Post-Fire Performance of Bolted Steel T-Joints with Varying Coating Thicknesses: Experimental and Finite Element Analysis

This study investigates the structural performance of bolted T-joints in steel elements exposed to elevated temperatures, with a focus on the influence of fire-resistant coatings. A total of 36 T-joint specimens were tested under four different temperature levels (300 degrees C, 450 degrees C, 600 degrees C, and 900 degrees C), incorporating three IPE section sizes and three fire-resistant paint thicknesses (200 mu m, 400 mu m, and 600 mu m). The experimental program aimed to evaluate the combined effects of temperature, cross-sectional geometry, and coating thickness on the axial load-bearing capacity and deformation characteristics of T-joints. To examine the influence of web geometry, T-sections were designed in accordance with Eurocode 3, and the flange-to-web thickness ratios (tf/tw) were varied between 1.52 and 1.58. Results showed that applying 200 mu m and 400 mu m coatings at 300 degrees C and 450 degrees C improved the axial load capacity by approximately 10% and 20%, respectively, compared to uncoated specimens. However, effective fire protection at higher temperatures (600 degrees C and 900 degrees C) required a minimum coating thickness exceeding 400 mu m. Finite Element Models developed using ABAQUS (2017) were designed to predict post-fire load-displacement behavior, stiffness degradation, and failure modes. Predictions were validated against experimental results, with deviations ranging from 0.97% to 9.73% for maximum load and 1.18% to 42.13% for energy dissipation, confirming the model's reliability in simulating the thermo-mechanical response of steel joints under fire exposure.

Journal

BUILDINGS

Year

2025

Volume

15

Issue

18

eISSN

2075-5309

DOI

10.3390/buildings15183257

WoS UID

WOS:001580757900001