Tallest Mass Timber Building in Italy: An 11-Storey 100% Timber Building in a Seismic Area

The project involves an 11-storey mass timber building in Rome, assembly commencing in February 2025. As structural engineers, we utilize Cross-Laminated Timber (CLT) for walls (lateral system) and slabs (rigid diaphragm), eliminating concrete. Situated in a seismic zone with significant wind forces, we developed bespoke steel connections, as standard ones are too weak for this “beast,” ensuring structural resilience. The structure achieves a 90-minute fire rating, meeting stringent safety standards.

We performed advanced Finite Element Method (FEM) analysis to create a digital twin, enabling precise simulations of lateral acceleration, compression perpendicular to the grain, and stability during earthquakes. Innovative solutions address compression perpendicular to the grain, enhancing durability.

Our scope includes production and assembly drawings through a Design for Manufacture and Assembly (DfMA) approach. Crucially, we closely collaborated with the architects from day one, facilitating cost-effective solutions and maintaining the project’s low budget. This early involvement underscores the importance of integrating structural engineering expertise from the start.

The building is mixed-use, primarily residential. This case study examines the integration of CLT in lateral systems and diaphragms, development of bespoke steel connections for seismic and wind load management, advanced FEM analysis, and benefits of early architectural collaboration.

Franco Piva

Engineer
Ergodomus Timber Engineering

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35 Stone: A Case Study for Utilizing Dowel Laminated Timber in Deep Green Workplace Design

Explore the ins and outs of 35 Stone, a regenerative ‘Living Building,’ that utilizes dowel laminated timber (DLT) to deliver a top-of-class workplace for Brooks Running headquarters’ expansion. This five-story, 182,000 GSF Class A+ hybrid mass timber-concrete office and retail building is located in Fremont, a vibrant urban village in Seattle. As a mixed-use destination, 35 Stone promotes health and wellness and an active lifestyle with its forward-looking biophilic design.

From concept to evolution and execution, this case study dives into healthy building materials and the design flexibility of a DLT floor system with a glulam structural frame. 35 Stone offers insight into structural revisions after construction starts, long-term viability, best practices for designing panel expansions, and strategies to prevent moisture propagation. Hear firsthand how using DLT can provide flexibility for future tenant improvements.

A benchmark for environmental stewardship, 35 Stone embraces Seattle’s Living Building Pilot Program, meeting the rigorous deep green requirements for certification and the Place, Beauty, and Materials petals of ILFI’s Living Building Challenge. This case study also invites the audience to examine how a mass timber framework can create a regenerative building that promotes a healthy workplace while stewarding its urban ecosystem.

Todd Mayne

Principal — AIA, LEED AP BD+C
Weber Thompson

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