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ALAMO NEX Construction, a Ferrovial company, successfully implemented an innovative design solution in the I35NEX Central project to avoid the full reconstruction of a deteriorated double 10’x7’ culvert located 45 feet beneath LP1604, a heavily congested highway in San Antonio, Texas. Instead of excavating from above, the team installed an aluminized steel arch pipe within the existing culvert, significantly reducing safety risks, and construction time.

This alternative solution, developed through close collaboration between the Design, Construction, and Health & Safety teams, aligns with Ferrovial’s “Hierarchy of Control” policy by eliminating hazards at the engineering stage. By avoiding large-scale excavation, the project minimized worker exposure to traffic, reduced heavy machinery use, and cut truck movements, improving overall site safety. Additionally, the approach shortened the timeline approximately by eight months improving greatly the construction schedule.

To maintain hydraulic efficiency, two additional 60” pipes were installed via jack and bore operations. The aluminized steel pipe’s lightweight design —less than 10% of reinforced concrete— allowed for quicker installation while ensuring a 75-year service life. The project’s structural and hydraulic analysis was groundbreaking, as there are very few examples at such a scale in Texas.

Completed in just five months (October 2023 – February 2024), with two additional months for final connections and headwalls, the project prevented major disruptions to ongoing highway improvements. Opting for full excavation would have required over 100,000 square feet of temporary walls in unstable fill, some nearly 50 feet high, significantly increasing risks and delays.

By prioritizing innovation, collaboration, and safety, ALAMO NEX Construction delivered a high-quality, time-effective, and safer solution for TxDOT, setting a new standard for culvert rehabilitation in Texas.