scholarly journals Effect of Angle between Pier and Center of River Flow on Local Scouring around the Bridge Pier

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3192
Author(s):  
Takuma Kadono ◽  
Shinichiro Okazaki ◽  
Yoshihiro Kabeyama ◽  
Toshinori Matsui
Keyword(s):  
Water Flow ◽  
Heavy Rainfall ◽  
River Flow ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Flowing Water ◽  
River Flows ◽  
Scouring Depth

In recent years, heavy rainfall disasters have caused frequent damage to bridge piers due to scouring and have resulted in the fall of bridges in many areas in Japan. The objective of this study was to investigate the effect of local scouring around the downstream of the piers on the local scouring around the center of the river flowing at an angle to the piers. It was found that when the center of the river flows at an angle to the piers, the scouring area becomes wider from the upstream to the downstream of the piers because of the longer inhibition width of the piers positioned perpendicular to the water flow. The downstream scouring depth tends to be smaller than the upstream scouring depth. In addition, the time to the onset of tilting deformation of the piers increases with the inhibition width of the piers positioned perpendicular to the flowing water.

scholarly journals Analysis of Water Flow Pressure on Bridge Piers considering the Impact Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Yin-hui Wang ◽  
Yi-song Zou ◽  
Lue-qin Xu ◽  
Zheng Luo
Keyword(s):  
Water Flow ◽  
Coupling Effect ◽  
Highway Bridges ◽  
Element Model ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Water Current ◽  
Fluid Structure ◽  
Impact Effect ◽  
The Impact

In order to investigate the effects of water current impact and fluid-structure interaction on the bridge piers, the mechanism of water flow impact on the bridge pier is firstly studied. Then a finite element model of a bridge pier is established including the effects of water flow impact as well as the water circumferential motion around the pier. Comparative study is conducted between the results of water impact effect, fluid-structure coupling effect, theoretical analysis, and also the results derived using the formulas specified in the design codes home and abroad. The results show that the water flow force calculated using the formulas provided by the codes should be multiplied by an impact amplifier to account for the effect of flood impact on the bridge pier. When the flood flows around the pier, the fluid-structure coupling effect on the bridge pier can be neglected. The method specified in the China guidelines ofGeneral Code for Design of Highway Bridges and Culvertstends to provide a larger result of the water flow force.

scholarly journals A Study on Interaction between Overfall Types and Scour at Bridge Piers with a Moving-Bed Experiment

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 152
Author(s):  
Wei-Lin Lee ◽  
Chih-Wei Lu ◽  
Chin-Kun Huang
Keyword(s):  
Large Scale ◽  
River Flow ◽  
Extreme Event ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Flow Conditions ◽  
Moving Bed ◽  
Directional Flow ◽  
Scour Hole ◽  
Additional Protection

River slopes can be changed due to an extreme event, e.g., a large-scale earthquake. This can uplift a riverbed greatly and thereby change the behavior of the river flow into a free or submerged overfall. Corresponding damage, including extreme erosion, on bridge piers located in the river can take place due to the aforementioned flow conditions. A reconstructed bridge pier in the same location would also experience a similar impact if the flow condition is not changed. It is important to identify these phenomena and research the mechanism in the interaction between overfall types and scour at bridge piers. Therefore, this paper is aimed at studying a mechanism of free and submerged overfall flow impacts on bridge piers with different distances by a series of moving-bed experiments. The experiment results showed clearly that bridge pier protection requires attention particularly when the pier is located in the maximum scour hole induced by the submerged overfall due to the z directional flow eddies. In many other cases, such as when the location of the bridge pier was at the upstream slope of a scour hole induced by a flow drop, a deposition mound could be observed at the back of the pier. This indicates that, while a pier is at this location, an additional protection takes place on the bridge pier.

scholarly journals Effects on Scour for Different Foundation Geometry of Compound Circular Bridge Piers

2019 ◽  
Vol 8 (2) ◽  
pp. 2439-2446
Keyword(s):  
Experimental Study ◽  
Rate Of Change ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flowing Water ◽  
Sound Design ◽  
Flow Conditions ◽  
The Past ◽  
Bridge Failure

This experimental study examines the variation of scour depth with time of Clearwater scour condition around compound circular bridge piers for steady flow conditions. Most of the circular bridge piers are resting on the bigger diameter caissons known as the compound circular bridge piers and are widely used in India for construction of road and railways bridge across the rivers. In past studies, it has been observed that most bridge failure occurs because of scouring due to flowing water around a bridge pier across a river. Most of the past studies were done on the uniform bridge pier and a very few studies have been done so far on scouring around non-uniform bridge piers. Estimation of scour depth is required for the economical and a sound design of bridge pier foundation. In present study, an experimental investigation has been done in a tilting flume for computation of rate of change of depth of scour with time at two different models of compound circular bridge piers by varying the foundation top position with respect to level of bed, i.e., 1. The foundation top at the level of bed, and 2. The foundation top below the level of bed (viz. 10mm, 20mm, 30mm and 40mm) for uniform sediments.

scholarly journals Effect of Soil Non-Uniformity on Scour For Circular Compound Bridge Piers

2019 ◽  
Vol 8 (2) ◽  
pp. 2051-2059
Keyword(s):  
Experimental Investigation ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flowing Water ◽  
Railway Bridges ◽  
The Past ◽  
Economical Design ◽  
Circular Compound ◽  
Bridge Failure

Bridge piers having a varying foundation diameter are known as compound bridge piers. In India for the construction of road and railway bridges circular compound bridge piers are mostly adopted. In past studies it has been concluded that 60-70% of bridge failure occurs because of scour around bridge pier across a river due to flowing water. Most of the past studies were done on the uniform bridge pier and a very few studies has been carried out so far on scour around compound bridge piers. For economical design of bridge pier foundation there is a need to determine the scour depth. In the present study, an experimental investigation has been carried out for computation of time variant change of scour depth for two different models of circular compound bridge piers over non-uniform soil for all possible cases of position of footing with respect to level of the bed, i.e., I. Footing at the level of bed, and II. Footing below the level of bed (1cm, 2cm, 3cm and 4cm) for non-uniform sediments

scholarly journals South Asia river-flow projections and their implications for water resources

2015 ◽  
Vol 19 (12) ◽  
pp. 4783-4810 ◽  
Author(s):  
C. Mathison ◽  
A. J. Wiltshire ◽  
P. Falloon ◽  
A. J. Challinor
Keyword(s):  
Water Resources ◽  
South Asia ◽  
River Flow ◽  
Climate Model ◽  
Asian Summer Monsoon ◽  
Regional Climate ◽  
Global Climate Models ◽  
Climate Projections ◽  
The South ◽  
River Flows

Abstract. South Asia is a region with a large and rising population, a high dependence on water intense industries, such as agriculture and a highly variable climate. In recent years, fears over the changing Asian summer monsoon (ASM) and rapidly retreating glaciers together with increasing demands for water resources have caused concern over the reliability of water resources and the potential impact on intensely irrigated crops in this region. Despite these concerns, there is a lack of climate simulations with a high enough resolution to capture the complex orography, and water resource analysis is limited by a lack of observations of the water cycle for the region. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. Two global climate models (GCMs), which represent the ASM reasonably well are downscaled (1960–2100) using a regional climate model (RCM). In the absence of robust observations, ERA-Interim reanalysis is also downscaled providing a constrained estimate of the water balance for the region for comparison against the GCMs (1990–2006). The RCM river flow is routed using a river-routing model to allow analysis of present-day and future river flows through comparison with available river gauge observations. We examine how useful these simulations are for understanding potential changes in water resources for the South Asia region. In general the downscaled GCMs capture the seasonality of the river flows but overestimate the maximum river flows compared to the observations probably due to a positive rainfall bias and a lack of abstraction in the model. The simulations suggest an increasing trend in annual mean river flows for some of the river gauges in this analysis, in some cases almost doubling by the end of the century. The future maximum river-flow rates still occur during the ASM period, with a magnitude in some cases, greater than the present-day natural variability. Increases in river flow could mean additional water resources for irrigation, the largest usage of water in this region, but has implications in terms of inundation risk. These projected increases could be more than countered by changes in demand due to depleted groundwater, increases in domestic use or expansion of water intense industries. Including missing hydrological processes in the model would make these projections more robust but could also change the sign of the projections.

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

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1251 ◽  
Author(s):  
Su-Chin Chen ◽  
Samkele Tfwala ◽  
Tsung-Yuan Wu ◽  
Hsun-Chuan Chan ◽  
Hsien-Ter Chou
Keyword(s):  
Laboratory Experiments ◽  
Horseshoe Vortex ◽  
Flow Fields ◽  
Bridge Pier ◽  
The Other ◽  
Bridge Piers ◽  
Vortex Strength ◽  
Numerical Tests ◽  
Scour Hole ◽  
New Type

A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

scholarly journals PERENCANAAN PERLINDUNGAN PILAR PADA JEMBATAN (Studi Kasus Bangunan Jembatan Trisula-Blitar)

2014 ◽  
Vol 8 (2) ◽  
pp. 158
Author(s):  
Winda Ekasari, Gerard Aponno, Moch. Sholeh
Keyword(s):  
River Flow ◽  
Hydraulic Engineering ◽  
Bridge Piers ◽  
Implementation Method ◽  
The Cost

Trisula bridge piers located at the delta of Brantas River do not have any protection from the stream of the river when flooding. The purpose of the design is to find out the scouring happens to piers caused by the river flow, to determine what kind of protection used to protect the piers, to plan the implementation method, to find out the cost, and the implementation time.Water discharge, pier dimensions, the span and depth of the river, the condition of piers, and velocity of the flow were needed to find out the scouring by Hydraulic Engineering Circular No. 18 application. The result was employed to determine the type of the protection. To find out the estimated costs were calculated through SNI-2012. Ms. Project were applied to find out the implementation time.Keywords: bridge, piers, scouring, partially grouted riprap

scholarly journals River Flows are a Reliable Index of Forest Fire Risk in the Temperate Tasmanian Wilderness World Heritage Area, Australia

2021 ◽  
Author(s):  
David MJS Bowman ◽  
Grant J Williamson
Keyword(s):  
Forest Fire ◽  
River Flow ◽  
Meteorological Data ◽  
Fire Risk ◽  
World Heritage ◽  
Fire Season ◽  
River Flows ◽  
World Heritage Area ◽  
Heritage Area ◽  
Forest Fire Risk

Fire risk can be defined as the probability that a fire will spread. Reliable monitoring of fire risk is essential for effective landscape management. Compilation of fire risk records enable identification of seasonal and inter-annual patterns and provide a baseline to evaluate the trajectories in response to climate change. Typically, fire risk is estimated from meteorological data. In regions with sparse meteorological station coverage environmental proxies provide important additional data stream for estimating past and current fire risk. Here we use a 60-year record of daily flows from two rivers (Franklin and Davey) in the remote Tasmanian Wilderness World Heritage Area (TWWHA) to characterize seasonal patterns in fire risk in temperate Eucalyptus and rainforests. We show that river flows are strongly related to landscape soil moisture estimates derived from down-scaled re-analysis of meteorological data available since 1990. To identify river flow thresholds where forests are likely to burn, we relate river flows to known forest fires that have occurred in the previously defined ecohydrological domains that surround the Franklin and Davey catchments. Our analysis shows that the fire season in the TWWHA is centered on February (70% of all years below the median threshold), with shoulders on December-January and March. Since 1954 forest fire can occur in at least one month for all but four summers in the ecohydrological domain that includes the Franklin catchment, and since 1964 fire fires could occur in at least one month in every summer in the ecohydrological domain that includes the Davey catchment. Our analysis shows that mangers can use river flows as a simple index that provide a landscape-scale forest fire risk in the TWWHA.

scholarly journals Stability of Sheet Water Flow Under a Glacier

1983 ◽  
Vol 29 (103) ◽  
pp. 374-382 ◽  
Author(s):  
J. Weertman ◽  
G. E. Birchfield
Keyword(s):  
Shear Stress ◽  
Water Flow ◽  
Sheet Thickness ◽  
The Other ◽  
Flowing Water ◽  
Ice Melting ◽  
Geothermal Heat ◽  
Melt Water ◽  
Primary Origin ◽  
Basal Shear

AbstractWalder recently analyzed the initial instability of water flow in a sheet under a glacier that is produced by greater heat production in the flowing water and thus the larger rate of ice melting where a perturbation has increased the water sheet thickness. We have looked at the problem from the other presumed final state. We assume that instabilities have finally caused all the water to flow in channels (R-channels) at the bed. We investigated whether these channels can collect enough of the water that is produced by the geothermal heat and the heat sliding to remain in existence. When a basal shear stress is present, the distance out to which a channel can collect water is not that much greater than the channel radius itself. It is concluded that it is not likely for the channel to be able to collect appreciable amounts of water that is produced at the bed. Hence despite the indication that an instability initially might grow in a water sheet, this instability either cannot develop to the point when the water flow is primarily in channels or else the water flow alternates cyclically between a state primarily of sheet flow and a state of channel flow. It would appear that the channels that do exist under a glacier have their primary origin in the melt water from the upper surface that pours down moulins and thus is already channelized by the time it reaches the bed.

https://fsri.org/research-update/fsri-releases-report-residential-flashover-prevention-reduced-water-flow-phase-1

2020 ◽  
Author(s):  
Daniel Madrzykowski ◽  
◽  
Nick Down
Keyword(s):  
Water Flow ◽  
Test Structure ◽  
Low Flow ◽  
Flowing Water ◽  
Water Spray ◽  
Water Supplies ◽  
Flow Rates ◽  
Prevention System ◽  
Reduced Water ◽  
Fire Experiments

This study was designed to be an initial step to investigate the potential of low flow nozzles as part of a retrofit flashover prevention system in residential homes with limited water supplies. Not all homes have water supplies that can meet the needs of a residential sprinkler system. Current alter- natives, such as including a supplemental tank and pump, increase the cost of the system. These homes could benefit from an effective fire safety system with lower water supply requirements. The experiments in this study were conducted in a steel test structure which consisted of a fire room attached to a hallway in an L-shaped configuration. Three types of experiments were conducted to evaluate nozzles at different flow rates and under different fire conditions. The performance of the nozzles was compared to the performance of a commercially available residential sprinkler. The first set of experiments measured the distribution of the water spray from each of the nozzles and the sprinkler. The water spray measurements were made without the presence of a fire. The other two sets of experiments were fire experiments. The first set of fire experiments were designed to measure the ability of a water spray to cool a hot gas layer generated by a gas burner fire. The fire source was a propane burner which provided a steady and repeatable flow of heat into the test structure. Two water spray locations were examined, in the fire room and in the middle of the hallway. In each position, the burner was shielded from the water spray. The results showed that for equivalent conditions, the nozzle provided greater gas cooling than the sprinkler. The tests were conducted with a fire size of approximately 110 kW, and water flow rates in the range of 11 lpm (3 gpm) and 19 lpm (5 gpm). The second set of fire experiments used an upholstered sofa as the initial source of the fire with the water spray located in the same room. As a result of the compartment size and water spray distribution, the nozzle flowing water at 23 lpm (6 gpm) provided more effective suppression of the fire than the sprinkler flowing 34 lpm (9 gpm) did. The nozzle was similarly effective with the ignition location moved 1.0 m (3.2 ft) further away. However, the nozzle failed to suppress the fire with a reduced water flow rate of 11 lpm (3 gpm). The results of this limited study demonstrate the potential of low flow nozzles, directly flowing water on to the fuel surface, with the goal of preventing flashover. Additional research is needed to examine larger room sizes, fully furnished rooms, and shielded fires to determine the feasibility of a reduced water flow flashover prevention system.

Sign in / Sign up

Export Citation Format

Share Document