Crushing behavior and protective performance of varying cores in UHPFRC-steel-foam sandwich structures: Experiment, optimal selection and application

摘要

A novel sandwich structure composed of ultra-high performance fiber reinforced concrete (UHPFRC) face panels and core steel structures has been demonstrated to possess good potential in infrastructure protections against accidental collision actions in the previous studies. The core structure plays a crucial role in energy absorption behavior and crashworthiness performance but has not yet been examined. Four different core structures (i.e., traditional frame (TF) type, ectopic frame (EF) type, corrugated plate (CP) type, and horizontal tube (HT) type) are prepared and tested under quasi-static crushing tests in this study. The influence of the polyurethane (PU) foam is also experimentally studied for various core structures. To identify the best performing configuration for structural protection, technique for order preference by similarity to an ideal solution (TOPSIS) method is utilized in the evaluation of the crushing performance. The weight values required in the use of the TOPSIS method are carefully examined based on the entropy method and different design purposes. The best-performing configurations are recommended for various weight values. Results indicate that filling the PU foam is often beneficial to polarize the performance of the UHPFRC-steel sandwich structure. The finite element (FE) modeling method is developed and validated by the crushing tests on different sandwich structures. The best-performing sandwich structures identified with an emphasis on high crushing force efficiency (CFE) are applied to develop new protective structures for improving the performance of bridge structures under rockfall impacts. Numerical results show that the proposed protective structures can effectively protect the bridge structure and reduce the damage caused by rockfall impacts.