Blueprint: Bridge-Scour Witness Instrument — Build Specification

Build specification for a low-cost bridge-scour witness instrument: a vertical chain of 16 tilt nodes at 0.20 m spacing against a bridge pier, read by a logger every 5.0 minutes under a three-consecutive-exceedance rule, with sacrificial links on the lowest section. DESIGN BLUEPRINT - SIMULATED, NOT MEASURED - NOT BUILT, NOT LOAD-TESTED. All performance numbers are from the source paper: 3.2 m depth range with 0.20 m uncertainty, 15-minute detection latency, detection probability 0.892 within one hour and 0.9999996 within six hours, model false-alarm rate 0.0110 per chain per year, computed battery life 9.32 years with service capped at 5.0 years, parts cost USD 191.40. Note: this design also exists as an identical published record, DOI 10.5281/zenodo.24108425; this blueprint is built once, citing 10.5281/zenodo.24108427 as its source.