Impact Assessment of Pier Shape and Modifications on Scouring around Bridge Pier

Abstract

Previous experimental research on utilizing pier modifications as countermeasures against local scour has focused primarily on circular pier. It is of utmost importance to further investigate the most suitable pier shape for pier modification countermeasure separately and in combination. This experimental study aims to reduce the stagnation of the flow and vortex formation in front of the bridge pier by providing a collar, a hooked collar, a cable, and openings separately and in combination around a suitable pier shape. Therefore, six different pier shapes were utilized to find out the influence of pier shape on local scouring for a length-width ratio smaller than or equal to 3. A plain octagonal shape was shown as having more satisfactory results in reducing scour compared to other pier shapes. Furthermore, the efficiency of pier modification was then evaluated by testing different combinations of collar, hooked collar, cable, and openings within the octagonal bridge pier, which was compared to an unprotected octagonal pier without any modification. The results show that by applying such modifications, the scour depth reduced significantly. The best combination was found to be a hooked collar with cable and openings around an octagonal pier. It was revealed that the best combination reduced almost 53% of scour depth, as compared to an unprotected octagonal pier.

Optimal Octagonal Hooked Collar Countermeasure to Reduce Scour Around a Single Bridge Pier

“…Over the recent years, significant research has been undertaken to analyze the influence of various factor on the development of the complex intricate vortex system at the bridge piers. Such factors perhaps separated by three different groups: (i) sediment factor, for instance size distribution, sediment density, and median size; (ii) flow parameters, such as flow depth and approach velocity; and (iii) pier dimension, shape, and type [3][4][5][6]. One of the prime causes broadly recognized as scaling up the scour threat to bridges is shape of pier.…”

“…One of the prime causes broadly recognized as scaling up the scour threat to bridges is shape of pier. Pier shape is very significant in the formation and strengthening of the vortex system [6][7][8][9]. The pier having any shape placed vertically in the riverbed and thereby immensely varies the flow fields, and it can be assumed that the large variations in the flow structures occurs due to different pier shapes, and thus varied scour patterns.…”

“…Studies of pier scour on shapes other than circular and rectangular shape are rather insufficient comparatively as stated by [8,14,15]. Recently, Farooq and Ghumman [6] performed experiments on scour in steady uniform flow, examining the impact of different pier shapes on maximum scour depth. It was concluded that a plain octagonal pier shape turns out to be as more satisfying in reducing scour in comparison of all other pier shapes.…”

Scour around Piers under Waves: Current Status of Research and Its Future Prospect

“…The shape and size of a pier are among the important parameters for the variation of scour depth. A detailed description of their effects was reported by Farooq and Ghumman [50]. Sumer et al [27] studied the impact of cross-sectional shape of the pier on the development of scour depth.…”

Effect Of Bridge Piers On Local Scouring At Alue Buloh Bridge Nagan Raya Regency

“…Different factors affect scouring around the bridge pier. Among them is the shape of the pier which will affect the flow pattern around the bridge pier and influence the creation and strength of the vortex (Farooq and Ghumman 2019). Rectangular pier shows the maximum scour depth of 6.3 cm and 2.6 cm which is minimum for rectangular piers.…”