MTI/MoDOT Transportation Geotechnical Research Program - Task 1

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Sequential Number

Identification Number

Matching Research Agency

Missouri Department of Transportation (MoDOT) and University of Missouri

Principal Investigator

Student Involvement

Project Objective

The general objective of this task is to develop methods and procedures for characterizing design parameters relevant to bridge foundations and earth slopes in a probabilistic manner to allow appropriate consideration of risk in the design process. The focus of these efforts will be to develop the knowledge, procedures, and techniques that will allow MoDOT to perform site characterizations that will produce the lowest cost transportation products possible on a system-wide basis. Specific objectives include:

• quantify “hidden” conservatism or “bias” in measurements of design parameters relevant to foundations and earth slopes based on current MoDOT practices and potential improvements to those practices

• develop methods to establish site specific variability in design parameters for use in LRFD design specifications based on laboratory and field measurements (note recommended LRFD specifications from other tasks will reflect influence of variability and risk)

Project Abstract

This project is one component of a comprehensive research program to develop new and improved LRFD specifications, and associated commentary documents, for design of bridge foundations and earth slopes. This specific portion of the work focuses on completing an extensive lab and field testing program to quantify variability and bias in relevant design parameters (e.g. shear strength and consolidation parameters) as a function of specific boring, sampling, and testing techniques. Results of this work will also lead to recommendations for improved site characterization procedures for MoDOT. Recommended procedures for establishing appropriate values of variability and/or bias in design parameters based on site specific testing will also be developed. Results from this task are crucial to development of improved, MoDOT specific load and resistance factors and to the broader objective of developing design techniques that will reduce costs while maintaining appropriate risk for bridges and earth slopes.

Anticipated Benefits

• These activities are absolutely necessary to develop improved, “MoDOT specific” load and resistance factors for foundations and earth slopes applications.

• This work will provide recommendations for improvements to current site investigation and testing practices that can help achieve cost savings for MoDOT projects.

• This task will also provide the basis and data to establish the value of different site investigation activities in various conditions so that MoDOT can use the most effective means available to characterize future sites.

Milestones

Relationship to other Research/Projects

This project is one component of a comprehensive research program to develop new and improved LRFD specifications for design of bridge foundations and earth slopes. Funding for this program is to be provided by the Missouri Department of Transportation, NUTC, and the University of Missouri – Columbia and Missouri University of Science and Technology. The program includes four broad tasks that, when integrated, will allow MoDOT to realize substantial and continuing cost savings for design of bridges and earth slopes. Task 1 includes activities to improve site characterization practices through a comprehensive laboratory and field investigation to quantify variability and bias in relevant design parameters. Task 2 includes a program of field load testing for bridge foundations and assessment of current and improved methods for design of bridge foundations. Task 3 involves assessment and evaluation of risks for bridge foundations and earth slopes and development of appropriate target risks for bridge foundations and earth slopes. In Task 4, the results of Tasks 1 through 3 will be integrated with analyses to develop new and improved LRFD methods for design of foundations and earth slopes. The principal deliverables from this program will be two new design specifications (one for Bridge Foundations and one for earth slopes), and three commentary documents to accompany the specifications. The commentary documents will detail the results of research produced in Tasks 1 through 3, provide justification for the new specifications, and provide guidance for implementation of the new specifications in MoDOT practice. 

Technology Transfer Activities

Technology transfer for this portion of the research program will be achieved through publication of one or more papers at technical conferences or in refereed journals. 

Transportation Research Board Keywords

bridge foundations, design, embankments, risk management