A new nine lane cable-stayed, long-span structure replaced the former Kosciuszko Bridge that crosses over Newport Creek in New York. The bridge is part of Interstate 278 and connects Brooklyn and Queens. As part of the early design phase, Hinman assessed the effects of a vehicle fire threat on the new structure. In addition, we provided peer review services for the explosion mitigation design performed by HNTB.
We used our in-house program FLaME (Fire Loading and Mitigation Evaluator) to model bridge geometry and the vehicle fire threat. FLaME is also capable of assessing mitigation strategies. The software synthesizes numerous existing techniques for calculating pool fire characteristics and radiation heat transfer into a single package with visualization capabilities.
Hinman understands that the requirement of cable stayed bridges is to maintain stability even with the loss of a cable. Knowing the typical safety factors that cables are designed for and the basic geometry of the bridge, we ran analyses to provide the minimum height of cable protection needed for the bridge. In fact, this minimum height is the baseline for the Phase 2 collaboration with the structural design team. By collaborating with the design team, Hinman redefined criteria for fire protection and provided an optimized fire protection bridge layout.
Hinman used the in-house program FLaME (Fire Loading and Mitigation Evaluator) to model the bridge geometry and the vehicle fire.
Hinman used FLaME to run a through-thickness analysis of the concrete towers. This analysis helped provide the design team with the expected critical heat penetration into the towers and a mitigation strategy to limit concrete spalling. Because of this, we were able to provide direction to the structural design team. Additionally, we increased resiliency of the tower in the event of a large vehicle fire threat on the roadway.
Known for our work for design mitigation to resist explosion effects, HNTB entrusted us to review and comment on their design. Accordingly, we submitted our comments as part of project deliverables.