Shippensburg University Performing Arts Facility and Student Recreation Center
- Location: Shippensburg, PA
- Owner: Shippensburg University, Shippensburg, PA
- General Contractor: Lobar, Inc., Dillsburg, PA
- Technique(s) Utilized: Micropiles
Background
Shippensburg’s geologic conditions, like much of Central and Eastern Pennsylvania, feature unpredictable and variable karstic limestone formations. The hard limestone is riddled with clay seams and voids, making deep foundation construction a challenge. Karstic areas are also prone to sinkhole activity. Micropiles, which have capacities derived primarily from friction as opposed to end bearing, perform well in karstic geology, where voids may underlie perceived competent rock.
For the new Shippensburg University Instructional Arts
Facility, project specifications initially called for caisson foundations. The general contractor accepted Nicholson’s value-engineered alternate foundation scheme using micropiles. Nicholson installed 185 micropiles with design loads up to 282 kips in compression and 150 kips in tension.
The piles, constructed with 7-inch (diameter) casing, ranged from 24 to 159 feet in length. The variable nature of the limestone led to the dramatic differences in pile lengths.
Three years later, Nicholson was awarded a contract to
install micropile foundations for a new 62,000-square-foot student recreation center. Nicholson installed 141, 7-inch micropiles for a total of 11,833 linear feet. The design loads were 150 kips in compression and 115 kips in tension.
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