Earth Reinforcement Testing

New Jersey Pier Corrosion Assessment

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New Jersey Pier Corrosion Assessment
Project Details
Location: Essex County, New Jersey
Client: HNTB Corporation
Client Contact: Mr. Juan S. Alfonso, P.E. (973) 434-3194

New Jersey Turnpike Bridge No. 75 in Essex County, New Jersey is a superstructure consisting of 16 three-span, continuous, rolled steel, multi-stringer units that support a composite reinforced concrete rock. The bridge carries the eastbound and westbound directions of Interstate 78, as well as portions of Interchange 14 ramps. The structure is supported by reinforced concrete pier caps, reinforced concrete columns, reinforced concrete pile caps, and untreated timber piles. Piers for the structure were constructed within brackish water and extend through muck-like soil where the water level is near or above ground surface. These piers were not designed to support lateral load.

In December 2017, 16 of 22 rocker bearings supporting the eastbound roadway at Pier W 90 collapsed, resulting in a vertical misalignment of the tooth joint at the roadway level. HNTB observed that the pier was tilted and reinforcing steel bars at the base of the pier were ruptured, HNTB postulated that the reinforcing steel bars ruptured due to corrosion and overload due to loss of section. HNTB needed to confirm that corrosion was a likely cause and to identify the factors contributing to corrosion at this site. HNTB engaged ERTesting at McMahon & Mann Consulting Engineers, P.C. to review existing data, make recommendations for additional sampling and testing of soil, groundwater, concrete and steel from the site, and identify factors that contribute to corrosion.

ERTesting concluded that soils at the site are corrosive due to high concentrations of chlorides, sulfates, and organics. The soil, which is saturated silt and clay, is low in oxygen content, particularly at depths greater than a few feet below the surface. These conditions are conducive to microbial induced corrosion via sulfate reducing bacteria.   

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