As part of the Miami-Dade Aviation Department’s (MDAD) ongoing infrastructure modernization program, the SkyTrain system at Miami International Airport’s Terminal D undergoes a multi-phase structural rehabilitation to address Alkali-Silica Reaction (ASR) damage in the substructure pier caps. This chemical reaction compromises the performance of concrete over time, affecting the structural integrity of the Skytrain Piers, prompting the need for targeted restoration efforts.

The rehabilitation begins in December 2023, following the discovery of extensive cracking in the supporting pier caps that leads to the partial closure of the SkyTrain. Repairs continue through Summer 2027.

The project focused on mitigating the ASR damage and restoring the durability and performance of the Skytrain’s supporting substructure to ensure long-term operational reliability and public safety.

KLINE was selected as the Structural Engineer of Record for all the phases of the Skytrain restoration program, leading the structural evaluation, design of repairs, and technical oversight for the rehabilitation of piers and girders impacted by ASR. Our team collaborated with Structural Builders & Restorations (SBR) to develop an effective repair method to mitigate the observed ASR problems.

Project Highlights:

KLINE’s work spans across multiple scopes and project phases, with a focus on ensuring safety, extending structural service life, and minimizing operational disruptions. Our team has provided:

• In-Depth Structural Evaluations: 
  Conducted comprehensive condition assessments on the SkyTrain piers and girders, including field investigations, core sampling, and GPR (Ground Penetrating Radar) scans to assess crack propagation, rebar locations, and material integrity. Specific focus areas included Piers 64, 66, 96, 98, and 106, which were performed in 3 different phases.

• ASR-Specific Restoration Design:       
  Developed multi-phase remediation strategies tailored to each damage level, ranging from full-face concrete removal and replacement with added steel reinforcement to lithium nitrate treatment, CFRP strengthening, and epoxy crack injections. Designs were optimized for compatibility with existing materials and APM system requirements.

• Preventive Terminal D Repairs:     
  Surveyed and mapped 66 remaining pier caps in Terminal D for crack evaluation and ASR treatment. Designed waterproofing details, epoxy injection solutions, and expansion joint remediation to ensure structural durability under operating conditions

Project Challenges & Solutions

Repairs take place in highly restricted, active terminal areas with no possibility of temporary shoring. KLINE develops detailed staged repair procedures that allow work to proceed without interrupting airport operations or closing restricted zones.

From jack-blocking for bridge lifts to restoring over 60+ girders and pier caps across North Terminal and Terminal D, KLINE’s technical leadership and collaboration with MDAD and SBR ensure structural longevity and operational continuity with minimal disruption to airport operations.