Closure to “Fire Resistance of Gypsum Board Protected Steel Columns with High Load Ratios” by Zheng Peng and Hossein Mostafaei

We thank Professor Gamble for his discussion. Professor Gamble did not raise any questions about the methodology and formulas developed in our paper. His comments mainly focused on the comparisons we did with solutions per ECCS (1985). We provide clarification to each of the items discussed by Professor Gamble:

For clarification, we plot the results without and with the modification (for light and heavy insulation) in Fig. 1, which replicates Fig. 14 of the original paper. The curve for heavy insulation, “Table Solution (Heavy),” is the one we presented in Fig. 14 of the original paper as “ECCS.” We performed the same comparison for the case shown in Fig. 15 of the original paper and achieved the same verification. Therefore, the ECCS curves in Figs. 14 and 15 are for heavy insulations.

Based on our communication with Professor Gamble, the results referenced in his discussion were obtained using a modified formula from his lecture note, which was not available when the paper was written. We did, however, compare the results here with the modified formula (Fig. 2). The modified formula did provide results somewhere between the test results and the Gamble (1989) formula. The “Gamble Lecture Note 2” curve is lower than the “Gamble Lecture Note 1” curve in Fig. 2 because we used the thermal properties obtained from the test results for “Gamble Lecture Note 1.” Professor Gamble, on the other hand, used generic values (e.g., lower thermal conductivity values) for the case labeled “Gamble Lecture Note 2.”