96

AR

CH

ITECT TH

E AIA

MA

GA

ZIN

E SEP

TEMB

ER 2

014

WW

W.A

RCH

ITECTMA

GA

ZINE.CO

M

CENTER

Text by Logan Ward Photos by Oki Hiroyuki

NATURALLY STRONG

See more images at

architectmagazine.com

For the restaurant’s nontraditional support structure, Vo Trong Nghia Architects leveraged the mechanical properties of bamboo to create inverted conical columns, which were mocked up and load tested prior to the project’s construction.

BAMBOO MAY BE the ultimate sustainable

building material. As one of the world’s fastest-

growing plants, it can sprout up to 4 inches per

day depending on variety, soil, and climate.

Vo Trong Nghia Architects’ design of

the Indochine Café in Kon Tum, Vietnam,

proves that the fast-growing grass can look

sophisticated—even when it is left in its

natural state.

Built in 2013 as part of a hotel complex

on the Dak Bla River, the 6,000-square-foot

open-air restaurant is elegant in its simplicity:

15 inverted cones made of bamboo canes rise

20 feet to create a fan vault of sorts that supports

a butterfly roof, also made from bamboo.

The columns are arranged in a 3-by-5 grid

in the café’s 60-foot-by-100-foot plan. Each

one is 20 feet in diameter at the top and tapers

to 5 feet at the base, which is anchored into a

concrete foundation with steel plates and bolts.

Traditional Vietnamese fish baskets served

as the inspiration for the columns. Principal

designer Vo Trong Nghia, founding partner of his

eponymous firm in Ho Chi Minh City, Vietnam,

first worked with the material as a child, helping

his family make bamboo tableware.

The challenge in designing large

structures with bamboo, he says, is respecting

its mechanical qualities. Bamboo is dense and

hard, but it can bend into strong, curved shapes.

Pound for pound, it has three to four times

the tensile strength of steel, but its behavior

depends on whether it is used in whole, cut in

cross-sections, or laminated.

Part of the strength of each column comes

from the arched geometry of its approximately

400 bamboo canes bound by rope and three

steel tension rings inside each cone at 5, 10, and

15 feet above finished floor. An internal central

cane bundle and four to eight diagonal cross-

braces provide additional support for the roof.

Fasteners and conventional construction

methods would have ruined the round-cane

DETAIL

FOR THE OPEN-AIR INDOCHINE CAFÉ IN KON TUM, VIETNAM, VO TRONG NGHIA ARCHITECTS TRANSFORMED THOUSANDS OF BAMBOO CANES INTO AN ORGANIC FAN VAULT.

98

AR

CH

ITECT TH

E AIA

MA

GA

ZIN

E SEP

TEMB

ER 2

014

WW

W.A

RCH

ITECTMA

GA

ZINE.CO

M

CENTER

texture highlighted in Nghia’s design. Steel-pin

joints, for instance, would generate localized

point loads that would split bamboo’s hollow

hardened cell walls and buckle its joints.

The 15 columns were thus prefabricated by

means of low-tech joinery—mostly synthetic

fiber and a few small nails. Finding structural

engineers was difficult, Nghia says. “We based

the design on traditional experience, but it

follows logical rules of structure. And we

always make a mock-up before construction,

placing weights on top to test how much the

bamboo bends.”

Likewise, it’s almost impossible to find

contractors experienced in traditional bamboo

construction techniques, even in Vietnam.

For example, to prevent insect infestation,

Nghia knew to soak the bamboo in mud and

smoke it dry. As his firm designs more bamboo

structures, he has had to hire and train his own

construction teams, which now work under a

subsidiary company, Wind and Water House.

In total, the café contains more than

10,000 bamboo canes, each about 5 years old

and costing roughly $1 each. Harvested from

Vietnam’s many forests, the bamboo bends into

strong, flowing shapes that Nghia loves.

Column Section

Bamboo arch

Surrounded by a man-made pond, the restaurant was built as part of a hotel complex along the Dak Bla River in Kon Tum.

Rope tie

Steel tension ringCentral bamboo bundle

Roof

• 5mm PVC panel

• ø35mm–55mm bamboo purlin

• 50mm thatch layer

• ø35mm–55mm bamboo purlin

• Bamboo rafter

Bamboo cross-bracing

Concrete foundation