Link To Latest Report : Coming Soon.
Background :
Culvert networks are a major component of U.S. infrastructure but are facing significant challenges due to aging, deterioration, and increased traffic demands. Many culverts were installed during the 1950s and 1960s and are now reaching the end of their service life. Over time, corrosion and wear damage the culverts, which weakens their structure and safety. As deterioration progresses, erosion can also weaken the soil around the culvert,, leading to potentially catastrophic events, such as sinkholes. Culvert failure can lead to serious environmental problems and cause road closures, resulting in major delays, inconveniences, and high costs of repair . Addressing these challenges is critical to maintaining infrastructure integrity and minimizing disruptions.
In this context, UHPC shotcrete emerges as a potential solution for the rehabilitation, repair, and retrofit of steel culverts . It has been successfully used to repair concrete elements such as beams and pipes, demonstrating its ability to enhance durability and strengthen the structural integrity of repaired components . In terms of steel structures, UHPC exhibits minimal carbonation development, extremely high resistance to chloride penetration and negligible corrosion rate , suggesting that UHPC shotcrete could serve as a protective layer, providing effective corrosion protection.
In the proposed research, UHPC will be sprayed onto the inner surface of steel culverts, creating a durable lining for repair and upgrade. This UHPC shotcrete lining is expected to enhance both tensile and compressive strength, thereby increasing the traffic load capacity of the culvert. Furthermore, demonstrating the long-term durability of the UHPC lining will establish it as a cost-effective and innovative method for halting deterioration and enabling structural rehabilitation of steel culverts.
Objectives :
The objectives of this research are to demonstrate:
- Development of optimized UHPC shotcrete mixtures for repair and upgrade of steel culverts.
- Mechanical and durability properties of UHPC shotcrete.
- Behavior of steel culverts with UHPC shotcrete layer through finite element modeling (FEM).
- Performance of full-scale steel culvert repair and upgrade with UHPC shotcrete.
- Development of practical guidelines for repair and upgrade of steel culverts with UHPC shotcrete.
Scope :
Task 1 – Literature Review.
This task involves conducting a comprehensive review of existing literature on steel culvert rehabilitation and UHPC shotcrete applications. The review will cover case studies, current practices, and standards to establish a solid foundation for the project.
Task 2 – Mix Design and Testing.
This task involves developing and testing UHPC shotcrete mixtures with varying compositions and properties. The variations will focus on optimizing strength, workability, and adhesion for spray applications.
Task 3 – UHPC Mechanical and Durability Testing.
This task involves conducting mechanical and durability tests on UHPC shotcrete samples. Tests will include compressive strength, freeze-thaw resistance, and chemical attack resistance to evaluate long-term performance in steel culverts.
Task 4 – FEM Analysis.
This task involves creating finite element models to simulate the behavior of steel culverts with a UHPC shotcrete layer. The analysis will consider varying shotcrete thickness, traffic loads, soil-structure interaction, and the mechanical properties from Task 3.
Task 5 – Steel Culvert with Sprayed UHPC Layer Testing.
This task involves conducting full-scale mechanical and durability tests on steel culvert samples. The tests will compare sprayed and unsprayed samples in terms of strength and environmental resistance, and the results will help refine the FEM model.
Task 6 – Guideines Developement.
This final task involves a full assessment of the findings, data, and analyses from the previous tasks into a comprehensive final report. The report will include procedural guidelines for the rehabilitation, repair, retrofit, and maintenance of steel culverts using UHPC shotcrete. Additionally, it will include rating guidelines for repaired or upgraded steel culverts. The guidelines will be based on both experimental and theoretical analysis.
Research Team :
Principal Investigator : Atorod Azizinamini, Ph.D., P.E.