CHI has performed multiple tasks/projects for the Verrazzano Narrows Bridge (VNB) between 2020 and 2022, and they include:

•  Light pole vibration investigation

•  Lower-Level Deck Rehabilitation (VN-81)

•  Traveler Runway Rail Redundancy Analysis

 

Light pole vibration investigation

Excessive vibration of several light poles on the upper-level roadway was observed and reported to MTA B&T. Under this task, CHI created finite element model of light poles and performed dynamic analysis to identify the causes of excessive vibrations and investigate mitigation measures. Field vibration measurements were conducted for identifying the mode shapes, frequencies and damping ratios. Great agreements were observed between the analytical and field measurement results. Wind tunnel testing was also performed by RWDI. In addition, CHI developed monitoring plans for more definitive determination of the causes. Conceptual retrofit schemes were also studied for future as-needed implementation.

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Lower-Level Deck Rehabilitation (VN-81)

Under this task, CHI’s team performed design of miscellaneous steel and concrete repairs for the lower level roadway decks. Design drawings, quantities and contract specifications were prepared for bidding. In addition, CHI will participate in the Construction Support Services when the Contractor is on board.

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Traveler Runway Rail Redundancy Analysis

Several fatigue cracks were identified in the traveler runway rails under the lower level roadway, causing concerns about the safety of these rails. CHI created detailed finite element models for the traveler rails and performed nonlinear stress analysis for several scenarios of fatigue cracks. The ultimate strengths and safety factors were established for these scenarios. A study report was prepared and submitted to MTA B&T.