In a home in the Dutch city of Alphen aan den Rijn cracks developed in the masonry due to the previous construction of an adjacent building. On July 31, 2017 a new crack was noticed and Allnamics was asked to ascertain whether any corrective action was required.

 

Initially  a visual inspection was performed and a plastic crack meter was installed.

 

Photo 1 Can you see the crack in the masonry?

 

Photo 2  The installed plastic crack meter.

 

Since this crack meter showed no obvious change in the crack width it was decided to carry out more precise measurements with Leiderdorp Instruments digital crack meters, which can detect displacements of 0.0061 mm (0.00025 in) and take a measurement as often as once every minute.  The meters were installed on March 16, 2017 and since that time the data logger sends daily reports with the measurements that are carried out every 15 minutes.

 

Photo 3  Step 1 : Installing anchors for the electronic crack meters.

 

Photo 4  Step 2 : Installing the electronics crack meters.

 

Photo 5 Step 3 : Placement of a protective case.

 

Photo 6 Step 4 : Connecting the sensors on the logger.

 

Photo 7 Step 5 : The closed protective case.

 

Graphic 1                The first measurements.

 

Graphic 2                An overview of the measurements of one year.

 

Want to know more about crack monitoring?  Send an e-mail to Martijn van Delft.  vandelft@allnamics.eu

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