Multi-Span Lateral Slide Laboratory Investigation – Phase 2

Project Information 
Link to the latest:  March 2023 Progress Report


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 of 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.


This project will involve laboratory testing of closure pour connections. The variables that will be addressed by lab testing are driven based upon field findings from a recently completed multi-span lateral slide project in Iowa.


The objectives of this project will be achieved via these three tasks:

  1. Summary of Phase I findings
  2. Laboratory Testing
  3. Summary and Recommendations
  • Task 1 – Summary of Phase 1 Findings
    • The work from Phase 1 of this project will be summarized, with the intent of presenting the aspects that will be of interest for the laboratory testing involved in this proposed phase 2 work. This summary will also include recommendations from the project’s advisory panel, prioritizing these elements for future study.
  • Task 2 – Laboratory Testing
    • A particular focus will be given to determining the relationship between early-age UHPC strength and lap splice strength development timing for UHPC closure pour applications, based upon input from the Iowa DOT. This is especially critical for ABC projects as determining when sufficient development/strength has occurred greatly impacts closure and construction period lengths. In other words, this aspect of the project will investigate the development of noncontact lap splice strength over time. The goal of this aspect will be to determine when a noncontact lap slice has sufficient strength to either open a bridge or to expose it to additional construction loadings.
    • A series of noncontact lap splice specimens will be constructed in the laboratory and tested for strength at varying periods of time ranging from hours to days after placement of the UHPC.
  • Task 3 – Summary and Recommendations
    • The data from Task 2 will be analyzed and summarized via graphs, tables and other data comparison efforts. Based upon those findings, recommendations will be made with respect to the variables that were analyzed in the finalized laboratory testing plan.

Research Team:

Principal Investigator: Justin Dahlberg
Co-Principal Investigator: Zhengyu Liu


Previous Progress Reports: