in this paper the effectiveness combination of bed sill and collar in reduction of local scour depth at cylindrical piers under clear water flow condition was investigated (v/vc=0.9). in the first of experiments, the bed sill was located in downstream and different distances from the piers. results indicated that minimum distance of the bed sill from the piers in downstream has maximum reductio...

Severe foundation scour may occur around monopile foundations of offshore wind turbines due to currents and waves. The so-called p-y curves method is suggested in the existing design recommendations to determine the behavior of monopiles unprotected against scour and the reduction of effective soil stress is accounted for by the extreme scour depth. This conservative design approach does not co...

The scour phenomenon around bridge piers causes great quantities of damages annually all over the world. Collars are considered as one of the substantial methods for reducing the depth and volume of scour around bridge piers. In this study, the experimental and numerical methods are used to investigate two different shapes of collars, i.e, rectangular and circular, in terms of reducing scour ar...

The most important causes of bridge failure are local scour. In this study, laboratory experiments were conducted to investigate the effectiveness of slot as a protection device in reduction of depth of scour at cylindrical piers under clear water flow conditions. The development time of scour depth at the circular pier with and without a slot as a protection device was conducted. The experimen...

A series of experiments was conducted to investigate the erosion behaviors of the noncohesive sediments downstream of smooth and rough aprons. A total of 33 tests were carried out with five different roughness conditions (k =0, 1, 1.85, 3.35 and 5mm) in a flume 0.5m wide, 0.6m deep and 9m long. For each run, s measurements were taken of the scour-hole profiles at the asymptotic or equilibrium s...

local scour around the abutment is of utmost importance in bridge failures. numerous methods such as riprap have been proposed to reduce the destructive effects of scouring; one of the ways to harness and reduce the local scour depth is installed protective collars around the abutment. in this paper effect of collar elevation (upper level, bed level and lower level), collar geometry and its siz...

Many of the huge structures like New Esna, and New Nega Hammadi Barrages face a great harmful caused by local scour downstream (DS) their stilling basins. It is planned to redesign many of these structures to minimize these harmful impacts of the DS local scour. This research paper presents the results of an extensive experimental investigation on using an optimized submerged curved deflector t...

local scouring around bridge piers is a natural phenomenon caused by the erosive process of flowing stream on alluvial beds. the 3d flow field around bridge piers interacting with the bed materials increases complexity of local scour process. the local scour depth develops in accelerated flows and if it is not predicted correctly, the bottom level of local scour hole will exceed the original le...