North Munn Bridge
Services Applied by VCS Engineering
Project Introduction
The North Munn Avenue Bridge over I-280 in East Orange, New Jersey, has a single reinforced concrete pier with five cylindrical columns. Stantec contacted VCS Engineering (VCS) to conduct a concrete corrosion investigation of the pier cap and columns of the bridge. Stantec won a project to replace the bridge's superstructure, which required an assessment of the substructure for design and possible repair purposes.
Project Scope
VCS performed a visual inspection of the pier cap and the supporting columns. Most of the deterioration appeared towards the edge of the pier cap, with a large amount of moisture retention, most likely due to the location of the draining system inside the pier cap. VCS also used techniques like ground penetrating radar and corrosion potential measurements to locate areas of concrete deterioration and determine if there is a potential future risk for concrete deterioration. VCS collected concrete cores to test for compressive strength, carbonation depth, and petrographic examination. VCS also collected powder samples in the columns for chloride concentration testing.
Project Solution
VCS determined that the structure is at moderate risk for chloride-induced corrosion. Chlorides at the steel depth were elevated, and there were areas of active corrosion. VCS recommended that Stantec use targeted corrosion protection involving discrete cathodic protection anodes. This would help mitigate the potential for chloride-induced corrosion in the areas that the corrosion potential survey indicated had the highest probability of active corrosion.
