Nikhil Raut

Response of high-strength concrete columns under design fire exposure

The behavior of RC columns, especially those fabricated from high-strength concrete (HSC), under design fire exposure is not well quantified. Results from fire resistance experiments on six RC columns are presented in this paper. The test variables include concrete strength (permeability), fire scenario, load ratio and the presence of polypropylene fibers in concrete mix. Data from these fire tests is used to validate a macroscopic finite element model specifically developed for tracing the fire response of RC columns. Results from fire tests and numerical studies are used to illustrate the comparative performance of HSC and normal-strength concrete (NSC) columns under design fire conditions. Results from fire experiments show that HSC columns exhibit lower fire resistance than that of NSC columns. However both HSC and NSC columns do not experience failure under most design fire scenarios. The addition of polypropylene fibers to concrete mitigates fire-induced spalling and enhances fire resistance of HSC ...

Response of Reinforced Concrete Columns under Fire-Induced Biaxial Bending

ACI Structural Journal, V. 108, No. 5, September-October 2011. MS No. S-2010-142.R3 received September 14, 2010, and reviewed under Institute publication policies. Copyright

Behavior of Circular Reinforced Concrete Columns Under Fire Conditions

A numerical model was developed for tracing the behavior of circular reinforced concrete (RC) columns over the entire range of loading from pre-fire conditions to collapse under fire. The macroscopic finite element based model utilizes time dependant moment-curvature relations of various column segments and the analysis is carried out in three stages; namely, establishing fire temperatures, calculating the heat transfer through the structure, and then carrying out strength analysis. The model, which accounts for high temperature nonlinear material properties, is capable of predicting the fire resistance of circular RC columns under realistic fire scenarios, loading conditions, and failure criteria. The validity of the model is established by comparing predictions from the computer program with results from full-scale fire resistance tests. The validated model is applied to undertake a set of parametric studies to quantify the effect of column size, load level, load eccentricity, and concrete strength on t...