Page - 98 - in Book of Full Papers - Symposium Hydro Engineering

Unformed RCC 4:1 Slopes: The preponderance of the FCO Spillway chute where RCC is placed as the foundation replacement material will have a spillway chute slope of 4:1. The placement of the final enriched layer of RCC on a 4:1 slope is an innovative method for this project as there are no known occurrences of RCC placement on 4:1 slopes anywhere in the World at the time this spillway design concept was developed. For the base RCC foundation replacement structure, the design intent included placement of RCC in horizontal lifts with a free-form 4:1 slope in the main chute area (see Fig. 8). As previously discussed, the FCO Spillway chute design included a final 30 cm (12-inch) thick lift of enriched RCC in the main chute placed on the 4:1 slope. A full-scale test program that included placing and compacting RCC on a 4:1 slope was successfully completed as shown in Fig. 9. This trial placement test was critical for confirming the placement procedures using heavy equipment on the steep slope as well as: confirming the placement method (efforts to get a smooth completed surface), the compaction process (number of passes to get required density), and RCC testing. The completed test fill was used to further test different concrete hardening compounds for possible use to further increase the durability of the exposed RCC material during the 2017-2018 Winter Flood Season. Based on the performance of the hardening materials during the trial placement, it was decided to apply the hardener only in the area immediately downstream of the aeration ramp on the completed chute. Figure 8- Free Form Construction of 4:1 Slope of RCC Figure 9 - Test Fill #2 for 4:1 Slope Placement 98