Analysis of Fire Resistance in Cellular Steel Beams with Sinusoidal Openings

Abstract

Fire safety is a major consideration in building design to protect lives and keep construction costs as low as possible. Understanding the behavior of structural fires is crucial for structural analysts during the building design process. This paper presented the numerical approach implemented within ABAQUS package to model some of the tests on Angelina steel beams at ambient temperature. There was generally a good agreement between the numerical models and the test results in terms of the failure load and the failure mode. Within the numerical validations, it was found that the failure mode (and failure load) of cellular beams with sinusoidal openings can be very sensitive to the size of the opening section. It was found that for a large opening size (ao/Ht=0.67), a total yielding of the four opening corners was observed. Then, for a small opening size (ao/Ht=0.42), the failure observed numerically was considered as the local buckling of two parts of the opening. Therefore, the numerical model should consider precisely the resistance of each opening quarter in the critical opening and their combination to obtain the failure mechanism of the opening.  Finally, study revealed that the Angelina steel beams with tangent fillet corners are more prone to web-post buckling failure due to their reduced are of web-post section, whereas this mechanism does not occur in the case of sinusoidal openings with non-tangent fillet corners due to their wider web-post area. Observations revealed that Angelina steel beams with smaller opening-spacing-to-height ratios undergo significant deformation, resulting in web-post buckling failure at ambient temperature.