REKAYASA JALAN 1 sem 5

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REKAYASA JALAN 1

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PERBEDAAN JALAN

PERKOTAAN DAN JALAN

ANTAR KOTA

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KLASIFIKASI MENURUT FUNGSI

JALAN

_{ARTERI PRIMER}

V TINGGI, JARAK JAUH

AKSES MASUK DIBATASI

KOLEKTOR

V SEDANG, JARAK SEDANG

AKSES MASUK DIBATASI

LOKAL

V RENDAH, JARAK DEKAT

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KLASIFIKASI MENURUT KELAS JALAN

FUNGSI KELAS MST [ton]

ARTERI I >10

II 10

III A 8

KOLEKTOR III B 8

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KLASIFIKASI MENURUT MEDAN

JALAN

JENIS MEDAN NOTASI KEMIRINGAN _{MEDAN [%]}

DATAR D < 3

PERBUKITAN B 3 – 25

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KENDARAAN RENCANA

kendaraan terberat yg dipakai dlm

perencanaan geometrik

KENDARAAN RENCANA MACAM KENDARAAN

KECIL MOBIL PENUMPANG

SEDANG TRUK 3 AS TANDEM, _{BUS BESAR 2 AS}

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SATUAN MOBIL PENUMPANG

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VOLUME LALU LINTAS

HARIAN RENCANA ( VLHR)

= smp/hari

volume lalin harian terbesar dalam setahun

VJR = VLHR x K/F smp/jam

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VLHR K [%] F [%]

> 50.000 4 - 6 0,9 -1 30.000 – 50.000 6 – 8 0,8 – 1 10.000 – 30.000 6 – 8 0,8 – 1

5.000 – 10.000 8 – 10 0,6 – 0,8 1.000 – 5.000 10 – 12 0,6 – 0,8

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KECEPATAN RENCANA

FUNGSI KECEPATAN RENCANA [km/jam]

JALAN DATAR BUKIT GUNUNG ARTERI 70 - 120 60 -80 40 – 70 KOLEKTOR 60 - 90 50 -60 30 – 50 LOKAL 40 - 70 30 -50 20 – 30 DAERAH YG SULIT, NILAI DI TABEL BISA DITURUNKAN 20

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= Ruang manfaat jalan (Rumaja) x b 1,5 m 5 m d c a _b c d

= Ruang milik jalan

(Rumija)

= Bangunan

= Ruang pengawasan jalan

(Ruwasja)

a = jalur lalu lintas d = ambang pengaman

b = bahu jalan x = b+a+b = badan jalan

c = saluran tepi

BAGIAN-BAGIAN JALAN

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CV CV CV CV CV CV 2/2 D

2 LAJUR – 2 ARAH DG MEDIAN

2/2 UD

2 LAJUR – 2 ARAH TANPA MEDIAN

4/2 D

4 LAJUR – 2 ARAH DG MEDIAN

4/2 UD

4 LAJUR – 2 ARAH TANPA MEDIAN

CV

2/1 UD

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• _{Here looks were considered unimportant. A continuous curve,}

beginning at the bottom of the picture and ending where the right lane disappears, would have been a much superior design.

[image:22.720.5.719.101.482.2]

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HORIZONTAL ALIGNMENT

•_{3. Be consistent, no surprises.}

•_{General Controls}

•_{1. As directional as possible and}

consistent with topography.

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[image:24.720.8.708.34.527.2]

Long Tangent - Short Curve Figure B-3.2a(ii)

• _{This photograph gives one the impression the}

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[image:25.720.52.715.107.433.2]

Flow With Natural Contours of the Terrain Figure B-3.2a(iii)

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[image:26.720.0.708.37.493.2]

Curvilinear Alignment

Figure B-3.2c(ii)

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HORIZONTAL ALIGNMENT

•4. Use long curves for small deflections.

•_{General Controls}

•_{1. As directional as possible and consistent with}

topography.

•_{2. Avoid minimum radii.}

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Small Deflection Angles

•_{For small deflection angles, use very}

long flat curves for appearance even

where not required by the design speed. Avoid minimum curves wherever

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HORIZONTAL ALIGNMENT

•_{5. Avoid sharp curves on steep}

hills.

•General Controls

•1. As directional as possible and consistent with topography. •2. Avoid minimum radii.

•3. Be consistent, no surprises.

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• A long spiral beginning at the first entrance at the bottom of the hill and ending near the position of the truck would have improved the appearance of this curve.

[image:30.720.90.633.142.391.2]

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HORIZONTAL ALIGNMENT

•_{6. Avoid broken back curves.} •General Controls

•1. As directional as possible and consistent with topography.

•2. Avoid minimum radii.

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Broken-Back Curve

• _{Broken-back horizontal curves are}

undesirable, especially at summits or sags. A sag profile intensifies the

broken-back effect. In each instance the use of a simple full curve is to be preferred. When similar curves are separated by a long straight,

appearance is improved by

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HORIZONTAL ALIGNMENT

•_{7. Avoid compound curves. (use}

spirals)

•_{8. Avoid abrupt reversals.}

•_{9. Reduce superelevation on bridge}

decks.

•_{10. Coordinate with vertical}

alignment.

•General Controls

•1. As directional as possible and consistent

with topography.

•2. Avoid minimum radii.

•5. Avoid sharp curves on steep hills.

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[image:34.720.0.716.96.464.2]

Horizontal Curvature on a Vertical Curve Figure B-3.2g(ii)

• _{Short vertical curvature at the end of a long horizontal}

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[image:35.720.0.716.86.479.2]

Horizontal Curvature on a Vertical Curve Figure B-3.2g(iii)

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[image:36.720.3.720.103.516.2]

Horizontal and Vertical Alignment Figure B-3.2b(iii)

• _{Because of straight alignment, one can often}

see a long distance ahead. When this

happens, it is almost impossible to avoid a roller coaster appearance. Also, any median

width changes are difficult to conceal. Observe the width change just above the grade

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[image:37.720.1.719.95.345.2]

Horizontal and Vertical Alignment Figure B-3.2c(i)

• _{The roller-coaster or the hidden-dip type}

profile should be avoided. In general, such profiles occur on relatively straight,

horizontal alignment where the roadway

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[image:38.720.13.712.78.426.2]

Horizontal and Vertical Alignment Figure B-3.2d(i)

• This drawing illustrates the effect of superimposing a short vertical curve on a relatively long horizontal curve. To

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[image:39.720.0.715.94.451.2]

Horizontal and Vertical Alignment Figure B-3.2d(ii)

• _{The sagging effect is clearly evident in}

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TIKUNGAN

NILAI SUPERELEVASI MAKSIMUM 10%

FULL CIRCLE fC

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Superelevation

α α Fcp Fcn Wp

Wn _F

f

Ff

α

F_c

W 1 ft

e

≈

R_v

cp f

p F F

W  

 



 cos sin cos

sin 2 2 v v s gR WV gR WV W f

W _ 

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Superelevation

 



 cos sin cos

sin 2 2 v v s gR WV gR WV W f

W _ 

      







 1 tan

tan 2 s v s f gR V

f   



f e



gR

V f

e _s

v

s  

 1

2

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KOEFISIEN GESEK f =0,14 –

0,24



max max



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Side Friction Factor

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SS  Lc = 0 DAN θs=⅟

2

∆

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Superelevation Transition

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PANJANG KRITIS

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Vertical Alignment

• _Objective:

– _{Determine elevation to ensure}

• _{Proper drainage}

• _{Acceptable level of safety}

• _{Primary challenge}

– _{Transition between two grades} – _{Vertical curves}

G₁ G₂

G₁ G2

Crest Vertical Curve

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Vertical Curve

Fundamentals

• _{Parabolic function}

– _{Constant rate of change of slope} – _{Implies equal curve tangents}

• _{y is the roadway elevation x stations}

(or feet) from the beginning of the curve

c

bx

ax

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Vertical Curve

Fundamentals

G₁ G₂ PVI PVT PVC L L/2 δ x Choose Either:

• G₁, G₂ in decimal form, L in feet • G₁, G₂ in percent, L in stations

c bx

ax

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Relationships

Choose Either:

• G₁, G₂ in decimal form, L in feet

• G₁, G₂ in percent, L in stations

G₁ G₂ PVI PVT PVC L L/2 δ x 1 and 0 : PVC

At the b G

dx dY

x   

c Y

x 0 and 

: PVC At the L G G a L G G a dx Y d 2 2 :

Anywhere 2 1 2 1

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Example

A 400 ft. equal tangent crest vertical curve has a PVC station of 100+00 at 59 ft. elevation. The initial grade is 2.0 percent and the final grade is -4.5

percent. Determine the elevation and stationing of PVI, PVT, and the high point of the curve.

G1=2.0%

G

2= - 4.5 %

PVI

PVT

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G1=2.0%

G

2= -4.5 %

PVI

PVT