A unified performance-based blast-resistant design approach for RC beams/columns

Abstract

Critical political and economic infrastructures are threatened by the intentional and accidental explosions. At present, the analytical model and design approach for blast loaded RC beams/columns considering both the local and global member responses are studied. Firstly, by classifying the damage levels from the local response perspective, i.e., no damage, spalling and breach of blast loaded RC beams/columns, based on total 119 shots of field explosion test, the critical scaled distance distinguishing the local and global responses of RC members is experimentally determined as 0.78 m/kg1/3. For local responses, the field explosion test based design chart of the logarithmic scaled thickness against the logarithmic scaled distance is plotted. Secondly, as for global responses, an improved SDOF model, incorporating the direct shear, flexural-shear and flexural responses of RC members, is established, which comprehensively considers the nonuniform distribution of blast load, strain rate effect, P-Delta effect, compressive arching effect and the rigid body rotation of supports. Furthermore, the proposed SDOF model is validated by seven sets of explosion tests on RC beams/columns with simply-supported and fixed-end boundaries from aspects of direct shear, flexural-shear, and flexural responses. Finally, a unified performance-based blast-resistant design procedure is proposed, and lays the foundation for an independently developed code named Tongji-RC-Blast, which is a reliable and efficient blast-resistant evaluation and design tool for the protective engineers and designers.