Campbell Scientific ST350 Strain Transducer for Structural Testing - Manual (Page 16)

Section 5. Mounting of Sensor to Various Surfaces
For closest Loctite Distributor call: 1 (800) 243-4874. NOTE
Once testing is complete, carefully loosen the 1/4-20 nuts from the tabs and
remove transducer. If one is not careful, the tab will pop loose from the
structure (particularly when testing concrete structures) and the transducer may
be damaged. Use vice grips to remove the tabs from the structure. If the tabs
remain with the transducer during removal, use vice grips to hold the bottom of
the tab while loosening the nut. DO NOT try to loosen the nut without keeping
the tab from twisting as the transducer can be damaged! The tabs can be re-
used by soaking them in acetone for 30-40 minutes to remove the hardened
adhesive. Be sure to cover the container since the acetone will evaporate
quickly and is very flammable!
5.2 Mounting Information for Different Types of
Surfaces
5.2.1 Steel
1. Examples:
Bridges, building components (columns, joists, floor systems, etc), large
mechanical equipment (tower cranes, mobile cranes, cooling towers, etc.),
liquid tanks, piles.
2. Methods for attaching the ST350 to steel:
a. Tab/Glue: See above.
b. C-clamps: Place transducer on specimen surface and tighten a
C-clamp over each raised bolt hole.
c. Threaded stud: Drill 1/4" holes in specimen at correct foot locations,
insert proper sized bolt, and tighten nut on each raised bolt hole.
3. Installation method for best measurements: All methods are sufficient.
4. Pitfalls to avoid during installation:
If the mounting surface is rough due to pitting or thick paint, smooth the
surface using acceptable methods.
If the mounting surface is not flat, a transducer can be installed in some
situations. Proceed with caution, ensuring not to distort the transducer as
damage may occur.
If the mounting surface is hot to the touch and/or the humidity level is
high, the glue may not stick as well as in other conditions. Although the
bonding strength is more than sufficient for taking measurements, when
loosening the nuts during the removal process, take extra care as the
mounting tab may pop off the member and the strain transducer can be
bent.
5-2