Experimental Study of the Use of Stakes to Prevent Driftwood and Natural Debris from Blocking Bridges

Norio HARADA, Kana NAKATANI, Yoshifumi SATOFUKA and Takahisa MIZUYAMA

Historically, Japanese bridges have been protected from blockage by stakes that control the passage of driftwood. It is important to clarify the function of these stakes; for example, stakes can be used to prevent debris accumulation near a pier. However, no design codes have been established for the optimal placement of stakes to prevent blockage. Furthermore, no studies have been conducted to compare the blockage prevention performance of stakes at different distances, or how their gradient with respect to the riverbed affects debris accumulation. We performed a laboratory-based experiment to observe the effects of stakes on the flow of driftwood within rivers. We found that driftwood passed between piers after rotating around the stakes. We conclude that bridges would be better protected by vertical stakes, which take advantage of this mechanism.

2018/1 177-182