Not Your Typical Truss Job


Not Your Typical Truss Job

An unusual project with an uncommon shape presented the kind of design challenge truss technicians don’t see every day.

The Farm Wisconsin Discovery Center will open this year near interstate I-43, under a stunning roof provided by Truss Systems based in Little Chute, Wisconsin. “It’s going to be a high-profile building,” noted Truss Systems President Steve Szymanski. “It’s high visibility,” he explains, and it’s big. “There’s 81-foot spans,” Steve says. “It’s not your typical truss job.”

Steve says he’s seen those spans in agricultural buildings around Wisconsin, but not often in a commercial building. Similarly, Truss Systems has certainly designed visitor centers before, but nothing that really compares to the vision set forth by the Wisconsin Agricultural Education Center Board of Directors. “It’s going to be a tourist destination,” says Steve.

The priority will be learning: “many Americans do not know where their food actually comes from, or how it is produced,” the Farm Wisconsin website notes. “Using local case studies, stories and exhibits, [the Discovery Center] will explore the historic, traditional, artisan and locally-produced agricultural products” of the state.

In addition, as described in a press release issued by Bayland Buildings, the builder on the project and a long-time customer of Truss Systems, the center will function as a wedding venue and will incorporate an operational barn. Steve says Truss Systems has done some retrofitting of barns being turned into wedding venues, but they’ve never worked on a project quite like this one.

“There’s actually a viewing section where students can come and watch a live calf birthing,” truss designer Dave Meyer notes. “I’ve never had to design a calf birthing center before.”

“You don’t do this kind of truss project every day,” adds Dave. “It’s a unique truss package.” For one thing, the collection of trusses supporting the Farm Wisconsin roof is incredibly diverse. Dave says most of his projects use multiple truss types, some more than others, but rarely as many as this project required. “I think I had 80 different truss types on this,” he said. “It’s not my largest project by far,” but at almost a week’s worth of work, it was an enormous project, timewise.

“The size, and what they were trying to achieve by having a vaulted ceiling across the entire front side of this building – the volume, the open concept – that’s what makes this unique,” says Steve. “There are some unique challenges to the wood truss system that’s going in there.” The initial step of the job, therefore, was very careful measurement.

“The first thing,” said Dave, “is we went out to the jobsite and field-verified all the dimensions.” Then he started designing by running all the trusses behind the parallel chord girder. “I started on the far left wing,” he explained, “because it’s just common trusses. Then, I went to the far right, which attached to the barn.” With the wings complete, he started moving forward from the back of the building, “running the 81-foot trusses toward the front to get to the primary girder.”

The girder itself came next. Dave designed a three-ply girder with a single interior bearing, in accordance with the original building plans. At that point, however, the building owners decided that instead of a drop ceiling hung below a flat bottom chord, the wanted a vaulted ceiling above an auditorium space. For Dave, that meant a change in the truss shape and an extra bearing point to adequately transfer the load. “When we switched that to a parallel chord detail, we had to add that interior bearing,” says Dave.

Next up on the design list were the corner girders that form the octagonal shape of the building entryway – an unusual shape that presented a satisfying challenge. “I do a lot of parallel chords,” says Dave, but this project was different from the rest. “What really stood out for me,” he explained, was that “the corner girders are holding the depth.” Maintaining a single wall height around the entire building to support a level soffit and single fascia was one of the most challenging parts of the design. The constraint of the truss depth meant Dave had to find creative solutions to accommodate the roof load.

“I realized I had to do the girders two-ply, one each side, because of the hip line,” Dave remembers. He ended up with 43-foot, double-ply parallel-chord girder trusses with “one on each side so there’s actually four plies right next to each other.”

To help the framers make sense of it all, Steve said that they pre-nailed all the multi-ply trusses, something that’s not standard practice for their market. “We’re getting asked more and more to do that,” Steve notes. “They may not have a flat surface at the jobsite.” And on a project like this one, there’s plenty to worry about during installation.

In fact, the framers on this project began asking for details as soon as they saw what they would need to install. “I’ve been in this 30 years,” Steve says, “and we take it for granted that they’re going to know what they’re doing out in the field. But they probably don’t!” In this case, he had no trouble understanding why. “After the framer called me, I started looking at it and said, ‘oh, yeah – I can see why you’re struggling with this!’ This was so complex, and everything had to be exact.”

Steve says it was great to be working with a customer he knew well, one he’d worked with before and who paid close enough attention to detail to ask a lot of questions up front. “There was so much more communication that was required for the framer to install this set of trusses,” Steve explains. A truss package that is routine for a component manufacturer can be overwhelming to a framing crew – and with good reason.

“We’re working with this stuff every day, but you take it out to the field,” says Steve, and it’s amazing that any framing crew is able to put the pieces together. In this project, he notes, the sheer size of the trusses was a significant factor. That was complicated by the fact that so many of the trusses were intersecting and tying into sub-girders.

To sort things out, Steve hung up the phone and started marking up the design drawings. He provided detailed dimensions, showing the site crew exactly where the hangers needed to be placed on the girders. “They’re skewable hangers,” he explains, “which means not only do they have to put them on, they have to bend them to the right angle and then they’re fastened onto the girder.” All of that, Steve adds, has to be done on the ground. “A lot of times, they set a girder truss and then they put the hanger on, but with these you have to put the hanger on first. That led to…I’ll call it a challenge…for the framer out in the field. And for us, too.”

With Steve’s help on the hanger placement, something he says he doesn’t do for any other job, the complicated installation went very well. “Obviously, it was great that the framer knew what he was doing,” said Steve. Still, he admits that there’s simply not enough detail in the layout for someone to make sense of this particular design. “It was really imperative that we had proper hanger placement. There was a lot of math involved, and a lot of figuring. I don’t see how they would have figured that out for themselves in the field.”

Dave agrees that, despite the extra effort required, the installation “went really well. They actually had all the trusses set in two days.” Steve adds that truss installations always go more smoothly with an experienced framer who knows what questions to ask. “There’s a lot more to it than, ‘here’s the trusses, here’s the layout, go to town,’” he says. With a project as complicated as this one, a successful install depended on good collaboration between the framer and the truss manufacturer.

Dave says that, given the chance to do the project again, he wouldn’t change a thing. “The uniqueness of the building,” he says, was what made the project both challenging and fun. “I like doing complex jobs,” says Dave. When a project demands skill, creativity, and a little extra effort, it’s all the more satisfying to drive by when the building is finished.

For Dave, taking his kids past the Farm Wisconsin building won’t just be an opening to discuss agriculture in the state. It’s also an opportunity to say, with pride, “Hey, look – I did that.”

Why two 2-ply girders instead of a 4-ply girder?

It’s all about the angle, Dave Meyer explains. If the girders intersected at 90 degrees, there would be no difference between two double-ply trusses sitting right next to each other and a four-ply truss. However, in this case, to make the distinct octagonal roof shape, the corner girders rest on the main girder at an angle. That means, says Steve Szymanski, “one is going to be slightly longer to pick up more of the bearing. There is a method to that madness!” The bearing area on the main girder is calculated separately for each of the two-ply trusses, and the differing lengths means each double-ply gets as much bearing as possible while maintaining the angle. Dave says his unique approach isn’t necessarily what every designer might think of. After more than twenty years of designing, he says, creative solutions have become a specialty.

About the Author: Dale Erlandson focuses on the individuals who make up the component manufacturing industry and how they are leaving their mark in their communities.