experimental and finite-element study on performance of infilled frame of multi-ribbed composite walls after fire

This paper studies the performance of infilled frame of multi-ribbed composite wall (mrcw) after fire, using a combined experimental and finite-element (fe) analysis method. to this end, 14 infilled frame specimens were tested under fire, where different fire conditions, including both single-side and double-side fire, were considered. after fire, they were tested under diagonal loads to evaluate their residual bearing capacities. based on the test results, the residual capacities of the specimens subjected to 60 min single-side fire, 60 min double-side fire, and 120 min single-side fire were about 3/4, 1/2, and 2/3, respectively, of those at room temperature. for specimens subjected to 120 min double-side fire, the bearing capacity was completely lost. corresponding to the two types of tests, two types of fe analyses were conducted, including temperature and mechanical loading analyses. a temperature-related reduction factor of the elastic modulus was adopted to account for the cracks in the autoclaved aerated concrete (aac) blocks after fire, due to the restraining effect of the ribbed beams and columns. good correlations were obtained between fe and test results. the fe model was further used to conduct a parametric study to evaluate different factors on the infilled frames’ residual capacities after fire. it was found that, compared with concrete strength and the height of the ribbed beams and columns, the grade of aac had the most significant effect on the infilled frames’ residual capacities. the residual capacities of the infilled frames with the same size decreased significantly with the increase of fire time. under the same fire time, the increase rate of the bearing capacity was higher when the height of the ribbed beams and columns was in the range of 70–90 mm. © 2022, iran university of science and technology.