This $1.7 billion, 17.3 km mass transit system aims to alleviate the traffic congestion in San Juan, the most densely populated city in Puerto Rico. It includes both underground and elevated rail sections and multiple stations. Tunneling was performed below the water table near the ocean in a Zone IV seismic area. Some of the major challenges involved the casting of massive concrete sections underground as well as the design of precast tunnel sections with special concrete mixtures, all of which were attained with innovative use of admixtures and supplementary cementitious materials as well as optimized concrete production. CA provided consulting services regarding the conformance with specifications, mixture proportions, concrete production, placement of concrete, curing techniques, concrete durability, quality control, and quality assurance during construction. In addition, the strengthening of the columns supporting the elevated sections of the rail to meet seismic Category IV design criteria in portions of the structure already built posed a major challenge, that we addressed with novel and innovative methodologies.

Rapid Urban Train System