Simulation Type

The following controls, located on the Input -> Simulation Parameters Page, are used to specify the type of Mechanistic-Empirical simulation to perform for the pavement project.

CalME has two types of Mechanistic-Empirical (ME) to select from:

•Deterministic - a single simulation is performed on the pavement structure using the specified input values

•Monte Carlo - many simulations are performed on the pavement structure using random values from a distribution of values for several input data items, such as thickness and and modulus. The number of simulations is specified in the Monte Carlo Variability parameter section. Monte Carlo takes into account within project construction variability.

In general, a Deterministic simulation is performed first in order to understand the basic response of the pavement structure. Once that is done, then a Monte Carlo simulation is performed with the number of simulations set to give at least 95% reliability for rutting and cracking.

The default number of simulations is set at 10 but more are needed to obtain the 95% reliability level. In most cases, at least 50 simulations will be required for typical designs.

The amount of CalME runtime required to perform the Monte Carlo analysis is directly dependent on the number of simulations and the Design Life (and the load on the server). For a four-layer structure, some example runtimes are:

•Design Life = 20 yrs                    Number of simulations = 10                    30 seconds

•Design Life = 20 yrs                    Number of simulations = 50                    93 seconds

•Design Life = 40 yrs                    Number of simulations = 50                    168 seconds

The question mark in the blue circle in the upper-right of the control group allows you to get help on the controls (this topic).