In the dissertation a new partly coupled numerical model for non linear analysis of homogeneous and partly delaminated curved RC structures exposed to mechanical and temperature load is introduced. Due to its complexity the model is divided into two phases. In the first phase the time and spatial distribution of temperatures in fire compartment is defined by temperature-time fire curves and FDS models. Obtained temperatures from the first phase and mechanical load are used as input parameters in the second phase of the presented model, where the distribution of temperatures, pore pressures, gaseous mixture of dry air and water vapour and stress-strain state are calculated. One of the novelties of the introduced model is the second phase, where chemical-hygro-thermal part and mechanical part of the fire analysis are partly coupled. The connection between the parts is considered with the changed geometry of structure due to concrete spalling. The second novelty of the introduced model is the mechanical part of the fire analysis, where a new group of strain based finite elements for non linear analysis of homogeneous and partly delaminated curved RC structures during fire has been developed. Finite elements are based on kinematically exact planar beam theory of Reissner, non linear material models for concrete and steel at elevated temperatures and costitutive laws for contact surface between beam layers. With the principle of additivity of strain increments temperature strains of concrete and steel, viscous strains of steel, transient strains and creep strains at elevated temperatures for concrete are considered. The restraining effect of soil on tunnel structure is employed with discrete non linear springs. Detailed numerical analyses have revealed, that the introduced model has good efficiency and accuracy and it si perfectly suitable for fire analysis of all kinds of homogeneous and partly delaminated curved RC structures, even tunnels. The parametric studies have showed that the changed geometry of structure due to concrete spalling significantly affects the time and the form of failure of tunnels during fire and that the contact stiffness between the beam layers strongly influences the distribution of internal forces in curved RC structures during fire.
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