Bridge & Infrastructure Scanning in Antioch, CA

Antioch owns the deepest structural inventory in east Contra Costa. State Route 160 leaves the city over the San Joaquin River and the Stockton Deep Water Ship Channel on the Antioch Bridge, dedicated as the Senator John A. Nejedly Bridge: a steel plate girder structure completed in 1978, about 9,504 feet long with a 460-foot main span and roughly 135 feet of vertical clearance over the channel, built to replace a lift bridge dating to 1926. Inland, the Highway 4 widening that finished in 2016 rebuilt much of the corridor through the city, widening the Hillcrest Avenue overcrossing, replacing the A Street and Cavallo Road undercrossings and the Roosevelt Lane pedestrian undercrossing, and adding eBART underpasses at A Street and Cavallo Road; a pedestrian bridge over Highway 4 serves the Antioch station at Hillcrest. Beyond the built edge, the reclamation district levees along the Delta margin are engineered structures in their own right.

Scanning suits all three families. On a river crossing, the soffit, girders, bearings, bent caps, and pier shafts are recorded from the deck, the approaches, the shoreline, and a vessel, and clearance is computed as a surface across the full navigable opening referenced to a stated water level rather than quoted from a sign. On highway and transit structures, the same method produces as-builts and clearance without occupying a lane for long. On a levee, the scanner captures crown, slope, and toe as a continuous surface, which is the only honest way to profile an embankment that a rod-and-level survey samples at intervals.

Control is observed before scanning on published NGS and CSRC stations, referenced to NAD83 State Plane and NAVD88, least-squares adjusted with independent checks reported to your engineer. On subsiding Delta-margin ground that reference is the whole point: a dated epoch is what a later scan is differenced against to quantify settlement, scour, or crown loss. See infrastructure scanning, Antioch 3D scanning, and deformation monitoring.