Predicting the fire rating of reinforced concrete columns: effect of load induced thermal strains (LITS)

Author(s): Hitesh Lakhani, Joško Ožbolt, Batsuuri Boldbaatar
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 462-469
Total Pages: 848
Language: English

Abstract: The behaviour of Reinforced Concrete (RC) structures at elevated temperatures is a complex problem to simulate. This is due to the dependency of various material properties (thermal/mechanical) on temperature; the damage caused due to thermal cracking and steep thermal gradients. At elevated temperature the total concrete strain consists of instantaneous stress related strain, Free-Thermal-Strains (FTS) and Load-Induced-Thermal-Strains (LITS). The least understood strain component and the one which has most uncertainties associated with it, is the LITS. This strain component basically accounts for strains due to chemical changes, moisture loss, transient creep, shrinkage etc.
In the present paper, a 3-D fully-coupled thermo-mechanical model, for predicting the fire rating of RC columns is discussed. The paper also presents a numerical study to compare the suitability of various LITS formulations for studying the behaviour of RC columns under fire. LITS formulations viz. Anderberg & Thelanderson model, Diederich’s model, Schneider’s model and Terro’s model were chosen for the study. It was observed that the predicted behaviour of columns in terms of axial deformations with exposure time and fire rating were very sensitive to the LITS formulation. The predicted fire rating of RC columns, using Schneider’s model, were in good agreement with the experimental results.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00