Using short piles for foundation of tall structure. Any shortcoming?
Using short piles for foundation of tall structure. Any shortcoming?
(OP)
Hi,
What's the general rule about using short piles for the foundation of tall building? The thing is the ground is neither good nor bad. 250mm square concrete piles only penetrated around 7m into the ground. With pile cap in place we are only looking at around 4.5m pile remaining in the ground supporting the structure. This is no longer so much a friction pile but rather end bearing pile.
Is it ok to use short piles or would I be better off switching to bored pile instead? Assuming over excavation of the ground does not happen and the piles remain in place. How about bearing capacity failure and heaving of the ground? Thanks.
Alex
What's the general rule about using short piles for the foundation of tall building? The thing is the ground is neither good nor bad. 250mm square concrete piles only penetrated around 7m into the ground. With pile cap in place we are only looking at around 4.5m pile remaining in the ground supporting the structure. This is no longer so much a friction pile but rather end bearing pile.
Is it ok to use short piles or would I be better off switching to bored pile instead? Assuming over excavation of the ground does not happen and the piles remain in place. How about bearing capacity failure and heaving of the ground? Thanks.
Alex





RE: Using short piles for foundation of tall structure. Any shortcoming?
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RE: Using short piles for foundation of tall structure. Any shortcoming?
RE: Using short piles for foundation of tall structure. Any shortcoming?
RE: Using short piles for foundation of tall structure. Any shortcoming?
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RE: Using short piles for foundation of tall structure. Any shortcoming?
The stricture is 7 stories high but the base is quite large. So lateral load issue would be minor in this case. My only concern with short piles as aeoliantexan pointed is the strength of the soil underneath to prevent bearing capacity failure. The piles were driven to set so they are founded on very good soil. We will be doing a static pile load test to confirm the capacity and settlement.
We have also decided to set a minimum depth of penetration of 9m for driven piles (before pile caps) and anything shorter than that we will opt for bored piles instead.
The soil we have here in Brunei is highly heterogeneous (if there is such a word) and hence to over excavate and replace with engineered fill for a raft foundation may not be a good way to go. Plus we have not used raft foundation before, experience wise we are kinda short on.
Anyway, thank you for all your responses and will update here when the load tests have been conducted with good results.
Alex
RE: Using short piles for foundation of tall structure. Any shortcoming?
You should make a settlement analysis. (Imaginary footing method, for example.) Then, you should decide on the length of your piles. If settlement is ok and if your piles are safe against the building load (if not increase pile length or diameter) you can go on.
RE: Using short piles for foundation of tall structure. Any shortcoming?
RE: Using short piles for foundation of tall structure. Any shortcoming?