The San Joaquin River Viaduct is a bridge currently under construction to carry California High-Speed Rail over the San Joaquin River. Most of the bridge is in the city of Fresno, California in Fresno County, although the portion north of the river will be in Madera County. It is the second major river crossing to be constructed as part of California High-Speed Rail, after the Fresno River Viaduct to the north.
The bridge will be 4,740 feet (1,440 m) long, and combines a double concrete arch span crossing the river with a pergola structure to carry the tracks laterally over the Union Pacific Railroad tracks. It will also cross Herndon Avenue and Golden State Boulevard. The river crossing is immediately upstream of the Union Pacific Railroad and California State Route 99 crossings of the San Joaquin River.
In 2012, the City of Fresno recommended building a through arch bridge with return arches to transition gracefully to the flanking box girder bridge segments, due to its visual appeal as a signature element along the northern approach to Fresno. However, conceptual drawings in 2016 showed a different arch structure lacking the return arch transitions.
The bridge is part of Construction Package 1, the contract for which was awarded in August 2013. Preliminary statnamic load testing on the riverbed occurred in February 2015 to test the stability of the bridge foundation in an earthquake. Construction began in April 2016, and was expected to take 2–3 years to complete.
As of February 2019, crews were installing metal decking over the river, concrete superstructure elements were being poured to the south of the river, and deck drainage was being installed on the completed sections.