Fire resistance of steel pipe-concrete columns

Purpose. The research is devoted to testing the method for calculating fire resistance limit of steel-pipe-concrete (SPC) columns under axial compression based on the results of fire tests of columns made of steel pipes with the internal cavity filled with concrete. Methods. The thermo-engineering part of temperature calculation in the cross-section of SPC columns under standard temperature conditions is performed in the ANSYS software package. The bearing capacity of the columns during heating (the strength part of the calculation) is determined taking into account the proposed calculation model at various levels of static load, cross-section sizes and various classes of steel and concrete. Findings. As a result of calculations actual fire resistance limits of SPC columns with axial load under standard temperature conditions were obtained. Comparison of calculation and experimental results showed that the use of the calculation method for the fire resistance limit of SPC columns provides satisfactory convergence with experimental data. Research application field. The obtained research results can be applied in designing unique buildings and structures taking into account the determination of the actual fire resistance limits of SPC columns using the tested method. Experimental and calculated data on the fire resistance limits of SPC columns showed that the required fire resistance limits can be achieved without the use of fire-resistant materials, and will help reduce metal consumption and construction costs. Conclusions. The method for calculating the fire resistance limit of steel-pipe concrete columns loaded with axial load gives satisfactory convergence with experimental data, which allows for assessing fire resistance of such structures not only considering the steel shell as permanent formwork, but also taking into account the bearing capacity of the steel frame, which will increase the accuracy of calculations, safety and stability of tasks in case of fire.