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Laboratory Overview | Laboratory Physical Modeling | Laboratory Numerical(CFD) Modeling | Ongoing Laboratory Activities | Hydraulics Laboratory Personnel | Research Publications | Office of Bridge Technology: Hydraulics | Projects

 

 

J. Sterling Jones Hydraulics Research Laboratory

 

Hydraulics Laboratory Research Program

Research Program
Functional area Initiative No. Task Description
Hydrology-Hydrology 1 Update precipitation frequency estimates for the Northwest and Texas (for the Office of Bridges and Structures (HIBS),the Resource Center (RC) and the National Oceanic and Atmospheric Administration (NOAA))
Hydrology - Extreme Events 2 Investigating the potential impact of extreme events on precipitation frequency estimates (for HIBS, RC, and NOAA)
Hydrology -Extreme Events 3 Nonstationary precipitation frequency estimates for Oregon and Washington (for HIBS and the Office of Planning, Environment, & Realty (HEP))
Hydrology - Extreme Events 4 Flood Frequency Estimation for Hydrologic Design under Changing Conditions (for HIBS and HEP)
Drainage-Design & Analysis 1 Modeling of hydroplaning flows for a series of road longitudinal slopes and cross slopes (for HIBS and RC)
Drainage-Design & Analysis 2 Curb Inlet computational fluid dynamics (CFD) modeling to update Toolbox (for RC)
Culvert s Aquatic Passage 1 Stream Simulation Design of Culverts for Aquatic Organism Passage (AOPP) (for HIBS, RC, Federal Lands Highway (FLH))
Culverts-Design and Analysis 1 Development of CFD models to research and improve inlets/outlets and energy dissipaters (for HIBS and FLH)
Bridge Hydraulics-Design & Analysis 1 3D Flow correction/calibration of the 2-dimensional model of Sedimentation and River Hydraulics (SRH-2D) (for HIBS, RC, and Every Day Counts (EDC-4))1
Bridge Hydraulics-Design & Analysis 3 FEMA Floodway Analysis and Delineation for SRH-2D (for HIBS)
Scour-Scour Countermeasures 1 Develop and Evaluate the Effectiveness of Scour Countermeasures (for the National Hydraulics Team (NHT) Working Group)
Scour-Scour Countermeasures 2 Rockery Wall Design Guidelines for River Environments (for NHT Scour Working Group)
Scour-General 1 Hydraulic Performance of Shallow Foundations for Support of Bridge Abutments (for NHT Scour Working Group/Geotechnical Research Program)
Scour-General 3 Revisit Abutment Scour Methodology in Hydraulic Engineering Circular 18 (HEC-18) (for NHT Scour Working Group)
Scour-General 4 Bridge Scour Design Reliability with load and resistance factor design (LRFD) Considerations (for NHT Scour Working Group and AASHTO TC H&H)2
Scour-Hydraulic Loading 1 Hydraulic Loading for Simple Pier Shapes, Abutments, Horizontal/Vertical Contractions and Complex Piers (for NHT Scour Working Group and the Virginia Department of Transportation (DOT)
Scour-Soil Erosion Resistance Overview Soil Erosion Resistance Analysis Levels (for NHT Scour Working Group)
Scour-Soil Erosion Resistance 1 In situ Scour Testing Device (ISTD) field validation tests (for NHT Scour Working Group)
Scour-Soil Erosion Resistance 3 Laboratory Erosion testing utilizing ex situ scour testing device (ESTD) and lab-ISTD (for NHT Scour Working Group)
Scour-Soil Erosion Resistance 5 Erosion and Geotechnical property correlation testing (for NHT Scour Working Group)
Scour-Stream Stability 1 Advanced Modeling of Extreme Event Impacts on Stream Stability (for HIBS and HEP)
Scour-Stream Stability 2 Develop Engineered Log Jams and Stream Barb Design Criteria (for Western Federal Lands (WFL))
Coastal-Extreme Events 1 Incorporating extreme event impacts into design of highways in the coastal environment (for HIBS and HEP)
1 EDC-4 refers to the fourth round of the Every Day Counts partnership, scheduled for 2017–2018.
2 AASHTO is the American Association of State Highway and Transportation Officials. TC H&H refers to the AASHTO technical committee on Hydrology and Hydraulics.

 

The prototype ISTD is shown in Figure 1. This picture shows the ISTD above a 10-foot-deep sump in the J. Sterling Jones Hydraulics Research Laboratory at Turner-Fairbank Highway Research Center. The sump is filled with sandy soil with the purpose to simulate a river bed condition. An aluminum tube with an inner diameter of 4 inches is driven into the sand bed. Inside that aluminum pipe a centered cylindrical erosion head with an outer diameter of three-and-a-half inches is positioned. The erosion head consists of two spacers and a clear acrylic body between them. The spacers maintain a small gap between aluminum tube and the cylindrical erosion head. The picture shows the erosion head before being lowered into the aluminum pipe by a servo motor and rope assembly. During a test water runs through the gap to the perimeter of bottom of the head. The only drain in the system is a small hole in the middle of the head. The small hole is connected to a vacuum pump through a flexible plastic hose. Between the perimeter and the center of the bottom of the erosion head is an erosion chamber shaped to allow a uniform concentric flow. The water running towards the drain produces an evenly distributed shear stress and entrains the sediment. A certain distance is maintained between the bottom of the erosion head and the soil surface. Four ultrasonic doppler velocimetry (UDV) probes reside in the erosion head. The probes measure the distance between the erosion head and the soil surface. When erosion occurs, the movement rate of the erosion head represents the erosion rate. This ensures an optimal shape for the erosion chamber.

 

The Laboratory In situ Scour Testing Device was designed to measure the erodibility of soils in a laboratory. A tested soil is accommodated in a transparent plexiglas tube with an inner diameter of 3 inches. The tube is half filled with sandy soil. A cylindrical erosion head with a diameter of two-and-a-half inches is fixed in the test tube above the soil. The special designed erosion head ensures uniform distribution of shear stress across the soil surface. Four ultrasonic doppler velocimetry (UDV) probes reside in the erosion head. The probes measure the distance between the erosion head and the soil surface. During a test, the distance is kept constant by using a motor to push up the soil in the test tube. Water flows down through the quarter-inch gap between the test tube and the erosion head. Water then flows radially toward the center of the erosion head. These radial flows generate horizontal shear stress to erode soils. In the center of the erosion head, an 8 millimeter diameter hole guides water out of the test tube. The pump power together with the distance between the erosion head and the soil surface can vary the magnitude of the shear stress acting on the tested soil.

 

The Demo-ISTD consists is a smaller version of the Lab-ISTD and was designed in order to demonstrate the erosion concept of the in situ scour testing device within a laboratory, classroom, or fair setting. The ITEM frame holds a transparent plexiglas tube with an inner diameter of 50 millimeters. The tube is half filled with cohesive soil and is connected to a piston that moves up and down. A cylindrical aluminum erosion head inside the tube with an outer diameter of 45 millimeters is fixed above the soil and includes a three-dimensional printed plastic erosion chamber at the bottom that is shaped to allow uniform concentric flow. In the center of the erosion head, an 8-millimeter-diameter hole guides water out of the test tube. The specially designed erosion head ensures uniform distribution of shear stress across the soil surface. It does this by directing water flow towards the center of the erosion chamber from the gaps between the test tube and erosion head. A pump station that recirculates water in the system consists of a sucking pump, pressure pump, and a water tank. A control unit is connected with the frame and the pump station and allows the engineer to control the device in a manual or PC-controlled remote view. A certain distance is maintained between the bottom of the erosion head and the soil surface by measuring the pressure difference between the inflow towards the erosion chamber and outflow that runs out of the test tube.

 

The photo shows the ESTD and its control station. It uses a pump and a moving belt to propel water in a 92-centimeter-long, 12-centimeter-wide, and 2-centimeter -deep channel. In this picture, the moving belt is lifted up to be visible. A direct force gauge accommodates a soil specimen (a diameter of 63.5 millimeters and a height of 20 millimeters) on its sensor plate.

 

The upper photo shows the pugger that mixes and de-airs the soil sample with a short cylindrical sample pushed out on the left. The lower photo shows a closeup of the sample in the erosion channel.

 

An isometric view of the multifunction (MFS) flume system design is shown with the 6-foot-wide channel modules. An inlet trumpet is located on the lower left corner, while a sediment catch and an outlet is shown at the upper right corner of the image. Between the inlet and the outlet the MFS is fitted with a 6-foot-wide testing channel to test the hydraulic performance and scour vulnerability of bridge substructure components.

 

The computer-generated image shows the velocity distribution in the trumpet and immediate downstream of the trumpet. The velocity is color coded. It shows that the velocity distribution downstream of the trumpet is reasonably uniform and free of adverse pressure conditions.

 

This photograph illustrates an underwater multibeam three-dimensional sonar digital image (acoustic image) of the rock riprap mattress installation around pier 3 of the Middle Fork Feather River Bridge. The digital sonar scan also shows the footing of pier 3 and the bathymetry of the river bed around the rock riprap mattress. The areal extent of the riprap placement is depicted in detail.

 

Coupled computational fluid dynamics and computational structural mechanics simulation results showing the dynamic pressure of a defined approach flow acting on the rock riprap mattress placed around pier 3 of the Middle Fork Feather River Bridge.

 

This image illustrates a physical scaled model of a geosynthetic reinforced soil- vertical-wall bridge abutment during a test in the tilting flume. The superstructure seats on top on the abutment inducing vertical loading according to the similarity theory. The performance of the abutment is tested against flow velocities similar to flood-flow conditions in the field.

 

The image shows two examples of as-built riprap installations around a scaled model of a geosynthetic reinforced soil (GRS) vertical wall bridge abutment that were part of the matrix of tests in this research study. Both riprap installation layouts are based on observed installations in the field and design guidelines from Hydraulic Engineering Circular 23 (HEC23). The top photograph shows a riprap layout that is installed flush with the channel bed.
The bottom photograph shows a riprap layout installed with a revetment slope to the abutment front face. Both riprap installations have the same extent from the abutment front face into the main channel. The performance of these two layouts was compared for clear-water scour conditions.

 

A photograph on the top shows a bathymetry scan of the scour hole around a scaled model (1:60) of the original pier 22 of the Feather River Bridge on Route 20 in Sutter County, California. The complex pier model has a 45-degree skew angle to the approach flow and is composed of 90 H-piles tied at the bottom by a rectangular footing. The scour hole is at a 50 percent stage of the maximum equilibrium scour and its deepest point is located at the outer downstream edge of the pier footing.
A figure on the bottom shows the computational fluid dynamics (CFD) simulation results of the 3D model described in the figure on the left, showing the bed shear stress distribution in the vicinity of pier 22 induced by simulated approach flow conditions occurred in March 2011. The largest value of the bed shear stress is right beneath and on the outer sides of the separated shear layers where the incoming flow is strongly accelerated.

 

The photograph on top shows a  full-scale 3D model constructed from underwater sonar bathymetry scans and a digital elevation model (DEM) showing the scour hole around the original pier 22 in the main channel of the Feather River Bridge on Route 20 in Sutter County, California. The complex pier model 90 H-piles tied at the bottom by a rectangular footing. The scour hole elevation is below the pier footing exposing 19 feet of the H-piles at the pier upstream corner.
The figure on the bottom shows the computational fluid dynamics (CFD) simulation results of the 3D model described in the figure on the top, showing the bed shear stress distribution induced by simulated approach flow conditions occurred in March 2011. The bed shear stress magnitude in the scour hole around pier 22 is lower than on the river bed upstream and downstream of the bridge opening.

 

 

Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101