Family home in Massachusetts

Martha’s Vineyard island | CRAFT Engineering Studio
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CRAFT Engineering Studio worked closely with Selldorf Architects on this single-family residence. The project consists of three different buildings – the main house, garage, and pool house. With an open architectural design and unpropped balcony, the two-story building of the main house sits on a steep bluff overlooking the ocean, exposing it to high winds and introducing numerous challenges in terms of the structural design of the vertical and lateral load resisting systems. Originally conceived in steel, both the client and architect wished to move to a predominantly wood solution.

About the project

Utilizing REVIT for all drafting, exhaustive CAD file sharing, and workflow management, CRAFT was able to leverage the tool (and its integration with RFEM) to configure their structure model based on the structural analysis.

They had also wanted to do their connection design in RFEM, but it wasn’t supported for such highly complex joint design. So they turned to IDEA StatiCa.

People usually turn to SolidWorks or Fusion 360 to configure their own calculations. But they are often ignoring how much time and effort it takes. IDEA StatiCa provides really well-defined manufacturing modeling functions and connections as well as the flexibility to create customized sections in terms of stiffening elements. It also offers a perfect system for performing code checks on structural members, allowing you to just concentrate on solving design issues.
Trevor Chou
Trevor Chou
Project Engineer – CRAFT Engineering Studio
United States

With an average floor height of 10 ft (3 m), the two-story moment frame consists of two spans of 21 ft (6.4 m) and 14 ft (4.3 m).

The architect designed a soft-story structure in order to leave a completely open space for the balcony area without obvious structural braces or support. So, the team had to design thermally broken un-propped balcony framing, for which they chose to combine a moment frame with deep multi-LVL timber girders intersected with orthogonal flitch beams to form the cantilevers and back spans.

The resulting steel node joint was designed to resist forces and moments in the two orthogonal axes. Initially, they wanted to use a central hollow section hub but then found it to be incapable of resisting the high moments from the moment frame girder because of insufficient out-of-plane stiffness in the box section walls.

We had to revisit the design. Thankfully, being able to visualize how forces can be transferred to different members in IDEA StatiCa led us to a better solution. We decided to go with a wide flange section hub as it creates great continuity in both of the orthogonal axes and allows a smooth force transition between members.
Trevor Chou
Trevor Chou
Project Engineer – CRAFT Engineering Studio
United States

The steel joint was redesigned with a wide flange section to preserve continuity in both axes while also ensuring a more direct transmission of forces and moments to the center of the hub.

Additionally, the balcony members required steel to run continuously through the thermal line of the building, so the team included a thermal break pad (from a customized material) to reduce risks from heat loss and condensation.

They used Dlubal RFEM to analyze and design the framing members and IDEA StatiCa to design intricate connections in multiple materials.

IDEA StatiCa has the flexibility to create custom materials and elements with complex geometries and templates for wood-to-steel connections that greatly reduced the time required to set up the model.
Trevor Chou
Trevor Chou
Project Engineer – CRAFT Engineering Studio
United States

Engineering challenges

The challenges in this project were many.

As we’ve already learned, not only was the building atop a steep bluff and needed to be able to resist high winds without shear walls or braces but to make things more complicated, the thermally broken, unpropped balcony introduced a second orthogonal design direction to the main moment frame – meaning shear, axial and moment capacity needed to be resisted in 2 directions at the node points.

The original design was conceived as a steel system. So CRAFT was working with a steel-type building topology with the driver to do as much of it as possible in structural timber and wood.

Although timber connection designs not supported by IDEA StatiCa, the tool was able to provide output forces at specific bolt positions. The team could then easily transfer these results to their in-house design spreadsheet (for wood-codified compliant bolt bearing checks) to verify the distribution of the force and then complete their structural design for the connection.

This meant we were able to rapidly prototype the connections in IDEA StatiCa – changing the bolt size, spacing and array arrangements etc. – and to then easily get out revised bolt forces for export to our own spreadsheets.
Martyn Sheard
Martyn Sheard
Senior Project Engineer – CRAFT Engineering Studio
United States

Solutions and Results

Due for completion in 2022, the double-story single-family home in Martha’s Vineyard is a stunning example of superior architectural and structural design.

Through their use of IDEA StatiCa software and close collaboration with the architect, thermal consultant, and fabricator, CRAFT successfully evolved a full steel frame into a hybrid wood solution, reducing the amount of steel required and keeping the structure of the building in line with traditional local construction.

They were the winners of an IDEA StatiCa Excellence Award 2021, beating 100 other entrants in the small-scale structures category to win.

About Craft | Engineering Studio

Based in New York, CRAFT provides structural engineering consulting services in the construction of new (and the alteration of existing) residential, commercial and special projects in traditional and non-traditional materials.

A visionary structural engineering studio, the CRAFT team is passionate about the ongoing conversation between structural engineering and architecture. Blending their experience and open-mindedness with top computational and analytical tools, CRAFT is able to offer its clients efficient, practical and innovative solutions to structural design – perfect for architects and designers looking for new approaches to structural engineering delivery.

As Project Engineer, Trevor Chou brings his experience in performing structural design and analysis for high-rise buildings and commercial housing (under US and Chinese building codes) and is passionate about integrating his knowledge of architecture and engineering.

Martyn Sheard is a Senior Project Engineer at the firm and has twelve years of experience in design and project management across a wide range of project types and scales, with a particular interest in the engineering of mass timber structures.

Learn what the engineers say about the project

CRAFT Engineering Studio

CRAFT Engineering Studio

United States
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