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LONG FOUNDATION DRILLING A ROLLER COASTER RIDE

BY PHIL PAOLELLI, LONG FOUNDATION DRILLING CO.

It happened the same as it had before: a sudden, unexpected phone call, this time in March of 2018, with the voice on the other end advising that Southside Constructors was reassembling their covert construction squad for a top-secret project on the North Carolina/South Carolina border. Mission code name: Project Snake Bite. This meant it was time to return to Carowinds and have some fun!

Carowinds is a 400-acre amusement park that opened in 1973 boasting dual citizenship with portions of the park located in both Charlotte, North Carolina and Fort Mill, South Carolina. With over 50 rides and attractions, Carowinds can keep young visitors and hardcore adrenaline junkies alike equally entertained. Owned and operated by Cedar Fair Entertainment Company, Carowinds is a “must see” attraction for the Carolinas and surrounding area.

Long Foundation Drilling Company (Long Foundation) was no stranger to Carowinds Amusement Park, as this was their third roller coaster in the past decade that utilized a drilled shaft foundation. In 2009, Long Foundation was commissioned to install a drilled shaft foundation for the roller coaster named “Intimidator.” Intimidator was inspired by the late NASCAR legend and North Carolina native, Dale Earnhardt. Climbing a 232-foot hill before racing down a 74-degree drop at 80 mph through 5,316 feet of track, has you going for the checkered ag in fearless Earnhardt style, on one of the top ten, tallest, steel hyper coasters in North America.

In 2014, Long Foundation again received the call to install a drilled shaft foundation for “Fury 325.” Fury 325 is the world’s fastest and tallest steel giga coaster. Riders climb a 325-foot hill and take an 81-degree
drop, all while reaching speeds of up to 95 mph, for the novelty of traveling through the two states of North
and South Carolina on over
1.25 miles of steel track.

Long Foundation’s previous experience at Carowinds had fostered familiarity with the kind of schedule required in the construction of a new roller coaster. As Steve Jackson, director of Maintenance and Con- struction at Carowinds put it, “When I found out Long Foundation had submitted a comparative bid for the coaster foundations, I was very con dent we would meet our deadlines. They understand our business and can make things happen, despite challenging schedules. Our experience with them on Intimidator and Fury 325 as- sured me we would be successful once again debuting our new coaster on time.”


Our previous experience also prepared us for the ever present, insatiable curiosity of the coaster hobbyists and the airtight security it necessitates. Although the closing of an attraction and the appearance of utility paint marks on the ground always sparks speculation about a new project, Carowinds’ requirement of signed con dentiality agreements from all parties involved, as well as the release of only the speci cations, geotechnical report, foundation layout and a detail sheet of the project, ensured that all the details of Copperhead Strike would be kept under wraps until the o cial announcement was made to the public. Carowinds’ security measures were so e ective, we had no idea what we were installing foundations for until the o cial announcement was made in August of 2018, two months after we began working on the project! For the duration of the project, we worked under the watchful eye of children at the top of the water slide, Blackbeard’s Revenge and coaster hobbyists, who took photographs in an e ort to obtain as much information as they could about the new attraction. I did not have to go onsite or call our superintendent for updates; all I had to do was go on Facebook and see all the posts and construction updates from the public. Carowinds stoked the re of public interest by adding teasers to the construction walls and increasing speculation about the new attraction.

The 2019 season would mark the opening of Carowinds’ largest invest- ment to date: Blue Ridge Junction, a themed area designed as a tribute to the majestic landscape and vibrantcolors of the Blue Ridge Mountain region, as well as the lazy pace and innate charm of the moonshine-producing culture that ourished there. Coiled and waiting for visitors at the center of Blue Ridge Junction would be Carowinds’ newest roller coaster, Copperhead Strike. Carowinds’ promotion for the new coaster cautioned visitors about the copperheads found by the old, broken-down barn nestled way, way back in the Blue Ridge Mountains. Granny Byrd has been creating her delicious “jam” in that barn for nearly 40 years; however, Granny’s “jam” has a little bite that can get you in a lot of trouble if you’re
caught with any of it.

Manufactured by MACK Rides GmbH & Co. KG of Waldkirch, Germany, Copperhead Strike has the distinc- tion of being the rst double launch roller coaster in the Carolinas. The half mile, 530-ton steel track blasts riders to over 50 mph in two seconds, then launches them into a series of fast, tight, close-to-the- ground maneuvers tangled with ve head over heels inversions, the most of any double launched coaster in North America.

Installation of drilled shafts at Caro- winds is always a challenge, but a tight schedule, excessive hard granite rock excavation, 46 years’ worth of utilities, granite rock, tight work space, granite rock, tight tolerances, two hurricanes—and did I mention gran- ite—collectively made Copperhead Strike a ride to remember for all involved in building it.

Geologically, Carowinds is nestled in the heart of the Piedmont Phy- siographic Province. Stretching from New Jersey to central Alabama, the Piedmont Province is a complex geol- ogy comprised of numerous rock formations of di ering materials and ages intermingled with one another, including the remnants of several ancient eroded mountain chains. To complicate matters, the Copperhead Strike site consisted of lls ranging in depths from 3.5 to 15 feet due to previous construction at the site that included a water park swimming pool. Residual soils consisting of sandy silts and silty sands ranged in depths from 3.5 to 28.7 feet. The transitional zone from residual soils and rock known as Partially Weathered Rock (PWR), is de ned as residual soils exhibiting N-values in excess of 100 bpf and extending to depths that range between 12.4 and 33 feet. Granite rock with recoveries ranging from 50 to 100 percent and RQD of 50 to 100 percent was encountered below the residual and PWR soils ranging in depths between 12.4 and 33 feet below ground surface. Groundwater was encountered at depths ranging between 9 and 27.5 feet.


Previous coaster constructions at Carowinds were long and sprawling, with track supports spread out in a lin- ear fashion. By contrast, Copperhead Strike is a small footprint coaster with all the shafts compressed in an approximately four-acre site, a fact that required extensive planning on rig placement and sequencing. Additionally, the shafts were not laid out in a traditional grid system, but rather followed the alignment of the coaster’s track, meaning that since the track repeatedly crossed over itself, the foundation drawing evolved into nothing more than a chaotic collection of circles.


The location chosen for Copperhead Strike meant that many utilities were in the footprint of construction. The use of large pier caps over the top of each shaft instead allowed vital utilities that con icted with the coaster foundations locations to be spanned. The drilling of each shaft required constant oversight to ensure that utilities and park operations were not disrupted. In the event a utility was discovered, shaft installation was halted until the Carowinds utility team could conduct an inspection and create a plan to construct around the utility without interruption.

Dan Peak, Clark Reder Engineering, specializes in roller coaster design engineering and points out a couple of key di erentiators when designing roller coaster drilled shafts.

• The ride manufacturer provides all of the design forces.
• De ection tolerances are usually the overriding critical design criteria.
• Cyclic loading and the lifetime design ride cycles must be considered.
• Ride foundations and other nearby structure foundations should be kept isolated.

Each shaft was designed with di erent loading criteria which had to be calculated in the eld to ensure each shaft had the required end-bearing and uplift-loading criteria met in the PWR and Rock as designed. Due to the highly variable depth and type of PWR and rock, as well as the di erent loading values assigned to each type of material, constant inspection of the material being excavated by the onsite geotechnical engineer and constant communication with the structural engineer was required. Every shaft re-quired a 2-inch percussion drilled test hole to ensure continuity of the rock. The onsite geotechnical engineers inspected the cleanliness of the shaft and the test hole to ensure no soil seams were present in the rock below bearing elevation.

Copperhead Strike is supported on drilled shafts ranging in diameter from 30 to 60 inches, and depths from 10 to 35 feet, and rock socket depth ranging from no rock socket required to 12 foot rock sockets. Long Foundation used the temporary telescoping casing methods to install the shafts. After shaft excavation and inspection, a full-length reinforcing cage speci cally designed for each shaft was placed and aligned. A 3,000-psi concrete with six to eight inch slump was then placed by the free fall method in the dry, utilizing Long Foundation’s specially designed concrete chutes, ensuring the concrete fell in the center of the shaft without striking the side wall or reinforcing cage.
Temporary casings were extracted during concrete placement until the proper cut o elevation was reached. Large pier caps that encased the anchor bolts required to hold the track supports for the coaster were then constructed over the drilled shafts. Due to the tight tolerances required, the location of the anchors bolts was veri ed twice by two independent surveyors before the pile cap was poured and a third time immediately after pile cap concrete placement.

When Long Foundation mobilized to the site and hit the ground running in June 2018, we immediately started to encounter extremely hard granite rock shallower than expected. The rock in the Charlotte, North Carolina area is known to routinely have an uncon ned compressive strength of 25,000-psi – 35,000-psi or more. Even over the small footprint of the project, the type of granite encountered changed from a salt and pepper granite with thick quartz veins to a blue granite so hard it seemed it couldn’t be scratched. Using three of our trusty Watson workhorses, we began doing what we do best—removing hard rock from the ground. Standard rock removal practices utilizing core barrels and rock augers worked some of the time; however, the use of roller cone air barrels internally fabricated at Long Foundation ultimately got the job done. Not only were the roller cone barrels able to cut a curf in the rock to create some relief for auguring, but we were successful on many occasions in breaking the rock cores intact and removing the full length core from the shaft without the use of any augers or other tools, saving a tremendous amount of time and wear and tear on the equipment. If the rock cores could not be extracted intact, the combination of drop hammers, augers, grinders, and operator experience succeeded in successfully removing the required rock sockets.

Mother Nature bestowed her own brand of challenges when the Charlotte area sustained the e ects of two hurricanes during the project. Hurricane Florence hit Charlotte in mid-September as a tropical storm carrying high winds and dumping over six inches of rain in a two- day period. High winds made an appearance again in mid-October, when Hurricane Michael made his way into Charlotte, this time releasing over six inches of rain in just a few short hours. Before the storms hit the project site, all the equipment and tools were boomed down and secured to protect the property and equipment. Once the winds subsided, the real work was in making the site clean and safe in the aftermath of the heavy rains.

In the end, all 263 drilled shafts were successfully installed with over 5,100LF of earth/PWR and over 600LF of hard granite rock being excavated. Copperhead Strike opened to the public on time on March 23, 2019. We are all used to installing drilled shaft for bridges, high rises, dams and utilities, but hearing the screams from people riding these roller coasters and knowing the joy they bring is a gratifying experience. We look forward to seeing what types of twists and turns Carowinds has in store next!

LONG FOUNDATION DRILLING TEAM

PROJECT MANAGEMENT
Phil Paolelli

SUPERINTENDENTS
Billy Powers and Rob Simpson

PROJECT TEAM
GENERAL CONTRACTOR
Southside Constructors

ENGINEER
Clark Reder Engineering

OWNER
Cedar Fair Entertainment Co.

RIDE SPECIFIC LINKS
www.carowinds.com/play/rides/copperhead-strike