Numerical modelling is a process whereby computers are used to reproduce the behavior of buildings.
Standard numerical modelling techniques use the finite element method, with linear elasticity analyses performed to reproduce non-complex structures.
However, to reproduce certain specific behaviors of structures, such as instability (buckling), cracking, contact between structures and long-term behavior, non-linear models must be used. INGPHI has the tools and knowledge required to perform all these different analyses, which are particularly useful for establishing the safety level of structures, predicting their behavior in the case of seismic activity, analyzing vibrations and predicting long-term behavior.
Analysis of Instability – Global and Local Buckling
Using a non-linear geometric analysis, the instability analysis predicts the buckling and deflection of slender structures.
The metal superstructures at Geneva’s CEVA stations were analyzed for instability to determine the loads that would cause buckling the metal beams. The section could then be made thinner based on this in-depth understanding of their behavior.
Cracking of Concrete Structures
Cracking is a common cause of damage and deterioration in concrete structures. Modelling the cracking of reinforced concrete is complex and the firm uses the Menétrey-William model for this process. This model considers the triaxial behavior of concrete, reproduces the location of cracks and considers the influence of the steel used for reinforcement.
After 40 years of use, many cracks had appeared in the decks of the bridges over the Paudèze. Numerical simulation didn’t only reproduce the cracks that had appeared, but also determined when they had appeared. It was thus possible to plan repair works with a comprehensive understanding of the case.
Analysis of Contacts
Contact problems must be analyzed when two parts of a structure can slide or interact with each other in some way. This requires specific analyses since the structure is modified as loads are applied.
As part of the process of strengthening the bridges over the Paudèze, steel deviators were used. They needed to be bolted inside the box section and an analysis of the contact between the steel plates was performed in order to verify the deviation force introduced in the bridge’s box section.
Complex Structures
Complex structures are structures with complex geometry or structures with large displacements.
The tensegrity roofing developed for a project in Ticino is a good example of a complex structure, since it is a light and supple structure where rigidity and stability are provided by a self-contained constraint system that combines bars under compression and cables in tension.
