Presentation Title

Measuring Seismic Building Response on the Cal Poly Pomona Campus

Faculty Mentor

Jascha Polet

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 137

Session

Poster 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Buildings have natural frequencies based on their shape, size, and building material. Knowing the natural frequency of a building can help determine how it might respond during an earthquake.

We carried out several installations of a broadband seismometer in a building located on the campus of California State Polytechnic University in Pomona to measure the frequencies and amplitudes recorded at different floors and locations within and around the building. The building has a futurist architectural style and consists of two different sections of different heights.

A total of eight seismometers were installed and each recorded seismic noise for about two hours. Then, we applied the H/V spectral ratio method on the seismic data using the Geopsy software. Based on established guidelines used to check the H/V curve reliability, most measurements provided reliable results.

The spectral ratio curve for each location showed the presence of several peaks, which indicate resonance frequencies. The first and second floor have peak frequencies below 1 Hz and amplification factors between 3 and 4. The fourth and fifth floor have frequencies higher than 1 Hz and amplifications higher than 7. A building of five to ten floors should have a natural frequency of about 1 Hz, which is close to these results. Data from the third floor indicated a higher peak frequency. In this location, the seismometer was placed on a balcony, which may have introduced an additional resonance.

Measurements around the building from a previous investigation produced similar values for the resonance frequencies of the soil column, which could mean that the shaking could be further amplified during an earthquake due to double resonance.

Keywords: earthquake, hazard, building, geophysics, seismology, resonance

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Measuring Seismic Building Response on the Cal Poly Pomona Campus

BSC-Ursa Minor 137

Buildings have natural frequencies based on their shape, size, and building material. Knowing the natural frequency of a building can help determine how it might respond during an earthquake.

We carried out several installations of a broadband seismometer in a building located on the campus of California State Polytechnic University in Pomona to measure the frequencies and amplitudes recorded at different floors and locations within and around the building. The building has a futurist architectural style and consists of two different sections of different heights.

A total of eight seismometers were installed and each recorded seismic noise for about two hours. Then, we applied the H/V spectral ratio method on the seismic data using the Geopsy software. Based on established guidelines used to check the H/V curve reliability, most measurements provided reliable results.

The spectral ratio curve for each location showed the presence of several peaks, which indicate resonance frequencies. The first and second floor have peak frequencies below 1 Hz and amplification factors between 3 and 4. The fourth and fifth floor have frequencies higher than 1 Hz and amplifications higher than 7. A building of five to ten floors should have a natural frequency of about 1 Hz, which is close to these results. Data from the third floor indicated a higher peak frequency. In this location, the seismometer was placed on a balcony, which may have introduced an additional resonance.

Measurements around the building from a previous investigation produced similar values for the resonance frequencies of the soil column, which could mean that the shaking could be further amplified during an earthquake due to double resonance.

Keywords: earthquake, hazard, building, geophysics, seismology, resonance