Question

It is proposed to design flexible pavement for 20 years by CBR method. The period of construction is 2 years and the traffic at the end of 2 years is 500CVPD, then the cumulative standard axles in msa is (lane distribution factor = 0.75, vehicle damage factor = 2.5 and traffic growth rate = 7.5%)

• A. 16.64 msa
• B. 19.75 msa
• C. 8.94 msa
• D. 14.8 msa

Answer 1

The correct option is D 14.8 msa

$\text{Cumulative standard axles}=\frac{365\times \left(\right(1+r{)}^n-1)}{r}\times A\times D\times F$
Given,
$A=500CVPD;D=0.75;F=2.5;n=20;r=7.5\%=0.075$
$\text{Cumulative standard axles}=\frac{365\times \left(\right(1+0.075{)}^{20}-1)}{0.075}\times 500\times 0.75\times 2.5$
$=14.818\times {10}^6=14.8msa$