Data Normalization and User Interface Design for the Nevada Department of Transportation Deep Foundation Load Test Database-Paper

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The paper describes the development of the Nevada Department of Transportation Deep Foundation Load Test Database (NDFLTD), created to support Load and Resistance Factor Design (LRFD) calibration for drilled shafts in the Las Vegas Valley. It combines full-scale load-test results with related boring logs and subsurface soil information, while allowing future data to be added.<br /><br />Built in Microsoft Access, the database has a user-facing interface and a relational back end. Engineers can filter projects by foundation type, diameter, depth, or soil-layer thickness; view boring logs and foundation performance reports; map project locations; and export results to PDF or Excel. Users can also create custom queries and reports.<br /><br />A central design challenge was organizing diverse data without unnecessary duplication. The authors applied database-normalization principles, aiming for the fifth normal form where practical. Most of the database reaches the fourth or fifth normal form, although some tables remain less normalized for ease of updating and reporting. Its structure accommodates projects with multiple shafts or borings, missing location details, and incomplete records, while encouraging more complete future data entry.<br /><br />The database contains 44 projects, with one to four test shafts per project; some project names and locations were withheld at providers’ request. Its data supported calibration of resistance factors for axially loaded drilled shafts, including a design approach for caliche soils and a nested Monte Carlo method that accounts for uncertainty in interpreting material properties.<br /><br />Overall, the NDFLTD provides engineers with an accessible resource for reviewing foundation locations, subsurface conditions, shaft properties, and load-test performance, and supports research and future LRFD work.

Keywords

Nevada Department of Transportation

deep foundation load test database

drilled shafts

LRFD calibration

boring logs

subsurface soil information

Microsoft Access

database normalization

load test results

Monte Carlo method