Tappan Zee Bridge

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Tappan Zee Bridge

Services: Demolition and Erection Plans, Permanent Splice Design, Temporary Platforms
Contractors: Tutor Perini Corporation
Owner: New York State Thruway Authority
Designer: HDR
Status: In Progress

The Tappan Zee Bridge Repair Project included the replacement of the three middle lane structures with three new precast concrete decks integrated with steel stringers on a nightly basis. Siefert Associates, LLC [SALLC] worked extensively with the contractor to streamline the construction process, optimize their means and methods and ultimately accelerate construction. SALLC provided specialized construction engineering support such as:

  1. Lower & Upper Causeway [Spans 2-166]
    1. Demolition and Erection Plans shown with two cranes supported on the existing structure. SALLC effectively merged the two stages originally planned on the contract drawings into one.
    2. Minimizing the required temporary supports utilizing 3D models to analyze the stresses in existing and new panels.
    3. Design of Temporary Platforms.
  2. West Deck Truss [WDT] [Spans 167-173]
    1. Demolition and Erection Plans shown with two cranes supported on the existing structure. SALLC proved that the existing structure, including all the members of the Floor Beam and gusset plates, is structurally adequate to support both cranes when lifting a “50 ft” panel instead of a “25 ft” panel.
    2. Design for all the permanent Splices of the WDT tailored to the preferred means and methods of the contractor.