Tsunami Nonlinear Analysis

ASCE 7-16 has established a framework for assessing the capacity of structures against Tsunami Loading allowing the use of performance-based criteria and nonlinear methods. A series of papers including the work by Petrone et al. [2017] and Baiguera et al. [2019] have presented a methodology including nonlinear analysis for the tsunami assessment of buildings following the ASCE 7-16 provisions which is implemented in Seismostruct.

For the performance of the analysis pre-defined time-histories of the inundation depth and velocity are used in order to calculate the Total Tsunami Force applied on the building at each time-history step. The time histories to be used can be the ones provided by ASCE 7-16 or different ones available within Seismostruct. The Total Tsunami Force at each step can be calculated using the relationships provided within ASCE 7-16 or in the work by Petrone et al. [2017] and Foster et al. [2017]. Nonlinear Tsunami Analysis can be performed in two phases:

The first phase includes the Variable Depth Pushover (VDPO) Analysis, during which the Total Tsunami Force at each step is distributed along the height and width of the area of the building affected by the Tsunami. The building response is calculated at each step similarly to a non-linear time-series analysis. When the VDPO phase is finished (either at the end of the analysis steps or due to divergence) the analysis can optionally move to the second phase the Constant Depth Pushover (CDPO) Analysis. During the CDPO phase the Tsunami depth is held constant and the lateral loads are increased monotonically until the building reaches a certain displacement defined as a certain percentage of the displacement at the end of the VDPO analysis. The CDPO analysis is similar to a response controlled Static Pushover Analysis. For a detailed presentation of the procedures during the Nonlinear Tsunami Analysis users are directed to the work by Petrone et al [2017] and Baiguera et al. [2019].