Complex Residential Steel Framing in New England

Designed in a mountainous region of New Hampshire, the project pushed connection engineering beyond the limits of standard spreadsheets while still operating within the tight spatial constraints typical of residential construction.

Following years of experience dominated by manual calculations and bespoke spreadsheets, the project became a proving ground for a more visual, nonlinear approach to connection verification, one that could keep pace with architectural ambition without compromising constructability or review efficiency.

“The first thing you ask is: have I done this exact connection before? And on this project, the answer was no. That’s when I knew I needed a different tool.”

About the Project

The residence was conceived as a multi-level steel-framed home embedded into a rocky hillside, with cantilevers extending in multiple directions. Structural steel was selected to achieve long spans and open interior spaces while minimizing member depth. However, the architectural vision came with structural consequences: varying beam sizes at different elevations, offset framing lines, and columns subjected to combined axial load and bending.

Environmental loading intensified the challenge. Ground snow loads exceeded typical residential values, with drift loads approaching 138 psf in localized areas. These demands translated into large moments at beam–column interfaces, particularly where cantilevered framing met HSS columns. The project’s success depended on connections that could reliably transmit these forces while fitting within narrow wall assemblies and ceiling zones.

“Residential projects don’t give you the luxury of space. You’re working within five-and-a-half or seven-and-a-quarter inches, and the connection still has to do everything a commercial one does.”

Engineering Challenges

The most critical challenge centered on wide flange beam–to–HSS column moment connections. Traditional solutions—such as wraparound plates or oversized assemblies—were impractical due to spatial constraints and constructability concerns. Each connection configuration varied slightly depending on elevation, beam size, and load demand, eliminating the efficiency of repeating a single standard detail.

Spreadsheet-based design quickly became a bottleneck. Each variation required careful modification, debugging, and rechecking of formulas, with a constant risk of overlooked variables. Verifying continuity through the HSS column, particularly under biaxial bending, added further complexity. Just as importantly, the resulting calculation packages were difficult for the engineer of record to review efficiently, increasing approval risk and turnaround time.

“You spend more time mowing the lawn—checking variables, debugging sheets—than actually engineering the connection. And you still don’t see how the stresses are really flowing.”

Solutions and Results

To address these challenges, SCADD Incorporated adopted IDEA StatiCa for nonlinear connection modelling and verification. Using its component-based finite element method, the team modelled each unique connection directly in three dimensions, including continuity plates, stiffeners, welds, and bolt groups.

Two representative connection types were developed. In high-moment locations, continuity plates were introduced through the HSS column to ensure plastic hinge development in the beam rather than local column failure. In lower-demand areas, simplified stiffened connections were verified without continuity plates, avoiding unnecessary fabrication effort. The ability to visualize equivalent stresses, deformations, and load paths in real time allowed the engineer to optimize each detail with confidence.

Crucially, loads were evaluated both with and without equilibrium forces in the column, enabling verification of true continuity behavior. This approach confirmed that stresses were properly transferred through the column height rather than being artificially absorbed at the joint. Compared with manual methods, the workflow eliminated hours of spreadsheet modification and significantly reduced review friction. Even as a new user, the engineer reported time savings measured in tens of hours across the project, with further gains expected as reusable connection libraries were built.

“With a picture, the engineer of record immediately understands what’s happening. That alone saves an enormous amount of review time and back-and-forth.”

Summary

The New England residence demonstrates how advanced nonlinear connection modelling can bring commercial-grade engineering rigor to high-end residential construction. By replacing opaque spreadsheets with visual, verifiable analysis, the project achieved efficient, code-compliant steel connections under extreme loading - while preserving architectural freedom and accelerating approval. For complex, one-off connection challenges, the workflow has fundamentally changed how future projects will be approached.