Transport Infrastructure

Only available on StudyMode
  • Topic: Asphalt, Tarmac, Road
  • Pages : 3 (440 words )
  • Download(s) : 58
  • Published : December 9, 2012
Open Document
Text Preview
1. AADF= 1000
n=20 years
r= 3.0%
Open in 2020
Cummulative traffic=AADF×365×1+rn-1r
=1000×365×1+0.0320-10.03
=9.808 million commercial vehicles
AADF=1000
Midterm year of 20 years start of 2020=2030
Vehicle Damage Factor (VDF)
VDF=0.350.93t-0.260.92t+0.0821.03.9F1550
Base year-1992
F= AADF=1000
Value of t;
t=2020+202-1992
t=38 years
VDF=0.350.9338+0.082-0.260.9238+0.0821.03.910001550
VDF=2.4065-2.0960.4156
VDF=2.4065-0.8712
VDF=1.54
Design traffic=VDF×cummulative traffic
=1.54×9.808 million
=15.1 msa

(b) CBR=9%
Determine the thickness for bypass
Design traffic= 15.1 msa
CBR=9%
Using graph; sub-base layer = 190mm thick.

(c). Dense bitumen macadam with 50 penetration bitumen (DBM50) asphalt base material. Thickness of base (structural) layer of the flexible pavement=? Thickness of surfacing layer= 45mm
Thickness of binder course layer (between surfacing & base layer) = 60mm Base (DBM) = 159mm
Design thickness= 159+60+45
Design thickness=264mm

2. Average Daily Traffic (ADT)= 4500
Percentage of Commercial Vehicles, Pc= 40%
Annual traffic growth rate (r) = 3%
Design period (x) = 20 years
CBR= 7%
Number of lanes= 2
Width of carriage way =7.50m
Width of shoulder = 1.00m
Initial Annual Commercial Traffic for one direction, v0
vo=ADFNo.of counted vehicles×Pc100×365
=45002×40100×365
vo=328500
Total number of commercial vehicles for one direction over a period of 20 years. x=20
v0=328500
r=3%
vc=vo1+rx-1r
vc=3285001+0.0320-10.03
vc=8826918.02
Total Equivalent Axles (ESA)
ESA=vee
Road equivalent factor (e) =3
=8826918.02×3
ESA=2.6×107
Capacity check, vx=v1(1+r)xno. of counted ADT lanes
vx=45001+0.03202
vx=4064vehicle/day1lane
c=IRT
c=20002×0.90×100100+2pc
T=100100+2Pc
T=100(100+2×0.4)
T=0.992
c=20002×0.90×0.992
c=893 vehicles per hour

C=10c
C=10×893
C=8930 vehicles/day1lane
C=8930>4064 (ok)

Thickness of layers of road TA= a1D1+a2D2+a3D3
a1, a2, a3; structural coefficient of each...
tracking img