ABSTRACT River infrastructures like bridges are prone to accumulations of transported large wood (LW) during floods. To contribute to an improved risk evaluation, the prediction of LW accumulation probability (AP) is crucial. Previous studies on LW AP focused mainly on the influence of a bridge deck. In the present study, flume experiments were conducted to investigate LW AP at bridge piers with special emphasis on (1) approach flow conditions, (2) bridge pier characteristics with different pier roughness, shape, diameter, and pier number, (3) LW characteristics, involving various log lengths, log diameter, log density, LW with and without branches, and uncongested versus (semi-) congested LW transport, and (4) channel bed, i.e. scour. Based on the experiments, AP is mainly a function of approach flow velocity and log length. The results were combined in a design equation to predict AP for risk assessment in engineering application.

中文翻译：

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桥墩木材堆积概率的实验室研究

摘要 在洪水期间，桥梁等河流基础设施容易堆积运输的大块木材 (LW)。为了有助于改进风险评估，LW 累积概率 (AP) 的预测至关重要。以前对 LW AP 的研究主要集中在桥面板的影响上。在本研究中，进行了水槽实验来研究桥墩的 LW AP，特别强调 (1) 引水条件，(2) 不同墩粗糙度、形状、直径和墩数的桥墩特性，(3) LW特性，包括各种原木长度、原木直径、原木密度、有和无分支的 LW，以及不拥挤与（半）拥挤的 LW 运输，以及 (4) 河道床，即冲刷。根据实验，AP 主要是接近流速和测井长度的函数。