After Baltimore bridge collapse, here's what to know about Milwaukee's Hoan Bridge and port

In the early morning hours Tuesday, a cargo ship crashed into the Francis Scott Key Bridge in Baltimore, causing it to collapse.

The bridge was struck at 1:30 a.m. and prompted a sprawling recovery operation on the Patapsco River. As of Friday morning, it was believed that six people were killed in the bridge's collapse, caused by the ship Dali.

USA TODAY reported that an allision, where a ship hits an immobile object, occurs about every 10 years. A 2018 report from the World Association for Waterborne Transport Infrastructure said there had been 36 major bridge collapses from 1960 to 2015, with 18 occurring in the United States. The outlet reported that two other bridges have been struck by a ship this year as well, both outside of the United States.

In Milwaukee, the most prominent bridge is the Interstate 794 Hoan Bridge, which crosses the Port of Milwaukee and connects the Bay View neighborhood with downtown.

The Hoan has avoided catastrophic incidents, but there was a scare in December 2000. At that time, the northbound lanes of the Hoan buckled and led the Wisconsin Department of Transportation to demolish the lanes and rebuild them.

In 2007, the Journal Sentinel looked back on that incident:

"The Hoan Bridge did not collapse, and no one was hurt or killed. But two of the three major girders holding up one section of the bridge had snapped, and the third girder was cracking. Two weeks later, a demolition team blew up the crippled section before it could fall on its own. The bridge did not reopen until February 2001," the Journal Sentinel reported.

"The Hoan Bridge failure was an unprecedented engineering mystery that took months to solve ... Eventually, investigators pinned the blame on the elaborate design of support components that appeared sound when they were installed in the 1970s. Like other parts of the bridge, they were supposed to bend, rather than break. But in extreme cold, the investigation found, those components could not bend under the weight of heavy trucks, and they broke instead."

Here’s what to know about the Hoan, accidents in the port and how they’re handled:

Hoan Bridge has an intriguing history — and future

The bridge — its full name being the Daniel Hoan Memorial Bridge — was opened in 1977. Construction on it began in 1970. It's named after Daniel Hoan, a former socialist city mayor.

The bridge is about 1.9 miles across and almost 52 feet wide.

It underwent a rehabilitation project in 2016 that included rebuilding its concrete deck.

How large of ships enter the Port of Milwaukee?

Ships the size of the vessel in Baltimore don't enter Milwaukee's port, according to Port Milwaukee, the city entity that operates the port. While the port receives some ships that are similar in length, they're only about half as wide.

The Dali, the ship that hit the Baltimore bridge, is 984 feet long and was headed for Sri Lanka on an almost monthlong trip.

Is the Hoan Bridge safe?

The Hoan Bridge is safe, according to the DOT. The Hoan is inspected every two years by certified bridge inspectors, the department said in a statement.

As part of that, the bridge is visually inspected and its condition is documented in a report that includes a "condition rating." The rating is on a scale through 9, with figures correlating to a good, fair, poor or severe condition of a bridge's part. It acts as a good indicator of the bridge's overall health, the department said.

The department provided details on the portion of the Hoan — different parts of the bridge are subject to individual inspections — that goes over the Milwaukee River.

The most recent inspection was done in October 2022 and found that the bridge was safe for travel. The Hoan's deck was at a 7 out of 9 rating, or "good," and the superstructure and substructure are in "fair" condition, with a 6 out of 9 rating.

"A 'fair' condition means structural elements are sound but showing minor signs of deterioration from environmental effects and traffic," the department's statement said. "The structural capacity is not affected by minor deterioration or other minor deficiencies."

Has a boat ever struck the Hoan Bridge?

The DOT said that, "to our knowledge," the Hoan has never been struck by a boat. The department said that the piers for the segment of the bridge over the river are on land. No boats have struck it because of height, either.

"The tallest vessel that we are aware of that has crossed beneath the bridge had many feet of clearance between it and the bridge," the department's statement said.

How are Hoan Bridge and Port of Milwaukee accidents avoided?

The port's statement said any foreign vessels — the Dali was a Singaporean-flagged ship — "are required to engage a United States or Canadian registered pilot to direct vessel navigation through critical areas of the Great Lakes."

There is also tugboat assistance for these vessels, which "provides an additional level of safety for the captain, pilot and owner of any vessel transiting the Port."

"Tug assistance coupled with a vessel's bow and stern thrusters and a skilled pilot significantly mitigates any risk to critical structures within the harbor," the statement reads.

Port officials also collaborate with various agencies to create incident response plans and joint operations plans, it said.

This article originally appeared on Milwaukee Journal Sentinel: Milwaukee's Hoan Bridge and Port of Milwaukee: what to know about them