EXPERIMENTAL STUDY AND NUMERICAL ANALYSIS OF CONCRETE CONTINUOUS SLABS SUBJECT TO TRAVELING FIRE

To investigate the effect of the traveling fire on the mechanical behavior of three-span continuous slabs, this paper conducted mechanical tests on the edge, middle-span and three-span specimens subjected to different fire sequences. The temperature, deflection, cracking, spalling and the failure mode were investigated. In addition, the fire behavior of one tested slab was simulated based on the numerical model. The model was used to investigate the effect of the geometrical nonlinear (linear) property and the concrete thermal strains on the moment distribution and the membrane action of different spans in the concrete continuous slab subjected to traveling fire. The results indicate that the cracking and spalling mainly occurred on the heated spans, with less cracks on the unheated spans. There were different failure modes on the top and bottom surfaces of the concrete slabs. Edge short cracks and short-span cracks appeared on the bottom and top surfaces, respectively. The deflection distribution of each span was dependent on its positon and the fire traveling direction. The maximum deflection was dependent on the fire duration and furnace temperatures. The numerical results showed that the fire traveling behavior had important effect on the maximum moment and the tensile or compressive membrane action of each span in the continuous slab. Compared to the Lie model, the prediction based on the EC2 model was relatively reasonable, and the effect of the geometrical nonlinearity should be considered in the analysis.