Author(s): Quanshuai Liu; Hongwu Tang; Dawei Guan
Linked Author(s): Hongwu Tang
Keywords: Local scour depth; Bridge pier; Clear-water condition; Temporal evolution; Design method
Abstract: Accurate estimation of local scour depth has long been considered to be an important step for the design of bridge piers. Methods currently serving in different countries are generally based on equilibrium equations, which can be classified as "equilibrium methods", and have been found to either overestimate or underestimate the local scour depth. The inaccuracy and uncertainty of equilibrium methods were discussed in detail, and can be mainly attributed to the impact of the concept of the equilibrium scour depth dse: (1) there is no objective and universal dse criterion for laboratory experiments; (2) it is difficult to judge the equilibrium of local scour in field; (3) the utilization of existing experimental data is limited; and (4) it is difficult to unify the dse criterion of database for equation establishment. In this study, we proposed a new design method for clear-water local scour depth based on temporal evolution characteristics. We collected data from 67 experiments from the referenced literature and conducted 4 in-house experiments. Using factor analysis and trial calculation, we derived a new temporal equation for local scour depth evolution, i.e., Eq. (1). Comparison in Fig. 1 showed that the maximum predicting error of the total 71 experiments was reduced from 162–534% using four existing temporal equations to 34% using Eq. (1).
Year: 2023