Discussion on "The impact of fire on seismic resistance of fibre reinforced polymer strengthened concrete structural systems"

The statement that “the analysis only considered one lateral loading cycle” gives rise to a query. Since the Column 6 failed during the second cycle in the experiment, why not use the experimental loading history to validate the numerical model? The authors did not give any explanation. In addition, the shape of structural hysteresis loop is an important index to evaluate the seismic performance of columns. Hence, the hysteretic response analysis of columns should be simulated in the numerical simulation to assess their seismic performances. The authors have mentioned that the fibre elements of the SAFIR software were used to model the columns in the analysis. In general, the fibre elements may be able to simulate the hysteretic response of the columns. In section 4.2, the authors referred to “the structural strengths of the concrete and steel were taken as the reduced values just after the fire exposure.” However, the authors did not give the reduced values of the structural strengths. In fact, the reduced values of the structural strengths have a great influence on the lateral bearing capacity of the columns. Consequently, the reduced values should be given directly in the paper. The authors referred to “in this case, the temperatures at the different locations were taken from the experimental results.” However, the temperatures at the different locations taken from the experimental results were not shown in the paper. The discussers believe that the temperatures taken from the experimental results should be given in the paper to compare with Fig. 9, which can help readers understand the simulation results of the paper. The authors explain that the ductility increases with exposure to increased temperatures, which gives rise to a series of queries. Why would the ductility of the Column 5 increase after fire exposure? Maybe this is due to the softening of the material after the fire. In addition, how would the ductility of the columns change after fire exposure after a long period of time? These questions are worthy of further investigation.