× Expand Courtesy of the Missouri History Museum Highway ramps approaching the Poplar Street Bridge around 1970

“They’re closing two eastbound lanes on the Poplar Street Bridge on Monday? But I have to go to East St. Louis on Tuesday!”

The news that the Poplar Street Bridge, now closing its fifty-second year of life as the primary interstate crossing in downtown St. Louis, is facing yet another month of lane closures was not met well at my house. What is the deal with that bridge? We call it Poplar, but it’s the former Bernard F. Dickmann Memorial Bridge; the official name was later changed to The Congressman William L. Clay Sr. Bridge (which is hard to spit out when you’re cruising down an interstate and thus used by virtually no one). Until the recent opening of The Stan Musial Veterans Memorial Bridge, Poplar was the only bridge in the United States to carry three interstates (55, 64, 70). Interstate 70 was peeled off to the north across the new bridge, which is just north of the Martin Luther King Bridge, formerly known as the Veterans’ Bridge.

The construction of the Poplar Street Bridge is a fascinating bit of history. While certainly not as revolutionary as the Eads Bridge, the next span just to the north, the Poplar Street Bridge was innovative in its own time and represents an important moment in mid-century bridge construction.

× Expand Courtesy of the Missouri History Museum The Poplar Street Bridge, around 1968

The eight-lane Poplar Street Bridge officially received approval from the Army Corps of Engineers in late 1961, with the proviso that construction start within two years and be complete four years later. The bridge was built by Sverdrup & Parcel and Associates, originally tasked with the job in 1960 by both the Missouri and Illinois highway departments. At first, numerous official names were proposed for the new bridge, ranging from the John F. Kennedy Memorial to the Sacagawea Bridge. Sacagawea was the Lemhi Shoshone woman who helped Lewis and Clark find their way. And if you’re still wondering who Bernard F. Dickmann was, he was the 34th mayor of St. Louis from 1933 to 1941. More recently, William L. Clay Sr. was the 1st Congressional District representative from 1969 to 2001. The popular name for the bridge comes, more simply, from its alignment over Poplar Street, which exists in purgatory under the elevated lanes of Interstate 64. Poplar Street, like all the arboreal names of downtown streets in St. Louis, takes its inspiration from the street grid of Philadelphia. Trees replaced the original French street names as St. Louis Anglicized itself.

Sverdrup & Parcels deputized Edwin J. Shields as the project manager for the new bridge. A veteran of bridge building from the Panama Canal project, he was described by the St. Louis Post-Dispatch as “a conservatively dressed, white-haired man with a retiring and serious manner.”

Like James Eads almost a century before him, Shields had to content with the constraints dictated by shipping on the Mississippi River. The spans must have 580 feet between the piers and be 55 feet above the 2 percent line—in lay terms, the point where the river level stays most of the year, barring historic flooding. Furthermore, all parties agreed that the new superstructure of the Martin Luther King Bridge had aesthetically spoiled the view of the Eads Bridge, and the Poplar Street Bridge should complement it instead.

Of the eight designs submitted for consideration, some were rejected outright for being two-decked or possessing obtrusive trusses, violating this “gentlemen’s agreement” about aesthetics. The decision-makers finally settled on a deck girder. As described in the Post, it was “slender and delicate, and like the Gateway Arch its lines are straight and flat.” I don’t know if I’d describe the Poplar Street Bridge as “slender and delicate,” but to each his own. The architects had a bigger challenge: At the time, the longest deck girder bridge ever completed had a span of 300 feet. The Poplar Street Bridge would require a center span twice that long.

The solution to those 600 feet came from Germany, in the invention of what is known as an “orthotropic bridge.” The weight of the concrete road deck is relieved by…removing the concrete road deck. In its place, a steel road deck with a covering of asphalt is applied, thus eliminating the prohibitively expensive load. This was first demonstrated at the Neckar River Bridge in Germany in 1950—and it worked. Shields and Sverdrup & Parcels had found a solution for a bridge that would not distract from the Gateway Arch—and its load could be lightened by one-third, an engineer’s dream for a bridge that size.

Bethlehem Steel took out a full-page advertisement in the Post, proud that it had provided the steel in the nation’s first orthotropic plate deck girder bridge. But the bridge would also have other long-term effects on the City of St. Louis. The Federal Highway Administration insisted the 3rd Street Expressway (now but a faded memory to most of us) could not exist at surface level, and the infamous “depressed lanes” were created to meet federal highway requirements to attach to the Poplar Street Bridge. Thus were the Gateway Arch grounds cut off from the city by the great trench that, in the most recent round of renovations to the national monument, City Arch River attempted to mend with the “lid.”

Interestingly, one of the primary “resident engineers” on the bridge was a German immigrant, Kurt Keller. He was born in Ladenburg, in what is now Baden-Württemberg—just a short distance from Mannheim, where the inspiration for the Poplar Street Bridge was built on the Neckar River. He left Germany in 1949, attending at what is now called the Missouri University of Science and Technology in Rolla and graduating with a degree in civil engineering in 1957. Shortly thereafter, he joined the Missouri Department of Transportation. Keller would come on late in the construction of the Poplar Street Bridge, in 1966, rolling up his sleeves to help with the longest project in the department’s history.

In late 1967, as the Poplar Street Bridge neared completion, the city and press began to take stock of this monumental undertaking. Final costs came in around $30 million, with several “starts and stops” in construction. Despite the innovation of the road deck, huge caissons—the sort James Eads had used—were needed to sink the concrete bridge piers down to bedrock, past the thick mud of the riverbed. Officials were still trying to figure out the spaghetti-like system of ramps that would connect the bridge to the interstates being built nearby; East St. Louis residents would be forced to use a temporary ramp on opening day.

I look back through the Post archives on Nexis, which only takes us back to 1989. In 1992, someone wrote, “The Poplar Street Bridge has been almost continuously under repair since its completion.” In 1993, the paper warned, “Poplar Street Bridge to Be Unpopular for Two Years.” Through the ’90s, there are reports of a cracked pier, cracked steel, repairs on expansion joints. In 2000, the bridge is made earthquake-ready. In 2004, a crack pattern is found. There are ramp and lane closures in ’05, ’06, ’07, then major closures in 2010, more in 2011, emergency repairs in 2012 and someone complaining about “MoDOT’s failure to reopen two lanes on the Poplar Street Bridge as promised.” In 2013, we learn that “exposed portions of the deck become slick during rain and snow.” In 2014, there is resurfacing. In 2015, sunken pavement and lane and ramp closures. In 2017, a two-year project is announced to extend the bridge’s lifespan.

And here we are. The Poplar Street Bridge is almost an allegory for America’s investment in infrastructure, autocentric development and society in general. A year or two ago, I remember watching in awe as engineers performed the mind-boggling feat of picking up one half of the span and moving it over, allowing for the construction of an additional lane. I hold my breath as I drive over the bridge, spotting bare steel in places where the thin layer of asphalt has worn off. I remind myself of the innovative orthotropic design. (Isn’t German technology always foolproof?) And as my knuckles whiten on the steering wheel, I resign myself: Throughout history, sometimes we need such necessary evils as the Poplar Street Bridge.