Roland Schenkel
Cartes-fiches 59 Cartes-fiches
Utilisateurs 6 Utilisateurs
Langue English
Niveau Université
Crée / Actualisé 17.01.2012 / 30.01.2019
Attribution de licence Pas de droit d'auteur (CC0)
Lien de web
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Crack detection (due to geothermic drills in Staufen, Germany). How can you detect the crack shown in the picture?


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How can you detect influencing parameters, like temperature?

By measuring them during data acquisition and correlate them to the measurements.

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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

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What could be the reason for a trend?

* Instrument got warmer

* sinking of the tripod

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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.

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Frequency measurement:

Acquisition rate of a GPS? Possible for this task?

20 Hz => possible

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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)|

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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!