Thatcher has been in business for 60 years. We
pride ourselves in our ability to complete projects on time and on budget. We
made our reputation building foundations for some of the largest structures in
Chicago; however, pounding the biggest piece of steel into the ground isn't
always the best solution. Sometimes the job can be done using something
smaller and less intrusive - a micropile
Micropile is
a misnomer. The typical capacities of a micropile are 20 to 100 tons, in
special cases some are greater than 200 tons. Micropiles were developed in the
1950's in Italy as a means to support historic buildings. Originally called
pali radice, they made their way across Europe over the next few years. They
first showed up on this side of the Atlantic in the early 1970's in Boston and
New York. It wasn't long before people started to realize micropiles might
have an application other than underpinning. Construction and material
standards were developed and the micropile was on its way.
Micropiles offer advantages over other types of deep
foundations:
- Micropile pile rigs are
small and able to get into places other
deep foundation rigs can't
- Micropiles are installed
in threaded sections of any length.
This makes micropiles ideal for low
headroom installations
- Micropiles cause minimal
vibration and noise
- Micropiles produce minimal
amounts of spoil. The typical micropile
is five, seven or nine inches in
diameter - much smaller than
other drilled foundations
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Micropiles are made of 50 to 80ksi steel casing and 4,000 to
5,000 psi grout. The casing is drilled down to a pre-determined depth or
socketed into rock, then tremie-filled with grout.
Here are the most popular sizes, assuming allowable steel
stress of 18ksi and 4,000 psi grout:
|
Diameter (in) |
Wall Thickness
(in) |
Weight (lbs./ft.) |
Allowable Load
(tons) |
| 5.0 |
0.362 |
18.00 |
56 |
|
5.5 |
0.415 |
23.00 |
73 |
| 7.0 |
0.498 |
35.00 |
114 |
|
9.625 |
0.545 |
53.50 |
186 |
The typical micropile installation is usually done in conjunction with
another type of foundation method. We can assist in the design of the
foundation system to minimize cost and potential problems. The earlier we are
involved in the process, the more we can help.
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Call us today and let us show you how we can help you complete your project
on time and on budget. |
