engleski

Finite-discrete numerical modelling of reinforced concrete structures

Crack opening is one of the dominant causes of nonlinearity in brittle and quasibrittle structures which leads to localized failure and stands out as a serious challenge in numerical modelling. Therefore, a realistic modelling of crack initiation and propagation is one of the key factors that affect the reliability of the model for analysing the structures, especially those subjected to earthquakes. The largest number of structures in the world’s most populated seismic areas is made of materials such as reinforced concrete, stone and masonry, in which localized failure dominantly influences the structural collapse. Sophisticated numerical models based on time dependent and incremental dynamic analysis can play an important role in simulating the behaviour of such structures. In this work 2D and 3D numerical modelling for analysis of reinforced concrete structures under static and dynamic load is presented. The model uses the finite-discrete element method ; thus taking into account the discontinuous nature of the concrete at the failure stages. This approach considers the structure as a deformable continuum until the opening of the cracks. The transition from the continuum to the discontinuum is a result of the crack initiations which are modelled through the contact elements implemented between finite elements. The interaction between discrete elements is considered through the contact interaction algorithm based on the principle of potential contact forces which are computed using penalty function method and the Coulomb friction law. The non-linear behaviour of the concrete in tension and shear takes into account strain-hardening, strain-softening and cyclic behaviour during dynamic loading. The model for reinforcing bars is based on an approximation of the experimental curves for the bar strain in the crack. The developed numerical model includes interaction effects between reinforcement and concrete as well as cyclic behaviour of concrete and steel during dynamic loading. Thus, it is possible to describe the crack initiation and propagation, collapse mechanism, energy dissipation by non- linear effects, inertial effects and contact interaction which are very important in the analysis of RC structures, especially those subjected to seismic load.

Numerical modelling ; Reinforced concrete structures ; Finite-discrete element method ; Static load ; Dynamic load

nije evidentirano