different of micro piles and piles

[sese]

is there different between piles and micro piles or it just the name and the only different is in the dimension.

 

[PEinc]

You know what regular piles are. Micro piles (also called minipiles and pin piles) are small diameter piles which are drilled and grouted into the ground, more similar to tiedown anchors. They usually use some type of steel bar or bars and/or steel casing pipe. The bar(s) is(are) grouted into the ground and/or the casing pipe is filled with grout. Search the web for micro piles, Nicholson Construction, Schnabel Foundation Company, or Moretrench American Corporation.

 

[rchanke]

A conventional pile is either steel or reinforced concrete, and either driven or cast inplace. These elements are generally quite large and involve some heavy equipment and large staging areas for installation. Conversely, micropiles can be used in applications where conventional piling is not convenient or possible, such as for underpinning or retrofitting existing buildings or structures. In addition a common application is the RMPW "Reticulated MicroPile Wall" for slope stability. As PEinc mentioned a micropile will be comprised of some kind of grout and a smaller steel element, either rebar or small diameter steel casing. I've recently been involved with an underpinning project where micropiles (steel casing) was/where installed into jet grouted soilcrete columns. What this yielded was a grout filled steel element encompassed in a soilcrete/grout column of a significant diameter (4-ft) where conventional piles of a similar axial capacity just could not be installed for access reasons.

Check out

http://tc17.poly.edu/mp.html

or

http://www.haywardbaker.com

This should give you a good start on micropiles.

 

[Anchorboy]

Conventional piling does require large equipment, however, you'll never drive thru N>100 anyhow so now that your into drilling then economically it makes sense to install micropiles.

Typically, micropiles have a cased upper length and resist compression and lateral forces well.

 

[Focht3]

Be careful on the lateral capacity! About 95% of the EI is developed in the steel casing. The joints are severe weak points - testing done at Illinois-Urbana shows that the joints may only provide 50% of the capacity of the "intact" pile sections...



Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See faq158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"

 

[pmkPE]

Try ABChance web site for gravity grouted micro piles. They use helical anchors/piles and allow a gravity feed of concrete/grout to form a column around the pile shaft which then adds resistance through friction in addition to "point" bearing at the helical plates.