Hyperbolic paraboloid shells made of diagonal laminated timber elements

This paper deals with the design, calculation, and construction of hyperbolic paraboloid shells made from mass timber elements. Considering the geometrical definition, hyperbolic paraboloid shells can be described as doubly ruled surfaces and can therefore be assembled from twisted rectangular plates. The membrane theory of the hyperbolic paraboloid shell is derived and compared to previous analytical approaches. A challenge is the realization of the shell using the orthotropic material timber. Therefore, the torsional stiffness of multi layered mass timber elements is determined by means of analytical and experimental investigations. Taking into account the semi-rigid connection between the layers, resulting in additional shear deformations, nailed and diagonal laminated timber elements are investigated towards the construction of HP-shells.