The Francis Scott Key Bridge collapsed in March 2024. Its replacement cost is approximately $2 billion. The economic damage is not $2 billion.
Combined bridge-and-port disruption modeling shows that GDP, employment, disposable income, and labor force all decline — but they recover on different timescales. GDP and output begin recovering by 2025-2026. Employment follows by 2026-2027. Labor force impacts persist through 2040 — sixteen years after a single structural failure.
The mechanism is cascading failure. The bridge collapse closed the Port of Baltimore, which disrupted supply chains that depended on that port, which reduced employment in logistics and manufacturing, which reduced consumer spending in the region, which suppressed new business formation, which reduced the labor force through outmigration. Each step amplifies the damage beyond the direct physical loss.
Bridge engineers design for loads — dead load, live load, wind load, impact load. This analysis argues they should design for position in the network. The bridge's value isn't its span; it's its connectivity. A $2 billion bridge can produce tens of billions in cascading economic damage because infrastructure systems are coupled, and the coupling is asymmetric. Losing one node affects all the nodes it connected.
The cost of a thing is not what it costs to build but what it costs to lose from the network it enables. Design codes that optimize for structural reliability without accounting for systemic connectivity will consistently undervalue the most connected infrastructure.