Investigation of the dynamic characteristics of the road bridge in Yerevan by recording microseisms

Abstract

Relevance. The investigation of the behavior of structures in natural conditions and a comparative analysis of their dynamic characteristics is an important task both for research purposes and for applied, particularly, for monitoring their technical condition and forcertification. Theproblem is relevant chiefly on the territory of Armenia, given the intensive high seismicity of the country. Thework presents the experimental results of examining the dynamic characteristics of a road bridge from microseismic records using seismic devices especially developed at IGES NAS RA. The bridge is located in the center of Yerevan and has an important significance. This bridge has been selected taking into account the fact that before that, experiments had been carried out on it to identify its dynamic characteristics.But for quite a long time, such research work has not been carried out at this facility. The aim of the paper is to check the actual state of the bridge, to compare the actual and previously acquired dynamic characteristics of the investigated bridge. Methods. The technique used by us to study the behavior of structures has been performed using a movable seismic station, which consists of 3 receivers - seismic sensors SM-3 (two horizontal and one vertical component), as well as a logger manufactured by IGES NAS RA, equipped with a wireless network (Wi-Fi), which provides communication with laptop computer.At 6 characteristic points of the bridge, as well as on its soil, the measurements of micro tremors have been carried out.The vibration frequencies of the bridge and soils in the transverse, longitudinal and vertical directions have been determined.The measurements have been made at night so that the vibrations of the soil and the bridge were caused only by natural microseisms. Results. As a result, a comparative analysis of the gained experimental values of dynamic characteristics and formerly obtained data has been executed. In the issue, it was found that the acquired new values of the frequencies of microseismic vibration of the bridge in the transverse and longitudinal directions are practically equal to the acquired old experimental corresponding frequencies. In addition, features of the joint work of the structure and soil have been found.