Effects of Debris on Bridge Pier Scour
Effects of Debris on Bridge Pier Scour
复制标题
碎片对桥墩冲刷的影响
DOI：
10.1061/40927(243)376
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
L. Girard
中科院分区：
文献类型：
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作者：
P. Lagasse;P. Clopper;L. Zevenbergen;W. Spitz;L. Girard
主要由树干和树枝组成的水上碎片（或漂流物）通常在洪水事件期间积聚在桥梁上。碎屑堆积会阻碍、限制或改变流经桥孔的水流方向，从而导致洪水、破坏性荷载或增加桥梁基础的冲刷。碎片堆积的大小和形状差异很大，从桥墩上的一小簇碎片到桥梁水道开口的几乎完全堵塞。泥石流堆积的影响可能从轻微的水流收缩到严重的水流收缩，从而导致严重的桥梁基础冲刷。目前，只有有限的指导，可根据关键的公共安全决策，在洪水泛滥的碎片易发河流。在公路桥梁的设计、运营和维护中，需要精确的方法来量化碎石对桥墩基础冲刷的影响。本文提供了一个预览的预期结果，从国家合作公路研究计划（NCHRP）项目24-26。该项目于2004年7月开始，定于2007年12月完成。预计这一研究项目将在两个相关问题上取得成果：（1）预测来自潜在的广泛变化的源区、具有不同地貌特征的河流和具有各种下部结构几何形状的桥梁上的碎片的累积特性，以及（2）开发改进的方法，用于量化桥墩处的冲刷深度和范围，同时考虑累积变量和水力参数的范围，和地貌因素。
Waterborne debris (or drift), composed primarily of tree trunks and limbs, often accumulates on bridges during flood events. Debris accumulations can obstruct, constrict, or redirect flow through bridge openings resulting in flooding, damaging loads, or increased scour at bridge foundations. The size and shape of debris accumulations vary widely, ranging from a small cluster of debris on a bridge pier to a near complete blockage of a bridge waterway opening. The effects of debris accumulation can vary from minor flow constrictions to severe flow contraction resulting in significant bridge foundation scour. Currently, there is only limited guidance available on which to base critical public safety decisions during flooding on debris-prone rivers. There is a need for accurate methods of quantifying the effects of debris on scour at bridge-pier foundations for use in the design, operation, and maintenance of highway bridges. This paper provides a preview of the results expected from National Cooperative Highway Research Program (NCHRP) Project 24-26. The project was started in July 2004 and is scheduled for completion in December 2007. It is expected that this research project will produce results on two related problems: (1) predicting the accumulation characteristics of debris from potentially widely varying source areas, in rivers with different geomorphic characteristics, and on bridges with a variety of substructure geometries, and (2) developing improved methods for quantifying the depth and extent of scour at bridge piers considering both the accumulation variables and the range of hydraulic and geomorphic factors involved.