Ultimate pier and contraction scour prediction in cohesive soils at selected bridges in Illinois.

摘要: This report presents the results of testing Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth cohesive soils at 15 bridges in Illinois. The SRICOS-EFA complex pier and contraction has two primary components. first component includes calculation maximum (Zmax). second is an integrated approach that considers a time factor, soil properties, continued interaction between (SRICOS runs). were compared to prediction non-cohesive based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, HEC-18 predicted higher depths than method. A reduction factor was determined each result make it match three types SRICOS run results. unconfined compressive strength (Qu) then matched with ranked order increasing Qu. Reduction factors grouped by Qu applied bridge site soil. These results, comparison Zmax calculation, show less half reduction-factor values lowest estimate scour; whereas, over half. tiered predicting developed. There are four levels this numbered complexity, fourth level being full analysis. Levels 1 2 involve can be completed without EFA data. Level 3 requires some surrogate 4 require streamflow input into SRICOS. Estimation techniques both data