Form-finding for free-curved reinforced concrete shell structure considering structural performance and construction formwork

Abstract

A computational approach for free-curved reinforced concrete (RC) shells that simultaneously considers structural performance and associated construction strategy is proposed. First, for the rapid design and construction process, a unit–formwork construction system (UFS), which uses multiple construction methods dependent on curvature, is developed, and a mock-up test is conducted to validate its effectiveness of UFS. Although the construction time was reduced, the construction costs were confirmed to be approximately twice those of conventional methods. Furthermore, the error between the measured surface coordinates of the plywood form board (PFB) and corresponding three-dimensional (3D) data is computed, and the study confirmed that the error in construction was within half of the required level. Second, a multi-objective optimization problem is formulated to obtain a shell configuration and a suitable distribution of curvatures on the PFB by minimizing the squared normal curvatures of a PFB surface and the strain energy of the completed shell structure under distributed loads. To assess the manufacturability of PFB, the normal curvatures on the surface of the PFB, which are represented as quadrilateral meshes, are calculated. Finally, numerical examples demonstrate the efficiency of the proposed method for designing a free-curved RC shell from the perspectives of structural design and constructability.