Piling in shallow waters (lake, pond) 2

[evilkudos]

I'm having a problem with piling here. A recent project that we have entails the construction of a theatre within a small pond (roughly 20 by 20, depth of pond roughly 2~3 metres). I am wondering what are the piling techniques available that can circumvent the conditions that we are facing?

1. Since the environment of the pond has to be preserved, we are not allowed to drain any sections of the pond for piling or foundation works.

2. Pollution to the ecosystem must be minimized. (hence eliminating the grouting method)

3. Access to the pond is limited to a small 2 lane road, separated by soft, sloping ground roughly 15 metres from the lake.

Is there anyone here who can offer any suggestions? Are there any conventional methods/ modifications that allows us to circumvent the restrictions imposed?

 

[PEinc]

You might consider helical screw piers such as those made by A. B. Chance Company and other companies. These piers are used often to support boardwalks built out over waterways.

 

[evilkudos]

Thanks for the reply, but the project is situated in Asia where the use of helical foundations are practically non-existant. It would not be cost effective for us to employ overseas contractors for what would be a relatively short work in a small project. Besides, we need to keep the cost down for tendering.

I'm looking more towards any conventional methods that can be used to circumvent the restrictions imposed.

 

[BigH]

Sounds to me as if you should make a drum raft or pontoon raft for piling rig support. Seems, with your restrictions, you are tied to driven piles. You didn't say where in Asia you are located nor the stratigraphy you are encountering (how deep would the piles need to be. In Asia you see a lot of precast concrete piles (say 300mm by 300mm) being used. I would say this would be your best bet. Use combination of raker piles and vertical piles so that your theatre "platform" acts as the pile cap (like a mooring dolphin). This should be as environment friendly as one could expect.