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Niagara Frontier Transportation Authority (N.F.T.A.)
ASR Studies- Robert Purcell Community Center
Where: Buffalo, NY
Problem: ASR Damaged Catenary Pole Concrete Foundations
Solution: Vacuum Impregnation restored structural integrity and test 10 years later show no further signs of damage from ASR.

Structural Restoration of ASR Damaged Catenary Pole Concrete Foundations

“Our last inspection program and study found no evidence of new or reoccurring deterioration. To date, there has been no visible evidence of ASR growth, or freeze thaw-degradation despite our harsh climate. The condition of these foundations confirms our earlier decision to specify the Balvac Process of Vacuum Impregnation. ….”

The Niagara Frontier Transportation Authority (N.F.T.A.) disregarded their consultant’s recommendation for total tear out and replacement. The choice of structural restoration was the Balvac Process of Vacuum Impregnation for damaged catenary pole concrete foundations at the N.F.T.A’s Buffalo, New York yard and shops facilities.

A comprehensive investigation and study was undertaken to establish the cause of the severely deteriorated concrete. The condition of disrepair was identified as advanced alkali-aggregate reaction. Laboratory testing determined that a low hardened air content resulting in initial freeze thaw cracking and the ingress of water advancing the ASR.

The state of deterioration rendered the foundations structurally compromised. Consideration was given to epoxy pressure inject the larger cracks and an external application of a sealer. However, it was strongly advised that this procedure would at best minimize the rate of deterioration, and the only means of eliminating the cause of deterioration would be total removal and replacement.

Further investigation was conducted identifying 75 foundations to be in this state of disrepair. Continuing exposure to the intrusion of water and freeze-thaw cycles advanced the deterioration process. At the time of this study, with the exception of a vacuum impregnation of repair resins, there was no history of successfully restoring structural integrity, or at least, providing long-term serviceability to ASR damaged concrete.

Balvac Inc. was brought in to access the damage and determine if the Balvac Process of Vacuum Impregnation was applicable to this condition of disrepair. N.F.T.A determined that, unless this technology was successfully, the only option was total replacement. The foundations were in the state of imminent failure.

“…After a thorough investigation of various materials and repair methods, we determined that positive pressure injection of epoxies, and total replacement were unacceptable solutions. The conventional methods were not only cost prohibitive, but could have potentially exacerbated the situation or disrupted operations. The Balvac Process was ultimately selected as the in-situ repair method to restore the integrity of the catenary pole foundations with minimal impact to operations.”

Niagara Frontier Transportation Authority
Richard R. Zynda, P.E.,
Project Manager

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