Hydraulics Pending Research

Optimum Bridge Deck Shapes to Minimize Pressure Flow Scour Phase II

The BOF is likely to be one that is inundated from time to time where the flow through the bridge opening is under pressure and causes concerns about amplified scour. The proposed study would utilize the PIV capabilities and the shear force sensor that have been developed for the TFHRC hydraulics lab to characterize streamlines and shear stresses on the channel bed for a variety of bridge deck shapes and positions above the bed.

Lift and Drag Forces on Bridge Decks Phase II

The BOF is likely to be constructed of lighter and more durable high performance materials which will lead to more concern about storm surges sweeping the deck off of the foundations as occurred on I10 during the 2004 Hurricane Ivan in Florida. The proposed study will utilize high tech force measurement techniques that have been developed in the TFHRC hydraulics lab to derive lift and drag coefficients for inundated bridge decks for a variety of approach flow conditions.

Scour in Cohesive Soils Phase I

Scour for cohesive soils is a very complex phenomenon that is not completely understood. A pending purchase request has been submitted by the Office of Bridge Technology (HIBT) to fund research to study the influence of turbulence on the erodibility of soils, which could significantly enhance the scour prediction. The TFHRC lab intends to develop and test a turbulence generator and a shear force sensor to be used as part of the investigation by the HIBT contractor.

Pier Scour Countermeasures Using Fluidic Devices

This study will include developing countermeasures by streamlining the shape/form of a bridge pier. A force balance to measure drag force will be used in the streamlining procedure. The streamlining process will be supported using a 3D Volume PIV. We will also study the influence of roughness elements and shields mounted on the side of bridge piers using a shear force device.

In-situ (field) Scour potential Testing Device using a Vertical Jet

This study is an exploratory laboratory investigation to determine the feasibility of using a high power jet to test various strata of soils in the field for scour resistance with out having to take soil samples to a lab for testing via an EFA or similar apparatus .We will start with small scale lab models of bridge piers and determine the power required to simulate scour in the lab and scale that to field size piers to determine feasibility of proceeding with the concept. Bart Bergendahl has asked for this investigation repeatedly.

Fish Passage in Large Culverts with Low Flows

The proposed is to study low flow hydraulics in large culverts. The study will be conducted by the FHWA at the Turner-Fairbanks J. Sterling Jones Hydraulic Research Laboratory in McLean, Virginia. Hydraulic variables will include flow depth, flow condition (laminar, transition and turbulent), Froude number and the variation of flow velocities within the culvert cross-section. Culvert variables will include size and shape, slope, sediment deposits and culvert material. The experiments will be conducted in a new designed culvert test facility where a 15 to 20 foot length of specified culvert geometries will be installed between the headbox and tail box. Only the symmetrical half of the culverts will be modeled allowing larger scale models (1:5). Current FHWA laboratory instrumentation can now achieve much more precise measurements than was possible a few years ago in order to evaluate these hydraulic characteristics under low flow conditions. An advanced particle image velocimetry (PIV) technology will be used for measuring instantaneous flow fields in the culvert. The particle image velocimetry technique (PIV) is an optical flow diagnostic based on the interaction of light refraction and scattering with inhomogeneous media.