Effect of the Froude number on assessment of the bridge afflux

Abstract

This paper presents the findings of laboratory model testing of arch and straight-deck bridge constrictions, in a symmetrical compound channel flume having different roughness conditions. Four different types of bridge models, namely a single-opening, semicircular arch bridge, a multiple-opening, semicircular arch bridge, a single opening, elliptic arch bridge, and a straight-deck bridge with and without piers, were used in the testing programme. The validity of the Biery and Delleur method developed for the single cross-sectional-shaped arch bridge constrictions was examined for a compound channel case. The effect of different definitions of the Froude number on the application of the Biery and Delleur method was also investigated. The results showed that the Biery and Delleur method agreed reasonably well with the University of Birmingham data presented in the current study, provided that the Froude number was defined in the same way as originally envisaged. Significant errors may result, however, from using this method with definitions of the Froude number that are more appropriate to compound channels.

Accuracy of the ISIS bridge methods for prediction of afflux at high flows

“…Full details of the apparatus and experimental procedures are given by Atabay (2001), Atabay & Knight (2002), Seckin & Atabay (2005) and Seckin et al (2004) in related studies using the same flume. The experimental apparatus and procedure are therefore only described briefly in this study.…”

“…This study is based on experimental work carried out in the hydraulics laboratory at the University of Birmingham. The data and a full description of the methodology are contained in a technical paper presented by Atabay & Knight (2002) and Seckin et al . (2004) to JBA Consulting Engineers and Scientists and the Environment Agency (EA): titled ‘Scoping Study into Hydraulic Performance of Bridges and other Structures, including Effects of Blockages, at High Flows (Bridge Afflux Experiments in Compound Channels)’.…”

Artificial neural network approaches for prediction of backwater through arched bridge constrictions

“…Several studies [9][10][11][12][13][14][15][16][17][18] have defined that the blockage ratios at sections 1 and 3 in Fig. 1, as J 1 (area of blockage of bridge at depth D 1 /area of flow) and J 3 (area of blockage of bridge at depth D 3 /area of flow) respectively, and Froude number at section 3 (Fr 3 ) are effective parameters in estimation of bridge backwater through arched bridge constrictions in rivers.…”

3D model for prediction of flow profiles around bridges

“…In the numerical model applications, a total of 25 runs, 5 for each case described above, was selected to test the performance of FLOW-3D. Details of the experiments including cross-sections of all bridge types can be found in Seckin et al (2008).…”