Form-finding of compressive structures using Prescriptive Dynamic Relaxation

•We present small strain truss and triangular elements for compressive form-finding.•We modify Dynamic Relaxation form-finding to include element prescription.•We provide forcing functions to achieve desired segmental geometry.•A scheme for equilibrium and geometrical convergence is verified.•Case studies validate the practical application of element geometry prescription.

This paper presents an adaptation of the Dynamic Relaxation method for the form-finding of small-strain compressive structures that can be used to achieve project-specific requirements such as prescribed element lengths. Novel truss and triangle elements are developed to permit large strains in the form-finding model while anticipating the small-strain behavior of the realized structure. Forcing functions are formulated to permit element length prescription using a new iterative technique termed Prescriptive Dynamic Relaxation (PDR). Case studies of a segmental concrete shell and a pedestrian steel bridge illustrate the potential for using PDR to achieve economic and environmentally considerate structural solutions.