Experimental investigation of steel beam-to-column end-plate joints under static and impact loading

Events like blasts, vehicle impacts, gas explosions, or terrorist attacks can induce dynamic structural responses. Traditional design practices focus on structures' static or quasi-static behavior, neglecting dynamic effects. However, the response of structural members and joints under dynamic loading can differ significantly from that under static loading. For instance, the mechanical properties of steel, such as yield strength and tensile strength, exhibit variations depending on the strain rate. Experimental impact load tests of members and connections are needed to validate FEM models, but a very limited number of such tests have been presented in the literature. This article presents experimental static and impact tests of double-sided extended steel bolted end-plate joints. The tests were carried out on three identical steel specimens of a beam-to-column system, with static tests on one specimen and impact tests on two other specimens. A free-falling concrete-steel package was used as the impact load, with varying values of its weight and the height of the fall. The structural responses of the joints and selected components were measured using advanced measuring equipment for experimental static and dynamic tests. In both static and impact tests, significant deformation of the connection elements, especially the column and end-plate, was observed. Moreover, local buckling appeared in the compression zone of the column web as well as fracture of the end plate below the lower flange of the beam. Based on the results of the deformation measurements, the actual strain rate and dynamic increase factor (DIF) were obtained.