Possible settlement cracking damage?

[mar2805]

Hi!
We were recently called to inspect upon an old Building (80 years old) wich started cracking last 5 years.
In the pictures attached you can see how almost every window or opening has diagonal cracks coming from the corners of the opening.
On the internal corner of the Building you can clearly see a large crack propagading up to the roof and on one facade there is a crack wich started on the roof and goes all the way down to the ground.
Building bearing walls are made from stone and mortar and are 60cm thick.
Slabs are from wooden beams covered with planks and boards.
Roof is wooden truss wich suprisingly has no damage at all.

My First gues is that these crack are from diferential settelemts.
Walls, not having any reinforcement, so an non-ductile elements started to crack imedeiatly upon "sinking"
Whats you opinion?

http://postimg.org/image/6el2tnyed/

http://postimg.org/image/c593gs823/

http://postimg.org/image/lpki2s5zh/

http://postimg.org/image/6qjfxublf/

p.s. download images to your disk so you can zoom in.

 

[oldestguy]

What country and what general soil types? I suspect shrinkage of soil due to trees taking moisture. Any trees nearby on the side suspected of settling?

 

[mar2805]

LOTS OF TREES NEARBY!
Around 12 pices!
To be more specific, lots of these:

http://en.wikipedia.org/wiki/Stone_pine

Around 4-6 pices only near the facade that has this crack from roof to the ground
Some of them have been cut down.
You can see the trunks let behind in this picture attached

http://postimg.org/image/oulfygpo7/

 

[oldestguy]

Is the soil type a medium to high plasticity clay? If so, shrinkage can extend very deep and a considerable distance from trees. I'd not do any drastic action until at least a check of soil types and the moisture conditions has been made. Underpinning usually not recommended, since shrinkage can be reversed.

I know of several cases where the shrinkage has been reversed by watering the ground at the building. Removal of trees also has worked, but more slowly.

 

[Ron]

Agree with oldestguy...since the building has been in place for 80 years and the issue is recent, probably related to trees pulling moisture from soil, thus increasing stress from the building. Also look at changes in drainage characteristics of the area...has there been a recent nearby development? Has anything nearby artificially (temporary or permanently) lowered the water table?

 

[mar2805]

Sorry for this looong delay.
The soil inspection will be in 6 months or so then we will Know egsact groung parametars.
In the mean time we also found out that the whole Building waste water is going into this old concrete septic tank located in front of the Building. YOu can see how near this is. The question of waterproof of this old tank is also questionable. If leaking the water will moist the ground directly under the foundations.

 

[oldestguy]

Assuming this is high plasticity clay ground, there could well be two things happening. The trees are drawing water out, with most effect near them and the tank is leaking into what had been "shrunken" ground and is causing expansion. Note how it is higher than adjacent ground. Also, its weight (density) is much less than soil near it.

I noted on one of my jobs (a school room building) where floors raised due to expanding clay and nearby footings didn't lift as much. Talk about a mess!!!