Study of I-Shape Steel Beams Subjected to Combined Fire and Impact Loading and Failure Assessment Method

To investigate the dynamic response and fire performance of steel beams under high temperature, drop hammer impact tests and numerical simulations were conducted on steel beams subjected to high temperatures. Three finite element (FE) models were established using the element coupling method to predict the impact dynamic behavior of the steel beams under the combined effects of fire and impact loads. The reliability and applicability of the developed FE models in predicting the impact dynamic response of steel beams in fire was examined through comparison of numerical results with experimental results. Based on the experimentally and numerically observed failure modes, a generalized plastic yield criterion for I-shaped steel beams section was proposed, which considers the synergistic effects of axial force, shear force, bending moment, strain rate, and temperature with the plastic deformation of the entire cross section as the criterion. The interaction functions and spatial characteristics between internal forces were presented. A new generalized yield (G-Y) method for evaluating the failure of components due to plastic hinges development without restricting the load type was proposed based on four types of interaction relationships combination, and the sensitivity of the G-Y method to different parameters for assessing the development of plastic hinges was systematically studied. Based on the proposed G-Y method, the mechanical behavior of steel beam subjected to multiple extreme load coupling effects was revealed.