An inside look at the Steel Dynamics’ flat roll steel mill project in Sinton, Texas.

• Brady Broom, PE, Engineering Manager at New Millennium, Hope, AR
• Lloyd Smith, PE, Structural Design Engineer at New Millennium, Hope, AR
• George R. Batcha, IV, PE, SE, Vice President of CSD Structural Engineers

A project of impressive scale. 

Our experts agree that what made this state-of-the-art Steel Dynamics project so significant was the sheer scale and the aggressive timeline. “It was a rigorous schedule, and we needed to do a lot of coordination in a very compressed amount of time,” says Brady Broom, engineering manager at New Millennium. 

“This flat roll facility has the biggest caster in the world and huge electric arc furnaces. The scale of this big mill project really pushed us to the limits and beyond to accommodate our client’s needs,” says George Batcha, vice president of CSD Structural Engineers. 

Early collaboration made success possible, even on a tight timeline.

This type of project is a once-in-a-lifetime achievement in the course of a structural engineer’s career, and collaboration is the key to success. “We were brought in from the beginning,” says Batcha. “We were involved from the layout stage when they were looking at the mill layout and process layout. From there, we were involved in sizing the cranes based on production needs. Our job as the structural engineer was to come in and put together an economical structure, utilizing as much material they make in terms of wide flange shapes, angles, channels and any of the hot roll steel shapes. Their goal was to get it all put together in record time, so everyone being on the same page was vital.” 

Working in lockstep helped the team come up with the most economical solutions along the way. 

“I view collaboration as both passive and active,” says Broom. “You know, passive collaboration is something that’s accomplished through the clarity of the drawings. CSD prepared drawings in a way that left little to the imagination. Of course, this job was so big and so complex, we had to do some active collaboration to make sure we understood. It’s vital for both types of collaboration to take place in order to keep jobs on schedule and on budget.”

“It was really amazing how well everything went because the drawings were so complete,” says Lloyd Smith, New Millennium engineer. “I wish all contract drawings were as complete as what we had on this one. When we had to tweak something, the CSD team adjusted what we needed to adjust and sent the drawings back as an addendum immediately.”

“I worked up a game plan to break the three large segments of this project into more bite-sized pieces to have draftsmen available and ready to get the drawings prepared,” says Broom. “One of our number one goals due to the timeline was to have minimal, if any, questions on our approval submissions. That’s where Lloyd and George came in and did a great job of coordinating and making things clear. We didn’t have to ask because we knew which way it was going before we prepared the drawings. Our goal was to have no questions so we could virtually go straight into production.”

Shipping challenges resulted from the sheer size of the material.

Even with a collaborative team of experts, an industrial building project of this magnitude comes with challenges, especially with girders that measure 106 feet in length and weigh 18 tons. “Some of the girders were so large, we had to get creative to get them down there,” says Smith. “We didn’t want to splice things because a splice in something with these large forces in the chords would have been even more complicated. To get it shipped, we had to coordinate with George before we even started design to make it manageable enough to ship the large pieces.”

In addition to their impressive lengths, these girders had 8-inch angle top and bottom chords and six massive beam connections built into them. “We knew we were going to be nearing the limitations of Joist Girders on the project,” says Batcha. “We worked really hard to try to utilize Joist Girders as opposed to going with the structural steel fabricated trusses. We knew what the spans were, we had big spans, we’ve had huge loads. What we didn’t know was how we were going to make this work. We always say that with enough time and money, you can do just about anything, but our goal really is to come up with an overall economical solution. In this case, that meant coming up with Joist Girders we could actually ship in one piece.”

The most economical solution in industrial building is not a one-size-fits-all solution. 

In the mill, there are three areas: the cold complex, the hot mill and the melt shop. Each area presented different challenges. “We had to try to do a Joist Girder that was within the realm of New Millennium’s capabilities while trying to reduce the building height,” says Batcha. “The Joist Girders we did, they weren’t necessarily the most economical Joist Girder, but it helped us reduce the height by several feet. And by reducing the building height, we reduced the size of the foundations. There’s real cost savings in that. Some people would look at it and say, ‘Those Joist Girders aren’t the most economical.’ And that’s a true statement. They’re not. But for this project, they were part of the most economical solution.”

Designing and building to weather local conditions.

Because of the location, down in South Texas on the coast, there were also large wind loads to consider. “Typically, when we design a building like this, you have your wind loads and you have your crane loads you have to design the building columns and foundations for,” says Batcha. “In this case, instead of going with columns that are only say like 6 or 8 feet apart, we’d go out to 10, 12 or 14 feet apart. Then we look at the foundations to find the most economical solution. We’re looking at the columns and coming up with depths that are reasonable, ensuring that we have economical shapes we need to do foundations, design the piers and the anchor rods. We looked at the longitudinal bracing and made sure we could resist the code-prescribed wind loads and still come up with an economical solution.”

Cost savings powered by team collaboration.

“The crane clearances are critical in the industrial buildings,” says Batcha. “We have to maintain enough height with the OSHA clearances above the top of the actual crane. And then again, we are trying to come up with the most economical Joist Girder design globally for the building structure. And going through these, there were some Joist Girders we looked at in the preliminary design phases with New Millennium. And then after the fact, as New Millennium was going through and fine-tuning their final design, they came back and said, ‘If we do this and we tweak this a little bit, we can save some money.’ The team ultimately reviewed the cranes and the clearances and made some determination in certain locations that resulted in cost savings.”

“I think joist products for this type of building were a great choice,” says Smith. “We used them for the wall girts, we used them for the roof. The job site panelized the erection process, which sped up everything. That’s a cutting-edge method of erection for these products that I think is going to be even more valuable in the future. Joist products are the right way to go for industrial building design.”