeam
=
584.00 cm
Beban tetap : 3 qbalok = b*h* 2400kg/m = 360 kg/m qhidup = 250 kg/m 3 qtanah = b * kedalaman tiebeam * 1600kg/m = 240 kg/m q tot = q balok+qhidup+qtanah = 850 kg/m faktor beban = 1.3 qu = 1.3*qtot Mu = 1/12*qu*L2 = 1105 kg/m = 3140.557 kg.m Penulangan Utama: - Akibat Momen: Mu = f Asfy (d-1/2a) Mu = 0.8 Asfy (d-1/2a)
, dimana
a= Asfy/0.85fc'b
Mu = 0.8 Asfy (d-(Asfy/1.7fc'b)) As = Mu /{0.8fy (d-(Asfy/1.7fc'b))} 2 2.23 cm
As1 =
- Akibat Tarik: Tu = f As*fy
As
As
min
perlu
As =
(Tu/0.7) fy
As2 =
2.44
= rmin*b*d =
4.73
= ( ( (
4.73 3 D16 3 D16 2 D16
, Tu = 10% Gaya Tekan = 6.826 Ton
cm2
, rmin = cm2
1.4/fy = 0.0035
cm2 ) ) )
,
digunakan besi :
D
16
Tul. Atas Tul. Bawah Tul. Pinggang
Penulangan Sengkang: Vu = 1/2 qu L = 3.23 Ton Vc = 1/6 fc'1/2 bd = 9.78 Ton Vs = Vu/f - Vc = -5.48 Ton Dicoba :
(Sengkang minimum) f 10 mm
Av*fys
smin < /3b < 41.87 cm smin < 1/2 h < 25.00 cm Sengkang dipakai :
f 10 -200
…… Av = 2.1/4. p f2 =
1.57
cm2
D. BORED PILE faktor beban = 1.3 Tekan (P
Tarik (T
1 bored pile)
= (Gaya Tekan + Berat beton) / 3 = 24.83 Ton
1 bored pile)
=
19.83 Ton
Pu = 1.3* P =
32.28
Ton
Tu = 1.3* tarik =
25.78
Ton
Penulangan Utama:
- Akibat Tekan: D
Pu = 32.28 Ton Pu = f 0.8*(0.85fc'*(Ag-As) + As*fy) {Pu/(0.65*0.8)}-0.85fc'Ag fy - 0.85fc' 2 = -36.39 cm
As = f =
0.40 m
As1
Ag = 1/4 p f2 = 0.1256 m2 2 = 1256 cm
- Akibat Tarik: Tu = Tu =
Asmin = 1%* Ag Asmin =
As =
2 12.56 cm
As2 = As As
Perlu
= (
= Max( As cm2 )
Perlu
min,
25.78
Ton
f As*fy (Tu/0.7) fy cm2
9.21
As1, As2) ,
12.56 7 D16
digunakan besi :
D
16
Penulangan Sengkang: Lateral (H
1 bored pile)
=
1.45
Ton
Vu = 1.3* tekan =
1.89
Vc = 1/6 fc'1/2 bd = 10.14 Ton Vs = Vu/f - Vc = -7.63 Ton
