It's All About the Connection

24 Jan, 2007 By: Kenneth Wong

ConXtech uses custom-developed technology to join structural steel design and manufacturing

In the world of structural steel, connections can make or break a project, both literally and metaphorically. Bob Simmons, a 30-year veteran of the structural concrete industry, developed an innovative system for connecting columns and beams. His patented invention, SMRSF (Simmons Moment Resisting Space Frame), uses standard HSS (hollow-structural section) columns and wide-flange beams with an interlocking connection. The custom-manufactured columns are welded with male-dovetailed inner-collar plates in the factory. The beams are robotically welded with female-dovetailed outer-collar plates on each end. At the construction site, the beams are lowered into place from above between the erected columns. The result is a stable steel structure that workers can assemble quickly. The method is the foundation of ConXtech, a design, manufacturing and construction service provider to the commercial residential housing industry.

Simmons Moment Resisting Space Frame, invented by ConXtech’s founder Bob Simmons, uses a bolted collar system to join columns and beams to build structural steel frameworks.

Another connector -- a less tangible link -- ties the physical steel structure to the digital model as well as the 3D columns and beams to the manufacturing plant. It’s ConXCAD, a highly customized version of the AutoCAD-based ProSteel 3D.

The Root of ConXCAD

ProSteel originated from Germany-based Kiwi Software GmbH, but the grunt work -- the complicated customization that transforms it into ConXCAD -- was done by Canada-based StrucSoft, the sole North American and South American distributor of ProSteel.

“Most companies use ProSteel as it comes out of the box, with very little customization, if any,” explains George Ajami, president of StrucSoft. “But we have found a niche in the market place among companies with, for the lack of better terms, difficult-to-meet needs. We have a team of programmers dedicated to customizing ProSteel for the specific needs of such customers.”

Rod Montague, director of structural detailing at ConXtech, was a long-time ProSteel user, fully aware of StrucSoft’s expertise. So ConXtech and StrucSoft inevitably crossed path. “The first time we met [with ConXtech’s chief technology officer and cofounder Simmons], he said he wanted to cut down the design time to a matter of hours,” Ajami recalls. “He wanted to have a system where he can answer a few questions about the footprint of the building --the grid’s location, the number of columns, etc. -- and [have the software] very rapidly generate the beams, bolts, welds and everything else.” Furthermore, the digital model would be the basis for automatically producing the shop drawings and CNC (computer numeric controlled) files required for manufacturing the steel pieces. Hourly turnaround time for this process was perhaps not a realistic goal, but, according to StrucSoft’s Ajami, ConXCAD enabled ConXtech to do within weeks what used to take months.

Iron Rules

The type of buildings ConXtech specializes in, StrucSoft’s Ajami observes, use standard components and follow certain structural formulas, making them suitable for rule-based approach, or what the industry now commonly refers to as parametric design.

“ProSteel is partially parametric out of the box [in contrast to a product like Autodesk Revit, which ships with full parametric capabilities],” Ajami explains. “In ProSteel, if you connect a beam to a column, then make the column bigger, the beam attached to it will automatically adjust. But you cannot move a column line two feet to the left and expect all the beams to automatically readjust while retaining spacing as per the engineering requirements for deck support. That’s what I mean by partially parametric.” To make it fully parametric, specifically for ConXtech’s purpose, StrucSoft added a set of rules to govern the behaviors of ConXCAD objects.

Here’s how ConXtech describes ConXCAD. The software comprises what might be comparable to jigsaw pieces for assembling a steel structure. The intelligent components -- 3D representations of ConXColumns and ConXBeams -- understand their relationships to one another. In other words, if you move a column, the beams attached to it automatically readjust themselves. Consequently, the entire digital infrastructure is, in a manner of speaking, aware of its internal components’ dimensions and its interrelations. Most importantly, its components are embedded with manufacturing requirements -- CNC (computer-numeric controlled) code -- and the design can be used for accurate cost estimation. When ready, the CNC files are transmitted to the manufacturing plant to produce the columns and beams needed for quick and efficient on-site assembly.

StrucSoft customized the commercial product ProSteel with ConXtech’s rules, turning the software into a fully parametric application.

Interacting with Commercial Architectural Programs

“We’ve been looking at the newer 3D programs,” says ConXtech’s Rod Montague. One product that caught ConXtech’s attention was Autodesk Revit. “Revit objects deal very nicely with morphing, coping with design changes, but at the present they don’t have the ability to handle manufacturing information,” he observes. He meant the CNC data. “Revit is an architectural tool,” StrucSoft’s Ajami similarly remarks, suggesting it’s not ideal for structural steel. “You can’t insert bolts, drill holes [in Revit objects], then export CNC files.”

The Autodesk press office confirms, “It’s true that Revit cannot read, import or export native CNC data on its own -- that is, not without the translation assistance of another program,” but also points out, “There are companies and creative individuals out there leveraging Revit information in their CNC workflow and getting this information out to their fabrication devices.” These companies include Because We Can, Living Homes and Marmol Radziner Prefab.

Because ConXCAD is compatible with nearly all AutoCAD-based products, ConXCAD can easily convert an Autodesk Architectural Desktop or Mechanical Desktop model into a ConXCAD 3D model, Montague says. ConXCAD was “developed to combine the design and fabrication processes into an integrated software solution using COM (Component Object Model) programming technology,” according to its makers. So the model can be imported into a finite-element analysis software, such as ETABS and SAP2000 from Compusoft Engineering or RISA-3D by Risa Technologies for structural analysis.

Hopes for Wider Adoption of ConXCAD

ConXCAD’s Simmons revealed, “Currently, [ConXCAD] is a tool we use. We take the architect’s 2D column layout and convert it to a ConXCAD 3D wireframe and populate it with our standard components.” His vision is, in the near future (12 months is his guess), the architects themselves will use the ConXCAD pieces as they construct their design. But he also admits, “The 3D modeling we now have in ConXCAD is a bit too complex and the learning curve is a bit too steep to expect architects to adopt it at this time.” For this reason, ConXtech isn’t currently offering the software to clients. Nevertheless, it’s an integral part of the services ConXtech provides. “We’ll manage that part [involving modeling in ConXCAD] and provide the entire design team with a dimensionally accurate 3D model that we also use as the data input for our manufacturing process,” Simmons explains.

For Specialized Needs

“There are many companies that have gone out and bought an expensive piece of software, only to find that it improves their workflow by a marginal amount,” says StrucSoft’s Ajami. This is particularly true in the case of companies that specialize in the fabrication of repetitive structures that are similar but not identical, in which some logic or some rules can be applied to automate the process. Ajami points out, “Other industries where this can be applied are industrial mezzanines, communication towers, offshore jackets, light gauge steel panels and metal buildings.”

In his view, the only way to get a dramatic increase in production for such companies is to customize the software to the specific operations of the buyer. “Traditionally companies described above end up buying a commercial program and accepting the limitations the program, or they hire a group of programmers in order to write an application from scratch, which is time consuming, expensive and risky,” Ajami says. “StrucSoft offers the ability to use ProSteel as a development platform on which to build custom applications. This is both a cost effective solution as well as time saving.”

About the Author: Kenneth Wong

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