The Ben Sawyer Bridge keeps glitching and Sullivan's Island finally got an answer

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The Ben Sawyer swing bridge failed four separate times this July. Not a rumor, not a one-off. Four documented malfunctions in three weeks, each one stranding traffic between Mount Pleasant and Sullivan's Island for anywhere from 12 minutes to close to an hour.

That is not normal, even for a 675-ton hunk of steel that spends its life in salt air. So the Post & Courier went under the bridge with Kevin Turner, SCDOT's Charleston-area district bridge engineer, to find out what's actually happening down there and, more importantly, whether Charleston's last swing bridge can take another direct hit like the one that nearly ended it.

Here's the mechanism most commuters never think about while idling at the gates. The whole swing span sits balanced on a single pillar and a set of greased wheels. Four locking mechanisms hold it in place until a boat needs through, at which point the arms drop, the locks withdraw, and 675 tons pivot on that one gear until the channel clears. The whole cycle takes about eight minutes on a good day.

The July failures traced back to something almost mundane: sensors. If a sensor that confirms a gate has fully closed gets corroded or glitches, the system assumes the worst and refuses to let the operator move the bridge, stranding cars on both sides. "The bridge is going, 'I'm not going to let the tender operate the bridge and open it up while traffic could potentially be approaching a hole in the road,'" Turner told the Post & Courier. Salt air being what it is, that's an occupational hazard for every part exposed to the elements.

There's also a legal wrinkle behind the timing complaints. Federal law bars the bridge from opening for most vessels during weekday rush hours, 7 to 9 a.m. and 4 to 6 p.m. Outside that window, boaters just radio ahead. On weekends, it opens on the hour, every hour, no questions asked. "Our goal is really not to pick winners or losers between the vessel traffic and the vehicular traffic," Turner said.

Then there's the history that makes all of this heavier than a maintenance story. The original Ben Sawyer span had no locking mechanisms at all, just friction and wedges, and Hurricane Hugo tore right through that in 1989, physically toppling the bridge and cutting Sullivan's Island and the Isle of Palms off from the mainland. SCDOT wanted to replace it with a stationary high-rise bridge afterward. Islanders fought back and won, insisting on a swing span that looked and worked like the one Hugo took down.

Which brings up the only question that actually matters heading into another hurricane season: could it happen again. Turner, who chooses his words like an engineer, still gave a straight answer. "We have the utmost confidence that we would survive a Cat-5 storm," he said. The current span carries hurricane ties that bolt the swing section down entirely, last used during Hurricane Dorian in 2019.

So the July glitches and a Category 5 are two very different conversations. One is an inconvenience. The other has an answer now, on the record.

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