← Back to Sessions

Vertical Component Impulse Response Functions in a High-Rise From Earthquake and Ambient Vibration Data

Description: 

Increasingly, interferometric techniques are being used to study the impulse response of engineering structures (bridges, tall buildings, etc.) and conducting structural health monitoring. Most of these studies have focused on the horizontal components, while little attention has been paid to the vertical components. These techniques are applied to data from Community Seismic Network MEMS accelerometers permanently installed on nearly every floor of a 52-story steel moment-and-braced frame building in downtown Los Angeles. The sensors relay continuous 24/7/365 acceleration waveform data and shaking intensity parameters using a cloud computing environment. Wavefield data from the instrumented high-rise from before, during, and after the 2019 M7.1 Ridgecrest, M6.4 Ridgecrest, and M4.5 El Monte, California earthquakes are processed for vertical component impulse response functions (IRFs), which show a distinct behavior from the horizontal IRFs. First, the wave speeds are of the order of 2000 m/s, while they are around 200 m/s for the horizontal components. The fundamental mode frequency of the vertical components (in line with the velocity) is an order of magnitude higher than that of the horizontal components (2 Hz vs. 0.2 Hz). The vertical component IRFs show a complicated behavior, including a discontinuous nature, as opposed to a very continuous IRFs observed for the horizontal components. We present observational as well as numerical constraints on the vertical IRFs to better understand their behavior and potential for structural health monitoring. For example they may lead to observations of the effects of cyclic loading due to longitudinal modes, including strength and stiffness degradation in connections when resonant amplitudes are large or long-duration, and activated during multiple earthquakes.

Session: General Seismology

Type: Poster

Date: 4/18/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Monica Kohler

Student Presenter: No

Invited Presentation: 

Authors