Smithfield-Liberty Helix Ramp Recognized by ICRI National / by Jeff Konkle

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Local ICRI Members Atlantic Engineering Services, Pittsburgh Parking Authority, Carl Walker Construction and BASF were recognized by the ICRI for their work on the Smithfield-Liberty Garage. The project won an Award of Excellence in the Longevity Category and was a finalist for the 2018 Project of the Year!

Originally constructed in 1964, the helix ramp of the Smithfield-Liberty parking garage in downtown Pittsburgh, PA is six levels of post-tensioned concrete slab with a perimeter knee wall cantilevered from a conventionally reinforced concrete cylinder. In late 1996, an evaluation of the helix ramp was undertaken to establish the cause of the observed distress in the structure. The cause of the deterioration was a mixture of high chloride levels, failing old patches, and improper coverage at the knee walls. Repairs consisted of hydro-demolition and replacement of the top 2.5-3” to remove the chloride soaked concrete and supplemental post-tensioning cables with a high-quality, 6000 PSI shrinkage compensated concrete repair material.

The rehabilitation of the Smithfiled-Liberty Parking Garage was completed in 1997 and over 20 years later, the structure exhibits no additional deterioration. No structural repairs or rehabilitation have been required since the work was completed.