Feasibility of Tubular Fender Units for Pier Protection Against Vessel Collision; Final rept

摘要

Vessel collisions with bridges are increasing at an alarming rate, as heavy vessels are making more frequent trips under more bridges. In the US, rigorous design of bridges for vessel collision was first incorporated by AASHTO Guide Specification and Commentary for Vessel Collision Design of Highway Bridges, in which a model to determine vessel collision forces required for designing bridge elements was introduced. The guide, of which portions have been adopted into the AASHTO LRFD Bridge Specifications, does not provide specific guidance for the design of pier protection systems. Given the high number of bridge structures in navigable waterways in the state of Louisiana, bridge pier protection is of concern to the LADOTD. It is desired that bridge fender systems that provide acceptable collision performance be identified. The goal of this project is to identify existing protective systems and propose new systems that can be used to mitigate the effects of bridge/vessel collisions. The focus of the effort is to identify or propose fender systems that are: (1) modular; (2) easily installed or replaced; (3) suitable for retrofitting existing bridges or for use in new construction; (4) crashworthy, i.e. highly damage tolerant with good energy absorption and stiffness characteristics; and (5) durable, with low life-cycle costs. Using a newly proposed multi-tiered performance-based design methodology, the performance of a number of alternative fender systems is evaluated and their suitability for bridge protection examined.