B -- GEOPHYSICAL IMAGING METHODS PERTAINING TO HIGHWAY DESIGN

Notice Date

September 7, 2001

Contracting Office

Federal Highway Administration, Central Federal Lands Highway Division (HPA-16), 555 Zang St., Room 259, Lakewood, CO 80228

ZIP Code

80228

Solicitation Number

DTFH68-01Q00343

Response Due

September 24, 2001

Point of Contact

Betty Nelson, 303-716-2016

Description

Study to advance the application of geophysical imaging methods to a variety of problems pertaining to highway design, construction, repair, and maintenance. Recent advances in digital high resolution geophysical imaging technologies can provide cost effective solutions for the non-destructive testing and evaluation of pavements, bridges, drilled shafts, and in subsurface characterization for a variety of applications pertinent to the Federal Highway Administration. The results of this study is intended to be used as guides for engineers and other project managers who are actively involved in assessing highway infrastructure and will be distributed within FHWA. The emphasis for this study is on defining the current state-of-the art in the appropriate geophysical imaging technologies as well as the appropriate selection and application of these technologies. It is expected that one of the results of this investigation will be the identification of promising geophysical imaging methods that will then be implemented on evaluation projects following this initial investigative phase. The criteria for evaluation will be 70 percent technical and 30 percent cost. The report submitted shall cover each of the listed topics which include: 1. Results of the literature review in the form of a bibliography. 2. Introductory Information, including a description of the highway engineering problem and overview of the geophysical techniques which may be utilized. 3. Detailed discussions for each geophysical application, (including discussions of back- ground theory, field equipment, survey design considerations, data processing, interpretation, limitations of the method). 4. A manual organized by type of problem (as listed below). The manual shall be organized in such a way that when faced with a problem the highway engineer can locate the problem and then see which geophysical methods are applicable to the problem and learn something of the strengths, weaknesses and limitations of the various geophysical methods. Links to the appropriate references should allow the engineer to learn more about the method(s) of interest. The investigations performed under this contract shall address but not necessarily be limited to the topics: BRIDGE STRUCTURES: Drilled Shafts: a. Determination of the depth of existing drilled shafts below surface. b. Depth of socketing of shaft into bedrock. c. Imaging defects within drilled shafts during construction. d. Rebar Quality and bonding to with concrete within existing shafts. e. Condition of concrete. f. Extent of Scour around Existing Shafts. Decks: a. Bridge Deck Stability (including vibration monitoring and analysis); b. Bridge Deck evaluations (determine rebar corrosion, concrete condition; c. Rebar condition; d. Concrete condition; e. Concrete integrity studies; f. Detection of incipient concrete spalling; g. Detection of corrosion of rebar; h. Evaluation of presence, pattern and density of rebar in a concrete structure. SUBSURFACE CHARACTERIZATION: a. Determination of rock depth for materials source areas, b. Locating shallow sand and gravel deposits, c. Mapping lithology, d. Depth to bedrock for foundations, e. Mapping bedrock topography, f. Mapping bedrock structure, g. Identifying potential weak zone in bedrock, h. Mapping fractures, i. Identification of roadbed underlain by expanding clays (determine clay content in swelling soils), j. Estimating clay mineral content, k. Detection and mapping of voids, abandoned mines and other cavities, l. Engineering properties of subsurface materials: Bulk, Young's and shear modulus, Porosity, permeability and saturation, m. Density, Determining Rippability of Rock, n. Detection and location of buried utilities, o. Location of underground storage tanks, p. Mapping groundwater surface, q. Mapping groundwater flow, r. Mapping contaminant plumes, s. UXO detection. PAVEMENTS: a. Map existing pavement thickness; b. Determine extent of bottom up cracking; c. Map depth of concrete over rebar mats; d. Map structural changes in roads over time; e. QA thickness of new pavements; f. Identify rock pockets within concrete; g. Detecting voids in or beneath pavements; h. Measurement and evaluation of vibrations caused by traffic and construction activity; i. Evaluation of condition and engineering properties of subgrade; j. Determine and map Pavement integrity; k. Mapping of thickness and extent of base course and subgrade materials; l. Variation of moisture conditions in the subgrade; m. Determine areas of segregation in HMA. OTHER APPLICATIONS: a. Monitor Vibrations due to traffic, b. Monitor Vibrations due to blasting, c. Monitor Vibrations for other construction activities, d. Provide recommendations on allowable, save and acceptable vibration levels. REFERENCES: a. Bibliography (online and offline sources). b. Suggested readings for each problem area and geophysical method to apply (online and offline sources).

Record

Loren Data Corp. 20010911/BSOL003.HTM (W-250 SN50X182)