Laboratory analysis of scouring around the river bridge pier

Podlokavanje u području mosta pojava je uklanjanja materijala s dna korita oko stupova, upornjaka ili nasipa. Jednu od komponenti potpunog podlokavanja čini i lokalno podlokavanje oko stupova mosta koje je uzrokovano ubrzanjem toka i stvaranjem vrtloga uzrokovanih kretanjem toka oko prepreke, odnosno stupa. Opisana pojava potencijalno može narušiti stabilnost mosta i sigurnost odvijanja prometa njime. Cilj ovog rada je utvrditi razmjere podlokavanja oko stupova mosta različite geometrije pri različitim hidrauličkim uvjetima (brzina toka, dubina toka i protok) na umanjenom modelu u hidrauličkom kanalu. Provedena su ispitivanja na 4 umanjena modela stupa različitih oblika u hidrauličkom kanalu duljine 2 m i širine 0,8 m nakon čega su se analizirali dobiveni podatci. Dobiveno je da je najveća udubina podlokavanja na stupu kvadratnog poprečnog presjeka, a najmanja na stupu kružnog poprečnog presjeka. U slučaju složenog oblika nije se dogodilo nikakvo podlokavanje ili je ono zanemarivo malo. Ispitivanjem je potvrđeno da je pogodniji onaj stup koji je oblikovan tako da mu je oblikom uzvodnog dijela smanjen otpor tečenju.Scour at bridge sites is the removal of bed material from around piers, abutments, and embankments. One of the components of total scour is local scour at bridge piers, which is caused by the acceleration of flow and by vortices resulting from flow around an obstruction, in this case, a pier. The described phenomenon can potentially disrupt the stability of the bridge and its traffic safety. The aim of this paper is to determine the extent of scour at bridge piers of different geometry under different hydraulic conditions (flow velocity, flow depth and flow) on a scale model in a hydraulic channel. Tests were conducted on 4 scale model piers of different shapes in a hydraulic channel, which was 2 m in length and 0.8 m in width. Following the tests, the conducted data were analyzed. It was determined that the largest scour depth was on a pier of square cross-section, and the smallest was on a pier of circular cross- section. In the case of the pier with a complex shape, no scour occurred, or it was negligibly small. Tests confirmed that the most suitable pier is the one that is shaped in such a way that the shape of the upstream part reduces its flow resistance