Ultimate fire resistance
In LIRA-SAPR program, when analysis on ultimate fire resistance of reinforced concrete and composite (steel and RC) structures is carried out, you will receive the temperature distribution along the section according to the specified time period in fire. Then physical and mechanical properties of materials are modified according to obtained temperature fields. The bearing capacity of structural elements is checked in normative load and, if required, appropriate area of reinforcement is added.
Analysis of fire resistance is implemented for standard types of sections (rectangle, ring, T-section, asymmetric T-section, I-section, cross, angle), composite (rectangular concrete section with various options for the location of rigid reinforcement and various pipe concrete sections) and plate elements.
Temperature accuracy is improved when the mesh is made denser automatically at edges subject to fire.
The FE mesh is generated so that its nodes are located not only within the thickness of the section, but also along its perimeter, as well as along the flanges and webs for structures with rigid reinforcement.
*.txt file of problem with analysis on fire resistance may be transferred to the 'Thermal analysis' system.
The *.txt file contains all parameters specified for the section and required for the thermal analysis (geometrical dimensions of the section, materials, edges subject to heating, ultimate fire resistance, thermal conductivity coefficient, heat capacity coefficient, density, convective heat transfer coefficient, etc.).
In the 'Thermal analysis' system, it is possible to modify the transferred section, e.g. to define a fire-proof screen.
The results of reinforcement selected for fire resistance are presented graphically: mosaic plots for reinforcement in plate and bar elements of the model. Reinforcement selected in analysis on fire resistance is presented as a certain row in the tables of results and in the 'Information about element' dialog box.
Analysis on fire resistance may be performed not only in a unified graphic environment, but also in the local mode for analysis of an individual reinforced concrete bar or plate element.
Forces for the element under consideration may be transferred from the VISOR-SAPR module or defined directly in the LARM-SAPR module.
According to the fire resistance data of an element, the cross-section may be transferred from 'VISOR-SAPR' module into the 'Cross-section Design Toolkit' module. The cross-section is transferred as divided into zones depending on the temperature distribution in each of its segment. Each zone has its own nonlinear stress-strain diagram of the main material and reinforcement with account of changes in physical and mechanical properties of concrete and reinforcement in high-temperature fire.