2008 – Inelastic seismic analysis of Dartmouth Intake Tower

Francisco Lopez, John Bosler

Abstract: A study has been undertaken to determine the structural adequacy of the Intake Tower for the Dartmouth Dam Low Level Outlet Works under the Maximum Design Earthquake (MDE). The tower is a reinforced concrete frame structure. The study included the definition of appropriate seismic inputs and nonlinear time-history analyses for different levels of ground shaking.

The behaviour of the tower was assessed in terms of material strains. The seismic acceleration-time history was applied to the model and the nonlinear analysis identified the locations in the structure which reached the following performance thresholds: cracking of core concrete, yielding of reinforcing steel, fracture of reinforcing steel and crushing of core concrete.

The results of the study showed that the tower was able to resist, without collapse, the loadings imposed by three different MDE acceleration time-histories. The predicted level of damage consisted of generalised yielding of reinforcement, formation of numerous plastic hinges at different locations in the tower and generalised spalling of cover concrete.

Overall, the structural response of the tower under the MDE events was considered satisfactory and met the performance requirement that structural collapse should not occur.

Keywords: intake tower, nonlinear, inelastic, time-history, seismic analysis.

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