CN Railway MSE Wall
Project Gallery
The Canadian National Railway Company (CN) planned to construct a mechanically stabilized earth (MSE) wall with metal reinforcements to support construction of a third track at the 212.17 Kingston Via Project. CN requested that ERTesting at McMahon & Mann Consulting Engineers, P.C. make recommendations to limit risk of failure of the MSE wall reinforcements, and corresponding disruption of service of the CN railway due to potential losses of serviceability from corrosion of the reinforcements.
ERTesting prepared a quality control and quality assurance plan for preconstruction sampling and testing of fill material to identify suitable sources of fill. We reviewed the design details for controlling infiltration of moisture or contaminants into the fill during service, and estimated the probability of meeting or exceeding the expected service life of 100-years. We provided plans for a performance monitoring system that could be incorporated into the construction of the wall to monitor corrosion rates and assess the conditions of reinforcements during service.
ERTesting installed the corrosion monitoring system in cooperation with the wall supplier (The Reinforced Earth Company). The corrosion monitoring system incorporated special removable inspection elements that were placed within the fill. These coupons are placed behind knock-outs formed at the front of selected precast concrete wall facing panels such that they may be easily removed and examined as necessary. Coupons were also instrumented for nondestructive corrosion monitoring via the linear polarization resistance (LPR) technique. In this manner results from LPR can be used to identify locations where coupons should be exhumed for visual observations and more detailed measurements of conditions and metal losses.
