Hydraulics Future Research

Future research being considered at the laboratory builds on results of current activity or completed laboratory research.

Pressure Flow Scour for Live Ved Conditions (using a sediment recircultaing flume)

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.

Scour in Cohesive Soils Phase II

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.

EFA Testing

The intent of this study is to evaluate potential enhancements to the Erosion Function Apparatus (EFA) developed by Texas A&M as part of an NCHRP project for estimating bridge scour in cohesive soils. EFA has been the technique used to measure the shear stress, which is used to transfer the soil test results to the bridge pier scour computations. Currently the EFA shear stress is an average computed value that does not account for the fluctuations that are associated with the extreme turbulence that occurs around a bridge pier.

Reevaluation of the Adjustment Factor for Coarse Bed Material Under Live Bed Scour Condition

The adjustment factor for course bed material decreases scour depth for armoring of the scour hole for bed material that have a D50 equal to or larger than 2.0 mm and D95 equal or larger than 20mm. Practitioners have experienced limitations using the equations in HEC 18 to derive the adjustment factor. This study will revisit and improve the methodology suggested in HEC 18.

Ship Collision Forces on Bridge Piers (Vessel Impact Study)

The determination of the impact load on a bridge structure during a ship collision is extremely complex and depends on many factors. The goal is to improve design guidelines and to develop a shock or impulse response spectra methodology to estimate an equivalent static impact load. This study will be a collaboration between the Hydraulic Lab and the Bridge Design and Construction Team under Eric Munley.

Buoyancy Forces on Culverts

Several culvert failures are caused by a situation when the culvert in and outlet is submerged and air bubble gets trapped in the culvert. The resulting buoyancy or uplift forces can be of such a magnitude that the whole culvert system is pushed upwards and fails. We will design a special force balance to measure uplift forces and are planning to develop design guidelines to be applied in the field.