Parametric study on composite beam with various connections under mid-span impact scenarios

• Detailed solid element models with high fidelity were built to replicate the composite beam subassemblies under the mid-span impact scenario. • Modeling techniques were validated against various test results from various test apparatuses to gain sufficient confidence. • Parameters related to impact load were investigated and discussed, of which some were evitable in an experimental research while the others were not cost-effective through an experimental test. • Parameters related to structural design were also investigated and discussed. • Quasi-static loading, which was commonly used in engineering design was compared with impact loading, which was the real load during a collapse event. The falling-debris-impact scenario occurred in several severe collapse events. It is of great practical significance to investigate the resistance of structures subjected to falling-debris impact. Finite element (FE) simulation of composite beams subjected to drop-weight impact was conducted in this research. Parametric analyses were carried out based on the validated FE models. The results showed that increasing the impact velocity could enhance the strain rate effect and increase the structural resistance of composite beams. In terms of structural design, the composite slab can increase the energy absorption capacities of specimens compared to bare steel beams and beams with the solid concrete slab. The increase of the strength or thickness of concrete in the composite slab, the thickness of profiled steel plate, the ratio of longitudinal reinforcement, and the strength of shear connection of the composite structure were all conducive to the impact resistance. The increase of the span-to-depth ratio would increase the failure displacement and decrease the maximum structural resistance and energy absorption capacity. Moreover, compared with the static loading condition, the energy absorption capacities of welded unreinforced flange – bolted web (WUF-B) and fin plate (FP) specimens under impact loading increased while the energy absorption capacity of reversed channel connection (RCC) specimens decreased.