Michael
There are a number of key requirements - on surface profile, road
stiffness, road alignment.... however the single most critical one is to
make sure that the scale is not proud of the road surface. If it is, you
will measure the stiffness of the tyre and not the weight of the
axle. Just a 0.5mm height differential can generate a very large error.
There is a book on Vehicle-Road Interaction that discusses the requirements
in some detail...
-Dave
At 13:31 28/11/2002 +1100, Michael Paine wrote:
>As part of a project for Austroads (Australian road authorities) I am
>gathering information about site requirements for the use of portable
>scales and weighbridges.
>
>A long standing requirement for portbale scales in Australia (at least
>NAASRA 1987) is that a for a "conforming site":
>*Longitudinal slope should be uniform and not exceed 3%
>*A tranversely crowned surface is satisfactory provided the wheel paths
>do not cross the crown
>* Firm surface (scales do not sink in)
>* Free of mounds and depressions capable of producing a variation in
>axle height more than 15mm within any axle group (my paraphrasing)
>
>Advice or link suggestions from RTT subscribers on this subject would be
>appreciated. Ultimately the site requirements will be published as part
>of national guidelines for measuring vehicle mass.
>regards
>Michael Paine
>
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