The recent spillway chute incidents during spill events in a sudden manner such as at Oroville Dam in 2017 (France, J.W., et al, 2018), and at Toddbrook Dam in 2019 (Balmforth, 2020) highlight the need for spillway chutes that are reliable, resilient and robust. Consequently, structural failure mechanisms for spillway chutes need to be understood and addressed. The main failure mechanisms for concrete spillway chutes can be classified into four broad categories (Daly & Pavlov, 2022):
• Structural failure due to excessive uplift • Structural failure due to loss of support and undermining • Structural failure due to excessive or unaccounted dynamic actions • Structural failure due to concrete deterioration, cracking or corrosion of reinforcement
Past spillway chute failures indicate that the first two structural failure mechanisms account for the majority of chute failures for that portion of the chute above maximum tailwater (USBR and USACE, 2019) (ICOLD, 2024). Design of spillway chutes and energy dissipaters below maximum tailwater must also address structure floatation due to submergence and hydrodynamic failure mechanisms. This new concept for concrete spillway chutes was developed for use above maximum tailwater but could be considered for those portions of the spillway chute below maximum tailwater.
Learning Objectives:
Describes a new design approach for concrete spillway chutes to address hydraulic potential failure modes caused by infiltration, stagnation pressure and cavitation.
Describes a new construction approach for concrete spillway chutes to address hydraulic potential failure modes reducing the cost and time to construct versus conventional methods.
Learn why current design and construction approaches for concrete spillway chutes require significant attention to detail when initially constructed, are subject to deterioration over time, and require maintenance/repair.
