Empirical Approach In Pavement Design

Empirical Design Approach

Empirical approach in pavement design means that the design methods depend entirely or largely on previous experience and previous experiments and more often, a combination of both. This approach in pavement design does not accurately and firmly determine and establish the basis of science. It can however be used confidently to the recognition of its limitations. During a design process a designer or an engineer will need a few inputs for determination. These inputs are loads, material, layer configuration and the environment which are determined by experience and experiments that worked. (WAPA Pavement Note on Empirical design).

Schwartz and Carvalho (2007) also state that an empirical design approach in pavement design is simply and solely based on previous experience that worked and

Empirical design approach depends solely on previous experiences and experiments and on the other hand, mechanistic design approach in pavements is computing the charts and tables during the process of design.

Mechanistic approach in pavement design takes these one step forward. The theory of mechanics is used to predict traffic loading and environmental conditions. The use of vertical compressive strain was first suggested by Kerkhoven & Mormon (1953) on the top of sub grade as a criterion to establish failure to reduce permanent deformation. Saal & Pell (1960) suggested the use of horizontal tensile strain at the bottom of asphalt layer which will minimize fatigue cracking.

These and many other suggestions and publications formed a part of institutions, states and agencies researches to improve the M-E approach in pavement design. The most recent M-E based method was the project (NCHRO, 2004) by the NCHRO 1-37A. this incorporated nationally calibrated models to predict distress induced by traffic loading and environmental