NCHRP - Scour Technology - Research
- Project 24-14: Scour at Contracted Bridges
Description: TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 83: Scour at Contracted Bridges describes and quantifies the influence of processes affecting scour magnitude in contracted openings and examines physical- and numerical-model studies. The report also includes interim guidance for applying scour-prediction methodology at contracted bridge sites for a wide range of common field situations and suggests future research designed to advance scour prediction methodology.
Status: Recently completed.
- Project 24-15(2): Abutment Scour in Cohesive Soils
Objective: The objective of this research is to develop a methodology for the prediction of abutment scour in cohesive soils consistent with the methodology developed for pier and contraction scour prediction developed under NCHRP Project 24-15.
Status: Research on this project continues. The listed project completion date is June 24, 2007.
- Project 24-20: Prediction of Scour at Bridge Abutments
Objective: The objective of this research is to develop more accurate and comprehensive methodologies for predicting abutment scour in cohesionless soils in compound channels (i.e., channels consisting of both floodplain and main channel sections). Parameters for extrapolating the methodology to predicting abutment scour in other than cohesionless materials will also be developed.
Status: Research, including laboratory experiments, for this project continues. The listed project completion date is April 30, 2007.
- Project 24-26: Effects of Debris on Bridge-Pier Scour
Objectives: The objectives of this research are to develop (a) guidelines for predicting the size and geometry of debris accumulations at bridge piers and (b) methods for quantifying scour at bridge piers resulting from debris accumulations.
Status: Research is currently underway to examine scour patterns resulting from typical debris configurations at bridge piers. The listed project completion date is December 17, 2007.
- Project 24-27: Evaluation of Bridge-Scour Research
Objectives: The objectives of this research are to: (a) critically evaluate bridge-scour research results completed since 1990, (b) make recommendations for adoption of specific research results into AASHTO policies and procedures, (c) recommend research needed to fill gaps where research results are not yet conclusive enough for adoption by AASHTO and wide-scale use by practitioners, and (d) draft the bridge-scour sections of the AASHTO manuals, "Policy for Design of Highway Drainage Facilities" and "Recommended Procedures for Design of Highway Drainage Facilities."
Countermeasure Selection and Design
- Project 24-07(2): COuntermeasures to Protect Bridge Piers from Scour
Objective: The objective of this research is to develop and recommend practical selection criteria for bridge-pier scour countermeasures, guidelines and specifications for design and construction, and guidelines for inspection, maintenance, and performance evaluation. The countermeasures to be considered include riprap, partially grouted riprap, cable-tied blocks, gabions, grout-filled bags and mats, and geotextile sand containers (used as a stand-alone countermeasure or as a filter).
Status: The preliminary draft final report is scheduled for submission in March 2006. The listed project completion date is September 30, 2006.
- Project 24-18 and 24-18A: Countermeasures to Protect Bridge Abutments from Scour
Objective: The objective of this research is to develop and validate selection criteria and guidelines for the design and construction of countermeasures to protect bridge abutments and approach embankments from scour damage. The countermeasures considered shall include but not be limited to: (1) riprap at abutments; (2) flow-altering devices such as guide banks, dikes, spurs, bendway weirs and other in-channel devices; and (3) nontraditional abutment scour countermeasures such as articulated or tied mats and blocks. Design criteria will include size, placement, and feasibility of using these devices.
Status: Research to develop selection criteria and guidelines for the application of each countermeasure continues. The listed project completion date is June 30, 2006.
- Project 24-23: Riprap Design Criteria, Specifications, and Quality Control
Objective: The objective of this research is to develop design guidelines, material specifications and test methods, construction specifications, and construction inspection and quality control guidelines for riprap at streams and riverbanks, bridge piers, bridge abutments, guidebanks, and other locations requiring scour countermeasures.
Status: Research is currently underway. The listed project completion date is September 30, 2006.