Lightweight curved surface structures composed of bending-active plate units

This paper presents a method for fabricating reversible curved surface plate units through active bending. The original flat plates were bent and self-stabilized by inserting braces into precut parallel slits in the plates. The units can be easily assembled into a modular structure and disassembled to be transported or stored in their flat form. The curvature of the units can be controlled by adjusting the length and the spacing of the slits. The deformation of the bent units were simulated using a geometrically nonlinear analysis in SAP2000 and compared with measured results from both small-scale and full-size models. It was found that the bending deformation was proportional to the ratio of the slit spacing to the plate width as well as the ratio of the brace depth to the slit length. An empirical function between the bent angle and the slit dimension factors for symmetric rectangular units was derived. Two lightweight structures, including a catenary arch that spanned 4.2 m and a geodesic dome with a diameter of 3.45 m, were built using 3 mm plywood units. 1/5-scale models were used to study the stability of the structures. The initial attempt to construct the catenary arch was unsuccessful due to the scale effect. The design was modified by adding out-of-plane stiffeners. It was found that the scale effect may be reduced by changing the geometry of the structure. A geodesic dome was then developed with reciprocally connected units. It was assembled multiple times at different sites.