STATICPH
Structural
- Sep 15, 2010
- 16
Hi all,
Background:
A client of mine got me involved in a small structure that basically exist out of a single garage front section. His client, an insurance company, requested him to redo the brick work higher than the plinth wall as it had a serious crack in it. However, he disagreed and got me in to convince them that he have to redo the whole structure (including the foundation). I suspected that the soil under the foundation have compressed and therefore the crack patterns.
Structure:
3.5m x 2m, The 3.5m wall have an opening for single garage, and on the sides the walls kick back for 2m, all walls are 3m high.
Remedial work and the root of the evil:
We have done the excavation to find an old garbage pocket under one side (measured 0.8m in the 3.5m direction the rest of the foundation we found a relatively stiff clay)of the structure’s footprint. At present we have removed 2m of garbage and it appear that we still have another meter of rubbish to remove (12mm rod cannot be pushed deeper into the fill), the rubbish have zero bearing strength. We intended to found 600mm under natural ground level....
Possible solution and other issues:
1) Floating raft – support are not favourable. I think that the raft may slip to the one side once foundation pressure is applied – the stiff clay sides might collapse horizontally into the garbage pocket once loaded. The clay wall will be vertical and of unknown depth. Would you agree?
2) "We could excavate all the way to Japan". What happen to garbage once you remove water from it? (it is within a water table or pocket) There is other structures close by that may not be damaged, and no way of knowing how big this garbage pocket is. Can garbage act in a plastic way as with active clay?
Any suggestions?
Background:
A client of mine got me involved in a small structure that basically exist out of a single garage front section. His client, an insurance company, requested him to redo the brick work higher than the plinth wall as it had a serious crack in it. However, he disagreed and got me in to convince them that he have to redo the whole structure (including the foundation). I suspected that the soil under the foundation have compressed and therefore the crack patterns.
Structure:
3.5m x 2m, The 3.5m wall have an opening for single garage, and on the sides the walls kick back for 2m, all walls are 3m high.
Remedial work and the root of the evil:
We have done the excavation to find an old garbage pocket under one side (measured 0.8m in the 3.5m direction the rest of the foundation we found a relatively stiff clay)of the structure’s footprint. At present we have removed 2m of garbage and it appear that we still have another meter of rubbish to remove (12mm rod cannot be pushed deeper into the fill), the rubbish have zero bearing strength. We intended to found 600mm under natural ground level....
Possible solution and other issues:
1) Floating raft – support are not favourable. I think that the raft may slip to the one side once foundation pressure is applied – the stiff clay sides might collapse horizontally into the garbage pocket once loaded. The clay wall will be vertical and of unknown depth. Would you agree?
2) "We could excavate all the way to Japan". What happen to garbage once you remove water from it? (it is within a water table or pocket) There is other structures close by that may not be damaged, and no way of knowing how big this garbage pocket is. Can garbage act in a plastic way as with active clay?
Any suggestions?