Basement dewatering

[longisland]

Hi,
I'm designing a carpark basement of a office tower. the basement is 3 ft below mean sea level & the water level recorded in the piezometer is roughly the same level. I'd appreciate if someone can shed some light on how to to ensure the basement is not subject to flood.
th

thanks

 

[Ron]

Are you concerned about flooding or moisture intrusion due to groundwater impingement? They are handled differently. Flooding is mitigated by correcting the drainage paths (divert from entry to basement). Moisture intrusion is mitigated by appropriate waterproofing of the basement walls, preferably on their outside surfaces.

Ron

 

[longisland]

Hi,
It's flooding I'm worried. I'm hoping to get more ideas on how to divert the ground water away from the building.

thanks

 

[Focht3]

What are the subsurface conditions? Sand? Gravel? Clay?

I think that you should be concerned with both moisture intrusion and flooding - and handle them at the same time. (You are likely to have a problem with variations in water levels due to tides and weather conditions, and your true water levels are probably closer to MSL. And moisture intrusion can lead to mold and mildew problems.) You'll need subfloor and wall drains (with continuous filter beds) as well as wall waterproofing.

The actual filter design and collector system design will depend on the subsurface conditions, problem geometry,etc.