This paper presents an experimental approach on the load of debris flow with woody debris for open type steel frame check dam structure. The hydraulic model experiments are carried out with various parameters, i.e., driftwoods containment ratio of debris and slit interval of the structure. When the debris contains woody debris, the driftwoods are gathered the front of debris, and slit interval of the structure is blocked by the stuffed woods. And the impact load acting on the column caused by debris flow with woody debris is smaller than the one caused by debris of gravels. The accumulation of driftwoods acts like a shock absorber for the columns. The accumulation of driftwoods induces the lopsidedness of static load for the columns, because the accumulation is formed unevenly.

Key wordsFload, debris flow with woody debris, steel frame check dam