any of you guys using a lightweight deflectometer to replace plate bearings? if so are results comparable and is it easy to convince the client of this?
Best thing I would suggest is downloading a copy of IAN 73/06 from the Standards for Highways Website in the UK. This document detials the methodology for this equipment, interpretation of the data and how it stacks up with more 'traditional' tests such as CBR's by plunger, TRL DCP's and static plate tests for the determination of CBR. This equipment will not replace static plate load tests wholesale, only the plate tests done to determine CBR values. Answers are in stiffness E, and this will become the norm for pavementt design over the next couple of years I think.
Convincing the Client may be more problematic, you have to understand what the equipment is telling you, and how this relates to design. If it is going to be used on a project, it needs to be included in the specifcation at the contract stage. Highways Agency in the UK are using it extensively, and it has also proven very useful in testing the highly variable Made Ground on the 2012 Olympics site.
I personally like the test as it measure performance of variable ground where compliance such as degree of compaction and air void content are difficult to measure with a high degree of certainty. Equipment trials are needed, and it is sensitive in operation. you need a good understanding of what it is telling you before you adopt it as a cure all method of test.
