Staying above ground

By Dustin Block

Milwaukee’s City Hall is in the middle of a large exterior renovation. Some of the work is needed because the building’s foundation is sinking. Rendering courtesy of Potter Lawson Inc.

At a Glance To get a picture of the pilings (above), imagine a concrete block 10 feet by 10 feet that sits in a building’s basement. Supporting the massive block of stone is a pile of untreated wood timbers buried into the ground four feet below the basement floor. The timbers are about a foot apart and sit upright in the ground. That’s what Milwaukee’s City Hall is built on — thousands of upright trees holding the massive structure afloat in what’s basically a swamp.

Gary Kulwicki cracks open a door in the bowels of Milwaukee’s City Hall and leads the way into a chilled brick labyrinth that runs under the historic building. “It’s like something out of Phantom of the Opera,” said Kulwicki, guiding the way through musty rooms with arched brick ceilings lined with the remnants of the cream-colored building material.

The rooms are timeless, save the stray bottle of 7-Up and the web of phone, cable and electrical wires running through the walls.

Kulwicki, facilities manager for the City of Milwaukee, moves with ease through the musty underbelly of the historic building. He notes end caps in the floor without looking down and, dressed in his dress slacks and tie, leads the way into a crawlspace. We’re beneath the basement and still not down far enough.

Milwaukee’s City Hall is sinking. It’s not as bad as it sounds, and to clarify, Kulwicki would rather not have to oversee the needed repairs. But when it comes to signature buildings like City Hall, profound maintenance is needed to keep the building operational.

“We expect City Hall to be functional for 400 to 500 years,” said Kulwicki, who has worked for the city for about 40 years. “As long as Milwaukee is a city, City Hall should be in use.”

Left unaddressed, City Hall’s minor dip could be a problem. The northeast corner of the building dropped 1.5 inches sometime between 1986 and 2003.

It hasn’t dropped farther in the past four years, and city staff measures yearly for further signs of deterioration.

Before we go on, let’s get one thing straight: the building’s drop has nothing to do with weight in City Hall, so no jokes about the heavy hand of government or cracks about the need to trim down.

The city’s Treasury Department is in the sinking corner, and Kulwicki assures it wasn’t an excess of city money dragging the building under.

Nope, the problem lies in the foundation of the foundation. It’s so deep into the ground you can’t get to it without hammering your way through a layer of granite to uncover wood pilings submerged in water and buried in what was once marshy land. That’s a lot to handle, so let’s break out a few points:

• A window at Milwaukee’s City Hall shows damage caused by the deterioration of the building’s foundation.

  Milwaukee built its City Hall in the Milwaukee River valley, an area marked by a downward slope in the city’s downtown from North Sixth Street to West Kilbourn Avenue.
  
  
• The city chose the site for Milwaukee’s second City Hall — the city outgrew the first — because it owned the land and because the site was centrally located.
  
  
• The site was an odd shape, but a unique, ornamental design fit the plot perfectly, and city leaders moved forward with the building.

But first they had to do something about that swamp. Builders sunk 2,530 pilings — basically tree trunks — into the ground to create a solid foundation to build on. It really was the only way to build on swampy ground at the time, and it was a perfectly safe method. Each piling can hold 40 tons, and builders at the time sunk far more pilings than were needed to support the building.

But like any wood, the pilings rotted. They were exposed to air, fungus grew, and the pilings began to deteriorate.

In 1958, the city hired an engineer named Orville Draught to study the foundations of several downtown Milwaukee buildings. Draught found pilings in the buildings were breaking down, and the city found that City Hall was no different.

Engineers responded with a remarkable system that pumped water into the foundation, helping to preserve the pilings. The system works like a reverse sump pump, forcing water into City Hall’s basement to prevent fungus from forming in the wood.

Gary Kulwicki, facilities manager for the City of Milwaukee, looks at plans from 1958 to repair the foundation of Milwaukee’s City Hall.

At a Glance Kulwicki worked 12-hour days for much of his career managing all of Milwaukee’s $1 billion in properties. City Hall is the jewel, a building on the National Register of Historic Places that is considered one of the great municipal buildings in the country. Despite retiring on Jan. 31, Kulwicki continues to work for the city part time helping to oversee the exterior renovation of City Hall.

For most of the building, the system works well. The city monitors the water levels regularly — those are the water valves Kulwicki has memorized in City Hall’s basement — and nearly all of the pilings are undisturbed.

But in the building’s northeast corner, problems were discovered. They began in 1985 when Kulwicki got a call from an alderman reporting a crack in his office wall.

City staff patched up the crack and all was fine until another crack appeared.

A building nearly 100 years old should be settled, so Kulwicki suspected an underlying problem. That’s when the slight drop in the building was detected.

Kulwicki helped track down the reason City Hall is sinking by reading a building foundations book written around 1910. That piece of light reading helped Kulwicki realize wood planks lying across the top of the pilings were being crushed.

The reason comes down to wood grains.

The grain of the upright timbers makes them remarkably strong, and near impossible to crack. The planking, which serves as a buffer between the pilings and granite blocks used to anchor City Hall, is laid cross-grain. That leaves the oak grillage vulnerable to being crushed.

In the book Kulwicki found, engineers realized the cross-grain planking could deteriorate. Unfortunately, the insight came about 20 years after Milwaukee’s City Hall was built.

A 2004 study photographed the foundation of City Hall’s northeast corner and found deteriorating pilings and crushed planking. The study concluded repairs would be necessary, ranging from reinforcing the original pilings with vices to drilling new, modern pilings to further distribute the weight of the building.

Raising City Hall’s northeast corner back up the 1.5 inches is not an option, Kulwicki said. The building is too big and too settled to be lifted.

But the foundation can be repaired to prevent further decay and damage. Cracks in the building’s façade, likely caused by the failing foundation, were noted during the past decade.

The repair work will be a major job. Workers likely will have to dig under the pilings, cut out a portion of each timber and insert a metal vice that will reinforce the foundation. It’s difficult, dangerous work that will require expert attention, Kulwicki said.

“You do it by crawling on your belly and digging out the marshy stuff by hand,” he said. “There’s no other way.”

Kulwicki kneels down in the sub-basement of Milwaukee’s City Hall. The building’s foundation is deteriorating, causing its northeast corner to sink 1.5 inches between 1986 and 2003.

Work on the pilings likely will begin in the next few years. The city needs to finish its three-year renovation on City Hall’s exterior first. The foundation work comes next, in part, to prevent further cracking on City Hall’s refurbished exterior.

Weaving through the building’s underbelly, a place few people venture or even consider, Kulwicki seems at home. He admires brick arches in a crawlspace no one sees, and reverently shows the grooves in stepped granite stones that were among the first pieces assembled in the building.

Riding an elevator, a city employee reminds Kulwicki that he retired a week earlier. Kulwicki responds by explaining that he’s being retained for his experience and because he’s taken on so many jobs over the years, there’s no one yet to replace him.

So one of his last jobs for the city will be to replace City Hall’s foundation and leave the building on solid ground for the next facilities manager.

“It’s a structural engineer’s dream when it comes to building restoration,” said Kulwicki, ready for one last challenge. “It reinforces the training provided to you.”