Virtual Shaker
The response of a building subjected to ground acceleration depends on the magnitude of acceleration and frequency components. The largest, full dynamic earthquake simulation of magnitude 8 on southern San Andreas was led by SCEC last year. The simulation included frequency components up to 2 Hz. This study was conducted to evaluate the response of two types of steel buildings with fundamental periods of 0.63 and 4.54 seconds subjected to acceleration records from SCEC M8 Simulation.
The buildings were simulated with Frame3D software, a building analysis program developed by Swami Krishnan at California Institute of Technology. Frame3D allows us to perform efficient three-dimensional nonlinear analysis of steel buildings subject to ground acceleration records. The building analysis results from Frame3D are processed using vShaker program developed at SCEC to produce structural animations. vShaker program combines structural response data from Frame3D and ground motion data to build three-dimensional geometric representation of the structure at specified time intervals. vShaker can then combine these snapshots to produce animations of structural motion with various viewpoints.
The two types of buildings were simulated at eight locations spread out across Southern California. The locations were chosen based on a previous study conducted by Krishnan et al., on response of tall steel building for magnitude 7.9 1857 southern San Andreas Earthquake. The choice of building locations allowed us to compare the results of building response from our study to those reported in the earlier study. The tall steel building with fundamental period of 4.54 seconds had comparable responses to those reported in Mw 7.9 earthquake study. Frame3D system is capable of dynamically evaluating the performance levels of the structural elements against know standards like FEMA-356. We plan to include capability in vShaker program to highlight structural damage in visualizations of building responses produced for significant earthquakes.
