Stress-strain curves for masonry materials exposed to fire action

On the basis of the results obtained by an extended experimental campaign aimed at the mechanical characterization of main masonry materials subjected to fire action, the variation factors of compression strength, ultimate strain in absence of preload and the apparent modulus of elasticity were detected in function of the temperature increasing. A uniaxial constitutive law was performed and validated on the stress-strain readings, allowing subsequent comparisons with the parametric curves proposed by European standards. The error indexes produced by the various constitutive models are also determined and compared. The out-of-plane mechanical behaviour of the horizontal cross sections is then investigated for masonry panels with full units: the adopted method is able to define the axial force-bending moment crushing domains for increasing exposure time to nominal fire, considering different types of stress-strain-temperature constitutive relations. (C) 2014 Elsevier Ltd. All rights reserved.