It is well established that the hemp plant provides tremendous benefits towards sustainability. Hempcrete has come to be widely accepted and has been adopted as an insulation/infill material in construction. However, hempcrete although being self-weight supporting up to a height of 30m, is not load bearing. Hempcrete construction therefore is always within a structurally performing timber frame. In order to reduce the dependency of timber, it is imperative that progress be made towards the load bearing potential of hemp stalks.
It is envisioned that hemp stalks , assembled in a geometrically efficient manner will be able to perform in this capacity. Over the years , Modece has twice developed such frames using varied techniques. Larger scale prototyping and testing will be required for further development. In order to achieve this, it is probable that industrial collaboration/ external participation will be required in the future.
PROTOTYPE 1
2012
Built using single sections of hemp stalks, the member was first assembled into 3 dimesional pyramid modules that were them all combined together to form the truss beam.
Junctions were bound in peeled hemp fibre and resin was used to achieve rigidity.
The member was successfully able to distribute load and bear weight.
PROTOTYPE 2
2021
As part of the experimentation phase of the Innovate UK programme, Modece began to test the ability of hemp stalks to be bent to form varied forms. This enabled the development of truss members without disconnected vertex joints. The techniques was combined with the hemp stalk clustering technique developed to form a hemp stalk cluster truss. The truss was bound with hemp twine and then wrapped in hemp fabric coated in Bio-resin.
The load bearing capacity was tested to observe deflection at progressive loading. On conclusion of the experiments, the truss was tested to observe failure. It was able to bear a load of approximately 500kgs over a span of 2m and a width of 200mm.
It is speculated that a series of such truss would therefore be able to withstand complex distributed loading and form floor or roof envolopes in building.
The truss was supported by space frame modules that formed base supports on either side. The base supports were constructed in a similar way to the truss itself making the complete load tranfer to the ground through hemp stalks.
