JANE & RICHARD

The Bian-He Rainbow Bridge from the 900yr old famous Chinese painting by Zang Zeduan

The arched bridge is formed from “woven” straight wooden logs - appealing to the local tradition of woven baskets.

THE INSPIRATION

The wider bridge with a side rail will provide a safer crossing for the community, especially as it is used by children to go to school.

The strong and robust design allows for the bridge used by variety of users - from barefoot farmers to buffalo.

USERS

As the bridge will be maintained by the local community, it is important to keep this as simple as possible. The redundant system of arches allows major members to be easily replaced as necessary.

SERVICEABILITY

Structural members will be protected by the floor deck, which can easily be maintained. The proposed deck system will be created from splitting bamboo in half and joined to form roman-like shingles.

The bridge structure is formed from locally sourced bamboo.

The modular system means spar lengths are limited to 6m-7m - suiting transportation and availability.

The compression arch system avoids tension connections that can be difficult with bamboo.

MATERIALS

The design provides a free span with abutments above the max water level.

Concept involves a series of arches that can accommodate variation in ground level

LOCATION

THE SOLUTION

One of the unique features of the Rainbow Bridge is its interlocking

arch made of wooden beams. This creates an arch that is as intricate

as it is strong

The form is rich in Chinese cultural and historical heritage in which arches traditionally express good emotion.

JANE & RICHARD

2500

ELEVATION 1:100

6400

CONSTRUCTION SEQUENCE

Fix channel sections using chemical anchors to form buttresses

Construct two outer arches on either side to support lateral members. Use temporary prop as required.

Thread members in to install arches in sequence.

Add rail verticals and members. Install decking.

The simple design results in a highly effective design that is capable of carrying people and cattle, is easy to build, does not require specialist tools or skill and uses component parts that are easy to transport.

The catenary shape of the arch is the optimal for supporting a uniform load over the bridge. The paired 3 and 4 spar arches are arranged to approximate the catenary shape, allowing the load to be carried by compression of the members.

Point loads require a bending stiffness to the arch to prevent local deformation of the arch. The pairing of the 3 and 4 member arches allows the bending stiffness of each spar to provide local restraint to the node at its midpoint against local deflection.

Lateral Bracing

3000

20000

Hand Rail (non-structural)

PLAN 1:100

Decking not shown for clarity