Problems engineers face in refurbishing pavements with overlays can be reduced by a new design package according to its developer, software specialist ECL.
ECL sales director Barry Blake says the PDS Overlay software will enable rapid assessment of overlay design to aid optimum solutions in terms of material quantities. The package also promises to allow quicker and more accurate estimating, and rapid reworking of designs.
'There are plenty of software products for highway design but very few aimed specifically at quantifying overlay material and designing solutions for pavement maintenance,' he says.
PDS Overlay is the latest addition to ECL's Professional Design System suite of software products, which includes ground modelling, site layout, highway design and drainage packages.
'The PDS suite has traditionally been targeted towards new build roads and housing developments. PDS Overlay has been added to answer a number of particular needs identified through discussions with highway engineers,' Blake says.
'Engineers need a sophisticated and accurate tool to enable better estimating and to make the design and redesign of overlay thicknesses and finished levels much quicker.
'Last minute requests for changes in design are common and good estimating is difficult if survey data is poor. One of the main benefits of PDS Overlay is its ability to alert the user to discrepancies in imported data.'
ECL says PDS Overlay can be used to evaluate the optimum use of materials and amount of planing required to achieve design crossfalls and vertical alignment. Or it can provide the change in elevation and alignment possible within the bounds of material available.
'PDS Overlay can be operated in the Windows 95, 98 and NT environments as a stand-alone package or with links to popular drafting packages and other programs in the PDS suite,' says Blake.
'The program uses digital ground modelling to develop a model of the existing road profile from information input in the form of a chainage and offset survey or data from a MOSS or AutoCAD DXF file. The user then enters overlay layer thicknesses, material densities and defines the desired finished levels and crossfalls at predetermined intervals.'
PDS Overlay's output is in the form of depths and quantities in up to five separate overlay layers and setting out data at any location, says Blake. A graphical display of areas of regulating material and planing can also be obtained with areas of common depth shown in coloured bands.
'Engineers have commented on the need for an immediate picture of where areas of maximum and minimum depths of regulating material occur.
Scott Wilson graduate engineer Leigh Kearsey, who works in the consultant's infrastructure department in Basingstoke, is well versed in the use of PDS.
'PDS is good for rapid design of domestic and industrial estate roads,' he says. 'ECL has got the ground modelling right, which enables the horizontal and vertical alignment to be designed confidently.'