6 - Finite element analysis of reinforced concrete beams at elevated temperatures

Abstract

In this chapter, the 1-D two-node layered composite beam element introduced in Chapter 4 is employed for predicting the structural behaviour of reinforced concrete beams under combined mechanical and thermal loadings. A nonlinear finite element analysis based on the heat transfer theory is firstly performed to determine the temperature distribution throughout the cross section of a reinforced concrete beam, in which four-node rectangular elements are utilised to discretise the cross section of the beam. The temperature-dependent material nonlinearity is then considered for each element in the cross section, and a simplified approach is applied to convert the 2-D numerical analysis into a 1-D result for the numerical simulation using the composite beam element. The nonlinear finite element analysis procedures for the modelling of reinforced concrete beams at elevated temperatures are also presented.