Cartes-fiches
Crack detection (due to geothermic drills in Staufen, Germany). How can you detect the crack shown in the picture?
Extensometers
How can you detect influencing parameters, like temperature?
By measuring them during data acquisition and correlate them to the measurements.
Can geodetic instruments also be used (for crack detection in a building)?
a) Tachymeter an two reflectors on SBB-bolts. b) levelling for sinking problems
What could be the reason for a trend?
* Instrument got warmer
* sinking of the tripod
Frequency measurement:
Acquisition rate of a Totalstation? Possible for this task?
5-7 Hz (leica says: 10 hz) => possible for lower frequencies.
* When the amplitude is to high for ATR without moving it’s good.
* When the tachy has to move => bad.
Frequency measurement:
Acquisition rate of a GPS? Possible for this task?
20 Hz => possible
Differences between geodetic and geotechnical instruments?
[Criteria / geodetic / geotechnical], [Accuracy/ mm (Leveling <0.5mm/km Doppelnivellement) / 2μm - mm], [Range / m - km (VLBI :-)) / μm - m], [Measuring in 2 or 3 dim. / possible with 1 sensor / usually 1 sensor for 1 dim.], [Costs/ ? (high) / ? (low)], [Absolute Measurements (Coordinates) / ✓ / ✕], [Development / for classical survey / specially for those purposes], ]Place of instrument / mostly away of the problem / directly at the problem (crackmeter, plumb)|
What is the easiest and cheapest method (to detect a crack in a wall)?
Plaster-Plate (Gips-Platte), take care that the predetermined breaking point is over the crack!
