Nonlinear analysis of concrete structures based on a 3D shear-beam element formulation

The present work deals with the development of an analysis-model applicable to large scale 3D beam structures of reinforced and prestressed concrete. The model is based on the finite element method and allows for large displacements through the Corotated Lagrangian description of motion and a variety of material nonlinearities in the short-time as well as the long-time regime. The loading may be both unidirectional and corotational. By relating all changes in loads, prescribed displacements, temperature, time and static system to a common history parameter, the response of a structure may be traced from the very start of construction to its completion, throughout the service life and finally into the ultimate load range. The key ingredient of the analysis-model is the new 3D shear-beam element formulation. It can handle the response of reinforced and prestressed concrete in each one and combinations of the axial, bending, shear and torsion modes.