Micropile, Screw Piles, and Helical Piers in Illinois & Missouri
Helical piles are a factory-manufactured steel foundation system consisting of a central shaft with one or more helix-shaped bearing plates, commonly referred to as blades or flights, welded to the lead section. Extension shafts, with or without additional helix blades, are used to extend the pile to competent load-bearing soils and to achieve design depth and capacity. Brackets are used at the tops of the piles for attachment to structures, either for new construction or retrofit applications. Helical piles are advanced (screwed) into the ground with the application of torque.
The terms helical piles, screw piles, helical piers, helical anchors, helix piers, and helix anchors are often used interchangeably by specifiers. However, the term 'pier' more often refers to a helical pile loaded in axial compression, while the term 'anchor' more often refers to a helical pile loaded in axial tension.
Helical piles are designed such that most of the axial capacity of the pile is generated through bearing of the helix blades against the soil. The helix blades are typically spaced three diameters apart along the pile shaft to prevent one blade from contributing significant stress to the bearing soil of the adjacent blade. Significant stress influence is limited to a 'bulb' of soil within about two helix diameters from the bearing surface in the axial direction and one helix diameter from the center of the pile shaft in the lateral direction. Each helix blade therefore acts independently in bearing along the pile shaft.
Multiple piles shall have a center to center spacing at the helix depth of at least four (4) times the diameter of the largest helix blade (ICC-ES AC358). The tops of the piles may be closer at the ground surface but installed at a batter away from each other in order to meet the spacing criteria at the helix depth. For tension applications, the uppermost helix blade shall be installed to a depth of at least twelve (12) diameters below the ground surface (ICC-ES AC358).
Maximum Allowable Mechanical Shaft Capacities (3,5)
Default Torque Correlation Factor (6) Kt (ft-1)
Maximum Installation Torque (ft-lbs)
Maximum Ultimate Torque Correlated Soil Capacity (6,7)Qu = Kt X T (kips)
Axial Compression (kips)
Axial Tension (kips)
Governed by AISC allowable capacity of single Ø3/4" (HA150) or (2) Ø3/4" (HA175) Grade 8 bolt(s) in double shear.
Governed by bearing at the bolt holes.
Capacities include a scheduled loss in steel thickness due to corrosion for black, uncoated steel. Scheduled thickness losses are for a period of 50 years and are in accordance with ICC-ES AC358.
Allowable compression capacities are based on continuous lateral soil confinement in soils with SPT blow counts ≥ 4.Piles with exposed unbraced lengths or piles placed in weaker or fluid soils should be evaluated on a case by case basis by the project engineer.
Listed mechanical capacities are for the shaft only. System capacities should also not exceed the installed torquecorrelated capacity or those listed in the respective bracket capacity tables.
Listed default Kt factors are widely accepted industry standards. They are generally conservative and are consistent with those listed in ICC-ES AC358. Site-specific K t factors can be determined for a given project with full-scale load testing.
Soil capacities listed are ultimate values at maximum installation torque. Allowable soil capacity values are obtained by dividing the ultimate values by the appropriate factor of safety (FOS). FOS is most commonly taken as 2.0, although a higher or lower FOS may be considered at the discretion of the helical pile designer or as dictated by local code requirements.
Square shaft piles may be considered for compression applications in soil profiles that offer sufficient continuous lateral support; e.g., in soils with SPT blow counts ≥ 10. Even in these higher strength soil conditions, buckling analyses should be considered, taking into account discontinuities and potential eccentricities created by the couplers
The ultimate capacity of a helical pile may be calculated using the traditional bearing capacity equation:
Qu = ? [Ah (cNc + qNq)]
Ultimate Pile Capacity (lb)
Area of Individual Helix Plate (ft2)
Effective Soil Cohesion (lb/ft2)
Dimensionless Bearing Capacity Factor = 9
Effective Vertical Overburden Pressure (lb/ft2)
Dimensionless Bearing Capacity Factor
Total stress parameters should be used for short-term and transient load applications and effective stress parameters should be used for long-term, permanent load applications. A factor of safety of 2 is typically used to determine the allowable soil bearing capacity, especially if torque is monitored during the helical pile installation.
Like other deep foundation alternatives, there are many factors to be considered in designing a helical pile foundation. Foundation Supportworks™ recommends that helical pile design be completed by an experienced geotechnical engineer or other qualified professional.
Another well-documented and accepted method for estimating helical pile capacity is by correlation to installation torque. In simple terms, the torsional resistance generated during helical pile installation is a measure of soil shear strength and can be related to the bearing capacity of the pile.
Qu = KT
Ultimate Pile Capacity (lb)
Capacity to Torque Ratio (ft-1)
Installation Torque (ft-lb)
The capacity to torque ratio is not a constant and varies with soil conditions and the size of the pile shaft. Load testing using the proposed helical pile and helix blade configuration is the best way to determine project specific K-values. However, ICC-ES AC358 provides default K-values for varying pile shaft diameters, which may be used conservatively for most soil conditions. The default value for the Model 288 Helical Pile System (2 7/8-inch diameter) is K = 9 ft-1.
Serving MO & IL including the Greater St. Louis area
Cities in Alexander County, IL Cairo Mc Clure Miller City Olive Branch Tamms Thebes Unity
Cities in Bond County, IL Greenville Mulberry Grove Pierron Pocahontas Smithboro Sorento
Cities in Calhoun County, IL Batchtown Brussels Golden Eagle Hamburg Hardin Kampsville Michael Mozier
Cities in Cass County, IL Arenzville Ashland Beardstown Bluff Springs Chandlerville Virginia
Cities in Champaign County, IL Bondville Broadlands Champaign Dewey Fisher Foosland Gifford Homer Ivesdale Longview Ludlow Mahomet Ogden Penfield Pesotum Philo Rantoul Royal Sadorus Saint Joseph Savoy Seymour Sidney Thomasboro Tolono Urbana
Cities in Christian County, IL Assumption Bulpitt Edinburg Kincaid Morrisonville Mount Auburn Moweaqua Owaneco Palmer Pana Rosamond Stonington Taylorville Tovey
Cities in Clark County, IL Casey Dennison Marshall Martinsville West Union Westfield
Cities in Clay County, IL Clay City Flora Ingraham Louisville Sailor Springs Xenia
Cities in Clinton County, IL Albers Aviston Bartelso Beckemeyer Breese Carlyle Germantown Hoffman Huey Keyesport New Baden New Memphis Trenton Clinton County
Cities in Marion County, IL Alma Centralia Iuka Kell Kinmundy Odin Patoka Salem Sandoval Vernon Walnut Hill
Cities in Mason County, IL San Jose
Cities in Massac County, IL Brookport Joppa Metropolis
Cities in Mclean County, IL Bellflower
Cities in Menard County, IL Athens Greenview Oakford Petersburg Tallula
Cities in Monroe County, IL Columbia Fults Hecker Maeystown Renault Valmeyer Waterloo
Cities in Montgomery County, IL Butler Coffeen Donnellson Farmersville Fillmore Harvel Hillsboro Irving Litchfield Nokomis Ohlman Panama Raymond Taylor Springs Waggoner Walshville Witt
Cities in Morgan County, IL Alexander Chapin Concord Franklin Jacksonville Literberry Meredosia Murrayville Waverly Woodson
Cities in Moultrie County, IL Bethany Dalton City Gays Lovington Sullivan
Cities in Perry County, IL Cutler Du Quoin Pinckneyville Tamaroa Willisville
Cities in Piatt County, IL Bement Cerro Gordo Cisco De Land Hammond La Place Mansfield Milmine Monticello White Heath
Cities in Pope County, IL Eddyville Golconda Herod
Cities in Pulaski County, IL Grand Chain Karnak Mound City Mounds Olmsted Perks Pulaski Ullin Villa Ridge
Cities in Randolph County, IL Baldwin Chester Coulterville Ellis Grove Evansville Menard Modoc Percy Prairie Du Rocher Red Bud Rockwood Sparta Steeleville Tilden Walsh
Cities in Richland County, IL Calhoun Claremont Dundas Noble Olney Parkersburg
Cities in Saint Clair County, IL Belleville Caseyville Dupo East Carondelet East Saint Louis Fairview Heights Freeburg Lebanon Lenzburg Lovejoy Marissa Mascoutah Millstadt National Stock Yards New Athens O Fallon Saint Libory Scott Air Force Base Smithton Summerfield
Cities in Saline County, IL Carrier Mills Eldorado Galatia Harrisburg Muddy Raleigh Stonefort
Cities in Sangamon County, IL Auburn Buffalo Cantrall Chatham Dawson Divernon Glenarm Illiopolis Loami Lowder Mechanicsburg New Berlin Pawnee Pleasant Plains Riverton Rochester Sherman Springfield Thayer Williamsville
Cities in Scott County, IL Alsey Bluffs Manchester Winchester
Cities in Shelby County, IL Cowden Findlay Herrick Lakewood Mode Oconee Shelbyville Sigel Stewardson Strasburg Tower Hill Windsor
Cities in Union County, IL Alto Pass Anna Cobden Dongola Jonesboro Millcreek Wolf Lake
Cities in Vermilion County, IL Allerton Alvin Armstrong Bismarck Catlin Collison Danville Fairmount Fithian Georgetown Henning Hoopeston Indianola Muncie Oakwood Potomac Rankin Ridge Farm Rossville Sidell Tilton Westville
Cities in Wabash County, IL Allendale Bellmont Keensburg Lancaster Mount Carmel
Cities in Washington County, IL Addieville Ashley Du Bois Hoyleton Irvington Nashville Oakdale Okawville Radom Richview
Cities in Wayne County, IL Barnhill Cisne Fairfield Geff Golden Gate Johnsonville Keenes Mount Erie Rinard Sims Wayne City
Cities in White County, IL Burnt Prairie Carmi Crossville Emma Enfield Grayville Maunie Mill Shoals Norris City Springerton
Cities in Williamson County, IL Cambria Carterville Colp Creal Springs Energy Freeman Spur Herrin Hurst Johnston City Marion Pittsburg
Cities in Bollinger County, MO Gipsy Glenallen Leopold Marble Hill Patton Sedgewickville Sturdivant Zalma
Cities in Cape Girardeau County, MO Altenburg Burfordville Cape Girardeau Daisy Delta Friedheim Jackson Millersville Oak Ridge Old Appleton Whitewater
Cities in Carter County, MO Ellsinore
Cities in Crawford County, MO Bourbon Cook Sta Cuba Leasburg Steelville Wesco
Cities in Franklin County, MO Catawissa Grubville Lonedell Luebbering Pacific Robertsville Saint Clair Sullivan
Cities in Iron County, MO Annapolis Arcadia Belleview Bixby Des Arc Ironton Middle Brook Viburnum Vulcan
Cities in Saint Francois County, MO Bismarck Blackwell Bonne Terre Doe Run Farmington French Village Leadwood Park Hills Valles Mines
Cities in Saint Louis County, MO Ballwin Bridgeton Chesterfield Earth City Eureka Fenton Florissant Glencoe Grover Hazelwood Maryland Heights Saint Ann Saint Louis Valley Park Affton Allenton Berkeley Black Jack Brentwood Clayton Crestwood Creve Coeur Des Peres Ellisville Ferguson Frontenac Jennings Kinloch Kirkwood Ladue Manchester Maplewood Normandy North County Oakville Olivette Overland Richmond Heights Rock Hill Saint John Sappington Shrewsbury Sunset Hills Town And Country University City Warson Woods Webster Groves West County Wildwood Winchester Woodson Terrace
Basement wall cracks like this one in Sullivan, Illinois allow water to leak in and potentially flood a basement. Woods Basement systems installs the FlexiSpan wall crack repair system to seal the crack and prevent further leakage.
The dirt crawl space in this Saint Louis, Missouri home...
The dirt crawl space in this Saint Louis, Missouri home was filthy, cluttered, and exposed to high humidity and mold growth. Woods Basement Systems installed a SmartSump sump pump system, sealed the crawl space with the CleanSpace vapor barrier, and installed the SaniDry dehumidification system to keep this crawl space clean and dry.
This Granite City, Illinois home suffered major damage after its...
This Granite City, Illinois home suffered major damage after its foundation wall bowed inward leaving nothing to support this external brick wall. As the foundation moved further away from the brick wall the brick wall began to sink which resulted in the damage shown in the before picture. Woods Basement Systems installed several foundation repair systems such as piers and anchors. After the foundation was repaired Woods Basement Systems installed basement waterproofing products such as WaterGuard and an UltraSump. WaterGuard is unique in that it sits on the footing of a home's foundation which keeps the WaterGuard from getting clogged up with dirt and mud. Damage such as the damage pictured can ocurr if foundation problems are ignored for too long. If you see that your basement walls are beginning to crack it is imperative that a foundation specialist diagnose the extent of the damage.
This Granite City, Illinois home had major foundation trouble originating...
This Granite City, Illinois home had major foundation trouble originating from a bowing foundation wall. As the wall bowed inward the brickwork on the exterior of the home began to sink which resulted in the damage shown in the before picture. Woods Basement Systems installed several foundation repair products ranging from piering to anchors and even installed waterproofing to ensure the basement did not end up flooded.
This Ballwin, Missouri home had water leaking in at the...
This Ballwin, Missouri home had water leaking in at the base of its walls. Woods Basement Systems installed WaterGuard to prevent water from building up around the outside of the walls of this basement. Water buildup can create hydrostatic pressure which leads to problems other than water leakage. WaterGuard is unique in that it sits on the footing of a home's foundation rather than in the dirt which prevents the WaterGuard from becomming clogged with dirt or mud. (please note that the concrete in the picture had not had time to cure prior to the taking of the picture)
This Ballwin, Missouri home had a sump pump installed by...
This Ballwin, Missouri home had a sump pump installed by Woods Basement Systems. Woods Basement Systems offers several waterproofing options ranging from sump pumps to WaterGuard. WaterGuard was also installed in this home. WaterGuard is a system designed to prevent water from building up around the walls of a home which can create hydrostatic pressure and cause problems other than leakage. (please note that the concrete in this photograph had not had time to cure prior to the taking of the photograph)
This Chesterfield, Missouri basement has leaks that leave the basement...
This Chesterfield, Missouri basement has leaks that leave the basement floor covered with water. In the before picture we see an entry point for water. WaterGuard was installed in this home which is a unique waterproofing system in that it sits on the footing of the home's foundation rather than in the mud which prevents the WaterGuard from clogging with mud. (please note that the concrete in the after picture had not had time to cure prior to the taking of the picture)
This O'Fallon, Missouri home had a sump pump but lacked...
This O'Fallon, Missouri home had a sump pump but lacked any other form of waterproofing. Woods Basement Systems serviced the existing sump pump and installed WaterGuard. WaterGuard is a waterproofing system that shunts water away from the home. WaterGuard is unique in that it sits on top of the footing of the home which prevents it from filling with dirt and mud.
This St. Louis, Missouri home had bowing walls as well...
This St. Louis, Missouri home had bowing walls as well as wall cracks. Woods Basement Systems installed wall anchors to repair the bowing walls. FlexiSpan is used to effectively repair and waterproof wall cracks.
This Ballwin, Missouri home had cracked walls as well as...
This Ballwin, Missouri home had cracked walls as well as bowing walls. Woods Basement Systems installed wall anchors to correct the bowing wall. FlexiSpan can be used to effectively repair and waterproof a wall crack.
Woods Basement Systems came into this St. Louis, Missouri home...
Woods Basement Systems came into this St. Louis, Missouri home to install a new sump pump. Woods Basement Systems offers various waterproofing options including WaterGuard. WaterGuard is unique in that it sits on top of the footing of a home which prevents it from becoming clogged with dirt and mud.
This Gerald, Missouri home had water leaking in around the...
This Gerald, Missouri home had water leaking in around the door shown. Adding a drain and WaterGuard in front of the door prevents water from leaking into the home. Woods Basement Systems offers several waterproofing systems that prevent water from entering a home. (please note that the concrete in the after photograph had not had time to cure prior to the taking of the picture)
This St. Peters, Missouri home had bowing walls which can...
This St. Peters, Missouri home had bowing walls which can lead to wall cracks that allow water to seep into a basement. Woods Basement Systems installed wall anchors to return the walls to their original shape.
This St. Louis, Missouri basement didn't have any form of...
This St. Louis, Missouri basement didn't have any form of waterproofing or a sump pump. Woods Basement Systems installed an UltraSump and WaterGuard. WaterGuard is unique in that it is installed on the footing of the home which prevents it from clogging with dirt. (please note that the concrete in the after picture had not had time to cure prior to the taking of the picture)
This St. Charles, Missouri crawl space had a dirt floor...
This St. Charles, Missouri crawl space had a dirt floor that was beginning to collect water. When water and dirt mixes mold begins to grow which creates foul odors. Installing CleanSpace in a crawl space provides an effective vapor barrier that prevents mold growth.
This Frontenac, Missouri crawl space had a dirt floor that...
This Frontenac, Missouri crawl space had a dirt floor that was holding water which is a formula for mold growth which causes foul odors. Woods Basement Systems installed CleanSpace which acts as a vapor barrier and also provides a clean area for the homeowner to use as storage.
This Westville, Illinois sump pump was outdated and inefficient. Woods...
This Westville, Illinois sump pump was outdated and inefficient. Woods Basement Systems installed a new sump pump with a battery backup. The battery backup means that even if the power goes out during a storm the sump pump will continue to run and keep water from filling the basement. Woods Basement Systems also offers several other waterproofing options to ensure that water nevers makes it inside the home.
This building in Hoopeston, Illinois has bowing walls which the...
This building in Hoopeston, Illinois has bowing walls which the occupants attempted to repair using caulk which does not fix a bowing wall problem, it merely covers it until it gets worse. Woods Basement Systems diagnosed the bowing walls and installed an anchor system to not only stop the walls from bowing in further but also to return the walls to their original shape.
This Belleville, Illinois home's walls were beginning to bow. Installing...