Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Civil and Environmental Engineering

Supervisor

Dr. Maged A. Youssef

Abstract

Fire safety of Reinforced Concrete (RC) buildings is an important design aspect that ensures structural integrity during fire events. As new codes are moving towards performance based design, practitioners are in need of rational design tools to assess the strength and serviceability of individual RC elements and the structure as a whole during fire. This thesis provides such tools for RC frames.

A previously developed sectional analysis method is extended to cover RC beams subjected to fire from three sides. An extensive parametric study is conducted to evaluate the equivalent stress-block parameters at elevated temperatures.

A novel method to track the behavior of continuous RC beams during standard fire exposure is proposed and validated. It is based on separating the effects of thermal deformations and vertical loads. The effective flexural stiffness and the thermal deformations of fire exposed RC beams are estimated based on a comprehensive parametric study.

A simple method to construct the interaction diagram of RC column exposed to fire is developed and validated. An existing simplified heat transfer method is extended to predict the average temperature distribution. A number of reasonable approximations are assumed to allow reaching closed form solution for the concrete compressive forces that correspond to a specific strain distribution.

A practical approach to track the fire performance of RC frames during fire exposure is proposed and validated. The effective flexural and axial stiffnesses as well as unrestrained thermal deformations of heated sections are used to predict the behavior of fire exposed RC structure.


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