Big Creek Dams 5 and 6 – Anchor Testing

Big Creek Dams 5 and 6 impound water along Big Creek near Big Creek, California and were constructed in 1921 and 1923, respectively. New increases to minimum instream flows (MIF) require increasing the diameter of existing MIF conduits through the dams. The dam owner contracted a consultant to design the larger MIF conduits and associated downstream valves along with various other accompanying improvements as needed to operate and maintain the system. Design of the new MIF conduits and accompanying improvements requires validation of in-situ concrete strength and the bonding capacity of proposed new anchors to the existing dam concrete as the proposed improvements entail coring a new MIF conduit through each dam and attaching a new valve platform to the existing dam surface at each dam. The dam owner contracted BDI to perform concrete material testing and anchor testing per guidelines provided by the designer of the new MIF improvements. The anchor tension testing portion of our scope of work included:

• Anchor Testing: Adhesive and grouted anchors were installed and tested to a specified tensile load at various locations near the planned improvement areas on the downstream surface of each dam.

This project required a diverse set of certifications and expertise, including SPRAT rope access certification, specialized training and custom BDI-designed equipment for anchor testing, and experience completing testing in the unique and challenging environmental conditions typical at dams. BDI’s team used rope techniques to access testing areas at the downstream surface of each dam. Adhesive and grouted anchors were successfully installed and tested to the specified tensile load at all planned test locations, and anchor tension testing results were provided via a technical report for each dam.