Location: Staten Island, NY and Bayonne, NJ
Owner: The Port Authority of New York and New Jersey
Contractors: Skanska Koch-Kiewit, JV

As the fourth largest arch bridge in the world, the Bayonne Bridge connects Bayonne, New Jersey and Staten Island, New York, spanning over the entrance to the Port Newark-Elizabeth Marine Terminal.  The height of ships serving the port was limited by the Bayonne Bridge. This limitation grew more serious with the Panama Canal's 2016 expansion that enabled bigger, New Panamax ships to reach the port from Asia. The Port Authority of NY&NJ awarded the contract to raise the Bayonne Bridge's roadway 65 feet at a cost of around $1.7 billion. The increased navigational clearance to the busiest port on the East Coast was achieved in June 2017, and the overall bridge project was completed in 2019.

Siefert developed a comprehensive strategy for the temporary works including Temporary Supports and Pile Foundations, Engineered Lift Plans for Demolition and Erection of the Main and Approach Spans, Rigging Design, with related Structural and Geotechnical Analysis. The engineered solutions minimized disruptions to the navigational channel below and to the roadway traffic, while maintaining stability of the existing truss arch.

Piers for the new viaduct approach spans had to be constructed directly through the existing roadway, which required selective demolition of the existing structure and pier bents. Temporary shoring towers were engineered to maintain the traffic flow and preserve the structural integrity of the bridge. Weak subsurface soil conditions warranted the design of deep micro-pile foundations with concrete pier caps.

There were 2 different types of temporary support towers designed, a heavy duty tower that supported the 10 feet deep edge girders and a light duty tower that supported the 6 feet deep floor beams. The towers had to be designed to support 2 lanes of live load traffic [HS-20, 36 tons each] and the segment haulers [600 tons] used to transport the precast pier segments across the bridge. Unique solutions were developed by Siefert to take advantage of the existing framing and to save the contractor time and money.

Siefert Associates meticulously formulated, evaluated, and provided detailed lift plans for the removal and replacement of all bridge components. These lift plans entailed extensive dimensional assessments to ensure that cranes with complicated rigging had ample clearance to safely lift and lower loads from the roadway to their final positions. Our teams assumed the responsibility of conducting a comprehensive analysis of the structural capacity of members and connections during all construction phases. This analysis was imperative to confirm the ability of the bridge deck and superstructure to support the substantial loads from cranes, heavy haul transporters, and excavators, all within the existing structure configuration at the time of the operation. Also, a geotechnical analysis was performed and working platforms and temporary roadways were designed for equipment operating on grade below and adjacent to the structure.

Location: Boston, MA
Owner: Massachusetts Department of Transportation
Contractors: Atlantic Coast Dismantling, LLC

To facilitate the safe demolition of this bridge, Siefert Associates, LLC was hired to perform bridge demolition analysis and prepare engineered lift plans. SALLC analyzed the existing superstructure for construction equipment loading, analyzed the staged removal of sections of the main span truss, and designed temporary bracing of the main span truss and approach span girders. The steel truss mainspan and most of the approach spans were removed with a large crane on a barge.

Location: Jersey City & Kearny, New Jersey
Owner: New Jersey Department of Transportation
Contractors: George Harms Construction Company & Atlantic Coast Dismantling

Siefert Associates, LLC was hired by the subcontractor to create working drawings, procedures, and calculations to demolish the existing vertical-lift bridge safely and efficiently. SALLC analyzed various equipment on the superstructure during operations, designed temporary support and bracing schemes, and devised alternative methods of demolition as required. The team was also hired by the general contractor to collaborate on the lift plans for the new approach spans and on-ramps, analyzing the stability of straight and curved girders throughout erection and designing bracing, as required.

Location: Tarrytown, NY
Owner: New York State Thruway Authority
Contractors: Tutor Perini Corporation & Tappan Zee Constructors

Siefert Associates, LLC was selected to provide services for the repair of the Tappan Zee bridge and the construction of the 3-mile long new bridge, which included several demolition and erection plans and the design of a 170ft bulkhead, a 1000ft temporary trestle bridge, and cofferdams to support construction. Other services included the analysis and engineered lift plans of curved steel girders, support of excavation, and the design of a temporary storage platform.