Crack movement gauges anyone know about them? 1

[daveh6729]

Does anyone know where I can get some plastis gauges that are glue to a concrete wall over an existing crack in order to detect future movement. I know I've seen them beofre, but Google is letting me down on this one.

 

[jike]

Avongard Crack Monitor is the one I am familiar with.

http://www.avongard.com/prod01.htm

 

[daveh6729]

Thanks a million jike..just what I was looking for!

 

[kxa]

Remember that crack movement may be a 3D movement. That means one plate of the gage could move against the other or move away from it. So, when placing them, try to position them such that they are not pushed against each other. Also, doing it this will allow you to measure any out-of-plane movements. One last advice, if you know one side is fixed (no movement) and the other side moves, put the clear plate on the side that moves.

 

[dik]

I often install concrete nails (drill 1/8" dia holes and install as two hardened steel pins and then use a dial gauge vernier caliper to measure. This works quite well.

Dik

 

[daveh6729]

Thanks for your input...I will have my client order the avonguard gauges...I think we can also measure lateral movement using feeler gauges between the two sides...thanks again for your responses...

 

[Ron]

daveh6729....I have used the Avongard monitors and the method Dik described. The old Soiltest company used to sell a kit that was a fancy way of doing what Dik described, but two hardened pins shot, hammered, or drilled into the concrete will work just fine.

One caution on any of these methods...try to normalize your readings by taking them at about the same time and temperature (if possible).

 

[Ussuri]

In the past I have used Demec Pips and vernier calipers. You fix three or four pips around your crack and just measure between them with the calipers. Dead easy.

 

[dik]

and install th'e pins 'square' to the wall... On the concrete nails I use, there's a little bright coloured rubber bushing for centering in the gun. I press this against the concrete substrate so that it's less likely that you're measuring from different locations on the pin. Measurements are taken ea day, then ea week then ea month for six months and then bi-annually depending on the movement observed. By using a vernier caliper, it is possible to locate the pins abour 4" apart and not as likely to be affected or affect the edge of the crack. If the movement exceeds the 6" capacity of the caliper, then you likely have a problem <G>.

Dik

 

[Bagman2524]

I've used a Whitmore strain gauge in the past. Seemed to work well.

 

[archeng59]

good stuff here. never thought about using the pins or nails. thanks.

 

[Ron]

Bagman2524...thanks! I was wracking my little brain to remember the name of that contraption that was sold by Soiltest. The Whittemore gage!

 

[PSlem]

I was never a fan of the nails as homeowners would record distance between two points but could never find the paper a year later. I recommend scribing two right angle lines at a 45* angle across the crack so a straightedge will always show the movement since they were first done. However if you are retained, spend the money for a more professional crack monitor.

 

[dik]

I haven't had any problems with homeowners losing paper and a year later, the distance can still be measured if necessary. Biggest problem is that many homeowners cannot afford the continuous housecalls by an engineer or the cost of recording equipment...

Dik

 

[daveh6729]

jeesh...my speeling is terrible! ~laugh~

 

[boffintech]

Ben Meadows has a crack monitor in their catalog. It's item # 6JF-101757. We have used these on a number of jobs. Although the same appears to be about $1 cheaper at

http://www.avongard.com/ordering.htm

However if you already have an account with BM it may be worth a buck to not deal with accounting.

 

[smullenpe]

My experience has been that plastic crack monitoring gauges works well but only if it's installed properly.

This

http://www.builderswebsource.com/tools/crackmonitor/crackmon.htm

crack monitor gauge seemed same as the avongard except it's cost little more.