George Vorobieff, former ISCP Director and General Manager-
Head to Head International Paper:
“Rigid pavement thickness design by spreadsheet”
—Beginning of Concrete Pavement Design Algorithms
from Nomographs to Computerization
1996
In 1996 at the Road96 Conference-Christchurch, New Zealand, George Vorobieff published a paper titled “Rigid pavement thickness design by spreadsheet”.
It was the first step towards the
Austroads concrete pavement design procedure
to shift from using nomographs (image to right) to computerization.
The two algorithms presented in the paper still relied on several tables from the 1992 edition of the Austroads pavement design guide (Part 2) to provide input into the design procedure.
1997-2004
The next stage was to establish algorithms that represented the data in the tables and to use these next set of algorithms to fully computerize the design procedure. Michael Moffatt, State Technical Leader-New South Wales-Australian Road Research Board (ARRB) was given the task to establish the algorithms that represent the data in the erosion factor tables. Michael’s report titled “Regression equations for determination of equivalent stresses and erosion factors for rigid pavement design” was published in 1997, and the new algorithms were then incorporated in the 2004 edition of the Austroads pavement design guide.
Vorobieff wrote 2 Visual Basic programs to automate the process, and the then Roads and Traffic Authority (RTA)—now Roads and Maritime Services (RMS)—developed a macro in first Lotus 123 (Rigid 5.0), and followed by the current Excel spreadsheet “Rigid Pavement Design”. Although this breakthrough was over 20 years ago, many young design engineers probably have never read the limitations of the design procedure when using the algorithms that appear obvious in the nomographs.
Vororbieff’s recommendation to young engineers:
“Please understand the origins of the design process
and its limitations when using the software.”
For more information, please contact:
George Vorobieff: vorobieff@headtohead.com.au
Michael Moffatt: michael.moffatt@arrb.com.au