jinghua zeng uses laminated semi-tubes to construct the cross easy chair

aalto university graduate jinghua zeng has designed an easy chair constructed using the basic element of semi-tubes laminated with linoleum and veneers. the cross structure of zeng’s design was realized from simple sketches to successive experiments and prototypes that led to inserting the tubes crosswise to make the final chair, giving the product its name.

perspective view of the second prototype

all images by jinghua zeng and chikako harada

the design process began by investigating the material structure of linoleum and its application in furniture design. although it has been used since the 1930s, it’s mostly applied on a flat surface such as table tops, but zeng questioned: ‘are there any other possibilities of linoleum?’ despite its limited flexibility, it’s hard to keep in the curved shape by just bending with hands. inspired by the existing techniques for bending veneer, zeng explored how to bend the linoleum and veneer into a half-cylinder shape with the mold, resulting in the semi-tubes.

side view of the second prototype

a series of controlled tests on semi-tubes laminated by veneer and linoleum were conducted to observe how the strength and surface conditions of the material structure would change with different variables. ‘the biggest problem of attaching linoleum on the curved surface is cracking on the turning edge,’ says zeng. however, with the special pre-treatment of linoleum, it becomes much more flexible and can be easily bent together with veneers. the most important finding of the preliminary tests was how to apply linoleum on the curved surface in a proper way, and similarly to bamboo, the result was a very light and stable structure.

front view of the second prototype

‘looking back to how alvar aalto designed classic furniture collections, I was impressed by the countless combination possibilities that a basic standard element could bring to furniture design,’ zeng says. therefore, in the further tests she explored further into the basic elements composed of linoleum and other materials, mainly wood and metal.

detail of the cross legs

among the standard elements created by the further tests, the cross structure by inserting two semi-tubes crosswise was both lightweight and stable enough for furniture construction. by cutting slots on the straight parts, two U-profile semi-tubes could be inserted into each other quite tightly. from a single element to a structural part, it marked a breakthrough in developing the semi-tube material structure.

details of the joint

the cross structure of the semi-tubes has the potential to adapt to various furniture products as a standard element. since chair design requires high stability of structure, zeng decided to start with designing an easy chair with this basic element. iterative tests were taken to find the best proportions for the chair. two prototypes of different proportions and details were finally developed. the cross structure not only acts as the main supportive part for the chair but also gives a very special character to the form.

details of the armrest

semi-tubes in C profile and U profile

samples of the preliminary tests

test samples in progress

example of the cross structure

samples of further tests

the chair in use

project info:

project name: cross chair

design: jinghua zeng

photography: jinghua zeng and chikako harada

designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: lynne myers | designboom