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 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 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 Marion County, IL Alma Centralia Iuka Kell Kinmundy Odin Patoka Salem Sandoval Vernon Walnut Hill
Cities in Massac County, IL Brookport Joppa Metropolis
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 Pike County, IL Barry Baylis Chambersburg Griggsville
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 Stark County, IL Bradford Castleton La Fayette Speer
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 Clinton County, IL Clinton County
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 Crawford County, MO Bourbon Cook Sta Cuba Leasburg Steelville Wesco
Cities in Dunklin County, MO Arbyrd Campbell Cardwell Clarkton
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
The before photo shows a cracked foundation wall in this Saint Louis home. Woods Basement Systems was able to repair the crack using the FlexiSpan crack repair system. The FlexiSpan system helps keep this basement dry by repairing, sealing, and keeping groundwater from leaking through the crack.
This Wright City homeowner was losing sleep over the bowed...
Wall Bowing 10 Inches in Wright City, MO Earth Home
This Wright City homeowner was losing sleep over the bowed wall in his earth home. Literally...his bedroom was one of the room located along the foundation wall that bowed in 10 inches. He called Woods Basement Systems, and System Design Specialist Rich Obermeier proposed 8 Geo-Lock™ wall anchors to stabilize the wall and prevent further movement.
One wall of this Wright City, Missouri earth home tilted...
One wall of this Wright City, Missouri earth home tilted in 10 inches, which led to a concerned homeowner contacting Woods Basement Systems to fix the wall. System Design Specialist Rich Obermeier surveyed the problem and recommended 8 Geo-Lock™ wall anchors to secure the wall and pull it back into place. The homeowner will not have to worry about any future movement, and the warranty is good for the life of the structure.
This crawl space in Anna, Illinois was a swamp. Resting...
This crawl space in Anna, Illinois was a swamp. Resting on a stone foundation, nothing separated the house above from the damp earth below except a thin plastic sheet. This sheet had torn and uncovered much of the dirt floor. Standing water and humidity created a musty smell that concerned the homeowner. Woods Basement Systems installed the CleanSpace vapor barrier to seal off the dirt floor, and the SmartSump sump pump system took care of the groundwater seepage.
This crawl space in Anna, IL rests on a stone foundation. Failed remnants of a thin vapor barrier could be seen before the project began. With nothing isolating the home from the damp earth below, groundwater seepage and humidity turned the crawl space into a swamp. Woods Basement Systems installed CleanSpace—a strong and durable vapor barrier—to seal off the dirt floor and encapsulate the crawl space, and we installed a SmartSump sump pump system to tackle the groundwater problem.
Basement are places where high humidity may collect and then...
Condensation From High Humidity in a Basement in Florissant, MO
Basement are places where high humidity may collect and then condensation issues may arise. Water vapor condenses on duct work when the AC is running and/or cold water pipes. In this case it was the water softener, full of cool water, causing condensation on the outside of the tank. So much water vapor reverted back to water, running down the tank, and making the basement floor so wet the homeowner thought they had a seepage problem. But it had not rained for a couple of weeks...?
SaniDry® took care of the problem. Our dehumidifier runs off of the same 6.8 AMPs as a 40 pint dehumidifier but ours is rated at 100 pints. It's LARGE blower can move the air better too but it is not noisy. We have a SaniDry® that is a low profile model for crawl spaces too.
This O'Fallon, Missouri crawl space had a vapor barrier installed...
This O'Fallon, Missouri crawl space had a vapor barrier installed to control moisture, however, their sump pump pit was holding water and did not have a sealed lid, which was allowing moisture to evaporate into the space any way.
Our CleanSpace® encapsulation vapor barrier seals the walls and dirt floor of a crawl space. Our crawl space sump pump, SmartSump®, has a sealed lid, high water alarm that could be connect via a smart device or home sercurity system, and battery backup sump pump.
Dirt crawl space problems like mold, wood rot, along with...
Dirt crawl space problems like mold, wood rot, along with high utility bills are common. We helped solve these problems in this Shiloh, Illinois home with our CleanSpace® vapor barrier and crawl space liner, designed to keep the space clean and dry!
Having a large sump pump pit with a single pump...
Having a large sump pump pit with a single pump is not enough to keep your basement dry all the time. For this St. Louis, Missouri basement, we installed our TripleSafe® sump pump system, which has three pumps. One is a battery backup sump pump. It also has a sealed lid, radon safe floor drain in the lid for condensation lines, high water alarm which can be designed to notify you on a smart device or home security system, and pump stands for elevating one of the other two pumps to alternate when they would run and pump water out of the basement.
Before this Carbondale, Illinois project began, mudflow had to be...
Stabilizing & Waterproofing Carbondale, IL Block Foundation
Before this Carbondale, Illinois project began, mudflow had to be cleaned up. The block foundation had cracked and bowed under hydrostatic pressure, the basement had leaked, and mud was everywhere. To secure the block foundation walls, Woods Basement Systems installed Geo-Lock™ wall anchors. Once the foundation was stabilized, a waterproofing systems was installed around the perimeter. The WaterGuard system rests on the concrete footing around the perimeter just below the slab floor. The WellDuct system catches water that would otherwise build up inside the window well and drains the water to the WaterGuard and away to the sump pump. This homeowner chose a dual sump pump system for double protection against groundwater seepage and a WaterWatch alarm to alert him of primary pump failure.
A stair-stepping crack through the brickwork is a possible sign...
Settling Foundation & Stair-Step Crack in Freeburg, IL
A stair-stepping crack through the brickwork is a possible sign of a foundation that is settling. These Freeburg, Illinois homeowners called us to take care of the crack and inspect their foundation.
Our push piers are placed beneath the foundation wall by removing some of the footing so the pier bracket fits close to the vertical foundation wall. The hydraulic ram smoothly installs the pier tubing and the excavated holes are filled in when completed.
Foundation wall cracks may be visible from the outside, but in...
Leaking Cracks in a Finished Basement in West Frankfort, IL
Foundation wall cracks may be visible from the outside, but in a finished basement they are hidden behind walls and insulation.
To make sure leaky cracks did not ruin this West Frankfort, Illinois finished basement again, a full perimeter WaterGuard® waterproofing drainage system with battery backup sump pump was necessary. Also, all wall cracks needed to be sealed to prevent leaks from causing mold and damage behind the finished walls. Our FlexiSpan® is combined with our waterproofing system sealing the entire wall crack from the top to down to the floor.
Street creep is when pressure from the roadway pushes the...
Typically, floor cracks are the last part of the basement to leak, but with a crack this size, waterproofing it before finishing a basement is important. Also, for the size of this St. Peters, Missouri basement, we installed another sump pump in the opposite corner from the one put in at the time of construction.
Our WaterGuard® has an ICC number to meet the new...
Our WaterGuard® has an ICC number to meet the new construction building code. Waterproof the basement right the very first time and save the headache and additional cost of having us out later! The homeowners who are now living in this Wildwood, Missouri home will never have to worry about their basement flooding for as long as they live in the home.
This Granite City, Illinois foundation wall bowed in 8 inches...
Repairing a Wall That Bowed 8 Inches in Granite City, IL
This Granite City, Illinois foundation wall bowed in 8 inches - you can see the point where the wall stopped along the "red" I-Beam.
We did an outside excavation to open up the space we needed to pull the basement wall back. ALL parts of our wall anchoring system are galvanized. Notice the "red" I-Beam and the scrapping too a lighter color looking like orange, showing the 8 inches we pull it back.
Make sure your sump pump does not back up, like...
Make sure your sump pump does not back up, like it did in this Mattoon, Illinois basement. If the water can not get out if the discharge line due to clogging or freezing, you could have a serious problem on your hands. Our IceGuard® discharge line solves that problem, allowing water to drain even if it clogs or freezes!
If you are draining a window well to the interior...
If you are draining a window well to the interior sump pump it needs to have:
A) Clog free path
C) Powerful sump pumps
D) Battery Backup sump pump
In this Effingham, Illinois basement, we installed our WellDuct® basement window well drain that combined with our TripleSafe® sump pump system and WaterGuard® basement waterproofing system can take care of A - D!
Older wooden framed windows are single pane and not energy...
Window Replacement for a Basement in Nashville, IL
Older wooden framed windows are single pane and not energy efficient. Our EverLast® basement windows are double pane, operate smoothly, and are energy efficient. Just look at the difference the windows made in this Nashville, Illinois basement! The homeowners were able to see and feel the difference almost immediately.
The crack and settling wedge of this Granite City, Illinois...
The crack and settling wedge of this Granite City, Illinois foundation was caused by a waterproofing system (BOX Drain Tile) that let mud and water get into the sump pump and overtime undermined the footing holding up that wedge of concrete. We installed a push pier to close the gap.