In 2016, we decided to explore a new approach to drilling foundations. At the time, we relied heavily on the tried and true method of open-hole foundational drilling. Although there’s nothing wrong with trusted construction methods, we couldn’t help but think that there was another way of doing this.
That’s where segmental drilling came in.
Like many other skills in construction, there’s a big learning curve with this new method.
We thought: Would our operators pick this up easily? Will this increase productivity once we’re running at full steam?
Segmental drilling brought up a lot of questions that we didn’t have the answers to. Now, after years of segmental drilling under our belts, learning from our mistakes, and weeks of training with international leaders in segmental drilling techniques, we are happy we made the leap.
So, what exactly is segmental drilling?
Segmental drilling is a method of drilling deep foundations that installs segmented casings as a hole is being drilled. The drilled shaft is essentially lined with metal casing as you advance the excavation for the permanent foundation.
Segmented casings are installed in 2 to 5-meter sections at a time, as an auger located within the casing removes the soil in the way. Casings are bolted together and inspected at every section as they work down into the earth.
Once we reach the required depth, we inspect the final casing, drop the reinforcement cage in, and pour the concrete to finish off the pile.
We’ve found that segmental casing eliminates the 10% excess concrete yields commonly encountered in open-hole drilling, saving us time and money while reducing waste.
What advantages does segmental drilling have over open-hole drilling?
The most significant advantage of segmental over open-hole drilling is safety.
Anytime you have an open-hole on your site, you’re inviting a greater risk to worker safety. Open holes can collapse with little warning, making them more dangerous than other deep foundational drilling methods.
In segmental casing, the drilled hole is consistently reinforced by a steel casing during construction. This extra reinforcement prevents collapses and closes holes faster than open-hole drilling.
In safety alone, segmental casing is worth every minute of extensive training to get up and running. The learning curve may be high, but the payoff is enormous.
Other than safety, segmental drilling out-produces open-hole drilling once your team has mastered the process. By eliminating the slurry process, we install rebar cages at an earlier stage and finish off piles before an open-hole foundation is completed.
Segmental casing is an excellent addition to Blount’s list of services. With safer construction and increased productivity, it’s clear we made the right decision by taking on this new challenge. We’re always looking for better ways to build, and we approach each new project as a chance to learn and grow.