Attachment 002 Table of Borings.pdf

This document is a Table of Borings specification for a geotechnical investigation supporting the Winchester Creek Bridge Replacement project in Oregon (FLAP Douglas 251(2)) scheduled for 2026. The investigation requires two bridge foundation borings (BH26-01 and BH26-02) at specified GPS coordinates near Winchester Creek. BH26-01 requires 30 feet of auger drilling and 80 feet of HQ core drilling to a maximum depth of 130 feet, with 30 Standard Penetration Tests (SPTs) and 2 Shelby samples, while performing suspension logging for seismic design. BH26-02 requires 30 feet of auger drilling and 20 feet of HQ core drilling to a maximum depth of 50 feet, with 14 SPTs and 2 Shelby samples. Both borings require truck-mounted rigs with traffic control and rolling closures, pavement patching, and utility avoidance measures.

The combined project totals 60 feet of auger drilling, 100 feet of HQ core drilling, 44 SPTs, and 4 Shelby samples across both locations. Critical specifications include HQ3 coring for all rock intervals, SPT sampling at 2.5-foot intervals (2.5, 5, 7.5, and 10 feet), and field verification of GPS coordinates due to their approximate nature. The document notes that all boring locations are subject to change based on proposed alignment alterations, with permitted relocations up to 50 feet from current positions.