*3.1.2. Maintenance*

To secure the bamboo stems together in a bundle or to make the crib form, suitable binding wires, binding materials or nails should be used so that the bamboo stems will not tear apart

In addition to the bamboo and binding wires, the live cuttings or rooted plants (if possible and according to the nature of the plant, longer than the depth of the crib wall to allow penetration into the soil at the back) and suitable fill materials are also required for the construction of crib walls. Generally, locally available slope or cut material is used as fill material for the crib wall construction. However, if the material contains very coarse gravel where roots cannot develop, a layer of fine, organic-rich material or humus material should be placed around the cuttings to promote the root growth. Large stones and boulders are not recommended as fill materials. The fill material should allow some degree of compaction, so that there will be no

Before starting the crib wall construction, bamboos, binding wires and cuttings should be stockpiled near the construction site. After setting out the layout of the wall, the foundation for the crib wall construction should be prepared according to the requirement of designed dimensions of the crib wall. The depth of foundation trench shall be between 0.3 and 0.5 m, depending upon the height of the bamboo crib wall. The foundation should be inclined at about 10–15° inwards (in-slope) to increase the stability against sliding. It is recommended to have at least one layer of cribs below the existing ground level to prevent the structure from

First, the header and stretcher elements should be prepared by making bundles of three bamboo stems of uniform size. The header elements are cut according to the designed length, which defines the total width of the crib wall. After the stretcher and header crib elements are prepared, the first two stretcher elements should be laid on the prepared foundation trench, parallel to each other. The spacing of these stretcher elements will be controlled by placing the

sliding and the foundation from getting undermined by any seepage water.

or break/bend along their length.

110 Bamboo - Current and Future Prospects

*3.1.1. Construction procedure*

large voids within the body of the crib structure.

**Figure 1.** Crib wall construction steps in Thankot (Nepal) 2002 [7].

After the crib wall construction, in dry weather and low soil moisture, it is recommended to irrigate the cuttings and other plants. After the successful establishment of the cuttings, during the initial growing stages, they should be protected from grazing, so that the young plants can grow undisturbed. If some cuttings do not thrive, additional cuttings should be inserted or planted on the wall to ensure green cover of the front face of the wall and stop the washing out of the structure's fill material. If the crib wall settles due to consolidation, an additional fill material should be added on the top of the wall. The vegetated crib wall should be well maintained for at least the first 2 years after construction (**Figure 2**).

In this bioengineering technique, bamboo and plant materials are used as structural elements to take some load and resist earth pressure. This type of crib wall could be used as an alternative to gabions or masonry retaining walls.

**Figure 2.** View of slide at Badikhel/Lalitpur, Nepal, in May 2003 and August 2003 [7].
