KADAR AIR
( MOISTURE CONTENT )
MAKSUD :
Test ini dimaksudkan untuk menentukan kadar air sampel tanah yaitu perbandingan berat air yang terkandung dalam tanah dengan berat kering tanah tersebut.
PERALATAN :
Cawan kedap air (tin box)
Timbangan ketelitian 0,01 gram
Oven
Desicator
Ayakan
BAHAN UJI/MATERIAL :
Tanah
PROSEDUR PERCOBAAN :
Bersihkan tanah dari batu kecil/krikil dengan menggunakan ayakan.
Timbang tin box yang akan dipakai berikut tutupnya lalu diberi nomor/tanda.
Masukan tanah yang telah diayak ke dalam tin box tersebut lalu tutup.
Timbang tin box yang telah diisi tanah tersebut.
Masukkan kedalam oven yang suhunya telah diatur sebesar 110℃ selama 24 jam sehingga beratnya konstan (tutup tin box dibuka).
Setelah dikeringkan dalam oven, tin box tersebut lalu dimasukkan kedalam desicator agar cepat dingin.
Setelah dingin, timbang kembali tin box yang telah berisi tanah kering tersebut.
Catatan :
Berat tanah yang diuji dan neraca yang dipakai harus disesuaikan dengan butiran tanah maksimum agar didapatkan hasil yang teliti.
Ukuran butir maks. Berat tanah uji min. Ketelitian
- 3⁄4 " 1000 gram 1 gram
- # 10 100 gram 0.1 gram
- # 40 10 gram 0.01 gram
Jika tidak tersedia oven pengering, maka pengeringan dapat dilakukan dengan cara :
digoreng diatas kompor;
dibakar langsung setelah disiram dengan spiritus (khusus untuk tanah yang tidak mengandung bahan yang mudah terbakar);
Menggunakan speddy moisture content test.
Masing-masing tin box dan tutupnya harus diberi tanda yang jelas agar tidak tertukar.
Pada waktu menimbang, tutup tin box selalu terpasang.
Untuk mendapatkan hasil yang dapat dipercaya, setiap sampel tanah diuji sebanyak 3 kali.
PERAWATAN :
Bersihkan tin box kedap air segera setelah percobaan selesai.
Jemur silica gel yang berada dalam desicator secara berkala untuk menghilangkan air yang diserapnya.
LAPORAN
NOMOR CONTOH DAN KEDALAMAN
A NOMOR TIN BOX I II III
B BERAT TIN BOX (gr) 12.2 12.2 12.4
C BERAT TIN BOX + TANAH BASAH (gr) 97.0 96.0 91.4
D BERAT TIN BOX + TANAH KERING (gr) 93.3 93 87.5
E BERAT AIR = C - D (gr) 3.7 3 3.9
F BERAT CONTOH KERING (gr) 81.1 80.8 75.1
KADAR AIR (W) = E/F ×100 % % 4.6 3.7 5.2
RATA-RATA (W) % 4.5
Rabu, 16 Juni 2010
UNCONFINED COMPRESSION.
MAKSUD DAN TUJUAN.
Untuk mengetahui ultimate Uncon fined Compression Strength dari tanah cohesive,baik untuk Undisturbed maupun Remolded.
Untuk mngetahui Sensitivity dari tanah tersebut.
Untuk megetahui kekuatan geser tanah tersebut.
ALAT ALAT DAN BAHAN YANG DI PAKAI.
Alat unconfined compression test, lengkap dengan load dial dan deformation dial reading.
Extruder.
Cetakan tanah (silinder kecil)
Timbangan dengan ketelitiban 0,1 gram dan jangka sorong.
Stop watch
Piringan penghancur tanah
Can.
Oven.
Gergaji kawat.
Sptula .
Plastik.
Vaselin .
Alat pemadam.
TEORI :
Unconfined compression test ini di lakukan untuk mengetahui unconfined compression strength.Dalam percobaan ini sudut internal fliction (∅ =0) dan lateral support (σ3=0), jadi hanya ada beban vertical ( σ1=0)dengan memberikan deformasi.Beban vertical yang menyebapkan contoh tanah menjadi retak di bagi dengan satuan luas yang di koreksi (A) di sebut compression strength (qu).
Dari diagram lingkaran mold dapat di hitung besarnya kekuatan geser tanah tersebut, yaitu :
Su = C =qu/2
Stress = p/A =τ
Strain =∆l/l=∈
∆L=LO-L / LI=LO-L∆.
A= A0/(1-∈).
Dimana:
L0 = Panjang contoh tanah mula-mula.
L = Panjang contoh tanah setelah mendapatkan beban vertical P.
∆L = Perubahan panjang contoh tanah akibat beban vertical P.
AO = Luas penampang contoh tanah mula-mula.
A = Luas penampang setelah di koreksi.
Bila yang di coba contoh undisturbed di peroleh undisturbed strength.
Bila yang di coba contoh remolded di peroleh remolded strength ratio dari undisturbed strength dan remolded di finiskan sebagai sensitivity.
Sensitivity =(Undisturbed strength)/(Remolded strength).
Dalam percobaan ini dimensi contoh harus memenuhi syarat :
2D ≤L ≤3D, Dimana :
D = diameter contoh tanah.
L = Tinggi contoh tanah.
Sebab bila L≤2D , Sudut bidang runtuhnya akan mengalami overlap.
Dan bila L≥3D ,berlaku sebagai kolom,aka nada bahaya tekuk.
Jadi yang ideal adalah : L : D = 2 : 1.
Klasifikasi tanah lanau dan lempung berdasarkan unconfined compression strength.
consistency Qu (kg / cm2)
Very soft
Soft
Medium
Stiff
Very stiff
Hard <0,25
0,25-0,5
0,50-1,0
1,0-2,0
2,0-4,0
>4,0
Klasifikasi tanah lempung berdasarkan sensitivity.
sensitivity Sifatnya.
1
1-2
2-4
4-8
8-16
>16 Insensitive clay
Low sensitive clay
Medium sensitive clay
Sensitive clay
Extra sensitive clay
Quick clay
PERCOBAAN.
Persiapan percobaan:
Contoh tanah undisturbed di keluarkan dengan extruder dari tabung dan di cetak dalam silinder kecil kurang lebih 7 cm.Dalam percobaan ini di pakai contoh tanah dari kedalaman 3 meter,4 meter ,5 meter.
Contoh tanah tersebut di keluarkan dari cetakan dan di periksa apakah memenuhi syarat: 2D≤L≤3D.
Permukaan tanah harus benar-benar rata,(pada ujung-ujungnya),agar terjadi pembebanan yang sentries dan merata pada seluruh permukaan.
Ukur diameter dan tinngi contoh tanah serta timbang beratnya.
Jalanya percobaan :
Contoh tanah di letakan pada alat unconfined compression test dan di atur supaya load dial dan devormation dial keadaan awal menunjukan angka nol. Plat pembeban di letakan tepat menyentuh bagian atas contoh tanah dan sentries terhadap sumbunya.
Percobaan di mulai dengan memutar engkol secara teratur,sehingga kecepatan deformation; 1% dari tinggi contoh permenit.
Pembacaan pada load dial di lakukan pada interval-interval ,15 ,30 ,45 ,1,,……dan seterusnya sampai pembacaan load dial konstan atau menurun, dimana contoh tanah di angap telah runtuh..
Gambar bentuk runtuhan tanah.
Setelah itu tanah di remolded yaitu contoh tanah di masukan ke dalam plastic dan diremas-remas dengan jari sampai hancur,kemudian semua tanah yang hancur tersebut di masukan kembali ke tabung silinder cetakan yang mana jumlah tanah dan tingginya harus sama seperti contoh undisturbed,agar di dapat kepadatannya dan kadar airnya.
Contoh tanah remolded tersebut di beri pembebanan seperti proses semula.
Gambar bentuk runtuhan tanah.
Masukan kedalam oven selama 24 jam,lalu di timbang untuk mengetahui kadar airnya..
Percobaan di ulang untuk contoh-contoh tanah yang lain dari kedalaman yang lain.
Catat kalibrasi alat.
PELAPORAN :
Buat grafik hubungan tegangan dan regangan.
Tentukaan ultimate unconfined compression strength undisturbed dan remolded pada tiap kedalaman.
Tentukaan sifat consistency tiap kedalaman.
MAKSUD DAN TUJUAN.
Untuk mengetahui ultimate Uncon fined Compression Strength dari tanah cohesive,baik untuk Undisturbed maupun Remolded.
Untuk mngetahui Sensitivity dari tanah tersebut.
Untuk megetahui kekuatan geser tanah tersebut.
ALAT ALAT DAN BAHAN YANG DI PAKAI.
Alat unconfined compression test, lengkap dengan load dial dan deformation dial reading.
Extruder.
Cetakan tanah (silinder kecil)
Timbangan dengan ketelitiban 0,1 gram dan jangka sorong.
Stop watch
Piringan penghancur tanah
Can.
Oven.
Gergaji kawat.
Sptula .
Plastik.
Vaselin .
Alat pemadam.
TEORI :
Unconfined compression test ini di lakukan untuk mengetahui unconfined compression strength.Dalam percobaan ini sudut internal fliction (∅ =0) dan lateral support (σ3=0), jadi hanya ada beban vertical ( σ1=0)dengan memberikan deformasi.Beban vertical yang menyebapkan contoh tanah menjadi retak di bagi dengan satuan luas yang di koreksi (A) di sebut compression strength (qu).
Dari diagram lingkaran mold dapat di hitung besarnya kekuatan geser tanah tersebut, yaitu :
Su = C =qu/2
Stress = p/A =τ
Strain =∆l/l=∈
∆L=LO-L / LI=LO-L∆.
A= A0/(1-∈).
Dimana:
L0 = Panjang contoh tanah mula-mula.
L = Panjang contoh tanah setelah mendapatkan beban vertical P.
∆L = Perubahan panjang contoh tanah akibat beban vertical P.
AO = Luas penampang contoh tanah mula-mula.
A = Luas penampang setelah di koreksi.
Bila yang di coba contoh undisturbed di peroleh undisturbed strength.
Bila yang di coba contoh remolded di peroleh remolded strength ratio dari undisturbed strength dan remolded di finiskan sebagai sensitivity.
Sensitivity =(Undisturbed strength)/(Remolded strength).
Dalam percobaan ini dimensi contoh harus memenuhi syarat :
2D ≤L ≤3D, Dimana :
D = diameter contoh tanah.
L = Tinggi contoh tanah.
Sebab bila L≤2D , Sudut bidang runtuhnya akan mengalami overlap.
Dan bila L≥3D ,berlaku sebagai kolom,aka nada bahaya tekuk.
Jadi yang ideal adalah : L : D = 2 : 1.
Klasifikasi tanah lanau dan lempung berdasarkan unconfined compression strength.
consistency Qu (kg / cm2)
Very soft
Soft
Medium
Stiff
Very stiff
Hard <0,25
0,25-0,5
0,50-1,0
1,0-2,0
2,0-4,0
>4,0
Klasifikasi tanah lempung berdasarkan sensitivity.
sensitivity Sifatnya.
1
1-2
2-4
4-8
8-16
>16 Insensitive clay
Low sensitive clay
Medium sensitive clay
Sensitive clay
Extra sensitive clay
Quick clay
PERCOBAAN.
Persiapan percobaan:
Contoh tanah undisturbed di keluarkan dengan extruder dari tabung dan di cetak dalam silinder kecil kurang lebih 7 cm.Dalam percobaan ini di pakai contoh tanah dari kedalaman 3 meter,4 meter ,5 meter.
Contoh tanah tersebut di keluarkan dari cetakan dan di periksa apakah memenuhi syarat: 2D≤L≤3D.
Permukaan tanah harus benar-benar rata,(pada ujung-ujungnya),agar terjadi pembebanan yang sentries dan merata pada seluruh permukaan.
Ukur diameter dan tinngi contoh tanah serta timbang beratnya.
Jalanya percobaan :
Contoh tanah di letakan pada alat unconfined compression test dan di atur supaya load dial dan devormation dial keadaan awal menunjukan angka nol. Plat pembeban di letakan tepat menyentuh bagian atas contoh tanah dan sentries terhadap sumbunya.
Percobaan di mulai dengan memutar engkol secara teratur,sehingga kecepatan deformation; 1% dari tinggi contoh permenit.
Pembacaan pada load dial di lakukan pada interval-interval ,15 ,30 ,45 ,1,,……dan seterusnya sampai pembacaan load dial konstan atau menurun, dimana contoh tanah di angap telah runtuh..
Gambar bentuk runtuhan tanah.
Setelah itu tanah di remolded yaitu contoh tanah di masukan ke dalam plastic dan diremas-remas dengan jari sampai hancur,kemudian semua tanah yang hancur tersebut di masukan kembali ke tabung silinder cetakan yang mana jumlah tanah dan tingginya harus sama seperti contoh undisturbed,agar di dapat kepadatannya dan kadar airnya.
Contoh tanah remolded tersebut di beri pembebanan seperti proses semula.
Gambar bentuk runtuhan tanah.
Masukan kedalam oven selama 24 jam,lalu di timbang untuk mengetahui kadar airnya..
Percobaan di ulang untuk contoh-contoh tanah yang lain dari kedalaman yang lain.
Catat kalibrasi alat.
PELAPORAN :
Buat grafik hubungan tegangan dan regangan.
Tentukaan ultimate unconfined compression strength undisturbed dan remolded pada tiap kedalaman.
Tentukaan sifat consistency tiap kedalaman.
TRIAXIAL
MAKSUD DAN TUJUAN.
Untuk mengukur unconsolidated undrained strength terhadap specimens yang berbentuk silinder dari tanah-tanah cohesive baik dalam keadaan undituded maupun remolded.Dengan jalan mengetahui parameter-parameternya yaitu sudut geser dalam tanah (0 ) dan nilai kohesi (c ) dari tanah tersebut.
ALAT-ALAT / BAHAN YANG DI PAKAI.
Satu set alat triaxial.
Pompa pengisap udara
Extruder untuk mengeluarkan contoh tanah.
Mold untuk mencetak tanah diameter kurang lebih 3,5 cm
Jangka sorong
Oven listrik dengan suhu 105 – 110 c.
Timbangan dengan ketelitian 0,01 gram
Alat untuk memasang membrane karet pada contoh tanah (karet kondom )
Gergaji kawat.
Spatula.
Kompresor listrik.
TEORI :
Untuk menghitung kekuatan geser tanah dapat di lakukan 3 (tiga ) macam percobaan.
Unconsolidated Undrained test.
Air tidak boleh berdrainase dari pori-pori tanah selama tekanan bekerja pada contoh tanah.Sehingga tidak dapat mengukur tegangan air pori.
Consolidated Undrained Test,
Contoh tanah mula-mula ditekan oleh tekanan air dalam sel sehingga mengakibat peningkatan tekanan pada air pori dalam contoh tanah secara tiba-tiba dan air dalam pori akan keluar.Kemudian contoh tanah berkonsolidasi.Drainase tidak boleh terjadi selama di beri tekanan.Percobaan ini dapat mengukur tegangan air pori.
Drained test.
Contoh dibebani dan di biarkan berdrainasi.Beban vertikal di berikan dengan kecepatan rendah,sehingga tekanan pori air dalam contoh tidak bertambah.
Dlam percobaan triaxial di lakukan percobaan Unconsolidated Undrained tanpa memperhatikan tegangan pori air.
RUMUS –RUMUS YANG DI PAKAI :
φ1 =k .M+φ3
A
Dimana : φ 1 =Tegangan vertical yang di berikan
φ3 =Tegangan horizontal yang konstan.
K = Kalibrasi pada proving ring
A = Luas penampang yang telah di koreksi
Ao/(1-∈)
Ao = Luas contoh tanah sebelum test
∈ =L/Lo
∆L= Perubahan panjang contoh tanah.
Lo= Panjang contoh tanah mula-mula.
φ3=Ko.φ.II
Dimana :
Ko =φv/(φh )=0,4 . s/d 0,8 (untuk clay non khesive )
H = kedalaman
φ = berat jenis tanah.
Kekuatan geser tanah =τ=c+φn tgn ∅
Mencari tegangan vertical ∆Q1= (K.M)/A1
Dimana : Q1 = Tegangan vertical yang di berikan kg/cm.
:Q3 = Tegangan horizontal yang konstan .kg/cm.
:M =Dial deformasi
:K = Kalibrasi dari proofing ring.
A1 = Luas penampang sampel tanah yang telah di koreksi. (cm).
Mencari kadar air = ka =(W,sat-Wdat)/(W,dat) x100%
Dimana = ka =kadar air
Wsat = Berat tanah basah
Wdat = Berat tanah kering ( oven )
Mencari berat isi tanah basah. Ydat =(W,dat)/(Y,dat)
: Ysat =Wsat/Vsat
Dimana ; Y dat =Berat isi kering
:Ysat = Berat basah
:Vsat =
φn= tegangan normal
=(φ1+φ3 )/2+(φ1-φ3)/2 cos〖2 ∅〗
τ=tegangan gaser
= (1-3)/2 sin〖2 ∅〗
PERCOBAAN.
Persiapan percobaan :
Contoh tanah undisturbed di keluarkan dengan mengunakan extruder dan langsung di cetak dengan ring pencetak.sebelumnya ring di ukur diameternya dan di beri valine.
Tentukan panjang contoh tanah 2 kali diameter cetakan tersebut kemudian keluarkan contoh tanah dari ring pencetak.
Ukur tinggi contoh tanah untuk di ketahui volumenya,kemudian timbang beratnya.
Contoh tanah lalu masukan dalam membran karet dengan bantuan mebran stretcher dan pompa pengisap di jaga jangan sampai contoh tanah rusak,demikian juga antara contoh tanah dan membran jangan sampai terdapat udara.
Contoh tanah yang telah di selubungi membran karet,bagian atas dan bagian bawah di pasang batu berpori kemudian di masukan kedalam tabung sel triaxial.
Bagian atas dari batu berpori di letakan plat penerus gaya yang di lengkapi dengan selang sebagai saluran keluar air tanah.
Setelah contoh tanah selesai di pasang dan berdiri tegak dengan baik,kemudian tabung sel di tutup rapat-rapat.
JALANNYA PERCOBAAN.
Sel triaxial di isi larutan glisering + air 50%,sampai penuh dengan memberi tekanan pada tabung glistering,di jaga jangan sampai ada udara di dalam sel triaxial dengan cara mengeluarkan udara melalu klep sebelum sel penuh terisi glisering.
Akibat dari pengisian glistering ini, pada sel tersebut terdapat tekanan yang menekan contoh tanah dari segala arh yang besarnya dapat di lihat pada manometer.fungsi tekanan ini adalah sebagai penganti tegangan lateral (φ3).
Tentukan besar φ3 dengan memutar krang dan memberi tekanan udara dengan compressor.misalkan ambil contoh tanah:
Kedalaman 2 m φ3 = 0,25 kg/cm:0,5kg/cm:0,75kg/cm.
Kedalaman 5 m φ3 =0,5 kg/cm:1,00kg/cm:1,50 kg/cm.
Jelaskan alat penekanan arah vertical dengan kecepatan penurunan 2% permenit dari tinggi contoh tanah.
Pembacaan load dial di lakukan setiap deformasi atau penurunan bertambah 0,5mm.
Pembebanan di teruskan hingga contoh tanah mengalami keretakan atau sampai pembacaan load dial turun kembali.
Kemudian cairan glistering di keluarkan dari tabung sel ketempat semula dengan jalan memberikan tekanan udara dari compressor,dan udara yang masih ada dalam tabung sel di buang.
Tabung sel di keluarkan dari unit triaxial lalu membran karet di lepas dan tanah di keluarkan dari sel triaxial.
Gambar bentuk atau garis-garis keretakannya.
Contoh tanah di timbang dan di masukan kedalam oven selama 18-24 jam.kemudian di timbang lagi dan di hitung kadar airnya.
Percobaan di lakukan lagi untuk contoh tanah lain,misalnya: di ambil 2 kedalaman- 2,00 m dan – 5,00m masing-masing 3 contoh dengan φ3 berbeda.
PELAPORAN :
Hitung kadar air contoh tanah .
Hitung tegangan horizontal (3) dan tegangan vertical (1)
Kemudian gambar diagram mohris untuk mendapatkan c dan Q.
MAKSUD DAN TUJUAN.
Untuk mengukur unconsolidated undrained strength terhadap specimens yang berbentuk silinder dari tanah-tanah cohesive baik dalam keadaan undituded maupun remolded.Dengan jalan mengetahui parameter-parameternya yaitu sudut geser dalam tanah (0 ) dan nilai kohesi (c ) dari tanah tersebut.
ALAT-ALAT / BAHAN YANG DI PAKAI.
Satu set alat triaxial.
Pompa pengisap udara
Extruder untuk mengeluarkan contoh tanah.
Mold untuk mencetak tanah diameter kurang lebih 3,5 cm
Jangka sorong
Oven listrik dengan suhu 105 – 110 c.
Timbangan dengan ketelitian 0,01 gram
Alat untuk memasang membrane karet pada contoh tanah (karet kondom )
Gergaji kawat.
Spatula.
Kompresor listrik.
TEORI :
Untuk menghitung kekuatan geser tanah dapat di lakukan 3 (tiga ) macam percobaan.
Unconsolidated Undrained test.
Air tidak boleh berdrainase dari pori-pori tanah selama tekanan bekerja pada contoh tanah.Sehingga tidak dapat mengukur tegangan air pori.
Consolidated Undrained Test,
Contoh tanah mula-mula ditekan oleh tekanan air dalam sel sehingga mengakibat peningkatan tekanan pada air pori dalam contoh tanah secara tiba-tiba dan air dalam pori akan keluar.Kemudian contoh tanah berkonsolidasi.Drainase tidak boleh terjadi selama di beri tekanan.Percobaan ini dapat mengukur tegangan air pori.
Drained test.
Contoh dibebani dan di biarkan berdrainasi.Beban vertikal di berikan dengan kecepatan rendah,sehingga tekanan pori air dalam contoh tidak bertambah.
Dlam percobaan triaxial di lakukan percobaan Unconsolidated Undrained tanpa memperhatikan tegangan pori air.
RUMUS –RUMUS YANG DI PAKAI :
φ1 =k .M+φ3
A
Dimana : φ 1 =Tegangan vertical yang di berikan
φ3 =Tegangan horizontal yang konstan.
K = Kalibrasi pada proving ring
A = Luas penampang yang telah di koreksi
Ao/(1-∈)
Ao = Luas contoh tanah sebelum test
∈ =L/Lo
∆L= Perubahan panjang contoh tanah.
Lo= Panjang contoh tanah mula-mula.
φ3=Ko.φ.II
Dimana :
Ko =φv/(φh )=0,4 . s/d 0,8 (untuk clay non khesive )
H = kedalaman
φ = berat jenis tanah.
Kekuatan geser tanah =τ=c+φn tgn ∅
Mencari tegangan vertical ∆Q1= (K.M)/A1
Dimana : Q1 = Tegangan vertical yang di berikan kg/cm.
:Q3 = Tegangan horizontal yang konstan .kg/cm.
:M =Dial deformasi
:K = Kalibrasi dari proofing ring.
A1 = Luas penampang sampel tanah yang telah di koreksi. (cm).
Mencari kadar air = ka =(W,sat-Wdat)/(W,dat) x100%
Dimana = ka =kadar air
Wsat = Berat tanah basah
Wdat = Berat tanah kering ( oven )
Mencari berat isi tanah basah. Ydat =(W,dat)/(Y,dat)
: Ysat =Wsat/Vsat
Dimana ; Y dat =Berat isi kering
:Ysat = Berat basah
:Vsat =
φn= tegangan normal
=(φ1+φ3 )/2+(φ1-φ3)/2 cos〖2 ∅〗
τ=tegangan gaser
= (1-3)/2 sin〖2 ∅〗
PERCOBAAN.
Persiapan percobaan :
Contoh tanah undisturbed di keluarkan dengan mengunakan extruder dan langsung di cetak dengan ring pencetak.sebelumnya ring di ukur diameternya dan di beri valine.
Tentukan panjang contoh tanah 2 kali diameter cetakan tersebut kemudian keluarkan contoh tanah dari ring pencetak.
Ukur tinggi contoh tanah untuk di ketahui volumenya,kemudian timbang beratnya.
Contoh tanah lalu masukan dalam membran karet dengan bantuan mebran stretcher dan pompa pengisap di jaga jangan sampai contoh tanah rusak,demikian juga antara contoh tanah dan membran jangan sampai terdapat udara.
Contoh tanah yang telah di selubungi membran karet,bagian atas dan bagian bawah di pasang batu berpori kemudian di masukan kedalam tabung sel triaxial.
Bagian atas dari batu berpori di letakan plat penerus gaya yang di lengkapi dengan selang sebagai saluran keluar air tanah.
Setelah contoh tanah selesai di pasang dan berdiri tegak dengan baik,kemudian tabung sel di tutup rapat-rapat.
JALANNYA PERCOBAAN.
Sel triaxial di isi larutan glisering + air 50%,sampai penuh dengan memberi tekanan pada tabung glistering,di jaga jangan sampai ada udara di dalam sel triaxial dengan cara mengeluarkan udara melalu klep sebelum sel penuh terisi glisering.
Akibat dari pengisian glistering ini, pada sel tersebut terdapat tekanan yang menekan contoh tanah dari segala arh yang besarnya dapat di lihat pada manometer.fungsi tekanan ini adalah sebagai penganti tegangan lateral (φ3).
Tentukan besar φ3 dengan memutar krang dan memberi tekanan udara dengan compressor.misalkan ambil contoh tanah:
Kedalaman 2 m φ3 = 0,25 kg/cm:0,5kg/cm:0,75kg/cm.
Kedalaman 5 m φ3 =0,5 kg/cm:1,00kg/cm:1,50 kg/cm.
Jelaskan alat penekanan arah vertical dengan kecepatan penurunan 2% permenit dari tinggi contoh tanah.
Pembacaan load dial di lakukan setiap deformasi atau penurunan bertambah 0,5mm.
Pembebanan di teruskan hingga contoh tanah mengalami keretakan atau sampai pembacaan load dial turun kembali.
Kemudian cairan glistering di keluarkan dari tabung sel ketempat semula dengan jalan memberikan tekanan udara dari compressor,dan udara yang masih ada dalam tabung sel di buang.
Tabung sel di keluarkan dari unit triaxial lalu membran karet di lepas dan tanah di keluarkan dari sel triaxial.
Gambar bentuk atau garis-garis keretakannya.
Contoh tanah di timbang dan di masukan kedalam oven selama 18-24 jam.kemudian di timbang lagi dan di hitung kadar airnya.
Percobaan di lakukan lagi untuk contoh tanah lain,misalnya: di ambil 2 kedalaman- 2,00 m dan – 5,00m masing-masing 3 contoh dengan φ3 berbeda.
PELAPORAN :
Hitung kadar air contoh tanah .
Hitung tegangan horizontal (3) dan tegangan vertical (1)
Kemudian gambar diagram mohris untuk mendapatkan c dan Q.
SAND DENSITY CONE TEST.
MAKSD DAN TUJUAN.
Pemeriksaan ini di maksud untuk menentukan kepadatan di tempat dari lapisan tanah atau perkerasan yang telah di padatkan.
ALAT-ALAT /BAHAN YANG DI PAKAI.
Botol trasparan untuk tempat pasir isi kurang lebih 4 (empat) liter.
Corong kalibrasi pasir diameter 16,51 cm.
Pelat untuk corong pasir.
Pasir bersih yang tidak mengandung bahan pengikat dan dapat mengalir bebas,bergradasi lewat -saringan no.200.
Timbangan kapasitas 10kg dengan ketelitian 1gram dan kapasitas 500gram dengan ketelitian 0,1gram.
Oven pengering.
Palu,sendok,kwas,pahat.
Can
TEORI
Perhitungan:
Isi botol =Berat air =(W2 - W1)cm3
Berat isi pasir=φp (W3 - W1)/(W2 - W1) gram
Berat pasir dalam coorong =(W4 - W5) gram
Berat pasir dalam lobang =(W6 - W7) - (W4 - W5)= W10 gram
Isi lubang =W10/φP =v e cm3
Berat tanah = (W8 - W9) gram
Berat isi tanah =φ = (W8-W9)/Ve gram/cm3
Berat isi tanah kering =φd lap =φ/(100+W) X 100% gram/cm3
Derajat kepadatan di lapangan =D = (φd lap.)/(φd lab.)X 100%
Dimana:
W1 = Berat botol + corong
W2 = Berat air penuh di botol + corong.
W3 = berat pasir penuh di botol + corong.
W4 = Berat pasir secukupnya di botol + corong.
W5 = Berat sisa pasir di botol + corong.
W8 = Berat tanah + tempat.
W9 =Berat tempat.
PERCOBAAN :
Menentukan isi botol pasir :
Timbang alat ( botol + corong ) =w1 gram.
Letakan alat dengan botol di bawah,bukalah krang dan isis dengan air jerni sampai penuh di atas krang.
Tutup krang dan bersikan kelebihan air.
Timbanglahlah alat yang terisi air =W2 gr.
Berat air =isi botol pasir.
Isi botol = berat air = (W2 - W1) CM 3.
Menentukaan berat pasir.
Letakan alat dengan botol di bawah pada dasar yang rata,tutup krang dan isi corong pelan-pelan dengan pasir.
Buka krang, isi botol sampai penuh dan di jaga agar selama pengisian corong selalu di isis paling sedikit setengahnya.
Tutup krang, bersikan kelebihan pasir di atas krang dan timbanglah = W3 gr.
Berat isi pasir = φp=((w3-w1))/((w2-w1)) gr.
Menentukan berat pasir di dalam corong :
Isi botol pelan –pelan dengan pasir secukupnya dan timbang = W4 gr.
Letakan alat dengan corong di bawah pada pelat corong ,pada dasar yang rata dan bersih.
Buka kran pelan –pelan sampai pasir berhenti mengalir
Tutup kran ,dan timbanglah alat berisi sisah pasir = W5 gr.
Berat pasir dalam corong = (w4 –w5) gr.
Menentukaan berat isi tanah.
Isi botol dengan pasir secukupnya.
Ratakan permukaan tanah yang akan di periksa.Letakan pelat corong pada permukaan yang telah rata tersebut dan kokohkan dengan palu di keempat sisinya.
Galilah lobang sedalam minimal 10 cm ( tidak melampui tebal satu lapisan pemadatan.)
Seluruh tanah hasil galian di masukan ke dalam can yang telah di ketahui beratnya = W9 gr,dan timbang can dan tanah = W8 gr.
Timbang alat dengan pasir di dalamnya = w6 gr.
Letakan alat pada tempat (b ) corong kebawah diatas pelat sehingga pasir masuk ke dalam lubang.setelah pasir berhenti mengalir ,tutup kran kembali dan timbang alat dengan sisa pasir = W7 gr.
Ambil tanah sedikit dari can untuk penentuan kadar air (W).
PELAPORAN.
Tentukaan kegunaan masing-masing alat dalam percobaan ini.
Buatlah sket alat sand density test beserta kelengkapannya.
Buat perhitungan dengan teliti.
Beri kesimpulan dalam percobaan ini.
MAKSD DAN TUJUAN.
Pemeriksaan ini di maksud untuk menentukan kepadatan di tempat dari lapisan tanah atau perkerasan yang telah di padatkan.
ALAT-ALAT /BAHAN YANG DI PAKAI.
Botol trasparan untuk tempat pasir isi kurang lebih 4 (empat) liter.
Corong kalibrasi pasir diameter 16,51 cm.
Pelat untuk corong pasir.
Pasir bersih yang tidak mengandung bahan pengikat dan dapat mengalir bebas,bergradasi lewat -saringan no.200.
Timbangan kapasitas 10kg dengan ketelitian 1gram dan kapasitas 500gram dengan ketelitian 0,1gram.
Oven pengering.
Palu,sendok,kwas,pahat.
Can
TEORI
Perhitungan:
Isi botol =Berat air =(W2 - W1)cm3
Berat isi pasir=φp (W3 - W1)/(W2 - W1) gram
Berat pasir dalam coorong =(W4 - W5) gram
Berat pasir dalam lobang =(W6 - W7) - (W4 - W5)= W10 gram
Isi lubang =W10/φP =v e cm3
Berat tanah = (W8 - W9) gram
Berat isi tanah =φ = (W8-W9)/Ve gram/cm3
Berat isi tanah kering =φd lap =φ/(100+W) X 100% gram/cm3
Derajat kepadatan di lapangan =D = (φd lap.)/(φd lab.)X 100%
Dimana:
W1 = Berat botol + corong
W2 = Berat air penuh di botol + corong.
W3 = berat pasir penuh di botol + corong.
W4 = Berat pasir secukupnya di botol + corong.
W5 = Berat sisa pasir di botol + corong.
W8 = Berat tanah + tempat.
W9 =Berat tempat.
PERCOBAAN :
Menentukan isi botol pasir :
Timbang alat ( botol + corong ) =w1 gram.
Letakan alat dengan botol di bawah,bukalah krang dan isis dengan air jerni sampai penuh di atas krang.
Tutup krang dan bersikan kelebihan air.
Timbanglahlah alat yang terisi air =W2 gr.
Berat air =isi botol pasir.
Isi botol = berat air = (W2 - W1) CM 3.
Menentukaan berat pasir.
Letakan alat dengan botol di bawah pada dasar yang rata,tutup krang dan isi corong pelan-pelan dengan pasir.
Buka krang, isi botol sampai penuh dan di jaga agar selama pengisian corong selalu di isis paling sedikit setengahnya.
Tutup krang, bersikan kelebihan pasir di atas krang dan timbanglah = W3 gr.
Berat isi pasir = φp=((w3-w1))/((w2-w1)) gr.
Menentukan berat pasir di dalam corong :
Isi botol pelan –pelan dengan pasir secukupnya dan timbang = W4 gr.
Letakan alat dengan corong di bawah pada pelat corong ,pada dasar yang rata dan bersih.
Buka kran pelan –pelan sampai pasir berhenti mengalir
Tutup kran ,dan timbanglah alat berisi sisah pasir = W5 gr.
Berat pasir dalam corong = (w4 –w5) gr.
Menentukaan berat isi tanah.
Isi botol dengan pasir secukupnya.
Ratakan permukaan tanah yang akan di periksa.Letakan pelat corong pada permukaan yang telah rata tersebut dan kokohkan dengan palu di keempat sisinya.
Galilah lobang sedalam minimal 10 cm ( tidak melampui tebal satu lapisan pemadatan.)
Seluruh tanah hasil galian di masukan ke dalam can yang telah di ketahui beratnya = W9 gr,dan timbang can dan tanah = W8 gr.
Timbang alat dengan pasir di dalamnya = w6 gr.
Letakan alat pada tempat (b ) corong kebawah diatas pelat sehingga pasir masuk ke dalam lubang.setelah pasir berhenti mengalir ,tutup kran kembali dan timbang alat dengan sisa pasir = W7 gr.
Ambil tanah sedikit dari can untuk penentuan kadar air (W).
PELAPORAN.
Tentukaan kegunaan masing-masing alat dalam percobaan ini.
Buatlah sket alat sand density test beserta kelengkapannya.
Buat perhitungan dengan teliti.
Beri kesimpulan dalam percobaan ini.
CONSOLIDATION
MAKSUD DAN TUJUAN
Untuk mencari koeffesien pemampatan / compression index (Cc ) dari suatu jenis tanah akibat pertambahaan beban.
Mencari /menghitung tegangan prakonsolidasi ( Pc ) sehingga dapat di ketahui apa tanah tersebut normally atau over consolidated.
ALAT – ALAT YANG DI PAKAI
1. Alat konsolidometer beserta anak beban.
2. Stop wath
3. Ring konsolidasi
4. Jangka sorong untuk mengukur dimensi ring
5. Timbangan dengan ketelibaan 0,01 gram
6. Extruder untuk mengeluarkan contoh tanah.
7. Gergaji kawat untuk memotong tanah.
8. Spatula untuk merapikan contoh tanah.
9. Vaselin.
10. Aquadestilata / air suling.
11. Oven dengan suhu 105c - 110c.
CONTOH TANAH YANG DI GUNAKAN.
Dalam percobaan ini digunakan contoh tanah Undisturbed dari kedalaman 100 m ,200 m ,300 m ,400 m dan 500 m.
PERCOBAAN:
1. Ring konsolidasi dalam keadaan bersih , di timbang beratnya,di ukur tinggi serta di ukur diameter dalam nya
2. Ring di beri vaselin
3. Dengan bantuan alat extruder, tanah di masukan kedalam ring secara hati-hati agar jangan rusak, lalu tanah di potong dengan gergaji kawat.
4. Ring dan tanah basah di timbang
5. Contoh tanah di ukur kadar airnya.
JALANNYA PERCOBAAN:
1. Konsolidometer di siapan,jarum pengukur serta bebannya.
2. Contoh tanah serta ring di letakan pada sel konsolidometer
3. Percobaan di mulai dengan beban 0,833 kg.
4. Dicatat angka penurunan pada jarum petunjuk,pada interval 0” 6 “15 “30” 1” 2” 4” 8” 15” 30” 60” 24 jam.
5. Pembacaan dilanjutkan dengan pembabanan 1,660, 3,320 ,6,640 ,13,280, 26,560 kg dengan ivestal waktu masing-masing 24 jam.
6. Di catat pula angka penurunan pada masing-masing beban dengan investal waktu yang sama seperti di atas.
7. Penurunan beban,rutannya sama seperti poin 5.
8. Selesai tanah basah dan ring di timbang kembali dan masukan ke dalam oven kurang lebih 24 jam
9. Ring dan tanah kering di timbang.
MAKSUD DAN TUJUAN
Untuk mencari koeffesien pemampatan / compression index (Cc ) dari suatu jenis tanah akibat pertambahaan beban.
Mencari /menghitung tegangan prakonsolidasi ( Pc ) sehingga dapat di ketahui apa tanah tersebut normally atau over consolidated.
ALAT – ALAT YANG DI PAKAI
1. Alat konsolidometer beserta anak beban.
2. Stop wath
3. Ring konsolidasi
4. Jangka sorong untuk mengukur dimensi ring
5. Timbangan dengan ketelibaan 0,01 gram
6. Extruder untuk mengeluarkan contoh tanah.
7. Gergaji kawat untuk memotong tanah.
8. Spatula untuk merapikan contoh tanah.
9. Vaselin.
10. Aquadestilata / air suling.
11. Oven dengan suhu 105c - 110c.
CONTOH TANAH YANG DI GUNAKAN.
Dalam percobaan ini digunakan contoh tanah Undisturbed dari kedalaman 100 m ,200 m ,300 m ,400 m dan 500 m.
PERCOBAAN:
1. Ring konsolidasi dalam keadaan bersih , di timbang beratnya,di ukur tinggi serta di ukur diameter dalam nya
2. Ring di beri vaselin
3. Dengan bantuan alat extruder, tanah di masukan kedalam ring secara hati-hati agar jangan rusak, lalu tanah di potong dengan gergaji kawat.
4. Ring dan tanah basah di timbang
5. Contoh tanah di ukur kadar airnya.
JALANNYA PERCOBAAN:
1. Konsolidometer di siapan,jarum pengukur serta bebannya.
2. Contoh tanah serta ring di letakan pada sel konsolidometer
3. Percobaan di mulai dengan beban 0,833 kg.
4. Dicatat angka penurunan pada jarum petunjuk,pada interval 0” 6 “15 “30” 1” 2” 4” 8” 15” 30” 60” 24 jam.
5. Pembacaan dilanjutkan dengan pembabanan 1,660, 3,320 ,6,640 ,13,280, 26,560 kg dengan ivestal waktu masing-masing 24 jam.
6. Di catat pula angka penurunan pada masing-masing beban dengan investal waktu yang sama seperti di atas.
7. Penurunan beban,rutannya sama seperti poin 5.
8. Selesai tanah basah dan ring di timbang kembali dan masukan ke dalam oven kurang lebih 24 jam
9. Ring dan tanah kering di timbang.
BATAS CAIR ( LL )
13 17 33 43
1 2 3 4
16.02 16.16 15.96 16.01
19.32 18.98 18.25 18.80
18.18 18.02 17.51 17.91
1.14 0.96 0.74 0.89
2.16 1.86 1.55 1.9
52.7 51.6 47.7 46.8
CBR LABORATORIUM.
MAKSUD DAN TUJUAN:
Untuk menentukan nilai CBR( California Bearing Ration) tanah atau campuran tanah agregat yang di padatkan di laboratium dengan kadar air tertentu pada kondisi unsoaked (tidak terendam)dan kondisi soaked (terendam).
ALAT-ALAT /BAHAN YANG DI PAKAI.
A..Untuk pemadatan benda uji.
Mold lengkap dengan peralatannya.
Hamer dengan berat 10 Lb.
Plat baja dengan sebelah sisi tajam ,untuk meratakan tanah yang di padatkan.
Senduk pengaduk tanah.
Gelas ukur.
Exstruder untuk mengeluarkan contoh tanah dari mold.
Tempat untuk mencampur tanah dengan air.
Jangka sorong.
Timbangan dengan ketelibaan 0,01 gram dan 0,1 gram.
Can .
Oven.
Kertas filter untuk alas tanah.
B. Untuk percobban CBR laboratorium.
Stop watch.
Beban permukaan untuk penestrasi dan beban permukaan untuk perendaman.
Piring logam yang berlubang-lubang kecil (perforated plate).
Alat pengukur pengembangan (swelling)
Mesin CBR yang di lengkapi dengan alat-alat dial ring, proving ring dan piston penetrasi.
CONTOH TANAH YANG DI GUNAKAN:
5 (lima) sample tanah permukaan masing-masing 5000 gr lolos saringan no,4 dengan ketentuan :
1 (satu) sample dengan kadar air optimum :2 (dua )sample dengan kadar air masing-masing 2,5% dan 5,0 % di atas optimum : 2 (dua) sample dengan kadar air masing-masing 2,5 % dan 5,0% dibawah optimum.
Kadar air optimum di dapat dari hasil percobaan compaction test.
TEORI:
CBR laboratorium ialah perbandingan antara beban penetrasi suatu bahan terhadap bahan standar dengan kedalaman dan kecepatan penetrasi yang sama.
Beban standar di peroleh dari percobaan dari batu pecah yang kelas A yang di angap mempunyai CBR 100%.
Dalam percobaan CBR laboratorium kekuatan batuh pecah diekivalenkan dengan standarload yang di nyatakan dalam hubungan antara penurunana dan besarnya tekanan pada contoh tanah tersebut.
CBR Laboratrium = beban/(beban standar ) x100%
Dimana =
Beban standar untuk penetrasi 0,1 inci =1000 psi
Beban standar untuk penetrasi 0,2 inci =1500 psi
Beban standar untuk penetrasi 0,3 inci =1900 psi
Beban standar untuk penetrasi 0,4 inci = 2500 psi.
Beban standar untuk penetrasi 0,5 inci = 2600 psi.
Beban dapat dari pembacaan load dial pada suatu penetrasi yang kemudian di kalibrasikan dengan kalibrasi proving ring, atau dapat juga di gunakan rumus :
1..untuk penetrasi 0,1 inci
CBR laboraotrium =tegangan (psi)/1000 (psi) x 100%
2..untuk penetrasi 0,2 inci
CBR laboratorium = tegangan (psi ) /1500 (psi) x 100 %.
Pada umumnya nilai CBR laboratorium di ambil pada penetrasi 0,1 inchi.
PERCOBAAN:
Persiapan percobaan:
Siapkan contoh tanah yang lolos saringan ASTM no 4, sebanyak 5x5 dan masing-masing sample di cari kadar airnya.
Tambakan air sesuai pada perhitungan pada masing-masing sample dengan kadar air yang di manta.
Contoh tanah di aduk sampai merata sehingga air meresap kadalam tanah dengan merata.
Contoh tanah di peram dalam plastic selama kurang lebih 24 jam agar kadar airnya merata.
Sebelum pemadatan di lakukan mold di bersikan dan di berikan oli.
Timbang berat mold, ukur diameter dan tinggi mold.
Siapakan kertas yang berbentuk bulat yang berfungsi sebagai penyekat alat ( filter ).
Timbang berat keping pemberat.
JALANNYA PERCOBAAN :
A.Pemadatan /compaction.
masukan piring pemisah (spacer disc) di atas keeping alas dan pasang kertas saring di atasnya.
Masukan sejumlah contoh tanah kedalam mold dan tinbang 56 kali sehingga di dapatkan tinggi lapisan padat 1/5 tinggi mold.
Lakukan sampai mencapai 5 lapisan di mana untuk lapisan terakhir di bantu dengan memasang collar (leher sambung).
Leher sambung /colla di lepaskan.Permukaan tanah di ratakan dengan mengunakan plat baja sehingga tepat pada bibir mold.Pekerjaan di lakukan dengan hati-hati agar di dapatkan permukaan tanah yang rata.
Setelah rata mold beserta isinya di timbang.
Kemudian di lakukan penetrasi / penekanan.
B.Penetrasi.
Letakan keping pemberat di atas permukaan contoh tanah seberat 4,5 kg/10 Lb.Sebelumnya berat lat yang sebenarnya harus di timbang dahulu.
Kemudian atur piston penetrasi pada permukaan benda uji sehingga tepat mengenai permukaan tanah.
Periksa dan atur loading dial dan penetrasi dial agar sebelum penetrasi di mula menunjukan angka nol.
Berikan pembebanan dengan teratur sehingga kecepatan penetrasi mendekati kecepatan tetap sebesar 1,27 mm/mnt atau 0,5 inchi /menit.
Lakukan pembacaan beban pada penetrasi.
0,0125 inchi.
0,0250 inchi.
0,0500 inchi.
0,0750 inchi.
0,1000 inchi.
O,1250 inchi.
0,1500 inchi.
0,1750 inchi.
0,2000 inchi.
0,2500 inchi.
0,3000 inchi.
0,4000 inchi.
0,5000 inchi.
Catat beban maksimum dan penetrasinya bila pembebanan mak simum terjadi sebelum penetrasi 0,5000 inchi.
Setelah penetrasi unsoaked selesai,pasang keping pengembangan di atas permukaan benda di uji dan kemudian di pasang keping pemberat 10 Lbs.Cetakan beserta beban di rendam dalam air sehingga air dapat meresap dari atas maupun dari bawah.Permukaa air selama perendaman harus tetap kurang lebih 2,5 cm di atas permukaan air benda di uji.
Pasang tripod beserta dial pengukuran pengembangan swelly di catat tiap waktu : 0,jam .1 jam.2 jam.4 jam.24 jam. 48 jam. 72 jam.96 jam.
Setelah 96 jam cetakan di keluarkan dari bak air dan meringkan selama kurang lebih 15 menit sehingga air bebas mengalir habis.harus di jaga agar selama pengeluaran air tersebut permukaan benda di uji tidak terganggu.
Ambil beban dari cetakan,kemudian cetakan beserta isinya di timbang.
Benda di uji CBR yang di rendam (soaked) telah siap di lakukan pengujian kembali seperti penetrasi unsoaked.
PELAPORAN :
Pelaporan harus mencantumkan hal-hal sebagai berikut:
Cara yang di gunakan untuk mempersiapkan dan memadatkan benda uji (standad compaction test atau modifaet compaction test)
Keadaan benda uji (direndamkan / tidak di rendam )
Kepadatan kering benda uji sebelum di rendam.
Kepadatan kering benda uji setelah di rendam.
Kadar air benda uji sebelum dan sesudah pemadatan dalam persen.
Kadar air setelah perendaman yang di ambil dari lapisan atas benda uji setebal 1 inchi.
Pengembangan (swelling) dalam persen.
Harga CBR (direndam / tidak di rendam ) dalam persen.
Harga CBR di renca di tetepkan pada 100 % pengujian pendapatan dan standar / modified.
13 17 33 43
1 2 3 4
16.02 16.16 15.96 16.01
19.32 18.98 18.25 18.80
18.18 18.02 17.51 17.91
1.14 0.96 0.74 0.89
2.16 1.86 1.55 1.9
52.7 51.6 47.7 46.8
CBR LABORATORIUM.
MAKSUD DAN TUJUAN:
Untuk menentukan nilai CBR( California Bearing Ration) tanah atau campuran tanah agregat yang di padatkan di laboratium dengan kadar air tertentu pada kondisi unsoaked (tidak terendam)dan kondisi soaked (terendam).
ALAT-ALAT /BAHAN YANG DI PAKAI.
A..Untuk pemadatan benda uji.
Mold lengkap dengan peralatannya.
Hamer dengan berat 10 Lb.
Plat baja dengan sebelah sisi tajam ,untuk meratakan tanah yang di padatkan.
Senduk pengaduk tanah.
Gelas ukur.
Exstruder untuk mengeluarkan contoh tanah dari mold.
Tempat untuk mencampur tanah dengan air.
Jangka sorong.
Timbangan dengan ketelibaan 0,01 gram dan 0,1 gram.
Can .
Oven.
Kertas filter untuk alas tanah.
B. Untuk percobban CBR laboratorium.
Stop watch.
Beban permukaan untuk penestrasi dan beban permukaan untuk perendaman.
Piring logam yang berlubang-lubang kecil (perforated plate).
Alat pengukur pengembangan (swelling)
Mesin CBR yang di lengkapi dengan alat-alat dial ring, proving ring dan piston penetrasi.
CONTOH TANAH YANG DI GUNAKAN:
5 (lima) sample tanah permukaan masing-masing 5000 gr lolos saringan no,4 dengan ketentuan :
1 (satu) sample dengan kadar air optimum :2 (dua )sample dengan kadar air masing-masing 2,5% dan 5,0 % di atas optimum : 2 (dua) sample dengan kadar air masing-masing 2,5 % dan 5,0% dibawah optimum.
Kadar air optimum di dapat dari hasil percobaan compaction test.
TEORI:
CBR laboratorium ialah perbandingan antara beban penetrasi suatu bahan terhadap bahan standar dengan kedalaman dan kecepatan penetrasi yang sama.
Beban standar di peroleh dari percobaan dari batu pecah yang kelas A yang di angap mempunyai CBR 100%.
Dalam percobaan CBR laboratorium kekuatan batuh pecah diekivalenkan dengan standarload yang di nyatakan dalam hubungan antara penurunana dan besarnya tekanan pada contoh tanah tersebut.
CBR Laboratrium = beban/(beban standar ) x100%
Dimana =
Beban standar untuk penetrasi 0,1 inci =1000 psi
Beban standar untuk penetrasi 0,2 inci =1500 psi
Beban standar untuk penetrasi 0,3 inci =1900 psi
Beban standar untuk penetrasi 0,4 inci = 2500 psi.
Beban standar untuk penetrasi 0,5 inci = 2600 psi.
Beban dapat dari pembacaan load dial pada suatu penetrasi yang kemudian di kalibrasikan dengan kalibrasi proving ring, atau dapat juga di gunakan rumus :
1..untuk penetrasi 0,1 inci
CBR laboraotrium =tegangan (psi)/1000 (psi) x 100%
2..untuk penetrasi 0,2 inci
CBR laboratorium = tegangan (psi ) /1500 (psi) x 100 %.
Pada umumnya nilai CBR laboratorium di ambil pada penetrasi 0,1 inchi.
PERCOBAAN:
Persiapan percobaan:
Siapkan contoh tanah yang lolos saringan ASTM no 4, sebanyak 5x5 dan masing-masing sample di cari kadar airnya.
Tambakan air sesuai pada perhitungan pada masing-masing sample dengan kadar air yang di manta.
Contoh tanah di aduk sampai merata sehingga air meresap kadalam tanah dengan merata.
Contoh tanah di peram dalam plastic selama kurang lebih 24 jam agar kadar airnya merata.
Sebelum pemadatan di lakukan mold di bersikan dan di berikan oli.
Timbang berat mold, ukur diameter dan tinggi mold.
Siapakan kertas yang berbentuk bulat yang berfungsi sebagai penyekat alat ( filter ).
Timbang berat keping pemberat.
JALANNYA PERCOBAAN :
A.Pemadatan /compaction.
masukan piring pemisah (spacer disc) di atas keeping alas dan pasang kertas saring di atasnya.
Masukan sejumlah contoh tanah kedalam mold dan tinbang 56 kali sehingga di dapatkan tinggi lapisan padat 1/5 tinggi mold.
Lakukan sampai mencapai 5 lapisan di mana untuk lapisan terakhir di bantu dengan memasang collar (leher sambung).
Leher sambung /colla di lepaskan.Permukaan tanah di ratakan dengan mengunakan plat baja sehingga tepat pada bibir mold.Pekerjaan di lakukan dengan hati-hati agar di dapatkan permukaan tanah yang rata.
Setelah rata mold beserta isinya di timbang.
Kemudian di lakukan penetrasi / penekanan.
B.Penetrasi.
Letakan keping pemberat di atas permukaan contoh tanah seberat 4,5 kg/10 Lb.Sebelumnya berat lat yang sebenarnya harus di timbang dahulu.
Kemudian atur piston penetrasi pada permukaan benda uji sehingga tepat mengenai permukaan tanah.
Periksa dan atur loading dial dan penetrasi dial agar sebelum penetrasi di mula menunjukan angka nol.
Berikan pembebanan dengan teratur sehingga kecepatan penetrasi mendekati kecepatan tetap sebesar 1,27 mm/mnt atau 0,5 inchi /menit.
Lakukan pembacaan beban pada penetrasi.
0,0125 inchi.
0,0250 inchi.
0,0500 inchi.
0,0750 inchi.
0,1000 inchi.
O,1250 inchi.
0,1500 inchi.
0,1750 inchi.
0,2000 inchi.
0,2500 inchi.
0,3000 inchi.
0,4000 inchi.
0,5000 inchi.
Catat beban maksimum dan penetrasinya bila pembebanan mak simum terjadi sebelum penetrasi 0,5000 inchi.
Setelah penetrasi unsoaked selesai,pasang keping pengembangan di atas permukaan benda di uji dan kemudian di pasang keping pemberat 10 Lbs.Cetakan beserta beban di rendam dalam air sehingga air dapat meresap dari atas maupun dari bawah.Permukaa air selama perendaman harus tetap kurang lebih 2,5 cm di atas permukaan air benda di uji.
Pasang tripod beserta dial pengukuran pengembangan swelly di catat tiap waktu : 0,jam .1 jam.2 jam.4 jam.24 jam. 48 jam. 72 jam.96 jam.
Setelah 96 jam cetakan di keluarkan dari bak air dan meringkan selama kurang lebih 15 menit sehingga air bebas mengalir habis.harus di jaga agar selama pengeluaran air tersebut permukaan benda di uji tidak terganggu.
Ambil beban dari cetakan,kemudian cetakan beserta isinya di timbang.
Benda di uji CBR yang di rendam (soaked) telah siap di lakukan pengujian kembali seperti penetrasi unsoaked.
PELAPORAN :
Pelaporan harus mencantumkan hal-hal sebagai berikut:
Cara yang di gunakan untuk mempersiapkan dan memadatkan benda uji (standad compaction test atau modifaet compaction test)
Keadaan benda uji (direndamkan / tidak di rendam )
Kepadatan kering benda uji sebelum di rendam.
Kepadatan kering benda uji setelah di rendam.
Kadar air benda uji sebelum dan sesudah pemadatan dalam persen.
Kadar air setelah perendaman yang di ambil dari lapisan atas benda uji setebal 1 inchi.
Pengembangan (swelling) dalam persen.
Harga CBR (direndam / tidak di rendam ) dalam persen.
Harga CBR di renca di tetepkan pada 100 % pengujian pendapatan dan standar / modified.
CHAPTER 4. OBSTACLE RESTRICTION AND REMOVAL
Note 1.— The objectives of the specifications in this chapter
are to define the airspace around aerodromes to be maintained
free from obstacles so as to permit the intended aeroplane
operations at the aerodromes to be conducted safely and to
prevent the aerodromes from becoming unusable by the growth
of obstacles around the aerodromes. This is achieved by
establishing a series of obstacle limitation surfaces that define
the limits to which objects may project into the airspace.
Note 2.— Objects which penetrate the obstacle limitation
surfaces contained in this chapter may in certain circumstances
cause an increase in the obstacle clearance altitude/height for
an instrument approach procedure or any associated visual
circling procedure or have other operational impact on flight
procedure design. Criteria for flight procedure design are contained
in Procedures for Air Navigation Services – Aircraft
Operations (PANS-OPS, Doc 8168).
Note 3.— The establishment of, and requirements for, an
obstacle protection surface for visual approach slope indicator
systems are specified in 5.3.5.41 to 5.3.5.45.
4.1 Obstacle limitation surfaces
Note.— See Figure 4-1.
Outer horizontal surface
Note.— Guidance on the need to provide an outer horizontal
surface and its characteristics is contained in the Airport
Services Manual (Doc 9137), Part 6.
Conical surface
4.1.1 Description.— Conical surface. A surface sloping
upwards and outwards from the periphery of the inner horizontal
surface.
4.1.2 Characteristics.— The limits of the conical surface
shall comprise:
a) a lower edge coincident with the periphery of the inner
horizontal surface; and
b) an upper edge located at a specified height above the
inner horizontal surface.
4.1.3 The slope of the conical surface shall be measured in
a vertical plane perpendicular to the periphery of the inner
horizontal surface.
Inner horizontal surface
4.1.4 Description.— Inner horizontal surface. A surface
located in a horizontal plane above an aerodrome and its environs.
4.1.5 Characteristics.— The radius or outer limits of the
inner horizontal surface shall be measured from a reference
point or points established for such purpose.
Note.— The shape of the inner horizontal surface need not
necessarily be circular. Guidance on determining the extent of
the inner horizontal surface is contained in the Airport Services
Manual (Doc 9137), Part 6.
4.1.6 The height of the inner horizontal surface shall be
measured above an elevation datum established for such purpose.
Note.— Guidance on determining the elevation datum is
contained in the Airport Services Manual (Doc 9137), Part 6.
Approach surface
4.1.7 Description.— Approach surface. An inclined plane
or combination of planes preceding the threshold.
4.1.8 Characteristics.— The limits of the approach surface
shall comprise:
a) an inner edge of specified length, horizontal and perpendicular
to the extended centre line of the runway and
located at a specified distance before the threshold;
b) two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the
extended centre line of the runway;
c) an outer edge parallel to the inner edge; and
d) The above surfaces shall be varied when lateral offset,
offset or curved approaches are utilized, specifically,
two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the
extended centre line of the lateral offset, offset or curved
ground track.
4.1.9 The elevation of the inner edge shall be equal to the
elevation of the mid-point of the threshold.
4.1.10 The slope(s) of the approach surface shall be
measured in the vertical plane containing the centre line of the
runway and shall continue containing the centre line of any
lateral offset or curved ground track.
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Figure 4-1. Obstacle limitation surfaces
Conical
Transitional
Approach Approach
Inner approach Strip
Inner horizontal
Conical
Take-off climb
B
A A
B
Approach Take-off climb
Conical Inner horizontal
Conical
Transitional
Section A-A
Section B-B
Approach Transitional
Inner horizontal
Inner approach
See Figure 4-2 for inner transitional and balked landing obstacle limitation surfaces and
Attachment B for a three-dimensional view
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4-3 25/11/04
Inner approach surface
4.1.11 Description.— Inner approach surface. A rectangular
portion of the approach surface immediately preceding the
threshold.
4.1.12 Characteristics.— The limits of the inner approach
surface shall comprise:
a) an inner edge coincident with the location of the inner
edge of the approach surface but of its own specified
length;
b) two sides originating at the ends of the inner edge and
extending parallel to the vertical plane containing the
centre line of the runway; and
c) an outer edge parallel to the inner edge.
Transitional surface
4.1.13 Description.— Transitional surface. A complex
surface along the side of the strip and part of the side of the
approach surface, that slopes upwards and outwards to the inner
horizontal surface.
4.1.14 Characteristics.— The limits of a transitional
surface shall comprise:
a) a lower edge beginning at the intersection of the side of
the approach surface with the inner horizontal surface and
Figure 4-2. Inner approach, inner transitional and balked landing obstacle limitation surfaces
B
B
A A
Balked
landing
Inner transitional
Inner transitional
Inner transitional Inner horizontal
Inner approach
Balked
landing
Balked
landing
Section A-A
Section B-B
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25/11/04 4-4
extending down the side of the approach surface to the
inner edge of the approach surface and from there along
the length of the strip parallel to the runway centre line;
and
b) an upper edge located in the plane of the inner horizontal
surface.
4.1.15 The elevation of a point on the lower edge shall be:
a) along the side of the approach surface — equal to the
elevation of the approach surface at that point; and
b) along the strip — equal to the elevation of the nearest
point on the centre line of the runway or its extension.
Note.— As a result of b) the transitional surface along the
strip will be curved if the runway profile is curved, or a plane if
the runway profile is a straight line. The intersection of the
transitional surface with the inner horizontal surface will also
be a curved or a straight line depending on the runway profile.
4.1.16 The slope of the transitional surface shall be
measured in a vertical plane at right angles to the centre line of
the runway.
Inner transitional surface
Note.— It is intended that the inner transitional surface be
the controlling obstacle limitation surface for navigation aids,
aircraft and other vehicles that must be near the runway and
which is not to be penetrated except for frangible objects. The
transitional surface described in 4.1.13 is intended to remain as
the controlling obstacle limitation surface for buildings, etc.
4.1.17 Description.— Inner transitional surface. A surface
similar to the transitional surface but closer to the runway.
4.1.18 Characteristics.— The limits of an inner transitional
surface shall comprise:
a) a lower edge beginning at the end of the inner approach
surface and extending down the side of the inner
approach surface to the inner edge of that surface, from
there along the strip parallel to the runway centre line to
the inner edge of the balked landing surface and from
there up the side of the balked landing surface to the point
where the side intersects the inner horizontal surface; and
b) an upper edge located in the plane of the inner horizontal
surface.
4.1.19 The elevation of a point on the lower edge shall be:
a) along the side of the inner approach surface and balked
landing surface — equal to the elevation of the particular
surface at that point; and
b) along the strip — equal to the elevation of the nearest
point on the centre line of the runway or its extension.
Note.— As a result of b) the inner transitional surface along
the strip will be curved if the runway profile is curved or a plane
if the runway profile is a straight line. The intersection of the
inner transitional surface with the inner horizontal surface will
also be a curved or straight line depending on the runway profile.
4.1.20 The slope of the inner transitional surface shall be
measured in a vertical plane at right angles to the centre line of
the runway.
Balked landing surface
4.1.21 Description.— Balked landing surface. An inclined
plane located at a specified distance after the threshold,
extending between the inner transitional surface.
4.1.22 Characteristics.— The limits of the balked landing
surface shall comprise:
a) an inner edge horizontal and perpendicular to the centre
line of the runway and located at a specified distance after
the threshold;
b) two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the vertical
plane containing the centre line of the runway; and
c) an outer edge parallel to the inner edge and located in the
plane of the inner horizontal surface.
4.1.23 The elevation of the inner edge shall be equal to the
elevation of the runway centre line at the location of the inner
edge.
4.1.24 The slope of the balked landing surface shall be
measured in the vertical plane containing the centre line of the
runway.
Take-off climb surface
4.1.25 Description.— Take-off climb surface. An inclined
plane or other specified surface beyond the end of a runway or
clearway.
4.1.26 Characteristics.— The limits of the take-off climb
surface shall comprise:
a) an inner edge horizontal and perpendicular to the centre
line of the runway and located either at a specified
distance beyond the end of the runway or at the end of the
clearway when such is provided and its length exceeds
the specified distance;
b) two sides originating at the ends of the inner edge,
diverging uniformly at a specified rate from the take-off
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4-5 25/11/04
track to a specified final width and continuing thereafter
at that width for the remainder of the length of the takeoff
climb surface; and
c) an outer edge horizontal and perpendicular to the
specified take-off track.
4.1.27 The elevation of the inner edge shall be equal to the
highest point on the extended runway centre line between the
end of the runway and the inner edge, except that when a
clearway is provided the elevation shall be equal to the highest
point on the ground on the centre line of the clearway.
4.1.28 In the case of a straight take-off flight path, the
slope of the take-off climb surface shall be measured in the
vertical plane containing the centre line of the runway.
4.1.29 In the case of a take-off flight path involving a turn,
the take-off climb surface shall be a complex surface containing
the horizontal normals to its centre line, and the slope of the
centre line shall be the same as that for a straight take-off flight
path.
4.2 Obstacle limitation requirements
Note.— The requirements for obstacle limitation surfaces are
specified on the basis of the intended use of a runway, i.e. take-off
or landing and type of approach, and are intended to be applied
when such use is made of the runway. In cases where operations
are conducted to or from both directions of a runway, then the
function of certain surfaces may be nullified because of more
stringent requirements of another lower surface.
Non-instrument runways
4.2.1 The following obstacle limitation surfaces shall be
established for a non-instrument runway:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.2 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1.
4.2.3 New objects or extensions of existing objects shall
not be permitted above an approach or transitional surface
except when, in the opinion of the appropriate authority, the
new object or extension would be shielded by an existing
immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual (Doc 9137), Part 6.
4.2.4 Recommendation.— New objects or extensions of
existing objects should not be permitted above the conical
surface or inner horizontal surface except when, in the opinion
of the appropriate authority, the object would be shielded by an
existing immovable object, or after aeronautical study it is
determined that the object would not adversely affect the safety
or significantly affect the regularity of operations of aeroplanes.
4.2.5 Recommendation.— Existing objects above any of
the surfaces required by 4.2.1 should as far as practicable be
removed except when, in the opinion of the appropriate
authority, the object is shielded by an existing immovable
object, or after aeronautical study it is determined that the
object would not adversely affect the safety or significantly
affect the regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
4.2.6 Recommendation.— In considering proposed
construction, account should be taken of the possible future
development of an instrument runway and consequent
requirement for more stringent obstacle limitation surfaces.
Non-precision approach runways
4.2.7 The following obstacle limitation surfaces shall be
established for a non-precision approach runway:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.8 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1, except in the case of the horizontal
section of the approach surface (see 4.2.9).
4.2.9 The approach surface shall be horizontal beyond the
point at which the 2.5 per cent slope intersects:
a) a horizontal plane 150 m above the threshold elevation; or
b) the horizontal plane passing through the top of any object
that governs the obstacle clearance altitude/height
(OCA/H);
whichever is the higher.
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Table 4-1. Dimensions and slopes of obstacle limitation surfaces —Approach runways
APPROACH RUNWAYS
RUNWAY CLASSIFICATION
Precision approach category
Non-instrument
Code number
Non-precision approach
Code number
I
Code number
II or III
Code number
Surface and dimensionsa 1 2 3 4 1,2 3 4 1,2 3,4 3,4
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
CONICAL
Slope 5% 5% 5% 5% 5% 5% 5% 5% 5% 5%
Height 35 m 55 m 75 m 100 m 60 m 75 m 100 m 60 m 100 m 100 m
INNER HORIZONTAL
Height 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m
Radius 2 000 m 2 500 m 4 000 m 4 000 m 3 500 m 4 000 m 4 000 m 3 500 m 4 000 m 4 000 m
INNER APPROACH
Width — — — — — — — 90 m 120 me 120 me
Distance from threshold — — — — — — — 60 m 60 m 60 m
Length — — — — — — — 900 m 900 m 900 m
Slope 2.5% 2% 2%
APPROACH
Length of inner edge 60 m 80 m 150 m 150 m 150 m 300 m 300 m 150 m 300 m 300 m
Distance from threshold 30 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m
Divergence (each side) 10% 10% 10% 10% 15% 15% 15% 15% 15% 15%
First section
Length 1 600 m 2 500 m 3 000 m 3 000 m 2 500 m 3 000 m 3 000 m 3 000 m 3 000 m 3 000 m
Slope 5% 4% 3.33% 2.5% 3.33% 2% 2% 2.5% 2% 2%
Second section
Length — — — — — 3 600 mb 3 600 mb 12 000 m 3 600 mb 3 600 mb
Slope — — — — — 2.5% 2.5% 3% 2.5% 2.5%
Horizontal section
Length — — — — — 8 400 mb 8 400 mb — 8 400 mb 8 400 mb
Total length — — — — — 15 000 m15 000 m 15 000 m15 000 m 15 000 m
TRANSITIONAL
Slope 20% 20% 14.3% 14.3% 20% 14.3% 14.3% 14.3% 14.3% 14.3%
INNER TRANSITIONAL
Slope — — — — — — — 40% 33.3% 33.3%
BALKED LANDING SURFACE
Length of inner edge — — — — — — — 90 m 120 me 120 me
Distance from threshold — — — — — — — c 1 800 md 1 800 md
Divergence (each side) — — — — — — — 10% 10% 10%
Slope — — — — — — — 4% 3.33% 3.33%
a. All dimensions are measured horizontally unless specified otherwise.
b. Variable length (see 4.2.9 or 4.2.17).
c. Distance to the end of strip.
d. Or end of runway whichever is less.
e. Where the code letter is F (Column (3) of Table 1-1), the width is
increased to 155 m. For information on code letter F aeroplanes equipped
with digital avionics that provide steering commands to maintain an
established track during the go-around manoeuvre, see Circular 301 —
New Larger Aeroplanes — Infringement of the Obstacle Free Zone:
Operational Measures and Aeronautical Study.
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4.2.10 New objects or extensions of existing objects shall
not be permitted above an approach surface within 3 000 m of
the inner edge or above a transitional surface except when, in
the opinion of the appropriate authority, the new object or
extension would be shielded by an existing immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.11 Recommendation.— New objects or extensions of
existing objects should not be permitted above the approach
surface beyond 3 000 m from the inner edge, the conical surface
or inner horizontal surface except when, in the opinion of the
appropriate authority, the object would be shielded by an existing
immovable object, or after aeronautical study it is determined
that the object would not adversely affect the safety or
significantly affect the regularity of operations of aeroplanes.
4.2.12 Recommendation.— Existing objects above any of
the surfaces required by 4.2.7 should as far as practicable be
removed except when, in the opinion of the appropriate
authority, the object is shielded by an existing immovable
object, or after aeronautical study it is determined that the
object would not adversely affect the safety or significantly
affect the regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
Precision approach runways
Note 1.— See 9.9 for information regarding siting of
equipment and installations on operational areas.
Note 2.— Guidance on obstacle limitation surfaces for
precision approach runways is given in the Airport Services
Manual, Part 6.
4.2.13 The following obstacle limitation surfaces shall be
established for a precision approach runway category I:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.14 Recommendation.— The following obstacle limitation
surfaces should be established for a precision approach
runway category I:
— inner approach surface;
— inner transitional surfaces; and
— balked landing surface.
4.2.15 The following obstacle limitation surfaces shall be
established for a precision approach runway category II or III:
— conical surface;
— inner horizontal surface;
— approach surface and inner approach surface;
— transitional surfaces;
— inner transitional surfaces; and
— balked landing surface.
4.2.16 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1, except in the case of the horizontal
section of the approach surface (see 4.2.17).
4.2.17 The approach surface shall be horizontal beyond the
point at which the 2.5 per cent slope intersects:
a) a horizontal plane 150 m above the threshold elevation; or
b) the horizontal plane passing through the top of any object
that governs the obstacle clearance limit;
whichever is the higher.
4.2.18 Fixed objects shall not be permitted above the inner
approach surface, the inner transitional surface or the balked
landing surface, except for frangible objects which because of
their function must be located on the strip. Mobile objects shall
not be permitted above these surfaces during the use of the
runway for landing.
4.2.19 New objects or extensions of existing objects shall
not be permitted above an approach surface or a transitional
surface except when, in the opinion of the appropriate authority,
the new object or extension would be shielded by an existing
immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.20 Recommendation.— New objects or extensions of
existing objects should not be permitted above the conical
surface and the inner horizontal surface except when, in the
opinion of the appropriate authority, an object would be
shielded by an existing immovable object, or after aeronautical
study it is determined that the object would not adversely affect
the safety or significantly affect the regularity of operations of
aeroplanes.
4.2.21 Recommendation.— Existing objects above an
approach surface, a transitional surface, the conical surface
and inner horizontal surface should as far as practicable be
removed except when, in the opinion of the appropriate
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authority, an object is shielded by an existing immovable object,
or after aeronautical study it is determined that the object would
not adversely affect the safety or significantly affect the
regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
Runways meant for take-off
4.2.22 The following obstacle limitation surface shall be
established for a runway meant for take-off:
— take-off climb surface.
4.2.23 The dimensions of the surface shall be not less than
the dimensions specified in Table 4-2, except that a lesser length
may be adopted for the take-off climb surface where such lesser
length would be consistent with procedural measures adopted to
govern the outward flight of aeroplanes.
4.2.24 Recommendation.— The operational characteristics
of aeroplanes for which the runway is intended should be
examined to see if it is desirable to reduce the slope specified in
Table 4-2 when critical operating conditions are to be catered
to. If the specified slope is reduced, corresponding adjustment
in the length of take-off climb surface should be made so as to
provide protection to a height of 300 m.
Note.— When local conditions differ widely from sea level
standard atmospheric conditions, it may be advisable for the
slope specified in Table 4-2 to be reduced. The degree of this
reduction depends on the divergence between local conditions
and sea level standard atmospheric conditions, and on the
performance characteristics and operational requirements of
the aeroplanes for which the runway is intended.
4.2.25 New objects or extensions of existing objects shall
not be permitted above a take-off climb surface except when, in
the opinion of the appropriate authority, the new object or
extension would be shielded by an existing immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.26 Recommendation.— If no object reaches the 2 per
cent (1:50) take-off climb surface, new objects should be limited
to preserve the existing obstacle free surface or a surface down
to a slope of 1.6 per cent (1:62.5).
Table 4-2. Dimensions and slopes of obstacle limitation surfaces
RUNWAYS MEANT FOR TAKE-OFF
Code number
Surface and dimensionsa 1 2 3 or 4
(1) (2) (3) (4)
TAKE-OFF CLIMB
Length of inner edge 60 m 80 m 180 m
Distance from runway endb 30 m 60 m 60 m
Divergence (each side) 10% 10% 12.5%
Final width 380 m 580 m 1 200 m
1 800 mc
Length 1 600 m 2 500 m 15 000 m
Slope 5% 4% 2%d
a. All dimensions are measured horizontally unless specified otherwise.
b. The take-off climb surface starts at the end of the clearway if the clearway length exceeds the specified distance.
c. 1 800 m when the intended track includes changes of heading greater than 15° for operations conducted in IMC, VMC
by night.
d. See 4.2.24 and 4.2.26.
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4.2.27 Recommendation.— Existing objects that extend
above a take-off climb surface should as far as practicable be
removed except when, in the opinion of the appropriate
authority, an object is shielded by an existing immovable object,
or after aeronautical study it is determined that the object would
not adversely affect the safety or significantly affect the
regularity of operations of aeroplanes.
Note.— Because of transverse slopes on a strip or clearway,
in certain cases portions of the inner edge of the take-off climb
surface may be below the corresponding elevation of the strip
or clearway. It is not intended that the strip or clearway be
graded to conform with the inner edge of the take-off climb
surface, nor is it intended that terrain or objects which are
above the take-off climb surface beyond the end of the strip or
clearway, but below the level of the strip or clearway, be
removed unless it is considered they may endanger aeroplanes.
Similar considerations apply at the junction of a clearway and
strip where differences in transverse slopes exist.
4.3 Objects outside the obstacle limitation surfaces
4.3.1 Recommendation.— Arrangements should be made
to enable the appropriate authority to be consulted concerning
proposed construction beyond the limits of the obstacle
limitation surfaces that extend above a height established by
that authority, in order to permit an aeronautical study of the
effect of such construction on the operation of aeroplanes.
4.3.2 Recommendation.— In areas beyond the limits of the
obstacle limitation surfaces, at least those objects which extend to
a height of 150 m or more above ground elevation should be
regarded as obstacles, unless a special aeronautical study
indicates that they do not constitute a hazard to aeroplanes.
Note.— This study may have regard to the nature of
operations concerned and may distinguish between day and
night operations.
4.4 Other objects
4.4.1 Recommendation.— Objects which do not project
through the approach surface but which would nevertheless
adversely affect the optimum siting or performance of visual or
non-visual aids should, as far as practicable, be removed.
4.4.2 Recommendation.— Anything which may, in the
opinion of the appropriate authority after aeronautical study,
endanger aeroplanes on the movement area or in the air within
the limits of the inner horizontal and conical surfaces should be
regarded as an obstacle and should be removed in so far as
practicable.
Note.— In certain circumstances, objects that do not project
above any of the surfaces enumerated in 4.1 may constitute a
hazard to aeroplanes as, for example, where there a
Note 1.— The objectives of the specifications in this chapter
are to define the airspace around aerodromes to be maintained
free from obstacles so as to permit the intended aeroplane
operations at the aerodromes to be conducted safely and to
prevent the aerodromes from becoming unusable by the growth
of obstacles around the aerodromes. This is achieved by
establishing a series of obstacle limitation surfaces that define
the limits to which objects may project into the airspace.
Note 2.— Objects which penetrate the obstacle limitation
surfaces contained in this chapter may in certain circumstances
cause an increase in the obstacle clearance altitude/height for
an instrument approach procedure or any associated visual
circling procedure or have other operational impact on flight
procedure design. Criteria for flight procedure design are contained
in Procedures for Air Navigation Services – Aircraft
Operations (PANS-OPS, Doc 8168).
Note 3.— The establishment of, and requirements for, an
obstacle protection surface for visual approach slope indicator
systems are specified in 5.3.5.41 to 5.3.5.45.
4.1 Obstacle limitation surfaces
Note.— See Figure 4-1.
Outer horizontal surface
Note.— Guidance on the need to provide an outer horizontal
surface and its characteristics is contained in the Airport
Services Manual (Doc 9137), Part 6.
Conical surface
4.1.1 Description.— Conical surface. A surface sloping
upwards and outwards from the periphery of the inner horizontal
surface.
4.1.2 Characteristics.— The limits of the conical surface
shall comprise:
a) a lower edge coincident with the periphery of the inner
horizontal surface; and
b) an upper edge located at a specified height above the
inner horizontal surface.
4.1.3 The slope of the conical surface shall be measured in
a vertical plane perpendicular to the periphery of the inner
horizontal surface.
Inner horizontal surface
4.1.4 Description.— Inner horizontal surface. A surface
located in a horizontal plane above an aerodrome and its environs.
4.1.5 Characteristics.— The radius or outer limits of the
inner horizontal surface shall be measured from a reference
point or points established for such purpose.
Note.— The shape of the inner horizontal surface need not
necessarily be circular. Guidance on determining the extent of
the inner horizontal surface is contained in the Airport Services
Manual (Doc 9137), Part 6.
4.1.6 The height of the inner horizontal surface shall be
measured above an elevation datum established for such purpose.
Note.— Guidance on determining the elevation datum is
contained in the Airport Services Manual (Doc 9137), Part 6.
Approach surface
4.1.7 Description.— Approach surface. An inclined plane
or combination of planes preceding the threshold.
4.1.8 Characteristics.— The limits of the approach surface
shall comprise:
a) an inner edge of specified length, horizontal and perpendicular
to the extended centre line of the runway and
located at a specified distance before the threshold;
b) two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the
extended centre line of the runway;
c) an outer edge parallel to the inner edge; and
d) The above surfaces shall be varied when lateral offset,
offset or curved approaches are utilized, specifically,
two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the
extended centre line of the lateral offset, offset or curved
ground track.
4.1.9 The elevation of the inner edge shall be equal to the
elevation of the mid-point of the threshold.
4.1.10 The slope(s) of the approach surface shall be
measured in the vertical plane containing the centre line of the
runway and shall continue containing the centre line of any
lateral offset or curved ground track.
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Figure 4-1. Obstacle limitation surfaces
Conical
Transitional
Approach Approach
Inner approach Strip
Inner horizontal
Conical
Take-off climb
B
A A
B
Approach Take-off climb
Conical Inner horizontal
Conical
Transitional
Section A-A
Section B-B
Approach Transitional
Inner horizontal
Inner approach
See Figure 4-2 for inner transitional and balked landing obstacle limitation surfaces and
Attachment B for a three-dimensional view
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Inner approach surface
4.1.11 Description.— Inner approach surface. A rectangular
portion of the approach surface immediately preceding the
threshold.
4.1.12 Characteristics.— The limits of the inner approach
surface shall comprise:
a) an inner edge coincident with the location of the inner
edge of the approach surface but of its own specified
length;
b) two sides originating at the ends of the inner edge and
extending parallel to the vertical plane containing the
centre line of the runway; and
c) an outer edge parallel to the inner edge.
Transitional surface
4.1.13 Description.— Transitional surface. A complex
surface along the side of the strip and part of the side of the
approach surface, that slopes upwards and outwards to the inner
horizontal surface.
4.1.14 Characteristics.— The limits of a transitional
surface shall comprise:
a) a lower edge beginning at the intersection of the side of
the approach surface with the inner horizontal surface and
Figure 4-2. Inner approach, inner transitional and balked landing obstacle limitation surfaces
B
B
A A
Balked
landing
Inner transitional
Inner transitional
Inner transitional Inner horizontal
Inner approach
Balked
landing
Balked
landing
Section A-A
Section B-B
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25/11/04 4-4
extending down the side of the approach surface to the
inner edge of the approach surface and from there along
the length of the strip parallel to the runway centre line;
and
b) an upper edge located in the plane of the inner horizontal
surface.
4.1.15 The elevation of a point on the lower edge shall be:
a) along the side of the approach surface — equal to the
elevation of the approach surface at that point; and
b) along the strip — equal to the elevation of the nearest
point on the centre line of the runway or its extension.
Note.— As a result of b) the transitional surface along the
strip will be curved if the runway profile is curved, or a plane if
the runway profile is a straight line. The intersection of the
transitional surface with the inner horizontal surface will also
be a curved or a straight line depending on the runway profile.
4.1.16 The slope of the transitional surface shall be
measured in a vertical plane at right angles to the centre line of
the runway.
Inner transitional surface
Note.— It is intended that the inner transitional surface be
the controlling obstacle limitation surface for navigation aids,
aircraft and other vehicles that must be near the runway and
which is not to be penetrated except for frangible objects. The
transitional surface described in 4.1.13 is intended to remain as
the controlling obstacle limitation surface for buildings, etc.
4.1.17 Description.— Inner transitional surface. A surface
similar to the transitional surface but closer to the runway.
4.1.18 Characteristics.— The limits of an inner transitional
surface shall comprise:
a) a lower edge beginning at the end of the inner approach
surface and extending down the side of the inner
approach surface to the inner edge of that surface, from
there along the strip parallel to the runway centre line to
the inner edge of the balked landing surface and from
there up the side of the balked landing surface to the point
where the side intersects the inner horizontal surface; and
b) an upper edge located in the plane of the inner horizontal
surface.
4.1.19 The elevation of a point on the lower edge shall be:
a) along the side of the inner approach surface and balked
landing surface — equal to the elevation of the particular
surface at that point; and
b) along the strip — equal to the elevation of the nearest
point on the centre line of the runway or its extension.
Note.— As a result of b) the inner transitional surface along
the strip will be curved if the runway profile is curved or a plane
if the runway profile is a straight line. The intersection of the
inner transitional surface with the inner horizontal surface will
also be a curved or straight line depending on the runway profile.
4.1.20 The slope of the inner transitional surface shall be
measured in a vertical plane at right angles to the centre line of
the runway.
Balked landing surface
4.1.21 Description.— Balked landing surface. An inclined
plane located at a specified distance after the threshold,
extending between the inner transitional surface.
4.1.22 Characteristics.— The limits of the balked landing
surface shall comprise:
a) an inner edge horizontal and perpendicular to the centre
line of the runway and located at a specified distance after
the threshold;
b) two sides originating at the ends of the inner edge and
diverging uniformly at a specified rate from the vertical
plane containing the centre line of the runway; and
c) an outer edge parallel to the inner edge and located in the
plane of the inner horizontal surface.
4.1.23 The elevation of the inner edge shall be equal to the
elevation of the runway centre line at the location of the inner
edge.
4.1.24 The slope of the balked landing surface shall be
measured in the vertical plane containing the centre line of the
runway.
Take-off climb surface
4.1.25 Description.— Take-off climb surface. An inclined
plane or other specified surface beyond the end of a runway or
clearway.
4.1.26 Characteristics.— The limits of the take-off climb
surface shall comprise:
a) an inner edge horizontal and perpendicular to the centre
line of the runway and located either at a specified
distance beyond the end of the runway or at the end of the
clearway when such is provided and its length exceeds
the specified distance;
b) two sides originating at the ends of the inner edge,
diverging uniformly at a specified rate from the take-off
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4-5 25/11/04
track to a specified final width and continuing thereafter
at that width for the remainder of the length of the takeoff
climb surface; and
c) an outer edge horizontal and perpendicular to the
specified take-off track.
4.1.27 The elevation of the inner edge shall be equal to the
highest point on the extended runway centre line between the
end of the runway and the inner edge, except that when a
clearway is provided the elevation shall be equal to the highest
point on the ground on the centre line of the clearway.
4.1.28 In the case of a straight take-off flight path, the
slope of the take-off climb surface shall be measured in the
vertical plane containing the centre line of the runway.
4.1.29 In the case of a take-off flight path involving a turn,
the take-off climb surface shall be a complex surface containing
the horizontal normals to its centre line, and the slope of the
centre line shall be the same as that for a straight take-off flight
path.
4.2 Obstacle limitation requirements
Note.— The requirements for obstacle limitation surfaces are
specified on the basis of the intended use of a runway, i.e. take-off
or landing and type of approach, and are intended to be applied
when such use is made of the runway. In cases where operations
are conducted to or from both directions of a runway, then the
function of certain surfaces may be nullified because of more
stringent requirements of another lower surface.
Non-instrument runways
4.2.1 The following obstacle limitation surfaces shall be
established for a non-instrument runway:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.2 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1.
4.2.3 New objects or extensions of existing objects shall
not be permitted above an approach or transitional surface
except when, in the opinion of the appropriate authority, the
new object or extension would be shielded by an existing
immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual (Doc 9137), Part 6.
4.2.4 Recommendation.— New objects or extensions of
existing objects should not be permitted above the conical
surface or inner horizontal surface except when, in the opinion
of the appropriate authority, the object would be shielded by an
existing immovable object, or after aeronautical study it is
determined that the object would not adversely affect the safety
or significantly affect the regularity of operations of aeroplanes.
4.2.5 Recommendation.— Existing objects above any of
the surfaces required by 4.2.1 should as far as practicable be
removed except when, in the opinion of the appropriate
authority, the object is shielded by an existing immovable
object, or after aeronautical study it is determined that the
object would not adversely affect the safety or significantly
affect the regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
4.2.6 Recommendation.— In considering proposed
construction, account should be taken of the possible future
development of an instrument runway and consequent
requirement for more stringent obstacle limitation surfaces.
Non-precision approach runways
4.2.7 The following obstacle limitation surfaces shall be
established for a non-precision approach runway:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.8 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1, except in the case of the horizontal
section of the approach surface (see 4.2.9).
4.2.9 The approach surface shall be horizontal beyond the
point at which the 2.5 per cent slope intersects:
a) a horizontal plane 150 m above the threshold elevation; or
b) the horizontal plane passing through the top of any object
that governs the obstacle clearance altitude/height
(OCA/H);
whichever is the higher.
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Table 4-1. Dimensions and slopes of obstacle limitation surfaces —Approach runways
APPROACH RUNWAYS
RUNWAY CLASSIFICATION
Precision approach category
Non-instrument
Code number
Non-precision approach
Code number
I
Code number
II or III
Code number
Surface and dimensionsa 1 2 3 4 1,2 3 4 1,2 3,4 3,4
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
CONICAL
Slope 5% 5% 5% 5% 5% 5% 5% 5% 5% 5%
Height 35 m 55 m 75 m 100 m 60 m 75 m 100 m 60 m 100 m 100 m
INNER HORIZONTAL
Height 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m 45 m
Radius 2 000 m 2 500 m 4 000 m 4 000 m 3 500 m 4 000 m 4 000 m 3 500 m 4 000 m 4 000 m
INNER APPROACH
Width — — — — — — — 90 m 120 me 120 me
Distance from threshold — — — — — — — 60 m 60 m 60 m
Length — — — — — — — 900 m 900 m 900 m
Slope 2.5% 2% 2%
APPROACH
Length of inner edge 60 m 80 m 150 m 150 m 150 m 300 m 300 m 150 m 300 m 300 m
Distance from threshold 30 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m 60 m
Divergence (each side) 10% 10% 10% 10% 15% 15% 15% 15% 15% 15%
First section
Length 1 600 m 2 500 m 3 000 m 3 000 m 2 500 m 3 000 m 3 000 m 3 000 m 3 000 m 3 000 m
Slope 5% 4% 3.33% 2.5% 3.33% 2% 2% 2.5% 2% 2%
Second section
Length — — — — — 3 600 mb 3 600 mb 12 000 m 3 600 mb 3 600 mb
Slope — — — — — 2.5% 2.5% 3% 2.5% 2.5%
Horizontal section
Length — — — — — 8 400 mb 8 400 mb — 8 400 mb 8 400 mb
Total length — — — — — 15 000 m15 000 m 15 000 m15 000 m 15 000 m
TRANSITIONAL
Slope 20% 20% 14.3% 14.3% 20% 14.3% 14.3% 14.3% 14.3% 14.3%
INNER TRANSITIONAL
Slope — — — — — — — 40% 33.3% 33.3%
BALKED LANDING SURFACE
Length of inner edge — — — — — — — 90 m 120 me 120 me
Distance from threshold — — — — — — — c 1 800 md 1 800 md
Divergence (each side) — — — — — — — 10% 10% 10%
Slope — — — — — — — 4% 3.33% 3.33%
a. All dimensions are measured horizontally unless specified otherwise.
b. Variable length (see 4.2.9 or 4.2.17).
c. Distance to the end of strip.
d. Or end of runway whichever is less.
e. Where the code letter is F (Column (3) of Table 1-1), the width is
increased to 155 m. For information on code letter F aeroplanes equipped
with digital avionics that provide steering commands to maintain an
established track during the go-around manoeuvre, see Circular 301 —
New Larger Aeroplanes — Infringement of the Obstacle Free Zone:
Operational Measures and Aeronautical Study.
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4.2.10 New objects or extensions of existing objects shall
not be permitted above an approach surface within 3 000 m of
the inner edge or above a transitional surface except when, in
the opinion of the appropriate authority, the new object or
extension would be shielded by an existing immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.11 Recommendation.— New objects or extensions of
existing objects should not be permitted above the approach
surface beyond 3 000 m from the inner edge, the conical surface
or inner horizontal surface except when, in the opinion of the
appropriate authority, the object would be shielded by an existing
immovable object, or after aeronautical study it is determined
that the object would not adversely affect the safety or
significantly affect the regularity of operations of aeroplanes.
4.2.12 Recommendation.— Existing objects above any of
the surfaces required by 4.2.7 should as far as practicable be
removed except when, in the opinion of the appropriate
authority, the object is shielded by an existing immovable
object, or after aeronautical study it is determined that the
object would not adversely affect the safety or significantly
affect the regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
Precision approach runways
Note 1.— See 9.9 for information regarding siting of
equipment and installations on operational areas.
Note 2.— Guidance on obstacle limitation surfaces for
precision approach runways is given in the Airport Services
Manual, Part 6.
4.2.13 The following obstacle limitation surfaces shall be
established for a precision approach runway category I:
— conical surface;
— inner horizontal surface;
— approach surface; and
— transitional surfaces.
4.2.14 Recommendation.— The following obstacle limitation
surfaces should be established for a precision approach
runway category I:
— inner approach surface;
— inner transitional surfaces; and
— balked landing surface.
4.2.15 The following obstacle limitation surfaces shall be
established for a precision approach runway category II or III:
— conical surface;
— inner horizontal surface;
— approach surface and inner approach surface;
— transitional surfaces;
— inner transitional surfaces; and
— balked landing surface.
4.2.16 The heights and slopes of the surfaces shall not be
greater than, and their other dimensions not less than, those
specified in Table 4-1, except in the case of the horizontal
section of the approach surface (see 4.2.17).
4.2.17 The approach surface shall be horizontal beyond the
point at which the 2.5 per cent slope intersects:
a) a horizontal plane 150 m above the threshold elevation; or
b) the horizontal plane passing through the top of any object
that governs the obstacle clearance limit;
whichever is the higher.
4.2.18 Fixed objects shall not be permitted above the inner
approach surface, the inner transitional surface or the balked
landing surface, except for frangible objects which because of
their function must be located on the strip. Mobile objects shall
not be permitted above these surfaces during the use of the
runway for landing.
4.2.19 New objects or extensions of existing objects shall
not be permitted above an approach surface or a transitional
surface except when, in the opinion of the appropriate authority,
the new object or extension would be shielded by an existing
immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.20 Recommendation.— New objects or extensions of
existing objects should not be permitted above the conical
surface and the inner horizontal surface except when, in the
opinion of the appropriate authority, an object would be
shielded by an existing immovable object, or after aeronautical
study it is determined that the object would not adversely affect
the safety or significantly affect the regularity of operations of
aeroplanes.
4.2.21 Recommendation.— Existing objects above an
approach surface, a transitional surface, the conical surface
and inner horizontal surface should as far as practicable be
removed except when, in the opinion of the appropriate
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25/11/04 4-8
authority, an object is shielded by an existing immovable object,
or after aeronautical study it is determined that the object would
not adversely affect the safety or significantly affect the
regularity of operations of aeroplanes.
Note.— Because of transverse or longitudinal slopes on a
strip, in certain cases the inner edge or portions of the inner
edge of the approach surface may be below the corresponding
elevation of the strip. It is not intended that the strip be graded
to conform with the inner edge of the approach surface, nor is
it intended that terrain or objects which are above the approach
surface beyond the end of the strip, but below the level of the
strip, be removed unless it is considered they may endanger
aeroplanes.
Runways meant for take-off
4.2.22 The following obstacle limitation surface shall be
established for a runway meant for take-off:
— take-off climb surface.
4.2.23 The dimensions of the surface shall be not less than
the dimensions specified in Table 4-2, except that a lesser length
may be adopted for the take-off climb surface where such lesser
length would be consistent with procedural measures adopted to
govern the outward flight of aeroplanes.
4.2.24 Recommendation.— The operational characteristics
of aeroplanes for which the runway is intended should be
examined to see if it is desirable to reduce the slope specified in
Table 4-2 when critical operating conditions are to be catered
to. If the specified slope is reduced, corresponding adjustment
in the length of take-off climb surface should be made so as to
provide protection to a height of 300 m.
Note.— When local conditions differ widely from sea level
standard atmospheric conditions, it may be advisable for the
slope specified in Table 4-2 to be reduced. The degree of this
reduction depends on the divergence between local conditions
and sea level standard atmospheric conditions, and on the
performance characteristics and operational requirements of
the aeroplanes for which the runway is intended.
4.2.25 New objects or extensions of existing objects shall
not be permitted above a take-off climb surface except when, in
the opinion of the appropriate authority, the new object or
extension would be shielded by an existing immovable object.
Note.— Circumstances in which the shielding principle may
reasonably be applied are described in the Airport Services
Manual, Part 6.
4.2.26 Recommendation.— If no object reaches the 2 per
cent (1:50) take-off climb surface, new objects should be limited
to preserve the existing obstacle free surface or a surface down
to a slope of 1.6 per cent (1:62.5).
Table 4-2. Dimensions and slopes of obstacle limitation surfaces
RUNWAYS MEANT FOR TAKE-OFF
Code number
Surface and dimensionsa 1 2 3 or 4
(1) (2) (3) (4)
TAKE-OFF CLIMB
Length of inner edge 60 m 80 m 180 m
Distance from runway endb 30 m 60 m 60 m
Divergence (each side) 10% 10% 12.5%
Final width 380 m 580 m 1 200 m
1 800 mc
Length 1 600 m 2 500 m 15 000 m
Slope 5% 4% 2%d
a. All dimensions are measured horizontally unless specified otherwise.
b. The take-off climb surface starts at the end of the clearway if the clearway length exceeds the specified distance.
c. 1 800 m when the intended track includes changes of heading greater than 15° for operations conducted in IMC, VMC
by night.
d. See 4.2.24 and 4.2.26.
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4.2.27 Recommendation.— Existing objects that extend
above a take-off climb surface should as far as practicable be
removed except when, in the opinion of the appropriate
authority, an object is shielded by an existing immovable object,
or after aeronautical study it is determined that the object would
not adversely affect the safety or significantly affect the
regularity of operations of aeroplanes.
Note.— Because of transverse slopes on a strip or clearway,
in certain cases portions of the inner edge of the take-off climb
surface may be below the corresponding elevation of the strip
or clearway. It is not intended that the strip or clearway be
graded to conform with the inner edge of the take-off climb
surface, nor is it intended that terrain or objects which are
above the take-off climb surface beyond the end of the strip or
clearway, but below the level of the strip or clearway, be
removed unless it is considered they may endanger aeroplanes.
Similar considerations apply at the junction of a clearway and
strip where differences in transverse slopes exist.
4.3 Objects outside the obstacle limitation surfaces
4.3.1 Recommendation.— Arrangements should be made
to enable the appropriate authority to be consulted concerning
proposed construction beyond the limits of the obstacle
limitation surfaces that extend above a height established by
that authority, in order to permit an aeronautical study of the
effect of such construction on the operation of aeroplanes.
4.3.2 Recommendation.— In areas beyond the limits of the
obstacle limitation surfaces, at least those objects which extend to
a height of 150 m or more above ground elevation should be
regarded as obstacles, unless a special aeronautical study
indicates that they do not constitute a hazard to aeroplanes.
Note.— This study may have regard to the nature of
operations concerned and may distinguish between day and
night operations.
4.4 Other objects
4.4.1 Recommendation.— Objects which do not project
through the approach surface but which would nevertheless
adversely affect the optimum siting or performance of visual or
non-visual aids should, as far as practicable, be removed.
4.4.2 Recommendation.— Anything which may, in the
opinion of the appropriate authority after aeronautical study,
endanger aeroplanes on the movement area or in the air within
the limits of the inner horizontal and conical surfaces should be
regarded as an obstacle and should be removed in so far as
practicable.
Note.— In certain circumstances, objects that do not project
above any of the surfaces enumerated in 4.1 may constitute a
hazard to aeroplanes as, for example, where there a
DIRECT SHEAR
MAKSUD DAN TUJUAN
Menghitung kohesi tanah (c) dan sudut tegangan geser tanah maksimum ∅ berdasarkan hukum coulomb
ALAT-ALAT YANG DIPAKAI
Satu unit alat direct shear yang terdiri dari :
Stang penekan dan pemberi beban
Penggeser untuk tanah dengan proving ring No. 13704 dan extensiometer
Cincin percobaan yang terbagi 2 (dua) dan penguncinya
Plat pembeban
Beban dari besi
Stop watch
Timbangan dengan ketelitian 0,1 gram
Jangka sorong
Alat pengaduk
Can
RUMUS-RUMUS YANG DIGUNAKAN
Teori
Dengan alat geser langsung, kekuatan geser dapat diukur secara langsung. Sampel tanah dipakai pada unit direct shear kemudian diberikan tegangan vertical (yaitu tegangan normal) yang konstan. Kemudian contoh diberikan dengan mengatur kecepatan bergerak (strain rate) yang konstan dan perlahan sehingga tegangan air pori selalu tetap nol.
Untuk mendapatkan c dan ∅ perlu dilakukan tegangan normal yang berbeda.
Menghitung tegangan normal :
Dimana :
σn = Tegangan normal
Pn = Beban normal
Berat bola + Penutup + beban
F = Luas contoh tanah
Menghitung gaya geser f dengan jalan mengalikan pembacaan extensiometer dengan angka kalibrasi Proving ring dan kemudian dihitung tegangan geser maksimumnya.
Dimana :
τ = Tegangan geser
f = gaya geser
(Pembacaan dari dial x kalibrasi)
F = Luas contoh tanah
PERCOBAAN
Persiapan Percobaan
Sediakan pasir secukupnya dan bersihkan dari kotoran yang ada (tapi tidak dicuci)
Ukur diameter shear box tiga kali, untuk mendapatkan luas bidang shear box
Penutup shear box dan bola logam penahan beban ditimbang
Jalanya Percobaan
Pasir yang telah dibersihkan, dimasukkan kedalam shear box (terlebih dahulu Shear box dikunci agar tidak dapat bergerak)
Permukaan pasir diratakan, kemudian ditutup dengan batu pori. Arah serat penutup harus tegak lurus dengan gaya geser yang diberikan agar pasir tidak tergelincir, sebab hal ini mempengaruhi besarnya tegangan yang akan terjadi
Extensiometer dan force dial dipersipkan (yaitu jarum penunjuk di nol kan)
Beban 5 Kg diletakkan pada alat penggantung, kunci shear box dibuka, kemudian percobaan dapat dimulai
Pada detik-detik 15, 30, 45, 60, . . . dan seterusnya, dilakukan pembacaan load dial dan dicatat
Bila saat pembacaan load dial menjadi konstan dan kemudian menurun, percobaan ini dapat dihentikan
Pasir yang ada dalam shear box dikeluarkan. timbang beratnya kemuduan masukan kedalam oven selama 24 jam, untuk mengetahui kadar airnya
Percobaan dilanjutkan dengan mengubah besi pembebanan normal dengan 10 Kg, 15 Kg, 20 Kg, 25 Kg, dan 30 Kg.
Untuk mendapatkan titik-titik lain pada grafik antara tegangan normal ( γn ) dengan tegangan geser ( τ )
Catat kalibrasi alat
PELAPORAN
Tentukan tegangan normal dan tegangan geser pada setiap pembebanan
Buat grafik hubungan antara tegangan normal dan tegangan geser untuk mendapatkan besar kohesi tanah dan sudut tahanan geser maksimum
MAKSUD DAN TUJUAN
Menghitung kohesi tanah (c) dan sudut tegangan geser tanah maksimum ∅ berdasarkan hukum coulomb
ALAT-ALAT YANG DIPAKAI
Satu unit alat direct shear yang terdiri dari :
Stang penekan dan pemberi beban
Penggeser untuk tanah dengan proving ring No. 13704 dan extensiometer
Cincin percobaan yang terbagi 2 (dua) dan penguncinya
Plat pembeban
Beban dari besi
Stop watch
Timbangan dengan ketelitian 0,1 gram
Jangka sorong
Alat pengaduk
Can
RUMUS-RUMUS YANG DIGUNAKAN
Teori
Dengan alat geser langsung, kekuatan geser dapat diukur secara langsung. Sampel tanah dipakai pada unit direct shear kemudian diberikan tegangan vertical (yaitu tegangan normal) yang konstan. Kemudian contoh diberikan dengan mengatur kecepatan bergerak (strain rate) yang konstan dan perlahan sehingga tegangan air pori selalu tetap nol.
Untuk mendapatkan c dan ∅ perlu dilakukan tegangan normal yang berbeda.
Menghitung tegangan normal :
Dimana :
σn = Tegangan normal
Pn = Beban normal
Berat bola + Penutup + beban
F = Luas contoh tanah
Menghitung gaya geser f dengan jalan mengalikan pembacaan extensiometer dengan angka kalibrasi Proving ring dan kemudian dihitung tegangan geser maksimumnya.
Dimana :
τ = Tegangan geser
f = gaya geser
(Pembacaan dari dial x kalibrasi)
F = Luas contoh tanah
PERCOBAAN
Persiapan Percobaan
Sediakan pasir secukupnya dan bersihkan dari kotoran yang ada (tapi tidak dicuci)
Ukur diameter shear box tiga kali, untuk mendapatkan luas bidang shear box
Penutup shear box dan bola logam penahan beban ditimbang
Jalanya Percobaan
Pasir yang telah dibersihkan, dimasukkan kedalam shear box (terlebih dahulu Shear box dikunci agar tidak dapat bergerak)
Permukaan pasir diratakan, kemudian ditutup dengan batu pori. Arah serat penutup harus tegak lurus dengan gaya geser yang diberikan agar pasir tidak tergelincir, sebab hal ini mempengaruhi besarnya tegangan yang akan terjadi
Extensiometer dan force dial dipersipkan (yaitu jarum penunjuk di nol kan)
Beban 5 Kg diletakkan pada alat penggantung, kunci shear box dibuka, kemudian percobaan dapat dimulai
Pada detik-detik 15, 30, 45, 60, . . . dan seterusnya, dilakukan pembacaan load dial dan dicatat
Bila saat pembacaan load dial menjadi konstan dan kemudian menurun, percobaan ini dapat dihentikan
Pasir yang ada dalam shear box dikeluarkan. timbang beratnya kemuduan masukan kedalam oven selama 24 jam, untuk mengetahui kadar airnya
Percobaan dilanjutkan dengan mengubah besi pembebanan normal dengan 10 Kg, 15 Kg, 20 Kg, 25 Kg, dan 30 Kg.
Untuk mendapatkan titik-titik lain pada grafik antara tegangan normal ( γn ) dengan tegangan geser ( τ )
Catat kalibrasi alat
PELAPORAN
Tentukan tegangan normal dan tegangan geser pada setiap pembebanan
Buat grafik hubungan antara tegangan normal dan tegangan geser untuk mendapatkan besar kohesi tanah dan sudut tahanan geser maksimum
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