11. perencanaan abutment
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PERENCANAAN ABUTMENT
Sketsa penampang abutmentAbutment direncanakan dibangun pada kedalaman 11,5 meter dari tanah dasar.a. Data tanah : = 1249 kg/m3 = 32,211o c= 0 w= 1000 kg/m3
b. Data lain : Bentang jembatan= 35 m Lebar jembatan = 12,2 mc. Data bahan struktur : Mutu beton= K-350 fc= 29,05 Mpa Mutu baja = U-39 fy= 390Mpa
d. Pembebanan :1. Beban struktur atasBeban dari struktur atas diambil dari reaksi pada rangka jembatan.P = 237648 kg2. Beban horizontal arah memanjangBeban horizontal memanjang diambil dari beban akibat rem pada gelagar memanjang.H = 648 kg3. Beban akibat berat sendiri dari abutment, berat tanah dan plat injak.
GayaBerat isibhlebarFaktorGaya
(kg/m)(m)(m)(m)bentuk(kg)
q224001.30.211624
W124000.80.214.215112
W224001.3214.2185200
W324002.0114.2168160
W424000.70.514.20.55964
W524002.30.514.2139192
W624000.30.514.20.52130
W724002.86.514.21609180
W824005.31.514.21270936
T112490.81.812.2121942.43
T212490.70.512.20.52666.62
T312491.56.512.21148568.55
T412491.51.012.2122856.7
S124003.20.2111536
S224003.28.81167584
S324003.22.510.59600
4. Beban akibat tekanan tanah.
Beban q kendaraan dibelakang bangunan penahan tanah diperhitungkan senilai muatan tanah setinggi 60 cm. (Bambang Supriadi, 2007. hal:42)q= 0,6 x 1249 kg/m2= 749,4 kg/m2
NotasiBerat isiByhFaktorGaya
(kg/m)(m)(m)bentuk(kg)
P1124914.211.30.5344909.71
P2749.414.2113241.38
H648
e. Perhitungan stabilitas abutment :1. Tabel momen akibat gaya vertikalGayaBerat isiBhByFaktorGaya vertikalLengan keMomen
(kg/m)(m)(m)(m)bentuk(kg)titik O (m)(kgm)
q224001.30.211624.005.303307.20
W124000.80.214.215112.003.6318531.00
W224001.3214.2185200.003.75319500.00
W324002.0114.2168160.002.25153360.00
W424000.70.514.20.55964.004.0324034.92
W524002.30.514.2139192.002.65103858.80
W624000.30.514.20.52130.001.382928.75
W724002.86.514.21609180.002.651614327.00
W824005.31.514.21270936.002.65717980.40
T112490.81.812.2121942.434.90107517.92
T212490.70.512.20.52666.624.0310754.46
T312491.56.512.21148568.554.45661130.05
T412491.5112.2122856.700.7517142.53
S124003.20.2111536.006.409830.40
S224003.28.81167584.006.40432537.60
S324003.22.510.59600.006.0357916.80
P2376482.25534708.00
JumlahMr4789365.82
2. Tabel momen akibat gaya horizontalGayaGaya horizontalLengan keMomen
(kg)titik O (m)(kgm)
P1344909.713.771299159.89
P23241.3810.8035006.89
H648.0013.308618.40
JumlahMg1342785.18
3. Kontrol stabilitas abutment terhadap gulingMomen penahan guling (Mr)= 4789365.82 kgmMomen penyebab guling (Mg)= 1342785.18 kgmAngka keamanan (SF)= 2,5
= 3,57 > 2,5OK!!
4. Kontrol stabilitas abutment terhadap gesertan = tan 32,211o= 0,63V= 1598900,3 kgH= 348799,09 kgc = 0A= 14.2 m x 5,3 m= 75 m2
= 2,88 > 2,5OK!!
5. Kontrol stabilitas abutment terhadap gaya dukung tanah Kasus 1 jika maka, Kasus 2 jika maka, dimana : dengan M = Mr - Mg= - = 3446580,64 kgmV= 1598900,3 kgL= 5,3 m
=0,494 < 0,88 Kasus 1diketahui := 1249 kg/m3Nc= 36,12= 32,211oNq=23,76c= 0N=22,84w= 1000 kg/m3SF= 2,5D= 11.5 mTegangan ijin tanah (fijin) =
= 432301,78 kg/m = 43,23 kg/cm
=33241,1 kg/m = 3,32411 kg/cm< 17,3 kg/cmOK!!
= 9396,3 kg/m = 0,93963 kg/cm< 17,3 kg/cmOK!!
f. Penulangan abutment :1. Bagian I
GayaBerat isibhPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
W124000.750.2115112.000.381917.00
W224001.2521185200.000.6353250.00
W424000.70.510.55964.000.784671.80
T112490.81.81121942.431.6536205.01
T212490.70.510.52666.620.782088.85
Jumlah120885.0598132.66
GayaBerat isibhPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
H6483.8-2462.40
P112490.31.810.5616.320.60-369.79
P2749.40.3111.0228.271.30-296.75
Jumlah1369.58-2661.54
95002.73
Penulangan :Mu= 95002.73 kgmPu= 120885.05 kgfc= 29,05 MPafy= 390 Mpah= 2000 mmb= 1250 mmd= 1000 100 = 900 mm
Diasumsikan sebagai balok :
= 0,0245
= 1,17 MPa
= 15,79
= 0,00031dipakai = 0,0036Kebutuhan tulangan:As = b d = 0,0036 x 1250 x 1000= 45 cm2As = 0,5 As = 0,5 x 45= 22,5 cm2Dari tabel digunakan :Tulangan tekan= 6 D32, As = 47,70 cm2Tulangan tarik = 6 D25, As = 30,40 cm2
Penulangan Geser :Vu= 120885.05 kgVu= 1,6 x 120885.05= 193416,08 kg= 0,6
= 2133464,55 N = 213346,455 kg
Sehingga,Vu< Vchanya perlu tulangan geser praktis 10 - 200.
2. Bagian II
GayaBerat isibHPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
W124000.750.21151122.1310863.00
W224001.25211852002.38202350.00
W324002111681600.7551120.00
W424000.70.510.559642.5315108.80
W524002.30.511391921.1545070.80
W624000.250.510.521300.08177.50
W724002.37.5116091801.15700557.00
T112490.81.81121942.4323.4074604.27
T212490.70.510.52666.6152.536755.42
T312491.57.511171425.253.05522847.01
T412491.511122856.70.7517142.53
Jumlah1032323.001582069.83
GayaBerat isibHPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
H648.0011.8-7646.40
P112490.39.810.518268.903.27-59678.40
P2749.40.3111.0228.279.30-2122.87
Jumlah19145.16-69447.67
1512622.16
Penulangan :Mu= 1512622,16 kgmPu= 1032323 kgfc= 29,05 MPafy= 390 Mpah= 1000 mmb= 2300 mmd= 1000 100 = 900 mm
Pemeriksaan eksentrisitas kolom :
emin= 0,1 x h = 0,1 x 1000= 100 mme > emin kolom dengan beban eksentrisRasio tulangan Ast = 1% 4 sisiAs = As = 0,0025 x b x d= 0,0025 x 230 cm x 100 cm = 57,5 cm2Tulangan tarik = 8 D32 = 63,5 cm2Tulangan tekan = 8 D32 = 63,5 cm2
Cek Keadaan Seimbang
cb = = 545,45 mmab = 0,85 x cb = 0,85 x 545,45 = 463,63 mm
Es= = 0,0002Fs= 0,0002 x 2000000 = 400 > fy ( Tulangan tekan sudah leleh )Pnb = 0,85 x fc x ab x b= 0,85 x 29,05 x 463,63 x 2300 x 10-1 = 1726685,62 kgPnb = 0,65 x 1726685,62 kg= 1036011,4 kg > Pu = 1032323 kg.... OK!
Cek Penampang Kolom = 146,53 cm
e = e + = 146,53 cm + = 186,53 cm
m = = 15,8
= = 0,0031
1 - = 1,07
1 - = 0,88
Pn = 0,85 x fc x b x d x = 10966289 kgPn = 0,65 x 10966289 kg= 7128087,8 kg > Pu = 1032323 kg .... OK!
Penulangan geserNu= 1032323 kgb= 2300 mmFy= 390 Mpah= 1000 mmFc= 29,05 Mpad= 900 mm = 0,6Vc= . b. d= . 2300. 900= 2521866,2 NVn= Vu/0,6= 1032323/0,6= 1720538,333 NSehingga,Vu< Vchanya perlu tulangan geser praktis 10 - 200.3. Bagian III
GayaBerat isibhPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
W124000.80.21151120.995048.10
W224001.32.011852001.23104370.00
W324002.01.011681600.40-27264.00
W424000.70.510.559641.388250.20
W524002.30.511391920.000.00
W624000.30.510.521301.23-2627.00
W724002.37.5116091800.000.00
W824005.31.5112709360.000.00
T112490.81.81121942.4322.2549370.47
T212490.70.510.52666.6151.383688.82
T312491.57.511171425.251.90325707.98
T412491.51.01122856.71.90-43427.73
Jumlah1304765.00423116.83
GayaBerat isibhPiasFaktorGaya VertikalLengan keMomen
(kg/m)(m)(m)bentuk(kg)titik O (m)(kgm)
H648.0013.3-8618.40
P112490.311.310.524289.423.77-91490.13
P2749.40.3111228.2710.80-2465.27
Jumlah25165.68-102573.81
320543.03
Penulangan :Mu= 320543,03 kgmPu= 1304765 kgfc= 29,05 MPafy= 390 Mpah= 1500 mmb= 1000 mmd= 1500 100 = 1400 mm
Tegangan yang terjadi di luar abutment :
fmaks = 172,46 kg/cm2fmin = 1,51 kg/cm2
x = 4,6 mm530 x = 525,41 mm
x = 78,92 kg/cm2
Mn= ( x 93,54 x 2,404322 ) + ( x 78,92 x 2/3 x 2,4044322)= 4224482,21 kgmMu = 1,4 x 4224482,21= 5914275,01 kgm
= 0,0245
= 0,38 MPa
= 15,79
= 0,000975dipakai min = 0,0035
Kebutuhan tulangan tiap 1 m lebar :As = min b d = 0,0035 x 1000 x 1400= 49 cm2As = 0,2 As = 0,5 x 49= 24,5 cm2Dari tabel digunakan :Tulangan utama = D29 100, As = 64,2 cm2Tulangan bagi = D29 200, As = 35,7 cm2