Link to Report: Coming Soon
Background :
Bridge deck expansion joints are among the most maintenance-intensive components of highway bridges, often leading to premature deterioration, increased repair costs, and reduced service life. Link slabs provide an effective alternative by enabling jointless deck configurations, improving durability, and reducing long-term maintenance demands. Despite their proven benefits, inconsistencies in design methodologies particularly regarding the need for deck debonding and the use of advanced materials such as Ultra-High-Performance Concrete (UHPC) have limited their broader adoption in Accelerated Bridge Construction (ABC) applications. Early studies recommended partial debonding near girder ends, while more recent large-scale investigations, such as SHRP2 R19A, concluded that debonding may not be required. At the same time, UHPC-based link slabs have demonstrated excellent crack control and durability, yet remain without standardized design guidance. This project aims to synthesize existing research, field applications, state DOT practices, and emerging material innovations to establish practical best practices for link slab design. To this end, the current study will (1) compile and evaluate past research and implementations, (2) compare conventional and UHPC-based link slab approaches, (3) conduct analytical and limited experimental verification to resolve conflicting recommendations, and (4) develop design provisions and example details suitable for ABC applications. The proposed work will produce a comprehensive synthesis report, validated guidance, and actionable recommendations for DOTs and practitioners. By clarifying design assumptions, addressing uncertainties in debonding requirements, and evaluating the role of UHPC, this study will promote the consistent and reliable use of link slabs in jointless bridge decks.
Objectives :
The objectives of this project are to:
- Synthesize existing research, field applications, and DOT practices related to link slabs for jointless bridge decks.
- Compare and evaluate alternative approaches, including conventional concrete, SHRP2 recommendations, and UHPC-based link slabs.
- Identify best practices and performance trends through analytical and experimental verification.
- Develop practical design guidance, including provisions, example details, and recommendations for ABC implementation.
This research will provide state DOTs and practitioners with clear, reliable information to design and construct durable link slabs, reducing uncertainty and promoting wider adoption in Accelerated Bridge Construction.
Scope :
Task 1 – Literature Review and Data Collection
This task will compile and review published research, SHRP2 findings, and state DOT reports related to link slabs. In addition, field performance data from implemented projects, including both conventional and UHPC link slabs, will be collected to establish a comprehensive knowledge base.
Task 2 – Synthesis of Practices
In this task, existing practices will be synthesized by comparing design philosophies such as debonded versus non-debonded slabs. Detailing approaches, material use, and construction practices adopted by agencies will be documented, and performance trends, advantages, and shortcomings will be identified.
Task 3 – Analytical and Experimental Verification
This task will involve analytical modeling to evaluate stress distribution, crack control, and serviceability of various link slab designs. Targeted verification, either numerical or experimental, will be conducted where critical gaps are identified, with particular emphasis on debonding requirements and UHPC applications.
Task 4 – Development of Best Practices and Design Guidance
Based on the findings from the earlier tasks, best practices will be established and practical design provisions will be developed. This task will also propose example details and guidance documents suitable for DOT adoption to promote consistent and reliable use of link slabs.
Task 5 – Technology Transfer and Final Deliverables
The final task will focus on technology transfer through the preparation of a comprehensive final report, technical briefs, design tables, and example plans for practitioners. The results will be disseminated through IBT/ABC-UTC webinars, workshops, and outreach efforts to state DOTs and other stakeholders.
Research Team :
Principal Investigator: Arslan Khan, Ph.D.
Co-Principal Investigator: Mahyar Ramezani, Ph.D.