Multi-Span Lateral Slide Laboratory Investigation: Phase 1

Background:

Lateral slide-in bridge construction (sometimes referred to as slide-in bridge construction) has gained increasing attention as a viable Accelerated Bridge Construction (ABC) approach.  With lateral slide construction, the majority of the bridge superstructure is constructed off alignment, typically parallel to the final position, and usually on a system of temporary works.  The construction of this portion of the bridge is often completed while the original bridge is still open to traffic.  In some instances, portions of the substructure are also constructed while the original bridge is still open to traffic – a technique designed to further reduce traffic impacts.  Common techniques for accomplishing this include building substructure elements outside of the original bridge footprint as well as using innovative techniques to complete construction under the bridge with consideration of clearance limitations, stability of the underlying soil, and others.  Once the construction of the superstructure is essentially complete, the original bridge is demolished and new substructure construction is completed.  Then, usually over a relatively short period time (hours to a day commonly), the new bridge superstructure is slid laterally from the temporary worksite onto the in-place substructure.

While many DOTs have completed lateral slide construction of single span bridges and have common connection details already established, these details do not directly apply to multi-span slides. The addition of more spans creates a more complex system that will require connections (and other details) that were previously not needed in a single span slide.  Further, the fact that the multi-span bridge will need to slide on abutments plus piers (as opposed to just abutments in a single span case) creates possible uplift and overturning scenarios.

Objective:

The main objective of this project is to analyze the behavior of bridge elements during multi-span lateral slide efforts to ensure proper performance and expected behavior. This objective will be achieved via instrumented laboratory testing.

Scope:

The following tasks will be performed to achieve the project objective:

  • Task 1 – Literature Review
    • For Task 1 of this project, the research team will compile all related information available in journals, conference proceedings, technical reports, and online resources in a concise and comprehensive summary. Note that match funds for this project are coming from an existing Iowa DOT project, so some of this work will be completed in conjunction with that project.
  • Task 2 – Establish Testing Plan
    • Following the presentation of information collected in Task 1, the research team will be prepared to determine the need for additional work and recommend the most appropriate additional investigations. Although it is too early to make predictions as to the need for additional work, it is the team’s opinion that additional work could be in the form of either analytical and/or experimental evaluations.  In either case, it is possible that the additional work could consist of full scale evaluations or the evaluations of individual connections on small scale components.
    • Based on the findings from Task 1, knowledge gaps with respect to the construction of a multi-span lateral slide bridge will be identified. These areas which would benefit from further investigation will be addressed via proposed laboratory testing. This task will result in multiple suggested laboratory testing plans that will be proposed for further work in Phase 2 of the project.
  • Task 3 – Summary and Recommendations for Phase 2
    • The efforts associated with Tasks 1 and 2 will be summarized and areas for future work will be identified. This will mainly consist of proposed laboratory testing that would be beneficial for agencies looking to proceed with a multi-span lateral bridge slide.

Research Team:

Principal Investigator:  Dr. Katelyn Freeseman
Co-Principal Investigators: Dr. Brent Phares, Justin Dahlberg
Research Assistant:  Cody Gastel