Excavation earth retaining structural system
Excavation earth retaining structural system
(OP)
I recently received shop drawings which shows an earth retaining structural system that I am not familiar with. The excavation is for the underground floors of a building. I would really appreciate it if someone can tell me the name of this structural system. It is essentially unreinforced concrete piles side by side that overlap 6" to each other and every 4rth concrete pile contains a structural steel member within it.
The intermediate unreinforced concrete piles (3 side by side) between the piles which contain the steel section are not embedded very deep into the soil (maybe 1') as compared to the piles with the steel section. The piles are 3' in diameter. Is this standard practice? Also, how can unreinforced concrete piles transfer one-way bending between the piles with the steel support? The concrete piles with the steel section are 11' apart approximately. Is the 6" overlap between each pile (I suppose they drill when the concrete is still fresh) have sufficient bond/shear transfer capabilities?
Thank you.
The intermediate unreinforced concrete piles (3 side by side) between the piles which contain the steel section are not embedded very deep into the soil (maybe 1') as compared to the piles with the steel section. The piles are 3' in diameter. Is this standard practice? Also, how can unreinforced concrete piles transfer one-way bending between the piles with the steel support? The concrete piles with the steel section are 11' apart approximately. Is the 6" overlap between each pile (I suppose they drill when the concrete is still fresh) have sufficient bond/shear transfer capabilities?
Thank you.






RE: Excavation earth retaining structural system
What so the calcs say? If they say nothing, I would require re-submittal with calcs showing how the system works
RE: Excavation earth retaining structural system
Thank you for the response. Would you know what the name is for this system?
There is no shotcrete. Calcs only show the capacity of the piles, nothing about load transfer between across the three unreinforced pile.
RE: Excavation earth retaining structural system
RE: Excavation earth retaining structural system
1. Retain any minor sluffing between the two steel pile, and
2. Serve as restraint against lateral buckling for the steel pile.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Excavation earth retaining structural system
RE: Excavation earth retaining structural system
The soil arches which reduces the load on the intermediate piers to something less than the full soil load, but they still need to span horizontally to the reinforced piers. They are glorified lagging so you still need some ability to span horizontally.
GalileoG,
The soil will arch. I was thinking that if the retained soil has a fair amount of cohesion it may be self supporting between the piers
RE: Excavation earth retaining structural system
This type of system is called a secant pile wall.
Hope this helps.
Brandon
RE: Excavation earth retaining structural system
The comments are arching is correct. Will arching occur? Depends on the soil structure. Sand would just run on you where something clayey may arch. This information has to come from the Geotechnical engineer.
RE: Excavation earth retaining structural system