Rigid inclusions are cementitious columns that are significantly stiffer than the surrounding soil and their stability is achieved without any lateral confinement of the surrounding soil . The purpose of the rigid inclusions is to improve the ground performance globally (i.e., increase bearing capacity, reduce settlement, and improve ground stability). A load transfer cushion or platform is typically installed between the top of the rigid inclusions and the bottom of the superstructure, which allows for more load sharing with the surrounding soil. Typical rigid inclusions are concrete columns (possibly installed into the ground with a classical piling technique), &/or grout columns.

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Project Details

Commencing in January of 2021, Hardman Construction mobilized to the Holland BPW site in Holland, MI to begin assembling equipment and installing test piles. The General Contractor, Davis Construction out of Lansing, MI, had high demands when it came to both scheduling and tolerances.

The job consisted of 2 load tests to be performed on 14” Rigid Inclusions that ranged from 55 to 60 feet in length. Once load tests were approved, Hardman started drilling the 300 +/- piles.

Going into the load testing phase in late December, Hardman had high expectations for how the piles would perform, and expectations were far exceeded. Both static load tests were performed, submitted and approved on time, and the piles tested were proven to 2.5 to 3+ times their design capacity!

The agreed upon start date for Hardman was early January of 2021, and the crew hit the ground running. It was critical to Davis’s schedule that crew finish all the piles under the main Digester in the first three weeks of drilling, which was around 260 piles. Hardman Construction blew this number out of the water by installing 260 piles in 10 working days, with a single day high of 32 piles.

As with most projects, there were many site coordination issues that came up due to the number of contractors on site performing various tasks. Weekly coordination meetings and planning amongst the contractors alleviated most of these issues.

Throughout the entire job, Hardman was able to work safely and effectively.  Holland BPW was a fantastic learning experience for young employees on site and an exciting job to be a part of for many veterans of the work that had knowledge to share.