Effect of attached outlets on the dynamic response of arch dams

Abstract

Attached outlets are integral components of arch dams to discharge flood. However, they are usually neglected in the current seismic analysis of arch dams for simplicity. This paper aims to analyze the effect of attached outlets on the nonlinear seismic response of arch dams. For this purpose, a 235 m high arch dam is analyzed as a case study. The results indicate that the effect of attached outlets on the seismic response of arch dams depends on the ground motion intensity. For the ground motions with a low peak ground acceleration (PGA), the effect of attached outlets on the concrete damage is slight and local, which is consistent with the existing perception. However, as the ground motion intensity increases, their effect extends to the entire dam body. In contrast, the influence of attached outlets on the joint opening is typically observed at the middle contraction joints. Furthermore, the model analysis demonstrates that the inertia effect of attached structures is the primary contribution to these phenomena. Finally, a simplified simulation approach is used for incorporating the influence of attached outlets by coalescing the mass to the dam surface.