Dynamic Monitoring vertical Deflectionof Small Concrete Bridge Using Conventional Sensors And 100 Hz GPS Receivers - Preliminary Results

Abstract

-The last four decades have been significant for Brazil"s highway network development. The country received financial incentives for its expansion and created various structural solutions for bridges and overpasses. Concurrent to this development, in recent years these structures have increasingly shown advanced deterioration stages due to the lack of preventive maintenance programs. Thus, this paper proposes the use of a GPS in a short-term monitoring plan to oversee the structural behavior of a curved reinforced concrete highway bridge already in service. Accordingly, this article presentsthe first research results with the L1 carrier and recorded data at 100 Hz in order to monitor the dynamic behavior of the central span of a small curved concrete bridge, the bridge over the Jaguari River in Extrema, Minas Gerais. The problem is that such structures exhibitsmall peak-to-peak amplitude vertical deflections-up to 5 mm.The challenge lies in the fact that the vast majority of Brazil"s highway network is characterized by small and medium sized concrete bridges. The bridge monitored in the study consists of two traffic lanes and a total length of 134 m, located in the Fernão Dias highway-BR 381, km 946 + 300m, Extrema, Minas Gerais. The bridge under study is significant to this work because this type of structure is largely found throughout the country. Thus, the line of work to be presented will contribute to implementing other monitoring actions forthese types of structures throughout Brazil -quickly and effectively,which will serve as a strategythat can beadded to the conventional monitoring methods. Therefore, GPS data observations were conductedfor two days using two GPS receivers with data sampling intervals of 0.01 seconds-100 Hz. The Continuous Wavelet Transform (CWT) was used as filtering model to analyze the frequency response of the bridge generated by the residues of the L1 double difference through the highest GPS satellite constellation.

A Review of Global Navigation Satellite System (GNSS)-based Dynamic Monitoring Technologies for Structural Health Monitoring

“…The finite element method (FEM) was applied to the bridge as a check. The results verify the consistency and feasibility of the dynamic performance for the concrete bridge monitored by this method [81,82]. So far, the PRM method has been verified on large, medium and small bridges.…”

“…Although the data and satellite selection strategies of the two algorithms are different, the calculated natural frequencies of the bridges are consistent. In Larocca et al [81,82], to verify the feasibility of GPS monitoring for the structure of reinforced concrete road bridges, a series of experiments were carried out. This is also part of the continuous development of the previously proposed PRM method to increase the GPS detection threshold so that it could also be used for the dynamic monitoring of small reinforced concrete highway bridges.…”

Determination of remaining resource of constructions of buildings after different influences

“…In general, monitoring of construction objects is a system of monitoring their technical condition, receiving and transmitting information to services that are responsible for the safety of facilities. It is an independent element of the scientific and technical support of objects in the process of their construction and operation, ensures the reliability of construction objects and allows to predict their durability [2,6].…”

Dynamic displacement monitoring by integrating high-rate GNSS and accelerometer: on the possibility of downsampling GNSS data at reference stations

“…Still, one of the limitations of GNSS is its lower sampling rate compared to conventional seismic sensors such as accelerometers. Current GNSS receivers usually acquire signals with a 20 Hz sampling rate; some record observations up to 100 Hz (Larocca et al 2014;Paziewski et al 2019). Such high-rate data may be subject to non-negligible time correlation (Moschas and Stiros 2015;Shu et al 2017).…”