Control of the Local Scouring Around the Cylindrical Bridge Pier Using Armed Soil by Geotextile

Abstract

Flood currents are considered threatening factors by creating local scour along bridge piers. One method for decreasing local scour is to strengthen the bed against imposed tensions. Among methods which can be appropriate in decreasing and controlling local scour of bridge piers directly is to put riprap beside bridge piers and to employ geotextile around them. Geotextiles form a large group of geosynthetic products produced from polypropylene and polyester fibers, and are used in separation, strengthening and reinforcing, filtration, and drainage. In the present study, the effect of geotextile layer in decreasing local scour of cylindrical single-pier was investigated and the best coverage pattern with the most effect was obtained so that layers with circular and oval shapes were put around the pier relative to its diameter, and the performance of each was compared with the unprotected pier. Test results showed by using geotextile with an appropriate cover, the scour location is transferred to downstream and the scour depth is decreased. These advantages can reduce the risk of pier failure when the duration of flood is short. The results indicate that the scour reduction increases as the layer area increased. In this case the oval layer has a better efficiency compared to the circular one.

A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour

“…Figure 4 depicts observed scour patterns around a pier without a hooked-collar and piers fitted with hooked-collars at different locations. The scour process of the single pier was consistent with those reported by several studies [14,[27][28][29]. Initially, the downflow dug a hole directly in front of the pier ( Supplementary Information, Figure S1).…”

On local scouring downstream small water structures

“…Solutions are sought, involving different coefficients, which characterize a given construction, based on identified factors that influence scour size and position ( Franke, 1960 ; Straube, 1963 ; Tarajmovič, 1966 ; Rossinski & Kuzmin, 1969 ). The formation and expansion of local scouring that results from time-varying, two-phase movement of water and sediment is one of the most undiscovered processes in hydrotechnical engineering ( Graf, 1998 ; Nouri Imamzadehei et al., 2016 ). Despite numerous studies carried out since the first decades of last century (for example Lacey, 1946 ; Ahmad, 1953 ; Breusers & Raudkivi, 1991 ; Lenzi, Marion & Comiti, 2003 ; Ślizowski & Radecki-Pawlik, 2003 ; Ben Meftah & Mossa, 2006 ; Kiraga & Popek, 2016 ; Pagliara et al, 2016 ; Kiraga & Popek, 2018 ; Al-Husseini, Al-Madhhachi & Naser, 2019 ), there is no sufficient and unquestionable basis for the mathematical description of the process of local erosion, and thus for a development of forecasts of scour holes that will occur during the design of structures.…”

Peer Review #1 of "On local scouring downstream small water structures (v0.1)"

“…Solutions are sought, involving different coefficients, which characterize a given construction, based on identified factors that influence scour size and position (Franke 1960;Straube 1963;Tarajmovič 1966;Rossinski & Kuzmin 1969). The formation and expansion of local scouring that results from time-varying, two-phase movement of water and sediment is one of the most undiscovered processes in hydrotechnical engineering (Graf 1998;Nouri Imamzadehei et al 2016). Despite numerous studies carried out since the first decades of last century (for example Lacey 1946;Ahmad 1953;Breusers & Raudkivi 1991;Lenzi, Marion & Comiti 2003;Ben Meftah & Mossa 2006;Kiraga & Popek 2016;Pagliara et al 2016;Al-Husseini, Al-Madhhachi & Naser 2019), there is no sufficient and unquestionable basis for the mathematical description of the process of local erosion, and thus for a development of forecasts of scour holes that will occur during the design of structures.…”