KAJIAN RESPON GEMPA DAN KERENTANAN BANGUNAN PUBLIK BERDASARKAN DATA MIKROTREMOR DI ACEH UTARA

Abstract

Analysis of building and soil interactions is an essential part of building construction appraisal. In this article, the response of buildings to earthquakes identified by determining the natural frequency of the soil and the value of the natural frequency of buildings on each floor, as well as examining the relationship between the natural frequency of the soil and the natural frequency of the building. This article will also identify attenuation factors for type of public buildings that have different functions, namely school and campus buildings, and determine the effect of resonance on building infrastructure. Analyzed public buildings include rest area buildings, elementary school buildings, junior high schools, and campuses. The variable number of floors is also an aspect that will be observed. Microtremor data research utilizes a near-broadband seismometer. The vibration recording device is placed on the ground, and the reviewed buildings are school and campus. Data collection was carried out when the condition of the building was not loaded, measurements were made on each floor of the building as many as 5 points on the floor and 1 point on the ground for 30 minutes at each measurement point. The methods used are Horizontal-to-Vertical Spectral Ratio (HVSR), Fast Fourier Transform (FFT), Floor Spectral Ratio (FSR), and Random Decrement Method (RDM). The calculation results show that the natural frequency value of the soil is in the range of 0.7 to 0.85 Hz except for the location of the campus building that the value reaches 6.868 Hz, the reason of this value is the type of soil in the area is dominated by hard rocks. The natural frequency of the building (f0) is in the range of 2.557 Hz to 4.292 Hz, a low frequency and meets the requirements of SNI, for the damping ratio of the building is in the range of 2.002 to 4.974%, the low category meets the attenuation standard of 2 to 5%, the five review buildings have a low resonance level, the natural vibration period of the building is in a safe limit according to SNI 17-02-2012 and the vulnerability index is low.