Elevation Reference

 

IV Reference Rods

 

Description

An "IV" is not an electronic sensor, but a long rod installed into the ground to serve as a fixed reference point for displacement or elevation measurements. The Invar Reference (IV) rod consists of an 8 to 12 foot long, ½ to ¾ inch diameter, metal rod, partially jacketed by a 1.5 inch diameter PVC pipe filled with waterproof grease. A wider 2" diameter "head" is attached to the top of the narrow rod, such that displacement or elevation devices can be placed on top. The 6 to 8 foot long grease-filled PVC jacket is designed such that frost heave and soil settlement forces will not grab and move the reference rod.

 

Manufacturer

The invar (IV) rods and PVC pipes were cut and machined by Mn/DOT and MnROAD facility staff members.

 

Location and Quantity

IV rods have been installed in several test cells, typically near the lane and shoulder joint. ii. IV rods have been moved to others cells to suit various studies.

 

LA Reference Rods

See IV Reference Rods for description and details. The only difference is that LA Reference Rods are made out of stainless steel rod, instead of invar rod.