Overlay Design

Optimise highway refurbishment/renewal design

The features within this part of KeyTERRA-FIRMA provide powerful routines to create cross section data for road surveys (e.g. for maintenance) and rivers. They include programs to help optimise overlay design for road re-surfacing schemes where pavement renewal is being designed within the existing carriageway. The existing section data is stored in a section level data file and can be input or modified with the dedicated editor or alternatively Microsoft Excel can edit this file. The simple format lists in specific columns Level, Code, Chainage and Offset. If you have any existing similar data contact us and we should be able to provide a conversion program to input this data to our standard “.dat” file. Users with an electronic system including a “Level Logger” will be able to input data directly subject to confirmation of data format.

Overlay design uses this dialogue to interactively relate the overlay design with the existing road and to optimise the amount of material etc.	The level data looks like this:
Overlay design may be a mixture of “hat” or vertical Alignment Designs for the centre and channel lines.