Computers and Concrete

Volume 37, Number 5, 2026, pages 859-876

DOI: 10.12989/cac.2026.37.5.859

AI based surrogate prediction model of fire endurance time for RC frame structure

HyunKyoung Kim , Ju-young Hwang

Abstract

Accurate prediction of fire-damaged RC structural behavior is essential for safety assessment; however, traditional numerical analysis becomes computationally intensive due to complex thermo-mechanical responses including non-mechanical strains at elevated temperatures. This study develops ML surrogate models (NN, XGB, LGBM) to predict RC member fire endurance time using a 4.37 million-point dataset generated from P-M diagrams obtained via high-fidelity numerical analyses. Tree-based ensembles outperformed NN in large-data regimes (test error 96%), providing superior interpretability through feature importance and monotonic constraints. Specifically, by defining the input conditions through a flexible 7-variable framework (B, H, BN, HN, M, P, R), this study enables the direct generation of P-M interaction diagrams under any arbitrary loading scenarios. Frame-level validation comparing predictive model and numerical analysis results on a 1-bay, 1-story RC frame confirmed applicability of proposed model with consistent column failure patterns, enabling very rapid predictions showing similar trends.

Key Words

extreme gradient boosting (XGB); fire-damaged RC; fire analysis; fire endurance time; neural network (NN)

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