GM2's Complex Bridge staff provided the bridge design as the Engineer of Record for these urban viaducts.  The San Antonio Downtown “Y” (IH-10 and IH-35) is the major artery for traffic moving in and out of downtown San Antonio.  To alleviate the congestion and improve capacity, the Texas State Department of Highways and Public Transportation chose to construct elevated expressways within the present rights-of-way to save on the high cost of rights-of-way acquisition.  

The San Antonio "Y" bridges (downtown I-10 and I-35) exemplify the value of precast segmental bridges for building in restricted urban areas while maintaining traffic. The structures, the first precast segmental concrete elevated interstate in Texas, were built within existing right-of-way over traffic. Three contracts totalling 1.3 million square feet of deck were built at a cost of $65.4 million, saving Texas DOT 11.6% ($8.5M) over the alternate design bid. Completed in 1989.

Expanding the existing urban interstate through San Antonio, Texas from six to twelve lanes without purchasing additional right-of-way was successfully accomplished with these graceful precast concrete segmental viaducts. GM2 designed the first three phases of this project for the Texas DOT. 

More than 4,000 precast segments were manufactured off-site and delivered to the site ready for erection using the span-by-span construction method. Cranes positioned on the end of the previously completed span lifted the delivered segments over the completed span onto temporary steel erection trusses for these 100'+ spans. Building from above allowed traffic on the adjacent interstate, frontage road and local cross roads to be maintained during construction in these key corridors.