Local scour, a complex phenomenon in river flows around piers with movable beds, can damage bridge piers during high floods. Predicting scour depth accurately is vital for safety and economic reasons, especially for large bridges. This study using hydraulic flume laboratory experiments compared diamond, square, and elliptical pier models of different sizes under steady clear-water conditions considering different flow rates and discharge levels to identify the most efficient shape with less local scour. Local scour, a complex phenomenon in three-dimensional flow around piers in rivers with movable beds, can lead to detrimental effects on bridge piers due to high flood velocities. Accurate prediction of scour depth is crucial for economic and safety reasons, especially for large bridges with complex piers. Hydraulic engineers are keen on forecasting the equilibrium scour depth. To achieve this, laboratory testing compared diamond, square, and elliptical pier models under steady clear-water conditions to identify the most efficient pier shape with less local scour. This research provides valuable insights for optimizing pier design to enhance bridge stability and resilience against scour-induced risks. A variety of configurations, including different sizes and shapes of piers were experimented with in the flume using diamond, square, and elliptical shapes. The test results showed that the local scour depth around elliptical piers was around 29.16% less, and around diamond piers, it was approximately 16.05% less compared to the scour depth observed around square piers with the same dimensions. The researchers also observed distinct patterns of scouring around different pier shapes. Specifically, the square-shaped piers displayed the highest level of scouring depth, that is, 48 mm, followed by the diamond-shaped pier which experienced a scouring depth of 48 mm while the elliptical-shaped piers experienced the least amount of scouring depth, that is, 34 mm. The test results also demonstrated that pier size significantly influences scouring, with an increase in pier size from 3 × 3 cm2 to 5 × 5 cm2 leading to a rise in scour depth by 26.04%. Moreover, this study findings also elucidated that an increase in flow results in an increase of in scouring depth i.e., elevating the discharge from 0.0026 cumecs to 0.0029 cumecs led to a 28.13% increase in scouring depth for the identical pier size. These findings provide valuable insights into the hydraulic behavior of various pier shapes and can aid in the optimization of bridge design and hydraulic engineering practices. The investigations further revealed that local scouring is sensitive not only to pier dimensions but also to other critical parameters, including flow rate, time of exposure, and the size of a pier.

Aly, A. M., & Dougherty, E. (2021). Bridge pier geometry effects on local scour potential: A comparative study. Ocean Engineering, 234, 109326. https://doi.org/10.1016/j.oceaneng.2021.109326

American Society for Testing and Materials. (2004). Committee D18 on Soil and Rock, Standard test methods for particle-size distribution (gradation) of soils using sieve analysis. ASTM International.

Brunner, G. W. (2016). HEC-RAS River Analysis System: Hydraulic Reference Manual, Version 5.0. US Army Corps of Engineers–Hydrologic Engineering Center, vol. 547.

Banazadeh, A., & Hajipouzadeh, P. (2019). Using approximate similitude to design dynamic similar models. Aerospace Science and Technology, 94, 105375. https://doi.org/10.1016/j.ast.2019.105375

Beg, M. (2010). Characteristics of Developing Scour Holes around Two Piers Placed in Transverse Arrangement. Scour and Erosion. https://doi.org/10.1061/41147(392)6

Bresnahan, T., Dickenson, K. (2002). Surfer 8 self-paced training guide. Golden Software Inc.

Bakht, B., & Jaeger, L. G. (1992). Simplified methods of bridge analysis for the third edition of OHBDC. Canadian Journal of Civil Engineering, 19(4), 551–559. https://doi.org/10.1139/l92-066

Chen, Y., Tang, F., Li, Z., Chen, G., & Tang, Y. (2018). Bridge scour monitoring using smart rocks based on magnetic field interference. Smart Materials and Structures, 27(8), 085012. https://doi.org/10.1088/1361-665x/aacbf9

Coleman, S. E. (2005). Clearwater Local Scour at Complex Piers. Journal of Hydraulic Engineering, 131(4), 330–334. https://doi.org/10.1061/(asce)0733-9429(2005)131:4(330)

Daryati, D., Widiasanti, I., Septiandini, E., Ramadhan, M. A., Sambowo, K. A., & Purnomo, A. (2019). Soil characteristics analysis based on the unified soil classification system. Journal of Physics: Conference Series, 1402(2), 022028. https://doi.org/10.1088/1742-6596/1402/2/022028

Dahe, P., Kharode, S. (2015). Evaluation of scour depth around bridge piers with various geometrical shapes. Evaluation, 2(7): 41–48.

Deng, L., & Cai, C. S. (2010). Bridge Scour: Prediction, Modeling, Monitoring, and Countermeasures—Review. Practice Periodical on Structural Design and Construction, 15(2), 125–134. https://doi.org/10.1061/(asce)sc.1943-5576.0000041

Dey, S. (1997a). Local scour at piers, part I: a review of developments of research. Int. J. Sediment Res., Beijing, China, 12(2), pp. 23–46.

Dey, S. (1997b). Local scour at piers, part II: bibliography. Int. J. Sediment Res, 12(2): 47–57.

Dargahi, B. (1982). Local scouring around bridge piers—A review of practice and theory. Bull, vol. 114.

Eddine, M. S., & Arjomandi, K. (2020). Assessment of the Accuracy of Bridge Evaluation Methods Outlined by CHBDC. presented at the Transportation Association of Canada 2020 Conference and Exhibition-The Journey to Safer Roads.

Ettema, R. (1980). Scour at bridge piers. 1980.

Farooq, R., Ghumman, A. R., & Hashmi, H. N. (2017). Influence of pier modification techniques for reducing scour around bridge piers. International Journal of Civil and Environmental Engineering, 11(4), 462–468.

Grimaldi, C., Gaudio, R., Calomino, F., & Cardoso, A. H. (2009). Countermeasures against Local Scouring at Bridge Piers: Slot and Combined System of Slot and Bed Sill. Journal of Hydraulic Engineering, 135(5), 425–431. https://doi.org/10.1061/(asce)hy.1943-7900.0000035

Galin, E., Guérin, E., Peytavie, A., Cordonnier, G., Cani, M., Benes, B., & Gain, J. (2019). A Review of Digital Terrain Modeling. Computer Graphics Forum, 38(2), 553–577. Portico. https://doi.org/10.1111/cgf.13657

Gampathi, G. A. P. (2010). Suitable Bridge Pier Section for a Bridge over a Natural River. Engineer: Journal of the Institution of Engineers, Sri Lanka, 43(3), 44. https://doi.org/10.4038/engineer.v43i3.6973

Heller, V. (2011). Scale effects in physical hydraulic engineering models. Journal of Hydraulic Research, 49(3), 293–306. https://doi.org/10.1080/00221686.2011.578914

Ismael, A., Gunal, M., & Hussein, H. (2015). Effect of Bridge Pier Position on Scour Reduction According to Flow Direction. Arabian Journal for Science and Engineering, 40(6), 1579–1590. https://doi.org/10.1007/s13369-015-1625-x

Ismail, S. (2009). Evaluation of local scour around bridge piers (River Nile Bridges as Case Study). Thirteenth International Water Technology Conference, IWTC, Citeseer, pp. 1249–1260.

Jalal, H. K., & Hassan, W. H. (2020). Effect of Bridge Pier Shape on Depth of Scour. IOP Conference Series: Materials Science and Engineering, 671(1), 012001. https://doi.org/10.1088/1757-899x/671/1/012001

Khan, M., Tufail, M., Ajmal, M., Haq, Z. U., & Kim, T.-W. (2017). Experimental Analysis of the Scour Pattern Modeling of Scour Depth Around Bridge Piers. Arabian Journal for Science and Engineering, 42(9), 4111–4130. https://doi.org/10.1007/s13369-017-2599-7

Kuchma, D. A., Hawkins, N. M., Kim, S.-H., Sun, S., & Kim, K. S. (2008). Simplified shear provisions of the AASHTO LRFD Bridge Design Specifications. PCI Journal, 53(3), 53–73. https://doi.org/10.15554/pcij.05012008.53.73

Li, Z., Tang, F., Chen, Y., Hu, X., Chen, G., & Tang, Y. (2021). Field experiment and numerical verification of the local scour depth of bridge pier with two smart rocks. Engineering Structures, 249, 113345. https://doi.org/10.1016/j.engstruct.2021.113345

Lai, J. S., Chang, W. Y., & Yen, C. L. (2009). Maximum Local Scour Depth at Bridge Piers under Unsteady Flow. Journal of Hydraulic Engineering, 135(7), 609–614. https://doi.org/10.1061/(asce)hy.1943-7900.0000044

Lyn, D. A. (2008). Pressure-Flow Scour: A Reexamination of the HEC-18 Equation. Journal of Hydraulic Engineering, 134(7), 1015–1020. https://doi.org/10.1061/(asce)0733-9429(2008)134:7(1015)

Lagasse, P. F., Schall, J. D., Johnson F., et al. (1995). Stream stability at highway structures. United States. Federal Highway Administration. Office of Technology Applications.

Melville, B., Coleman, S. (2000). Bridge scour Water Resources Publications. LLC, Colorado, USA; 2000.

Masjedi, A., Shafaei BEJESTAN, M., & Esfandi, A. (2010). Experimental study on local scour around single oblong pier fitted with a collar in a 180 degree flume bend. International Journal of Sediment Research, 25(3), 304–312. https://doi.org/10.1016/s1001-6279(10)60047-9

Panici, D., & de Almeida, G. A. M. (2018). Formation, Growth, and Failure of Debris Jams at Bridge Piers. Water Resources Research, 54(9), 6226–6241. Portico. https://doi.org/10.1029/2017wr022177

Richardson, E. V., Davis, S. R. (1995). Evaluating scour at bridges. United States. Federal Highway Administration. Office of Technology Applications.

Raudkivi, A. J. (1986). Functional Trends of Scour at Bridge Piers. Journal of Hydraulic Engineering, 112(1), 1–13. https://doi.org/10.1061/(asce)0733-9429(1986)112:1(1)

Raudkivi, A. J., & Ettema, R. (1983). Clear‐Water Scour at Cylindrical Piers. Journal of Hydraulic Engineering, 109(3), 338–350. https://doi.org/10.1061/(asce)0733-9429(1983)109:3(338)

Shahriar, A. R., Ortiz, A. C., Montoya, B. M., & Gabr, M. A. (2021). Bridge Pier Scour: An overview of factors affecting the phenomenon and comparative evaluation of selected models. Transportation Geotechnics, 28, 100549. https://doi.org/10.1016/j.trgeo.2021.100549

Sotiropoulos, F., Diplas, P., Khosronejad, A. (2012). Scour around Hydraulic Structures. In Handbook of Environmental Fluid Dynamics, Volume Two, CRC Press, 2012, pp. 88–103.

Tang, Y., Chen, Y., Tang, F., Liang, Y., & Li, Z. (2023). Field experiment of a novel semi-active smart rock system for sensing bridge scour depth. Structures, 53, 1150–1159. https://doi.org/10.1016/j.istruc.2023.05.021

Tang, F., Chen, Y., Li, Z., Hu, X., Chen, G., & Tang, Y. (2019). Characterization and field validation of smart rocks for bridge scour monitoring. Structural Health Monitoring, 18(5–6), 1669–1685. https://doi.org/10.1177/1475921718824944

Tejada, S. (2014). Effects of blockage and relative coarseness on clear water bridge pier scour.

Vijayasree, B. A., Eldho, T. I., Mazumder, B. S., & Ahmad, N. (2019). Influence of bridge pier shape on flow field and scour geometry. International Journal of River Basin Management, 17(1), 109-129.

Zhang, G., Liu, Y., Liu, J., Lan, S., & Yang, J. (2022). Causes and statistical characteristics of bridge failures: A review. Journal of Traffic and Transportation Engineering (English Edition), 9(3), 388–406. https://doi.org/10.1016/j.jtte.2021.12.003

Zhang, L., Wang, P., Yang, W., Zuo, W., Gu, X., & Yang, X. (2018). Geometric Characteristics of Spur Dike Scour under Clear-Water Scour Conditions. Water, 10(6), 680. https://doi.org/10.3390/w10060680

Zevenbergen, L. W. (2010). Comparison of the HEC-18, Melville, and Sheppard Pier Scour Equations. Scour and Erosion. https://doi.org/10.1061/41147(392)108