“Water is essential for life, health and human dignity” World Health Organization
In a previous post Dream Big: Engineering our world, we showed a video of our students designing and constructing a water supply system in Peru with Engineers without Borders. In our CEE 546 Form Finding of Structural Surfaces Course, teams of engineering and architecture students were challenged to develop the shape of a membrane so that it channels rainwater into a 2 or more storage shipping containers. The membrane water harvester is meant to double up as a shading canopy for a small community.
Figure 1: Inverted conoid membranes with interesting seam layout pattern. (project Laura Salazar, Ryan Roark and Annie Levine)
The entire design would preferably be demountable and fit within the container (to be transported and deployed elsewhere). Such a deployable low-cost system, would aid temporary or permanent recovery efforts in disaster struck areas, cut-off clean water supply.
Figure 2: An assymetric membrane conoid configuration with a ring hoop connection at the top of the mast to reduce stresses in the membrane. Sun and rain shading studies for one and a coupled module (project Veronica Boyce, Emma Benintende and Dorit Aviv)
For this project the students experimented with physical form finding techniques using a flexible fabric such as lycra as well as a numerical form finding technique based on the force density method to arrive at and fine tune their shapes.
Figure 3: Spline stressed arch supported membranes with an elegant solution to ensure the stability of the boundary arches. Active bent arch spans in the order of 25m and is stabilised from buckling by the pre-stressed membrane. Cross-ventilation envisaged (project Devin Dobrowolski, Andrew Percival and Andrew Rock)
The generated shapes drew upon the 4 archetypal membrane forms: the saddle, the ridge and valley, the conoid and the arch supported membrane system. The students steered their forms to have sufficient anticlastic curvature for stiffness and rainwater flow. They also paid attention to appropriate membrane and edge cable pre-stress levels and connection detailing.
Figure 4: Ridge and valley system poses a great challenge to achieve anticlastic curvature in the membrane. This curvature is achieved here by positioning the supports close together and having a substantial height difference between the low an high points. (project John Cooper and Vivek Kumar)
Figure 5: A variation on the saddle shape. (project Peter Wang, Miles McCaulay, Jedi Lau and Ji Shi)
Author: Sigrid Adriaenssens