The quantitative estimation of the vulnerability of brick and concrete wall impacted by an experimental boulder

Abstract. There is little historic data about the vulnerability of damaged elements due to debris flow events in China. Therefore, it is difficult to quantitatively estimate the vulnerable elements suffered by debris flows. This paper is devoted to the research of the vulnerability of brick and concrete walls impacted by debris flows. An experimental boulder (an iron sphere) was applied to be the substitute of debris flow since it can produce similar shape impulse load on elements as debris flow. Several walls made of brick and concrete were constructed in prototype dimensions to physically simulate the damaged structures in debris flows. The maximum impact force was measured, and the damage conditions of the elements (including cracks and displacements) were collected, described and compared. The failure criterion of brick and concrete wall was proposed with reference to the structure characteristics as well as the damage pattern caused by debris flows. The quantitative estimation of the vulnerability of brick and concrete wall was finally established based on fuzzy mathematics and the proposed failure criterion. Momentum, maximum impact force and maximum impact bending moment were compared to be the best candidate for disaster intensity index. The results show that the maximum impact bending moment seems to be most suitable for the disaster intensity index in establishing vulnerability curve and formula.