Soal 1: Alinemen Vertikal Tipe Cekung (jarak Pandang > Panjang Lengkung Vertikal)

Exercises Geometric Design

Nursyamsu Hidayat

(Oct 10, 2012)

Soal 1: Alinemen Vertikal Tipe Cekung (Jarak Pandang > Panjang Lengkung Vertikal) PTV B

Suatu lengkung vertical mempunyai data sbb: Stationing A

: 0 + 000

Elevasi A

: 1176 m

g2 = 10% A

Stationing PVI

: 0 + 300

Elevasi PVI

: 1200 m

PLV

EV

: 10 %

X

PVI g1 = ? %

Kecepatan rencana (VR) : 40 km/jam g2

PPV

A

X

LV

Jawab: Kelandaian A – PVI (g1) 𝑔𝑔1 =

𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸. 𝑃𝑃𝑃𝑃𝑃𝑃 − 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸. 𝐴𝐴 1200 − 1176 ∗ 100 = ∗ 100 = 𝟖𝟖% 𝑠𝑠𝑠𝑠𝑠𝑠 𝑃𝑃𝑃𝑃𝑃𝑃 − 𝑠𝑠𝑠𝑠𝑠𝑠 𝐴𝐴 (0 + 300) − (0 + 000)

Perbedaan kelandaian A = [ g2 - g1 ] = 10% - 8% = 2% (Lv cekung)

Jarak pandang 𝐽𝐽ℎ = 0.278 ∗ 𝑉𝑉𝑅𝑅 ∗ 𝑇𝑇 +

𝑉𝑉𝑅𝑅2 402 = 0.278 ∗ 40 ∗ 2.5 + = 𝟒𝟒𝟒𝟒. 𝟑𝟑𝟑𝟑 𝒎𝒎 254 ∗ (𝑓𝑓𝑝𝑝 ± 𝑔𝑔) 254 ∗ (0.35 ± 0.01)

Panjang lengkung vertikal 1. Berdasarkan syarat keluwesan bentuk Lv = 0.6 * VR = 0.6 * 40 = 24 m 2. Berdasarkan syarat drainase Lv = 40 * A = 40 * 2.0 = 80 m 3. Berdasarkan syarat kenyamanan pengemudi (Berdasarkan waktu tempuh maximum (3 detik) untuk melintasi lengkung) 𝐿𝐿𝑣𝑣 =

𝑉𝑉𝑅𝑅 40 ∗ 𝑇𝑇 = ∗ 3 = 33.33 𝑚𝑚 3.6 3.6

4. Berdasarkan syarat pengurangan goncangan 𝐿𝐿𝑣𝑣 =

𝑉𝑉𝑅𝑅2 ∗ 𝐴𝐴 402 ∗ 2 = = 8.89 𝑚𝑚 360 360

Diambil Lv terbesar = 80 m

Civil Eng. Diploma Program, Vocational School, GMU

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Exercises Geometric Design

Nursyamsu Hidayat

Cek syarat Jh < Lv; 46.33 m < 80 m ……….OK Cek panjang minimum Lv 𝐿𝐿𝑣𝑣 𝑚𝑚𝑚𝑚𝑚𝑚 =

𝐽𝐽 ℎ2

405

=

46.33 2 405

= 5.3 𝑚𝑚 < 80 m ……….OK

Lv min = Y * A = 3 * 2.0 = 6.0 m < 80 m ……OK

𝐸𝐸𝑣𝑣 =

𝐴𝐴 ∗ 𝐿𝐿𝑣𝑣 2 ∗ 80 = = 0.20 𝑚𝑚 800 800

X = ¼ * Lv = ¼ * 80 = 20 m 𝑌𝑌 =

𝐴𝐴 ∗ 𝑋𝑋 2 2 ∗ 202 = = 0.05 𝑚𝑚 200 ∗ 𝐿𝐿𝑣𝑣 200 ∗ 80

Stationing lengkung vertikal Sta PLV = Sta PVI – ½ Lv = (0+300) – ½ 80 = 0 + 260 Sta A

= Sta PVI – ¼ Lv = (0+300) – ¼ 80 = 0 + 280

Sta PPV = Sta PVI = 0 + 300 Sta B

= Sta PVI + ¼ Lv = (0+300) + ¼ 80 = 0 + 320

Sta PTV = Sta PVI + ½ Lv = (0+300) + ½ 80 = 0 + 340

Elevasi lengkung vertikal Elevasi PLV = Elev. PVI – ½ Lv * g1 = 1200 – ½ 80 * 0.08 = 1196.8 m Elevasi A

= Elev. PVI - ¼ Lv * g1 + y = 1200 – ¼ 80 * 0.08 + 0.05 = 1198.45 m

Elevasi PPV = Elev. PVI + Ev = 1200 + 0.20 = 1200.20 m Elevasi B

= Elev PVI + ¼ Lv * g2 + y = 1200 + ¼ 80 * 0.10 + 0.05 = 1202.05 m

Elevasi PTV = Elev. PVI + ½ Lv * g2 = 1200 + ½ 80 * 0.10 = 1204 m

Civil Eng. Diploma Program, Vocational School, GMU

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