C. Lázaro

Mechanical models in computational form finding of bending-active structures:

This article reviews the different aspects involved in computational form finding of bending-active structures based on the dynamic relaxation technique. Dynamic relaxation has been applied to form-finding problems of bending-active structures in a number of references. Due to the complex nature of large spatial deformations of flexible beams, the implementation of suitable mechanical beam models in the dynamic relaxation algorithm is a non-trivial task. Type of discretization and underlying beam theory have been identified as key aspects for numerical implementations. References can be classified into two groups depending on the selected discretization: finite-difference-like and finite-element-like. The first group includes 3- and 4-degree-of-freedom implementations based on increasingly complex beam models. The second gathers 6-degree-of-freedom discretizations based on co-rotational three-dimensional Kirchhoff–Love beam elements and geometrically exact Reissner–Simo beam elements. After reviewing and comparing implementation details, the advantages and drawbacks of each group have been discussed, and open aspects for future work have been pointed out.

Detailing and construction of the pantadome roof structure for a bullring in Xàtiva (Spain)

This paper describes the detailing and construction of a roof structure for a bullring in Xátiva (Spain). The roof has been built by means of a new version of the Pantadome system. The roof dome is spherical shaped with a 42 m diameter central opening and an exterior diameter of 101,6 m. It is supported on 44 columns distributed along a 86,4 m diameter circumference. The structural system is formed by radial truss lattices pinned to the columns and to the inner ring and supported by the action of an outer tension ring, radial tension members and tension (upper chord) and compression (lower chord) in the inner ring. The structure was built near the ground and lifted by shortening 44 radial strands with jacks attached to the inner ring. Strand forces have been transferred to permanent tension members at the end of the process. The kinematics of the deployment has been analyzed. Forces in the jacks have been obtained theoretically from the kinematics and compared with the measured values. Special details, developed for the attachment of the jacks and the force transfer are described. The development of the lifting process together with the results of the geometrical survey show that the new erection system allowed the construction of the dome in a quick and safe way.