2820 E. Michigan Ave.
Ypsilanti, MI 48198

Phone: (734) 528-3100
Fax: (734) 528-2478
info@niemicorp.com



FOUNDATION PILING



We specialize in many types of piling. Our crews can expertly install sheet piling, timber piling, auger cast piling, pipe piling, H-piles and helical piles/piers. Our staff can assist with specifying the proper piling material for your job, or we can easily work with your engineers to successfully complete any project. Below are pictures of projects we have recently completed.



Steel H-piles



H-Piles are a low displacement pile that are typically installed using impact pile hammers. Foundation H-piles are used to support the foundation loads of buildings, bridges and other structures on soil that may otherwise be unsuitable, by transferring the foundation loads to more suitable bearing strata, such as hardpan or bedrock. Common HP sizes are 8”, 10”, 12”, & 14”.



Steel pipe piles



Steel pipe piles are a higher displacement pile than an H-pile, and are typically installed using impact pile hammers. Like H-piles, foundation pipe piles are used to support the foundation loads of buildings, bridges and other structures on soil that may otherwise be unsuitable, by transferring the foundation loads to more suitable bearing strata, such as hardpan or bedrock. Pipe piles can be installed open-ended, or close-ended with a boot plate (end-closure plate) attached to the tip of the pipe. Typically closed-ended pipe piles are filled with concrete after they are driven to bearing. Even though close-ended pipe piles may displace more soil as the are being driven, soil displacement can be minimized by predrilling the pile locations prior to the pile being installed.



Timber Piles



Timber piles can be used for structure foundation support, typically where there are lighter load requirements. Timber piles are typically installed with impact and vibratory pile hammers. Timber piles can be CCA pressure treated or untreated. Timber piles are also used in marine applications for docks, mooring piles, fender systems, and dolphin piles.



Helical Piers/Piles



Helical piers or piles can be used for new structure foundation support and underpinning of existing footings and foundations. Helical piers typically come in round shaft or square shaft segments. The lead or bottom section has a series of helices, with common diameters being 8”, 10”, 12”, & 14”. Helical piers are installed utilizing a hydraulic drive motor attachment mounted on a backhoe, excavator, or skid steer loader. The lead section (with the helices) is installed first by rotating it into the soil. Once the lead section is drilled in, extension sections are then bolted on using a mechanical coupling, and the helical pier is advanced further into the soil, adding on additional extensions as needed, until the desired capacity is reached. The capacity is generally determined using a torque indicator where a formula is used to interpret the torque into the capacity.


Helical piers can also be load tested to verify capacity.


The Niemi Corporation is a certified A.B. Chance helical product installer.



Auger Cast piles



Auger cast piles are installed my utilizing a drilling system comprised of a hydraulically driven drill with a hollow stem continuous-flight auger (CFA). Common auger cast pile diameters range from 12” to 24”. Auger cast piles can be used for foundation support, similar to steel H-piles, pipe piles, or timber piles however instead of utilizing pile hammers, an auger cast pile is installed by drilling vertically into the soil with the CFA down to a specified tip elevation. Once the drilling depth is achieved, a grout pump is used to pump fluid grout through a series of grout hosed through the drill unit, down through the stem of the CFA, where the grout then is forced out a porthole at the bottom (or cutting head) of the CFA. The grout is continued to be pumped for a brief period of time before the auger starts to be slowly extracted out of the hole. As the CFA is extracted, the pressurized grout continues to fill the void, eventually forming the auger cast pile. Once the CFA is fully extracted, resteel can be inserted vertically into the fluid grout.

Auger cast piles can also be used as earth retention systems by drilling series of auger cast piles, side-by-side to form either a tangential or secant auger cast pile retaining wall.


Pile load testing



The capacity of foundation piles can be verified by performing a load test. A load test can be either a static load test or a dynamic load test utilizing the Pile Driving Analyzer (PDA).


Piles can be statically load tested to verify compressive, tensile and/or lateral capacities. We perform our compressive static load tests per ASTM D 1143, our tensile static load tests per ASTM D 3689, and our lateral load tests per ASTM D 3966.


A static load test involves utilizing a hydraulic ram to jack against the pile being tested, or test pile, in a series of set load increments over a period of time, and measuring the distance the pile moves under the loads utilizing a series of dial gauges mounted to the test pile. Once the test load is reached, usually twice the pile design load for compression piles, the load is held for a period of time, afterwhich the loads are removed incrementally and the amount the pile rebounds is measured and recorded.


Usually a loading crib or reaction pile with a frame is constructed to be used for the ram to jack against and force the test pile down (for compressive tests), up (for tensile tests), or horizontally (for lateral tests).


A less expensive and less time-consuming method of pile load testing is dynamic pile testing, utilizing a Pile Driving Analyzer. In this method, a series of strain-gauges are mounted within the top few feet of the pile, and are either hard wired though a series of cables, or a wireless remote transponder is connected to a PDA monitor on the ground. As the test pile is driven, information such as stress/strain, pile hammer efficiency and capacity are instantaneously fed to the technician on the ground through the PDA.