The Journal Gazette
 
 
Sunday, April 01, 2018 1:00 am

Bridge lopsided by design

Engineer proud of IPFW landmarks

ROSA SALTER RODRIGUEZ | The Journal Gazette

Kurt Heidenreich knows some people have had a strong reaction to the new pedestrian bridge over Coliseum Boulevard East connecting the IPFW and Ivy Tech campuses.

With a giant curved single pylon and dual curved-sided triangles only on the IPFW side, people have told him the bridge looks unusual, even lopsided. But it's all by design, and the bridge is stable and safe, said Heidenreich, the bridge's designer.

“We're not reinventing the wheel,” he said with a wry smile.

At 53, Heidenreich, a Fort Wayne native who graduated from Purdue University with bachelor's and master's degrees in engineering, has both a pedigree and a legacy in bridge design.

In addition to IPFW's latest bridge, he designed the 246-foot-long pedestrian bridge over Crescent Avenue, with its distinctive triangular central pylon support. And the Ron Venderly Family Bridge hovering over the St. Joseph River? He designed that, too.

That makes the IPFW campus a sort of open-air museum for Heidenreich's bridge aesthetic – work that's a far cry from what the president of Fort Wayne's Engineering Resources civil engineering firm started out doing decades ago.

That's when Heidenreich was designing utilitarian highway bridges for the Allen County Highway Department, where his father, the late Edward H. Heidenreich, was a bridge designer for many years.

The elder Heidenreich had a sterling reputation, said Bill Hartman, the highway department's current director, of his former boss. Kurt Heidenreich followed in his father's footsteps, Hartman said.

“I've known him since he was 10 years old,” Hartman said, recalling that, as a student, Kurt Heidenreich spent summers working for the department on construction jobs and preliminary bridge surveys, all the while soaking up real-world knowledge.

“It's a legacy, those two. His dad was a heck of a designer, and then he stood right up and carried the ball,” Hartman said. Engineering Resources is now a go-to civil engineering firm in the region, Hartman said.

“I knew since fourth grade that's what I wanted to do – do bridges,” Heidenreich said, noting his first professional span was probably a tiny highway bridge near Smith and Yohne roads outside Fox Island park.

“Most of what we do, and certainly what I did, is very routine and traditional,” he said. “Occasionally, you get the opportunity to do something unique, and I was blessed to have three chances at that at IPFW.”

Textbook case

Heidenreich said he got his first IPFW bridge design job in part because he and Greg Justice, the campus director of physical plant, knew each other from working together at a previous job.

For the second and third bridges, a request for proposals and federal funding meant the selection process was more formal, Heidenreich said.

The technical aspects of the three bridges vary, he said, but they build on each other's designs and his basic philosophy: “You let the site dictate what the bridge design will be.”

The first bridge took on its now-familiar shape because it needed to cross a road, which meant supports couldn't go in the lanes of traffic, Heidenreich explained.

“The A-frame pylon structure solved those problems,” he said. The steel pylons and their supports were placed on each side of the road and steel cables were hung from the intersection point of the pylons and attached to the bridge.

“The bridge decking supports the pylon laterally and the pylon supports the bridge vertically. The cables connect the bridge to the pylon,” he said.

Finished in 2005, the bridge got an arched, covered walkway because IPFW officials wanted it to be user friendly in all kinds of weather for students going from dorms on the east side of Crescent to the main part of campus, Heidenreich said.

The Venderly bridge is also a cable-supported bridge, known in the trade as a cable-stayed bridge. Site considerations there included the width of the river, Heidenreich said.

The university didn't have the ability to remove debris that might snag on supports in the water – so it was more or less the same problem as the first bridge, he said.

Solving the problem led to the tall pylons at both ends of the 385-foot span. Sometimes students call the structure the “clothespin bridge” because of the pylons' resemblance to clip clothespins.

But the bridge needed another element if it was not to be “tortionally unstable,” Heidenreich said. To keep it from twisting and oscillating in high winds, stainless-steel bent plates were added along the edges of the bridge below the railing to deflect the wind – and streamline the bridge aesthetically.

“If a bridge isn't stable, it can rip itself apart, and one actually did – the Tacoma Narrows Bridge. There's a video (online) of it happening,” Heidenreich said.

The bridge in Washington state collapsed in a gale in 1940, months after completion. The dramatic event earned the span the nickname Gallopin' Gertie for its behavior before crashing, Heidenreich said. No one died, but the bridge became a textbook case, he said.

More recently, a pedestrian bridge collapse last month at Florida International University pushed structure and safety into the national spotlight.

The local bridges are not like the bridge at Florida International, which collapsed March 15 causing six deaths. The local bridges are concrete and steel and built on supports on site, Heidenreich said.

Although weight limits typically aren't a major consideration with a pedestrian bridge, both the Venderly and Crescent Avenue bridges also were designed to bear enough weight and be wide enough that maintenance vehicles could use them, Heidenreich said.

“It gets a lot of use,” Heidenreich said of the Venderly bridge, finished in 2009 and linking the main campus with IPFW's Steel Dynamics-Keith E. Busse Alumni Center and the Hefner soccer fields complex across the river. Walkers, runners and cyclists on the Rivergreenway trail also use the bridge.

'No mistake'

Heidenreich acknowledges a bit of a love-hate relationship with the latest bridge, known as the Parker Cole Crossing. That's mostly because it's still unfinished, although it's projected to be done on schedule by July.

Much of the bridge had to be built between 11 p.m. and 5 a.m. because of road traffic, he said. That's why Coliseum was closed overnight Thursday, as a crew that had been waiting for the weather to break poured the bridge's concrete decking.

The weight of the concrete will cause the bridge to deflect 20 inches so that its two ends will finally meet each other, Heidenreich said.

Seeing the gap has left some motorists wondering, but “there was no mistake,” he said.

Parker Cole's design considerations, he said, included a 17-foot clearance for heavy trucks and space limitations.

More space on the IPFW side and a building blocking the expected path on the Ivy Tech side meant the bridge ramp on that side had to be turned and the support system built only on the IPFW side.

That led to what is technically known as an asymmetrical cable-stayed bridge. There are similar designs elsewhere, including one in Taiwan, Heidenreich said, but the design is not typical.

Still, he finds the bridge artistic. Bridge designers typically deal with “a lot of straight lines. ... You don't get to work with curves much,” he said.

“It's probably more aesthetic than the other bridges. And you can see it from a long way away. It's kind of like a frame (for the scenery),” he said. “It's pretty dramatic.”

Residents also are in for a surprise when the bridge is finished. It will light up and be able to change color at night with more than 200,000 LED lights.

“The bridge will actually glow,” Heidenreich said. “Rather than lighting the bridge, the bridge becomes a light.”

According to IPFW officials, all three bridges are designed to withstand state standards of winds of more than 90 mph and short seismic events.

The bridges are inspected by the Indiana Department of Transportation every five years, although only one, the Parker Cole, is owned by INDOT, campus officials said.

'I love IPFW'

Already Heidenreich's other bridges have become Fort Wayne landmarks. They are frequently photographed and have appeared in tourist and IPFW promotions. They've also formed the backdrop for graduation photos and marriage proposals.

The Crescent Avenue Bridge is this month's image on the 2018 calendar of the American Society of Civil Engineers.

And Heidenreich had a photo of the Parker Cole bridge at sunrise – the sun shining at the center of the bridge – as the screen saver for his work computer.

What's next? Heidenreich said probably not another IPFW pedestrian bridge.

“As far as I know, there's not another one in the works,” he said, noting he is now designing the tree canopy walkway feature of Fort Wayne's riverfront park.

“I'm a big believer in that, if you let the structure do what it's supposed to do, it'll be elegant,” he said when asked how it feels to create landmarks.

“I love IPFW,” he added, noting he took courses, taught there and serves an advisory role in the civil engineering department.

“My hope is that these bridges would be an attractant to this campus,” he said. “They will all become what they will become, in time.”

rsalter@jg.net 


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