Abstract

The state of Florida, including the Tampa Bay region, is considered one of the most vulnerable areas in the United States to hurricanes and severe tropical weather. A particular vulnerability stems from the fact that Tampa Bay receives all of its petroleum—gasoline and diesel—through Port Tampa Bay, which can be impacted by hurricanes and tropical storms, as well as other disasters. If the port is unable to receive ships due to hurricane wind or storm surge, fuel cannot be delivered to the area, and transportation is impeded. One promising way to avoid this reduction in transportation functionality is to diversify the fuels used. This paper summarizes previous fuel challenges and vulnerabilities experienced by key Tampa Bay fleets after the area’s most recent tropical event—Hurricane Irma in 2017—in order to explore ways to improve the resilience of Tampa Bay to natural disasters. Some of these strategies include maintaining emergency fuel supply, prioritizing fuel use, developing innovative real-time resource sharing mechanisms, strategically placing the assets around the region to assist with the recovery, investing in backup generators, planning for redundancies in fuel supply networks, and diversifying fuel sources by incorporating alternative fuel vehicles into the fleet.

Abstract

A large number of breakaway-type highway signs toppled over during hurricane María in Puerto Rico.  The cause was the unintended rupture of the fuse plates, a key component of the breakaway system.  The design of fuse plates is unusual because two opposing constraints must be precisely balanced: 1. they must be weak enough to rupture during collision of an errant vehicle, thus minimizing injuries to passengers and damage to the vehicle, but 2. strong enough to resist wind loads.  These uncommon constraints attracted the interest of the authors.  The following question guided the research: Could classical stress analysis, in conjunction with established failure theories, predict the failure of an actual fuse plate that fractured during hurricane María?  This investigation fills a gap in the literature by examining a more refined classical model of the stresses than previously considered.  A wind gust speed of 155 mph at the top of the sign was assumed.  The yield and ultimate strengths were obtained experimentally with one tensile specimen machined from a failed fuse plate.  The classical stress analysis, in conjunction with the von Mises yield failure criterion, accurately predicted yielding of the fuse plate; however, higher wind speeds would have been required to reach fracture.  It was concluded that the simplified model available in the literature is adequate to predict yielding.  Its error was less than 1% when compared to the more refined model developed in this study.