Experimental Study of the Influence of Non-Hydrostatic Pressure in Rip Rap Pier Protection

The non-hydrostatic pressure distribution is one of the main factors that affect the particles motion threshold around piers. The present paper focuses on the comparison of the motion threshold between circular-shaped and square-shaped piers under the influence of the non-hydrostatic pressure factor. A total of 30 runs were performed with different geometric dimensions and different Rip Rap diameter protection. The hydrostatic pressure factor distinguishes quite well between circularshaped and square-shaped piers. Comparison with other authors has been made in order to extract some conclusions and confirm the experimental data. The nonhydrostatic pressure distribution on bed surfaces is very important to distinguish between different behaviors in sediment transport bed processes; local scour protection around piers is only an example. The main idea would be finding the threshold of motion of the Rip Rap around the circular-shaped and square-shaped base piers.