The City, The River, The Bridge: Before and After the Minneapolis Bridge Collapse (review)

On 1 August 2007, an eight-lane highway bridge at Minneapolis collapsed into the Mississippi River. With thirteen dead, the immediate human cost was light compared to what could have been. Other costs raised the tally of losses over time: a city disrupted for fourteen months until a replacement span opened, overall losses placed at $300 million, and an incalculable blow to public confidence in the infrastructures that sustain modern life.

The Interstate 35 bridge had provided an essential corridor for the Twin Cities campus of the University of Minnesota. Fifteen months after the collapse, the university held a symposium where its faculty drew on their diverse fields and direct experiences to reflect on the event and its significance. From that conference comes this edited collection of nine essays. Such a genesis seldom produces a book of real stature, and this example proves the rule. Some contributors offer notable insights, but too often the essays wander into ponderous academic mush or pleasant diversions.

Three chapters provide the real strength here. An essay by two civil engineers describes their forensic engineering that uncovered the proximate cause of the collapse. Roberto Ballarini and Minmao Liao pinpoint three causes: a mistake in the original 1967 design resulted in gusset plates (used to connect structural members) that were half the thickness of the Federal Highway Association standard of that era; over its service life, the bridge's roadway deck received an additional two-inch skin of concrete, raising the loadings on its structural members by 30 percent; just before its collapse, repair crews parked a temporary load of heavy construction materials on the span—ironically, enough for a repair project, albeit one unconnected to its basic design flaw. Presented as engineering analysis, this is really a story about change over time. Had historians authored the chapter, however, they surely would have tried to answer a question unaddressed here: why did the 1967 designers and builders fail to follow the codes of their day, ordering half-inch steel for the gusset plates instead of one-inch?

Another strong chapter, by Patrick Nunnally, examines the processes and politics involved in designing and building the replacement span. Beyond the basic facts, Nunnally explores the interests that spoke out for a design improvement in the new crossing, for a chance to escape history and make a new, grand entrance for the city. They lost, although the new bridge has a lean grace that has met with general approval. In keeping with his own training as a planner, Nunnally also explores why the collapse and the politics of its aftermath did not allow for any substantive conversations about new approaches to regional transport needs. Put simply, why did the private automobile again triumph, again at taxpayer expense? In this interesting exploration, I wished Nunnally had also drawn on history; Christine Meisner Rosen explored similar issues in The Limits of Power: Great Fires and the Process of City Growth in America (1986).

The other well-built chapter is the only one by a historian. John Anfinson looks at two earlier and pivotal episodes when Minneapolis collided with its own river. His essay offers some perspective on remembering and forgetting events both pivotal and passing. In the Gilded Age, Minneapolis became a major center for flour milling, thanks to the Saint Anthony Falls at the city's center. But in 1869, a new miller tried to get into the business by building a tunnel under the river, diverting a portion of the water to a less-crowded site downstream. Instead the tunnel collapsed, drawing into its bed nearly the entire flow of the Mississippi. This disaster threatened the rationale for the city itself, and the problem continued, more or less, until the Army Corps of Engineers built a solution across the river in 1876. Anfinson also explores Minneapolis's tangled efforts to use the Mississippi both to derive safe drinking water...