Flexural behaviour of selected plants under static load

Abstract. One of the principal purposes of soil bioengineering is the application of vegetation layers from a civil engineering point of view. Living plants are used to reinforce slopes and to control erosion. For a standardised implementation, it is essential to quantify the effectiveness and to assess technical parameters for such bioengineering systems. The objective of this study is to investigate the flexibility of stems and branches of different riparian species of the area of Southern Brazil suitable for soil bioengineering (Phyllanthus sellowianus Müll. Arg., Sebastiania schottiana (Müll. Arg.) Müll. Arg., Salix humboldtiana Willd., and Salix×rubens Schrank). Fifty specimens (green stem samples) were collected in the surroundings of Santa Maria, state of Rio Grande do Sul, Brazil, and subjected to static bending tests. Their overall deformation behaviour (elastic and plastic) is of crucial importance for bioengineering systems. Thus, additional to the state of the art of material parameters, a new parameter is introduced: the "angle of flexibility". This parameter describes the elastic and plastic deformation behaviour of a plant under load in a more engineering practival experience. The results show that the species of Phyllanthus sellowianus is the most flexible species, followed by Sebastiania schottiana, Salix humboldtiana and Salix×rubens.