Mangrove Structure

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Denegri Bessai Studio was invited by Toronto-based curator Sara Nickleson of the Design Exchange to develop a full-scale pavilion using 3D printing. The Mangrove Structure, on display May 15-August 30th at the Design Exchange’s offsite location, 363 King St. W., is an airy alcove constructed using flexible rods and 3D printed connectors.

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The Mangrove Structure is an ultra- lightweight composite construction assembly that takes advantage of two complimentary material systems for its basic character and organization. The first is a networked system of bending-activated structural elements made from engineered pultruded glass-fiber reinforced plastic (GFRP) rods at a diameter of 3/8”. Bending-active members gain compressive strength when held in bending. These elements are sprung into a network of structural shapes through a second complimentary network of complex node and floor connections. This second system is comprised of custom digitally designed node clusters that are manufactured through state-of-the-art digital modeling and 3D printing techniques. Each connector is unique although typologically categorized into ‘apex cluster’, ‘x-node’ and y-node’ types. There are twelve nodes in the installation. Each has been engineered, shaped and subdivided to suit 3D printing materials and tolerances, while providing adequate structural support for the system. Several of these are advanced prototypes, one exploring more complex and integrated local joinery, another 3D printed in its entirety in stainless steel.

The light weight and relative strength of the structural elements combined with the infinite local variation of the node components make for a very versatile construction assembly. Like the coastal mangrove forests from which this installation takes its name, the mangrove structure gains resilience through networked connections and represents a skeletal infrastructure that harbours a variety of potential elements, spaces and ‘habitats’. Through its multiple connection points, each element of the structure helps to support the rest.

digitization of study model

The form of Mangrove was developed through a series of physical modelling exercises that gradually move up in scale from 1:24 to 1:1 full-scale mock-ups and prototypes.
An initial study-model of the rod network at 1:24 was used to find the basic form the Mangrove. Once we found a form that worked well within the space – allowed for a adequate headroom, good circulation, and appropriate height of 3D printed elements – we digitized the model with a digitizing arm, and began work on the 3D printed elements

detailed model

For the larger model, scaled at 1:12, 3D printed nodes were added to the rod system, completing a feedback loop between digital and physical versions of the Mangrove.

assembly sequence

plan

elevation

node inventory for 3d printing

structural testing

To develop a full-sized prototype of the Mangrove, we initiated a collaboration with Cast Connex, a local engineering firm with expertise in cast structural components in construction and bridge design. We prototyped a variety of different components varying the thickness, tolerance, shear key size, material, and adhesives for the 3D printed nodes. Each node was engineered, shaped, and subdivided to suit 3-D printing materials and tolerances, while providing adequate structural support for the system.

completed 3d printed nodes

The assembly of each unique node was carefully tested, refining the choice of adhesive and the design of the mechanical shear connections between the node segments.

The lower nodes were made from a material called ABS (Acrylonitrile butadiene styrene), while the apex nodes were fabricated from PLA (Polylactic Acid). One, though, was printed entirely in stainless steel.

on-site installation

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2015

Developed in Collaboration with:
Cast Connex Engineering – Carlos de Oliveira, Michael Gray, Tarana Haque
Entuitive Engineering – Peter Olendzki
Heliolytics – Michael Yan

Fabrication:
University of Toronto: Daniels Faculty of Architecture Fabrication Lab
Ryerson University: Design Fabrication Zone; Department of Architectural Science Fabrication Lab
Plastech Fabrication and Distribution
Cutting Edge CNC

Photography: Scott Norsworthy