Bridge & Infrastructure Scanning in El Cerrito, CA

The dominant structure in El Cerrito is not a bridge over a river but two and a half miles of aerial guideway. The BART Richmond line runs elevated the length of the city, with both El Cerrito Plaza and El Cerrito del Norte built as aerial side-platform stations, and the Ohlone Greenway runs 2.7 miles directly beneath it from the south city limit to the north, where the tracks cross over San Pablo Avenue near Baxter Creek Gateway Park. That guideway is a continuous inventory of columns, bent caps, precast girders, bearings, and expansion joints sitting over a public path, a street grid, and station platforms. Around it, San Pablo Avenue is State Route 123, Interstate 80 runs along the western edge with its interchanges, and Cerrito Creek and Baxter Creek pass under the grid in culverts and crossings, some daylighted after culvert failure and some still buried, all of which the city maintains.

Aerial structure is awkward to survey and straightforward to scan. Setups on the greenway, the street, and the platforms capture the underside of the guideway, the column and bent geometry, the girder soffits, bearing seats, and joint openings without anyone working at height or on the trackway, and the same data yields clearance beneath the structure across the full width of whatever passes under it. Control is observed with GNSS and total station, adjusted by least squares with independent checks on NAD83 State Plane and NAVD88, so the cloud carries coordinates a transit or public works reviewer can act on and a later scan can be compared against. Where seismic retrofit, joint replacement, station modification, or adjacent construction is planned, a baseline epoch differenced against a later one measures deflection and settlement across whole surfaces instead of at a few points.

Deliverables are registered E57 or RCP clouds, clearance envelopes, DWG or DXF sections, elevations, and framing plans, surface models of decks, soffits, and channel inverts, and epoch comparison exhibits. City-owned bridges and culverts advancing through the federal Highway Bridge Program and Caltrans Local Assistance carry documentation expectations we scope to. See infrastructure scanning, El Cerrito 3D scanning, and deformation monitoring.