Finite element based micro modelling of masonry walls subjected to fire exposure: Framework validation and structural implications

• Published in: Engineering structures Vol. 213; no. C; p. 110545
• Main Authors: Prakash, P. Ravi, Azenha, Miguel, Pereira, João M., Lourenço, Paulo B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.06.2020; Elsevier BV; Elsevier
• Subjects: Bowing; Brickwork; Construction materials; Finite element method; Fire exposure; Fire resistance; Masonry; Material properties; Mechanical analysis; Mechanical properties; Mechanics (physics); Modelling; Mortars (material); Nonlinear systems; Nonlinear thermal gradients; Strain; Temperature dependence; Thermo-mechanical analysis; Thermomechanical analysis; Two dimensional models; Walls; Fire resistance; Nonlinear thermal gradients; Masonry; Thermo-mechanical analysis
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.110545

•A 2-D finite element based micro-modelling framework for thermo-mechanical analysis of masonry walls.•Effects of temperature-dependent geometric and material nonlinearities are considered.•FE model is validated against the experimental data of half-scale masonry wall subjected to fire.•A detailed discussion is presented on the thermo-mechanics in the considered masonry structures. This paper presents a 2-D finite element (FE) based micro modelling framework for thermo-mechanical response history analysis of solid brick masonry structures subjected to fire. The 2-D FE framework considers geometric and material nonlinearities, and transient states of strain in conjunction with the temperature-dependent material properties. Material nonlinearity within the 2-D FE model is considered by the temperature-dependent total strain rotating crack model. The FE framework is validated against the thermo-mechanical response of a half-scale masonry wall subjected to one-sided fire exposure, and it is observed that the predictions of the FE framework are reasonably accurate. Utilizing the validated FE framework, thermo-mechanical response history characterization is performed on a full-scale masonry wall subjected to one-sided fire exposure. Critical physical phenomena which include thermal bowing, heat diffusion, unit-mortar thermo-mechanical interaction, cracking and stress profiles within the masonry structures are studied intricately. Furthermore, thermo-mechanics within representative volumes enclosing unit as well as mortar and their correlation with the global thermo-mechanical response is studied. Such 2-D micro-scale thermo-mechanical computations on masonry walls followed by a detailed discussion on their thermo-mechanics are one of the novel features of the present study. It is observed that thermal bowing resulted from a complex interaction between thermal dilation and cracking and crushing in the mortar and unit within the masonry structure.