David Rubenstein Treehouse at Harvard University

The David Rubenstein Treehouse is a mass timber structure built in true post and beam fashion. The Studio Gang design team aimed to create a greener-built conference space that embraced the community and outdoor environment.

The angular façade profile for the building produces challenging load paths back to internal structure. To maintain aesthetic integrity, all steel connections were also concealed within the glulam beam elements. TriPyramid designed and manufactured the most complex of the steel nodal elements that support the column and beam joints at the second and third floors. The steel fabrications terminate up to 11 complex load paths into a single work point. Through extensive finite element analysis in Ansys, using custom-built load applications and restraints, we confirmed performance for each node in all expected building conditions.

To achieve the necessary precision within extremely tight tolerances, we designed one- and two-piece fabrications with critical faces machined after welding. CMM scanning probes were also used on every steel-to-timber work point to ensure accuracy of the fabrications to within 1/16”. Individual weldments weighed up to 2,200 lbs and stood seven feet tall when assembled. In total, 34,000 lbs of steel were processed into 32 weldments over a 12-week period. By beginning deliveries just five weeks into fabrication, we maintained a steady twice-weekly delivery schedule to keep the project on track.