Deep Foundations – Comparing the Displacement of Pipe Shaft Helical Piles

Posted by Jason Herron, P.E., C.W.I. on May 14, 2021 1:00:00 PM

Helical piles are a displacement piling system that moves the soil away from the central axis of the shaft. This has many advantages that include no spoils to remove, but also comes with disadvantages as the shaft diameter increases. The helical piling industry categorizes pipe helical piles into low, medium, and high displacement. Each category has advantages and disadvantages that a specifying engineer must consider when selecting a pile that is applicable and economical for the project.

Low Displacement

The largest volume pipe shaft helical pile used in the North American market are low displacement pipe piles. Low displacement piles are defined as piles with central shaft diameters up to 4.5 inches.

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Topics: Foundations, Civil, Engineering, High Capacity Piles

How to Determine Helical Pile Capacity with Limited Soil Data

Posted by Josh Lindberg on Apr 21, 2021 7:40:00 AM

On many construction projects, soil borings are not completed due to the property owner wanting to reduce costs or, quite simply, being unaware of the need to obtain soil strength data for foundation design. During the installation of CHANCE® Helical piles, monitoring torque can provide real time data defining underlying soil strength and its load capacity. As a helical pile is installed (screwed) into increasingly denser/harder soil, the resistance to installation (called installation energy or torque) will increase. The higher the torque, the higher the axial capacity. In most projects, the installation torque increases with depth, and the capacity of CHANCE helical piles can be determined at the time of installation. Regardless of whether the pile is being installed in clay or sand soil, the torque to correlation factor (Kt) for each shaft size, is multiplied by the effective installation torque (T), resulting in the ultimate capacity for each pile. The standard equation for ultimate capacity is Kt * T. The torque correlation factors for CHANCE helical piles can be found in the CHANCE Technical Design Manual-4th Edition. The effective torque is the average torque taken over the last 3 feet of installed depth, measured in 1 foot increments.

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Topics: Foundations, Civil, Engineering, Contractors, Torque

Helical Piles vs Concrete Drilled Shafts (Caissons)

Posted by Shawn Downey on Mar 2, 2021 4:39:03 PM

There are several solutions engineers and contractors can choose from when a deep foundation is required. With a deep foundation the structure’s load is transmitted to soils that are deeper in the ground. A deep foundation is used when a shallow foundation is not possible, not practical, or will not carry the load. Examples are weak, unstable, or expansive surface soils. Two popular options for deep foundations are helical piles and drilled shafts, also known as drilled piers or caissons.

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Topics: Construction, Foundations, Helical Pile Benefits, Civil, Engineering

Helical Piles: New Technology or Just Back In Style?

Posted by Dave Bruce on Jan 28, 2021 7:00:00 AM

The first question we often get is, “are helical piles a new technology?”. Though they are growing each year in use and popularity, many Geotechnical and Structural Engineers are often unfamiliar with the technology. Complicating the matter is that, in many cases, students who will be our future engineers know very little about helical piles and their history. The truth is that helical piles [a.k.a. screws, screw piles, helical piers, helicals] appeared on the scene in the early 1800s. Alexander Mitchell (1780-1868) applied the use of screw piles in 1836 for moorings and, in 1838, for a lighthouse foundation. To put things into perspective, screw piles preceded the advent of Portland Cement [1850’s] and first use of a gasoline-powered automobile [1886]. According to some historians, screw piles were the major foundation technology of the 19th century.

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Topics: Foundations, Helical Pile Benefits, Civil

ATLAS® Resistance Piers: Frictional or End Bearing?

Posted by Intech Anchoring Systems on Dec 3, 2020 10:30:00 AM

ATLAS Resistance Piers are a versatile underpinning solution for existing structures that are in a state of movement and distress. The system components and installation methods lend themselves to a very quick and relatively easy installation. It is also a very cost-effective means of transferring structural loads from the foundation level to a suitable soil or rock bearing material.

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Topics: Foundations, Civil, ATLAS Resistance Piers

Helical Piles: Out with the New, in with the Old

Posted by EBS Geostructural on Nov 17, 2020 9:45:00 AM

Though the concept of urbanization accelerates the cities we live in, a resurgence in the restoration of heritage buildings is still very much alive. Located in Toronto’s busy downtown, 642 King St. W. is a 30,000 ft² four-storey, restored brick and beam building of mixed office and retail space.

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Topics: Foundations, Civil, Helical Pile Applications

3 Reasons to Use Helical Piles to Secure Solar Panels

Posted by CHANCE Foundation Solutions on Nov 2, 2020 10:15:00 AM

Technological advances have turned solar power into a viable alternative energy source on both the individual and industrial level. People everywhere are discovering that the installation of solar panels on their homes can significantly diminish their carbon footprint and slash domestic energy bills. But making large-scale solar energy generation a reality presents more of a challenge.

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Topics: Foundations, Civil, Helical Pile Applications

Helical Pile Foundation Engineered to Support Hillside Boardwalk Trail

Posted by Walder Foundation Products on Aug 21, 2020 11:15:19 AM

Helical piles have been gaining notoriety as an ideal foundation solution for many types of trails, boardwalks, and walkways. The town of Ashland, Virginia sought a pedestrian and bicycle trail constructed to connect Carter Park to the existing Ashland trolley line trail. The trail is an easy half-mile walk along a very straight and level path. To connect Carter Park to the Ashland Trolley Line Park trail a boardwalk was needed over the steep embankment along Walder road. The Ashland Trolley Line Park Trail is a Greenway trail which is protected and managed for conservation and recreational purposes.

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Topics: Construction, Foundations, Helical Pile Applications

How To Build A Lasting Pool Foundation

Posted by Foundation Technologies, Inc. on Aug 4, 2020 9:15:00 AM

As with a foundation on a home, the foundation of a swimming pool can experience sinking due to unstable or poorly compacted soil. Ensuring a pool is constructed on a deep, lasting foundation will protect the owner investment and save them from costly future repairs. Whether you're a contractor building a backyard pool or an indoor aquatic center, starting on a firm foundation is key for the long-term success of any project, and there are a wide range of variables in the design process.

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Topics: Construction, Foundations, Helical Pile Applications

Vertical and Battered Helical Pile Groups to Mobilize Lateral Load Capacity

Posted by Jason Herron, P.E., C.W.I. on Jul 9, 2020 8:15:00 AM

Helical piles have become a common piling system in the North American construction market.  They are used for many applications with low to moderate tension and compression loads.  Slender helical piles, less than 4.5 inches in diameter, have historically been used for light shear loads of 1 to 5 kips in vertical applications. This method derives the lateral capacity as a function of the pile’s allowable structural bending moment and the allowable passive earth pressure of the soil. It is common to analyze the capacity of the piles by theoretical slender pile equations, P-Y curves, or software programs that model P-Y response. An adequate safety factor or a service limit on the allowable deflection is applied to the allowable loads to determine an applicable pipe size. In recent years larger piles, with diameter greater than 5.5 inches, have been used for larger lateral loads.  Large diameter piles have been designed for loads in excess of 20 kips. 

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Topics: Foundations, Helical Pile Benefits, Engineering

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