SOLUTION

WJE performed an in-depth hands-on inspection of all above-water components of the bridge to document extensive deterioration conditions, identify locations for nondestructive testing and material sampling, and determine locations and quantities of deterioration for the development of accurate repair quantity estimates. The inspection included the bridge deck, historic railings, superstructure, substructure, approach spans, and abutments. Field testing included delamination surveys, corrosion surveys, reinforcement surveys, carbonation testing, ultrasonic thickness testing, strain relief testing, and X-ray florescence testing. Laboratory analysis included concrete compressive strength and elastic modulus testing, chloride analysis, petrographic analysis, and steel properties testing.

WJE issued a comprehensive condition evaluation report, which included deterioration maps, synthesis of the inspection results, identification of the deterioration mechanisms by element, service life estimates by element, and conceptual input on rehabilitation alternatives. WJE developed repair drawings and specifications and served as engineer of record for the rehabilitation aspects of the rehabilitation alternative selected by MnDOT. The repair design included a range of customized concrete repairs types, several independent cathodic protection systems for the reinforced concrete elements, and repair details and specifications for the historic aluminum railings. Construction is expected from 2020–2022 for a total construction cost of over $100 million. WJE will be providing construction phase services during the work.