In Japan, stakes that collect driftwood have long been used to prevent the blockage of bridges. However, design codes are not established; thus, stake installations differ for individual bridges. It is important to clarify the function of these stakes; for example, stakes can be used to prevent rubbish from accumulating near a pier. In this paper, we demonstrate a fundamental experiment that explored the function of traditional stakes as a countermeasure against driftwood accumulation. It was found that driftwood passes between piers after rotation about the stake. The functionality of these countermeasures against natural debris was confirmed. Consequently, it is suggested that stakes should be installed vertically at bridges to divert both drift wood and natural debris and protect the bridge.
