Communication framework for Hybrid Fire Testing: developments and applications in virtual and real environments.

The response of structural systems to fire loads is typically assessed through performing 'standard' fire tests on individual members under constant mechanical boundary conditions. Full scale tests showed different behavior compared to the standard tests, but remain impractical. A promising approach to predict the behavior of full scale tests through testing individual structural members is Hybrid Fire Testing technique, where a subset of the structural system (Physical Substructure PS), is physically tested, while the remaining structure (Numerical Substructure NS), is simultaneously numerically analyzed. During the test, the mechanical boundary conditions on the PS and NS are continuously updated, and the updates are enabled by the communication framework. The communication framework is a key element for a successful hybrid fire testing and this paper will present the development of such communication in MATLAB. To validate the communication framework, first, a single degree of freedom linear system was analyzed, followed by a ten-story steel frame structure exposed to design fire. The analysis of the latter underlined the importance of considering the effect of the cold surrounding in assessing the fire behavior of structures under design fires. Sensitivity analysis showed the importance of several parameters (time step and substructures stiffness) in hybrid fire testing.