C+S August 2023 Vol. 9 Issue 8 (web)

Tech & Software

Expanding Roads without Major Land Purchases As traffic in San Antonio continued to grow, the city needed to expand its road system. In particular, the section of Interstate 35 between Loop 410 and Loop 1604 needed extra capacity. As well as adding three lanes in each direction for 21.8 miles, the project required the development of new interchanges at each loop, full pavement reconstruction of loop 1604, and partial replacement of existing barriers and sidewalks. The Texas Department of Transportation awarded the project to Ferrovial Construction through its subsidiary Alamo NEX Construction. However, since the project is in a dense urban area, the TxDOT was unable to make major land purchases to expand the highway in a traditional manner. As a result, the highway had to be constructed within an elevated viaduct to avoid disruption to the many adjacent buildings. Alamo NEX had to determine the optimal method for designing the needed number of lanes within a tight space. Ferrovial and Alamo NEX Create a 3D Digital Twin to Build a Viaduct Road in a Tight Urban Area Bentley Applications Improved Collaboration among Teams and Resolved Thousands of Clashes during Design By Amy Heffner

Credit: Architect D2 Group

Reaching the Limits of 2D Design As Alamo NEX planned how to accommodate the viaduct, the potential design grew increasingly complex. They needed to determine how to place the substructure of bridges between the existing mainlines and frontage road. This was no easy feat as the footprint had to be minimized, and the frontage road would have to be moved to create room for the foundation. The new viaducts would overhang existing roads, requiring traffic to be moved away due to safety requirements. Even with the viaduct design, Alamo NEX had to reuse as much of the existing infrastructure as possible. As a result, they needed to determine how to connect the new elements to existing assets. Since the company also faced a challenging supply chain, the team wanted to eliminate the most expensive elements that would normally go into a road project, such as steel spans. Alamo NEX previously designed road projects using traditional 2D methods, though this technique typically resulted in conflicts during construction that resulted in costly redesigns and a considerable loss of productivity. “More often than not, we will find a substantial amount of conflicts in the field that need a significant effort by our company,” said Carlos Gonzalez, vice president, engineering services, design operations lead North America with Ferrovial Construction. The organization needed a more efficient way to design the project to meet its strict requirements.

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AUGUST 2023

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