Project Overview

THE ECO BEND, STEAM-LAM TREE LOG is a green object towards an eco timber architecture. This combination consists of two technologies: laminating & steam-bending wood, which the whole fabricating process has been ideally produced in an environment-friendly way from its material sourcing, wood bending to its final defined form. The idea of using tree trunks is the benefit of a round-wood pole is stronger than a square sawn-wood of the equal cross-sectional area.

The bent log objects are engineering-designed as a vigorous but elegant component in order to be confidently able to bear structural giant loads, compression and tension forces, as an example of a steam bent chair carrying a person's weight. The researcher suggests that this novel methodology provides a new possibility of timber architecture in using large-span objects as a functional arch through sustainable technique ways.

Organisation

En-Kai Kuo

Team

En-Kai Kuo, the researcher / developer of THE ECO BEND, STEAM-LAM TREE LOG, based on his individual timber-technique research of Design + Make master programme of the AA School with the below supporters by the course team and classmates.

This Graduate - Object developed with its conjunction project Sawmill Shelter team with:
Students: En-Kai Kuo and Rolando Madrigal, Eleni McKirahan, Diego Saenz, Paolo Salvetti, Evgenia Spyridonos, Trianzani Sulshi
Construction coordinator: Edward Coe
Workshop manager: Charlie Corry-Wright
Forester: Christopher Sadd
Programme Directors: Martin Self, Emmanuel Vercruysse
Project Tutor: Charley Brentnall
Structural Engineering: Arup

Project Context

The unconventional idea of steam-bending straight tree log to create architectural-scale arches was the brainchild of En-Kai Kuo, based on his timber-technique research of the AA School Design + Make master programme with the supporters by the course team and classmates, and experience working with a local furniture maker Petter Southall.

The creation brings the breakthrough where proves tree-size roundwood can be made pliable by using the new steam bending methodology. This object has been experienced a period of bending tests from a small piece wood to entire tree trunks, which specifically were set by a series of a strategic arrangement of cutting and steam bending. This innovative bending technique involves laminating and steaming. Using roundwood acts much stronger than the same cross-sectional area of the square sawn timber. The steam bent logs were used as structural columns for the programme team project - Sawmill Shelter (2017) in Hooke Park. The bent columns of shelter hold its anticlastic surface curves in two directions where was pulled tightly by steel-cable anchors to resist both downward snow loads and uplift from wind. This attempt shows an unconventional performance of a revolutionary project in timber architecture.

Project Innovation

This novel technique provides an alternative approach. In the bend, En-Kai exhibited how the conventional art - steam bending wood can cooperate with its nowadays counterpart - glued lamination wood (glulam) into a noteworthy merging technique, Steam-Lam, so that a large stiff tree trunk turning into a desirable curve becomes feasible. This combination optimises both merits of the techniques, laminating and steam-bending through an eco means. The steam-bent ends of the tree logs were first to cut into longitudinal slices by a sawmill machine, but laminated without adhesive, then softened in a scalable heat-resistant bag filled with a period of vigorous steam and bent along with the iron formers by using a 2-tone tensile sling into a parabolic shape. A special 2.4 by 4-metre jig was used to steam bend the laminated trunk around a defined radius. The shapes of the bent trees were final formed and secured by bolts and screws, instead of using chemical glue, well-organised over through the stack of the arch planks.

This new way of steam bending laminae highly keeps its tree log appearance, retaining the original cross-section profile. In other words, its grain patterns keep adjacent to each other after they were sliced into multiple planks, which means that the physical structure is held in tack. The hybrid methodology made the breakthrough of a size limitation, which the conventional steam bending wood technique is no longer limited to a small-scale range of projects such as wooden furniture or boats.

Design Challenge

In conjunction with the master programme team project - Sawmill Shelter, provided a practical challenge for the object - THE ECO BEND, where this object performed its potential resistant ability to the reality. By utilising digital software to define the canopy shape, the grid-roof structure was designed to adjust its tensile state, which each lath carries up to two tonnes of tension, demonstrating the remarkable strength by tightening two ends of a series of tensile steel cables individually. One end attaches to a steel frame beam, and the other parabolically flows with the bent logs into the earth. The about 25cm diameter of bentwood objects was required in order to conquer massive tensile forces of each lath from its strong tensile canopy.

The steam-lam logs used two structural wood species - Douglas fir and larch. The hands-on 18 hockey-stick-shaped objects support one end of the canopy, standing like a tree fence for reducing wind and rain effects on the sawmill. Meanwhile, those log bends visually merge with its forest surroundings where the trees collected from. Due to the double-curve form of the canopy, the 18 bends own 18 different ranges of the radius. Therefore, the challenge of fabricating process was making an adjustable bending jig a curve of 50-110cm radius.

On the next stage, Eco Bend has challenged the two-direction-curve in one object that has prototyped for a structural system of curved-grid-beams & arch-columns for applying an art museum installation (see the last image).

Sustainability

The goal of THE ECO BEND, STEAM-LAM TREE LOG is to provide a possibility of creating large bent timber objects through an eco-friendly process. It expects this approach can be encouraging users to have a rethink of material choices and uses with regards to the environment between manufacturing fields and hands-on natural ways.

For the sake of environmentally friendly, STEAM-LAM TREE LOG has been well-considered created throughout the fabricating period. This hybrid-techniques component excludes chemical processes, such as adhesive elements make up of considerable chemical ingredients.

Thanks to the woods thinning seasons, the material of the steam-bent objects were directly taken from its surrounding, in which is an ongoing attempt for the woodland campus to maximise self-sufficiency without conveying long distances of transportation. This is a high win-win situation, where the thinning routine not only improves the forest into healthy living conditions as well as the material in sustainable and effective uses.