Pavement Design Methods 1.pdf

Structural Design Of Pavements Dr. Md. Mizanur Rahman

CE 6505

EXAMPLE 1: An 8 lane divided highway is to be constructed on a new alignment. Traffic volume forecasts indicate that the average annual daily traffic (AADT) in both directions during the first year of operation will be 12 12,000, 000 with the following vehicle mix and axle loads. Passenger cars (1000 Ib/axle) = 50% 2-axle single-unit trucks (5000 Ib/axle) = 33% 3-axle single-unit trucks (7000lb/axle)= 17% The vehicle mix is expected to remain the same throughout the design If the g g life of the pavement. p expected annual traffic growth rate is 4% for all vehicles, hi l determine d t i th the d design i ESAL ESAL, given i a design period of 20 years.

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Solution:

EXAMPLE 2: The projected vehicle mix for a proposed 2-lane rural highway during its first year off operation i i given is i b l below: Passenger cars = 66% Single-unit Single unit trucks: 2-axle, 4-tire = 18% 2-axle,, 6 tire = 8% 3-axle or more = 4% Tractor semi trailers and combination 3 axle l = 3% 4 axle = 1% If the first y year AADT 3000,, and g growth rate is 5%, and the design period is 20 yr, determine the accumulated ESAL, using truck factors.

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Solution:

Prof. Dr. Md. Mizanur Rahman

Prof. Dr. Md. Mizanur Rahman