In August 2011, immediately after the 5.8 magnitude earthquake that originated in central Virginia occurred, Roanoke Catholic school contacted SK&A for assistance in evaluating the condition of the school’s gymnasium. A co-educational, college preparatory institution, Roanoke Catholic serves students from Pre-K through the 12th grade.
Originally constructed in the 1960’s and designed by another firm, the gymnasium’s structural system and roof is based on a sophisticated hyperbolic paraboloid-shaped, concrete shell design. The three-inch thick, concrete shell roof is supported on four concrete crucifix columns, one at each corner, arranged in a square grid pattern. In addition, the roof shell is supported along its edges with edge beams of varying thickness. Horizontal thrust generated from the unfolding of the shell structure is balanced with bonded, post tensioned, tie beams around the perimeter of the structure, located at the top of the crucifix columns.
SK&A’s Design and Repair & Restoration Divisions collaborated to provide two stages of evaluations, through the use of 3D modeling and analysis followed by an on-site visual condition survey. Using SAP2000, an advanced 3D modeling software system, SK&A modeled the entire structure, checking against the facility’s original drawings. Analyzing the “true-to-form” model, our engineering team assessed seismic, wind, gravity and snow loading conditions, comparing results to current code and loading assumptions.
Following the modeling analysis, SK&A performed a visual condition survey of the facility, took photos and prepared a report of the corrosion-related deterioration due to age and past water leakages at the roof of the structure. No major structural deficiencies were identified from the limited visual inspection, but the completion of recommended repairs would restore the structure’s appearance as well as extend its projected life well into the foreseeable future.