Design Museum's Street Seats Challenge

Design Museum's Street Seats Challenge

This summer Design Museum brought the Street Seats international design challenge to Portland. A team of Holst designers came together to design a city bench that will become a permanent installation in the City of Portland.

We saw the Street Seats prompt as an opportunity to showcase the reclamation, applications, and versatility of recycled construction waste. We began by carefully considering what waste materials we could responsibly source to provide the durability needed for a long-term installation, deciding on reclaimed wood and recycled concrete. The second stage of the design process focused on form and construction feasibility. The goal was to create a versatile modular system that minimized waste in construction.

Fractal Rock is a modular bench system that is sustainable and scalable. The plywood modules serve dual functions as formwork for the concrete modules and as pieces in the final assembly. The triangular prism shape allows for an infinite number of configurations which can be tailored to variable site parameters. It allows versatility without diminishing the foundations of sustainability.

Competition entries were submitted from 24 countries and 22 U.S. states, and fifteen semi-finalist designs were chosen to be fabricated and installed in downtown Portland. Selected as a semi-finalist design, we fabricated Fractal Rock for a six-month installation. Given just three weeks to construct the bench, we quickly considered which specific wood and concrete would be most appropriate for the long installation periods; given Portland’s rainy climate, durability was a primary concern. After testing several materials, fabrication began using marine-grade plywood and a small-size recycled concrete aggregate.

To construct Fractal Rock, we cut plywood for five wood modules and assembled them for concrete pouring. Creating triangular shapes with concrete proved an unexpected challenge; we came up with a creative way to caulk tight corners (using another common waste product, plastic straws) and poured the concrete carefully to avoid weak or blunted edges. After the concrete modules were done, we pulled apart the wood modules reassembled them, and treated them with a sealant to prevent water damage.

The Street Seats exhibition opened on August 9th, and the semi-finalist benches will be on display outside the World Trade Center Portland until February 2019. Five benches will be permanently installed on the plaza. The remaining seats will move to permanent locations around the city of Portland.

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