Tugas Besar
Struktur Bangunan Beton
BAB III
PERENCANAAN PELAT LANTAI DAN ATAP
PERENCANAAN DAN PERHITUNGAN PELAT
PEMBEBANAN PADA PELAT
Pelat Atap
Beban mati
Berat sendiri = 0.12 m x 2400 kg/m3 =288 kg/m2
Berat Plafond + Rangka =7 kg/m2 + 11 kg/m2 =18 kg/m2
Berat Sanitasi & Plumbing =20 kg/m2 x 10 kg/m2 =30kg/m2
Berat finishing (1cm) =21kg/m2
Pd total=357kg/m2
Beban hidup
Berat Hidup Atap PL= 287kg/m2
Kombinasi beban =1.2PD+1.6PL = 888kg/m2
Pelat Lantai
Berat Mati
Berat sendiri = 0.12 m x 2400 kg/m3 =288 kg/m2
Berat Plafond + Rangka =7 kg/m2 + 11 kg/m2 =18 kg/m2
Berat Sanitasi & Plumbing =20 kg/m2 x 10 kg/m2 =30kg/m2
Berat finishing (2cm) =2 x 21 kg/m2 =42kg/m2
Berat Keramik =5kg/m2
Pdtotal=383 kg/m2
Berat hidup
Berat lantai PL=718 kg/m2
Kombinasi Beban=1.2Pd+1.6PL= 1609 kg/m2
PERHITUNGAN PELAT
DATA PELAT
Tebal Pelat atap = 0.12 m
Selimut Beton = 20 mm
Tulangan Rencana atap = 12 mm
Tulangan Rencana lantai = 16 mm
Mutu Baja(fy) = 350 Mpa =3500kg/cm2
Mutu Beton(fc) = 35 Mpa =350 kg/cm2
dx= 120 cm – 20 – 12/2 cm = 94 mm
dy =120cm– 20 – 12 – ½ (12 ) = 82 mm
PERHITUNGAN
Tahapan yang digunakan dalam menentukan tulangan lentur plat adalah sebagai berikut:
Menentukan data-data d, fy, fc', dan Mu
Menentukan batasan harga tulangan dengan menggunakan rasio tulangan yang disyaratkan sebagai berikut :
Hitung rasio tulangan yang dibutuhkan :
Menentukan luas tulangan (AS) dari ῤ yang didapat
β1 = 0,85 – 0,05 pasal 10.2.7.3 SNI 2847 2013
Fc=35 Mpa >28 maka β1 = 0,85 – 0,05= 0,85 – 0,05 = 0,8
ρbnce = = = 0,043
ρmax 0,75 x ρbalance = 0,75 x 0,043 = 0.032
min = = = 0.0043
Dalam perhitungan penulangan pelat jika Ly/Lx<2 lihat PBI 1971 tabel 13.3.2 maka di dapat rumus momen sebagai berikut:
Mlx = 0.001 . qu . Lx2 . X
Mtx = -0.001 . qu . Lx2 . X
Mly = 0.001 . qu . Lx2 . X
Mty = -0.001 . qu . Lx2 . X
Mlx = momen lentur pelat per satuan panjang di lapangan di arah bentang lx.
Mly = momen lentur pelat per satuan panjang di lapangan di arah bentang ly.
Mtx = momen lentur pelat per satuan panjang di tumpuan di arah bentang lx.
Mty = momen lentur pelat per satuan panjang di tumpuan di arah bentang ly.
12
1
2
PELAT ATAP TYPE 1 UKURAN (4 m x 6 m)
Lx = 360 cmLy = 565 cm 40/60
Lx = 360 cm
Ly = 565 cm
35/50 35/50
40/60
Ly= 600-2(30/2)=565 cm
Lx=400-2(40/2)=360 cm
PBI 1971 tabel 13.3.2 didapat persamaan momen sebagai berikut : (Iy/Ix = 1,6)( b=1000mm)
Mlx nilai X = 37
Mtx nilai X = 79
Mly nilai X = 16
Mty nilai X = 57
Mlx = 0.001 . qu . Lx2 . X = 0.001 x 888 x 3,62 x 37 = 426 kgm
Mtx = -0.001 . qu . Lx2 . X = -0.001 x 888 x 3,62 x 79 = - 910 kgm (+)
Mly = 0.001 . qu . Lx2 . X = 0.001 x 888 x 3,62 x 16 = 185kgm
Mty = -0.001 . qu . Lx2 . X = -0.001 x 888 x 3,62 x 57 = - 656 kgm (+)
Momen arah x
Mnx = = = 1138 kgm
Rn = = = 128734 =1,3 N/mm2 = 1,3 Mpa
perlu = = = 0,0038
Asperlu = . b . dx..
= 0,0043 x 1000 x 94
= 405 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12 mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Momen arah y
Mny = = = 820 kgm
Rn = = = 121951 =1.2 N/mm2 = 1.2 Mpa
perlu = = = 0,0036
Asperlu = . b . dy.
= 0,0043 x 1000 x 82
= 353 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12 mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
PELAT ATAP TYPE 2 UKURAN (4 m x 3.5 m)
Ly = 360 cmLy = 320 cm40/60
Ly = 360 cm
Ly = 320 cm
35/40 25/35
40/60
Lx= 350-(35/2)-(25/2)=320 cm
Ly=400-2(40/2)=360 cm
persamaan momen sebagai berikut : (Iy/Ix = 1.2)(b=1000mm)
Mlx nilai X =28
Mtx nilai X = 64
Mly nilai X =20
Mty nilai X = 36
Mlx = 0.001 . qu . Lx2 . X = 0.001 x 888 x 3,22 x 28 = 255kgm
Mtx = -0.001 . qu . Lx2 . X = -0.001 x 888 x 3,22 x 64 = - 582 kgm (+)
Mly = 0.001 . qu . Lx2 . X = 0.001 x 888 x 3,22 x 20 = 182 kgm
Mty = -0.001 . qu . Lx2 . X = -0.001 x 888 x 3,22 x 36 = - 328 kgm (+)
Momen arah x
Mnx = = = 685 kgm
Rn = = = 77490 =0,8 N/mm2 = 0,8 Mpa
perlu = = = 0,0023
Asperlu = . b . dx..
= 0,0043 x 1000 x 94
= 405 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12 mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Momen arah y
Mny = = = 386 kgm
Rn = = = 57406 =0,6 N/mm2 = 0,6 Mpa
perlu = = = 0,0017
Asperlu = . b . dy
= 0,0043 x 1000 x 82
= 353 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12 mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
PELAT LANTAI TYPE 1 UKURAN (4 m x 6 m)
Lx = 360 cmLy = 565 cm 40/60
Lx = 360 cm
Ly = 565 cm
35/50 35/40
40/60
Ly= 600-2(35/2)=565 cm
Lx=400-2(40/2)=360 cm
PBI 1971 tabel 13.3.2 didapat persamaan momen sebagai berikut : (Iy/Ix = 1,6)( b=1000mm)
Mlx nilai X = 37
Mtx nilai X = 79
Mly nilai X = 16
Mty nilai X = 57
Mlx = 0.001 . qu . Lx2 . X = 0.001 x 1609x 3,62 x 37 = 772 kgm
Mtx = -0.001 . qu . Lx2 . X = -0.001 x1609 x 3,62 x 79 = - 1648 kgm (+)
Mly = 0.001 . qu . Lx2 . X = 0.001 x 1609x 3,62 x 16 = 334 kgm
Mty = -0.001 . qu . Lx2 . X = -0.001 x 1609 x 3,62 x 57 = - 1189kgm (+)
Momen arah x
Lapangan
Mnx = = = 965 kgm
Rn = = = 109212 =1,1N/mm2 = 1,1 Mpa
perlu = = = 0,0032
Asperlu = . b . dx..
= 0,0043 x 1000 x 94
= 405 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Tumpuan
Mnx = = = 2060 kgm
Rn = = = 233137 =2,3 N/mm2 = 2,3 Mpa
perlu = = = 0,007
Asperlu = . b . dx..
= 0,007 x 1000 x 94
= 658 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 678 mm2)
Momen arah y
Lapangan
Mnx = = = 418 kgm
Rn = = = 62281 =0,6N/mm2 = 0,6 Mpa
perlu = = = 0,0017
Asperlu = . b . dx..
= 0,0043 x 1000 x 82
= 352 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Tumpuan
Mny = = = 1487 kgm
Rn = = = 221314 =2,2 N/mm2 = 2,2 Mpa
perlu = = = 0,0066
Asperlu = . b . dy
= 0,0066 x 1000 x 82
= 539 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 565 mm2)
PELAT LANTAI TYPE 2 UKURAN (4 m x 3.5 m)
Ly = 360 cmLx =320cm40/60
Ly = 360 cm
Lx =320cm
35/50 35/35
40/60
Lx= 350 - (35/2) - (25/2) =320 cm
Ly=400-2(40/2)=360 cm
persamaan momen sebagai berikut : (Iy/Ix = 1.2)(b=1000mm)
Mlx nilai X = 23
Mtx nilai X = 64
Mly nilai X = 20
Mty nilai X = 56
Mlx = 0.001 . qu . Lx2 . X = 0.001 x 1609 x 3,22 x 23 = 378 kgm
Mtx = -0.001 . qu . Lx2 . X = -0.001 x 1609x 3,22 x 64 = - 1055kgm (+)
Mly = 0.001 . qu . Lx2 . X = 0.001 x 1609x 3,22 x 20 = 330 kgm
Mty = -0.001 . qu . Lx2 . X = -0.001 x 1609x 3,22 x 56 = - 923 kgm (+)
Momen arah x
Lapangan
Mnx = = = 445 kgm
Rn = = = 50551 =0.5 N/mm2 = 0.5 Mpa
perlu = = = 0,0015
Asperlu = . b . dx..
= 0,0043 x 1000 x 94
= 405mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Tumpuan
Mnx = = = 1242 kgm
Rn = = = 140517 =1,4 N/mm2 = 1,4 Mpa
perlu = = = 0,0041
Asperlu = . b . dx..
= 0,0043 x 1000 x 94
= 405mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Momen arah y
Lapangan
Mnx = = = 488 kgm
Rn = = =57715 =0,6N/mm2 = 0,6 Mpa
perlu = = = 0,0025
Asperlu = . b . dx..
= 0,0043 x 1000 x 82
= 386mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
Tumpuan
Mny = = = 1085 kgm
Rn = = = 161493 =1,6 N/mm2 = 1,6 Mpa
perlu = = = 0,0047
Asperlu = . b . dy
= 0,0047 x 1000 x 82
= 384 mm2
Smax = 300(280/(2/3 x fy))=250 mm
Jika dipakai tulangan 12mm, As = 0,25 x 3,14 x 122 = 113 mm2
Dipasang tulangan lentur 12-250 mm (As pakai 452 mm2)
