Micropiles

With Chicago’s ever-increasing urban expansions it is not always possible to find good supporting soils at or close to surface grade for new construction. With this, foundation elements like Micropiles have been designed to transfer compressive loads down to a suitable load bearing stratum. United Structural Systems of Chicago is the leader in deep foundation applications such as Micropiles.

Taller and more slender structures subjected to wind loads need foundations capable of supporting compressive, uplift and lateral loads. Instead of large mass concrete foundations, Micropiles offer smaller and deeper drilled pile foundations which are a more economical while supplying an environment friendly alternative. Their simple and unique design has made micro piles very popular in the specialty foundation market.

There are many names for Micropiles – minipiles, pin piles and root piles being the most common. These deep foundation piles are rotary drilled and grout reinforced small diameter piles which can be installed to depths of 200 feet and through very dense layers of soil and rock. Their sacrificial bit is designed to drill through these tough soils and embed themselves in load bearing rock layers, while maintaining a grout column around a structural steel member in the center of the column.

Hollow bar micropiles are mainly used as a friction pile to take tension and or compressive loads. Typical sizes are 30mm (1-3/16”) to 73mm (2-7/8”) and typical uses include foundation underpinning, new construction, retaining wall tieback and soil nailing.

Micropile Underpinning

Cracks and settlement are facts of life when it comes to construction using concrete foundations. There have been many methods of repairing structures once they have settled, including helical piles, push piers and micropiles. Each has its own advantages and applications where they should or should not be used. Helical piles are a simple and cost effective solution to light weight structural repairs. Push piers are great for lifting heavy structures in a cost effective manner. Now, United Structural Systems and micropiles are growing in popularity for reducing the effects of settlement in new and existing structures.

Micropiles were originally designed for underpinning structural repair applications more than 50 years ago. Today, United Structural Systems of Chicago continues this original application through the use of a Patent Pending steel bracketing system. This unique system allows for hollow bar micro piles to be installed under buildings that are resting on unsupportive, debris laden soils. Our engineered bracketing system incorporates a full manifold lifting system for precise, even lifting of structures and equipment pads. United Structural Systems is the only contractor that is approved to use this engineer approved system in the Chicago area. For more information please contact us.

New Construction Micropiles

United Structural Systems of Chicago can also install micropiles for new construction applications. Micropiles have the ability to drill down through debris laden soils that many other types of piles cannot. These grouted pin piles create a grouted column through the toughest soils and can be imbedded into bedrock. Using relatively small drilling equipment, these piles can be installed in limited access and low overhead conditions with little to no vibration that could affect surrounding buildings. The continuous tremie cement grout operation of installing hollow bar Micropiles guarantees 100% grout cover so no additional corrosion protect is then required.

United Structural Systems of Chicago’s process of installing Micropiles begins with drilling into bedrock using our specialized drilling rig. Soil cuttings are expelled with air, water or grout followed by grouting the column that has been created by the sacrificial carbide bit and threaded rod. The Micropile tops are cut to elevation and a sleeve is inserted to adapt to the ECP micropier bracket system. Load testing can be easily performed on production piles or test piles near the proposed locations.

Micropiles and United Structural Systems can solve your toughest jobs whether it is underpinning a commercial building or as a deep foundation element under a new construction project. When only the best products installed by the best company will do, call United Structural Systems of Chicago.

Micropiles and USS of Chicago

The inherent advantages of micropiles have made them grow in popularity and acceptance by contractors and engineers alike over the past several years. With our advancements in drilling equipment and underpinning brackets, Micropiles are sure to become more popular in the toughest foundation repair situations around Chicago.

Call us to learn more about Micropiles!