Story thread · 39 reports / 22 sources

How extreme heat impacts Chicago’s bridges: The Rundown

wbez.org · 10dShare

Good afternoon! It’s Friday, and this newsletter will be off Monday for Labor Day. I’ll be seeing if I can actually handle four days of ARC Music Fest (plus an aftershow). But first, here’s what you need to know today. 1. Here’s how extreme heat affects Chicago’s moveable bridges Two Chicago bridges got stuck in a raised position due to severe heat this week, causing hours of disruptions and traffic jams. When closed, Chicago bascule bridges like DuSable Lake Shore Drive bridge are somewhat protected from thermal expansion due to cooler air from the river below, said Jim Phillips, founder of ChicagoLoopBridges.com. “Once raised, the bridge leaf is exposed to higher temperatures and it expands,” he said. (A leaf is the part of the bridge deck that spans the river.) Sometimes the expansion “is enough to cause problems returning the leaf to the closed position.” As my colleague Amy Yee reports, this has happened before, though it isn’t very common. ChicagoLoopBridges.com features a 2010 p

First report: DuSable Lake Shore Drive bridge malfunctions due to heat, leading to major traffic jam — nbcchicago.com, 12d