Prestressed Concrete Thermal Behaviour

The structural fire safety capacity of concrete is very complicated because concrete materials have considerable variations. Constitutive relationships for prestressed normal-strength concrete (NSC) and high-strength concrete (HSC) subjected to fire are needed to provide efficient modelling and to meet specific fire-performance criteria of the behaviour for prestressed concrete structures exposed to fire. In this paper, formulations for estimating the parameters affecting the behaviour of unconfined prestressed concrete at high temperatures are proposed. These formulations include residual compression strength, initial modulus of elasticity, peak strain, thermal strain, transient creep strain and the compressive stressstrain relationship at elevated temperatures. The proposed constitutive relationships are verified with available experimental data and existing models. The proposed relationships are general and rational, and show good agreement with the experimental data. More tests are needed to further verify and improve the proposed constitutive relationships