Modification for End Area Rule Used in Volume Calculation of Highway Pavements

Abstract

Volume calculation of earth work of road pavements is very important section in project cost estimation. Practically it is very difficult to calculate the actual volume of a pavement as the cross section varies by its width, height, shape and formation level. The conventional calculation method is to use end area rule which calculates the area between two consecutive sections as the product of average area of sections and distance between sections assuming there is a linear variation of sectional area between two sections. The actual volume of the section deviates from the calculated volume using end area rule due to the violations of assumptions of the equation. This study was carried out to investigate on the errors of application of end area rule in volume calculations of highway pavements. The actual volume was calculated by a numerical analysis by integration and also by preparing a model using computer software. A modification factor was developed using the perpendicular distance between the centroids of cross sections and end area rule was applied with this modification factor. The validity of the results is evaluated by comparing the calculated volume with actual volumes obtained by mathematical and software models. It was concluded that a volume can be calculated up to a better accuracy using this modification factor together with the end area rule.