Louise & Arianna || CONSTRUCTED || 1
CONSTRUCTED Louise Leung + Arianna Mao
2 || CONSTRUCTED || Louise & Arianna
Louise & Arianna || CONSTRUCTED || 3
INTRODUCTION History
The cardboard chair, now an ubiquitously designed object, was probably sparked in the 1972 by Frank Gehry with his collection of cardboard furniture called “Easy Edges”. His designs were wildlysuccessfuland have been featured in London’s Design Museum and has spawned new innovation in cheap, economical and environmentally friendly furniture using cardboard.
Goals
We were really interested in the environmental friendliness of the cardboard chair. We wanted to reuse a unwanted material and explore all the possibilities that cardboard can offer in terms of a chair. We set a few parameters to guide ourselves along in this project. 1. Comfort - we noticed that a major flaw with most designs of cardboard chairs is that they are quite uncomfortable. We theorize that is is due to the planar nature of cardboard and that to accomodate for the curves of the human body would mean compromising the structural integrity of the corrugations in the cardboard. 2. Structurally stable - we thought this was particularly important because we wanted the chair to be stable in the long term. We thought that the most environmentally friendly chair is a chair that gets used and can last for a long time. 3. Use as little cardboard as possible - this was a challenge in reduction. When thinking of recycling materials, there’s the three mandates of the three R’s - reuse, recycle and reduce. We thought it would be best to try to go for all three. We also tried to use cardboard that has already been bent, as cardboard chairs typically are made from “clean” cardboard.
Research
Our research really tried to address three main areas. We examined different methods of constructing a cardboard chair. We wanted to research structural integrity of construction, so we looked into material properties and examined precedents for which we thought were particularly relevant. Most importantly, we researched ergonomics of chairs and found a vast resource pool on the subject. We tried to incorporate this information to make a chair that is both comfortable and reduces long term strain.
4 || CONSTRUCTED || Louise & Arianna
STRUCTURAL TYPES
layered
lightweight construction
Lightweight construction gets its structural integrity from a variety of sources - corner integrity, folds, using a honeycomb pattern, etceteral. This allows the lightweight construction to be folded up, it is easily transported and manufatured and is very economical in its material usage. However, as the main goal of lightweight construction is to be lightweight, this impairs the longterm integrity of the material. Since the goal is to be economical, there is less concern with the comfort of the person using it, and tends to be less comfortable.
Layered construction is the most solid construction type. It is very stable because of all the layers of cardboard supporting it. It likely also to be quite comfortable, because having many layers allows each layer to be custom cut such that it fits around the body. However, layered construction requires a very large quantity of cardboard and labour to construct. It is also heavy and takes up a lot of space without being able to be folded away or stored.
slotted
Slotted chair construction uses the structural integrity of support structures to uphold the human body. Slotted chairs are essentially like layered chairs, but they remove the excess bulk and keep only the supporting beams. They are easy to construct, but difficult to construct by themselves as it requires a lot of carving.
Louise & Arianna || CONSTRUCTED || 5
MATERIAL PROPERTIES compressive strength
We thought that it was important to try to find data about the compressive strength of cardboard. We thought that Cardboard Tubes: Tensile/Compressive Strength: 8.1N/mm2 Long Term Tensile/Compressive Strength: 0.8/2.2 N/mm2 E value: 1000-1500 N/mm2
tubular
Tubular structures are made from paper tubes. In our research on material properties, we found that paper tubes are actually the strongest form. This is probably because of the even distribution of force all along the arched and curved forms. However, we found that most tube structures didn’t use the tubes vertically, which would be a more efficient use of the structural integrity.
Honecomb Sheets:6.9 N/mm2 Bending strength: 6.9 N/mm2 Design tensile: 0.6 N/mm2 E Value: 1000 N/mm2 Source: Cardboard in Architecture, Mike Eekhout
We also found in our research that the directionality of the corrugation is important to the support of the chair. When the corrugations are perpendicular to the floor plane, the force of gravity acting down on the chair is in the same direction as the corrugations, so the corrugations transmit the force downward. below: cardboard material study
6 || CONSTRUCTED || Louise & Arianna
Chair Design Standards
ERGONOMICS
Louise & Arianna || CONSTRUCTED || 7
In our research, we realized there are two important measurements to consider when constructing a chair: the popliteal height (the distance from the underside of the foot to the underside of the thigh at the knee) and the buttock popliteal height (the horizontal distance from the rearmost part of the buttocks to the back of the lower leg). More than just considerations about fitting the scale to the human body, we found that it was important to mold the chair around the contours of the body. This is, we found, the reason for the success of comfortable chairs. We also found that it is important for the chair to “give� a little to be more comfortable. This give is the same principle of elasticity as bending knees when jumping -- it softens the landing. The give also helps to bend the cardboard around the body to give a more comfortable fit.
8 || CONSTRUCTED || Louise & Arianna
PRECEDENTS
examining precedent structures
We decided that it was important to build models of precedents so that we a) get a feel for the material and b) get a 3D hands on experience of why certain forms work or not.
Louise & Arianna || CONSTRUCTED || 9
drawings & models
WORKS IN PROGRESS
10 || CONSTRUCTED || Louise & Arianna
OUR CHAIR
Louise & Arianna || CONSTRUCTED || 11
banana box recycling
the “give”
support structures