Structural Health Monitoring During Induced Seismic Events in Oklahoma Using Real-Time Seismogeodetic Data

Session: Advances in Real-Time GNSS Data Analysis and Network Operations for Hazards Monitoring
Type: Oral
Date: 4/30/2020
Time: 02:30 PM
Room: 230 + 235
Description: 

Seismogeodetic observations from collocated Global Navigation Satellite System (GNSS) sensors and strong-motion accelerometers have been demonstrated to provide broadband information about building motion during strong shaking in shake table experiments. To test the applicability of this broadband data stream to structural health monitoring of an example of vulnerable building stock, we have installed GNSS and strong-motion accelerometers on a 12-story building on the Oklahoma State University campus, which experiences shaking from regional induced seismicity. The data from case examples of M4.5 earthquakes have been used to improve kinematic ground motion modeling and finite element models (FEMs) of the response of this aging reinforced concrete structure, not originally designed to withstand seismic loading.

The initial analyses of the building response indicate that the dominant frequencies of the building motion are 1.3 Hz and 2.2 Hz for the north-south direction and 2.5 Hz for the east-west direction. This is consistent with the aspect ratio for the building; however, the frequencies are higher than those predicted by the FEM.

The model was updated to consider infill walls in the concrete frame and nonlinear behavior of structural components. This was implemented in the CSi SAP2000 FEM model with stiffness modifiers for the columns and struts. An optimization problem was set up to find the optimal set of material input parameters that minimize the difference between the observed and modeled modal frequencies. This modified model leads to a much better representation of the lowest two modes of motion.

We describe the current GNSS and seismic data transmission system used for the structural monitoring, the recent upgrades to include rotational motions from gyroscopes and the future modifications for real-time operations. The planned developments will take advantage of the Antelope real-time system designed for seismic data and expanded here to accommodate simultaneous transmission of GNSS data using the same ring buffer protocol.

Presenting Author: Harriet Z. Yin

Authors