blank space

South Dakota Department of Transportation
Project Synopsis
SD1998-04


Title: Estimation of Ice Thickness and Strength for Determination of Lateral Ice Loads on Bridge Substructures in South Dakota
Project Researcher: USGS, USGS
Project Manager: Daris Ormesher
Research Period: 10/1/1998 - 9/30/1999
Status:
Cost: $75,000.00

Problem Statement: Estimating lateral ice loads on bridge piers is difficult. Bridge substructures experience complex and variable loads caused by ice movements due to water currents, wind, and expansion forces. Structural analysis usually assumes that the maximum load exerted on piers is limited by the crushing strength of ice and the ice depth. Maximum values of ice thickness and strength that could be expected for various geographical areas or water sheds in South Dakota are not known with any certainty. AASHTO design values for the crushing strength of ice range from 100 to 400 psi, resulting in a tremendous variation in substructure design. The Department presently estimates ice thickness and strength for use in the AASHTO Design Method. For major rivers and reservoirs the department uses a one (1) foot thickness with a strength of 100 psi is assumed. For minor streams a more simplified method is used.

The research is to acquire field data on ice thickness and strength by correlating select physical properties of ice to weather, geographic area, and other field conditions to develop an improved method to estimate ice thickness and strength.



Findings:

Research Objectives:
1  To identify a model that will predict ice thickness in South Dakota.
2  To develop a database that will aid in the prediction of ice thickness in South Dakota.
3  To predict maximum ice thickness and strength properties on major rivers and reservoirs in South Dakota in order to minimize risk and uncertainty in the design of bridge substructures.

Research Tasks:
1  Meet with the project’s technical panel to review the project scope and work plan.
2  Review and summarize literature pertinent to prediction of ice thickness and strength for design of bridge substructures. Review existing databases on weather or hydrological information that are relevant to the project.
3  Identify the magnitude of uncertainty in costs and safety from using various ice thickness and strength parameter combinations for design of bridge substructures.
4  Construct a database with all required parameters necessary for the ice thickness prediction model.
5  Identify three representative sites on the Missouri River and three representative sites on the James River in South Dakota for field data collection. Sites will be approved by the Technical Panel.
6  Identify sampling frequency and necessary data to be collected at each site to predict ice thickness.
7  Submit a Technical Memorandum by June 30, 1999 and meet with the technical panel by July 31 to review completed tasks and field data collection work plan.
8  Purchase and install instrumentation necessary to collect data identified in task 6.
9  Collect data necessary for the prediction of ice thickness.
10  Collect ice and water samples to determine strength properties of ice at the sampling sites.
11  Use collected data to determine the validity of existing models for the prediction of ice thickness.
12  Recommend a model to determine maximum ice thickness and a mechanism to determine strength design values for specific sites including the methodology to update these values for the design of bridge substructures.
13  Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, and recommendations.
14  Make an executive presentation to the SDDOT Research Review Board at conclusion of the project.

Documents Available:
SD1998_04_Final_Report.pdf

blank space