Assessment of Antenna Mounting Building Structural Strength using Microtremor Analysis

Abstract

Any satellite tracking ground station requires fully steerable dish shaped antenna for fixed satellite services. Antenna foundations require special consideration, because they transmit dynamic loads to soil and foundation system, in addition to static loads due to self-weight of foundation, antenna and its accessories. Antenna foundations are of ground foundation or roof top i.e on buildings based on Radio Frequency requirements. To install antennas on existing building, the building should have required strength. To assess the building strength, building natural frequency and damping ratios are determined using Microtremor recorded data. For rotating Antennas, the required building frequency should be more than 8 Hz to avoid resonance effect of antenna structure natural frequency with servo frequency. In this study, the data is collected for building located at National Remote Sensing Centre, ISRO, Shadnagar, Hyderabad by mounting sensor at 3 locations of building. The data collected is analyzed using View 2002 software. FFT analysis is carried out to identify predominant natural modes and frequencies of the Building.