PSI - Issue 17

Joyraj Chakraborty et al. / Procedia Structural Integrity 17 (2019) 387–394 Joyraj Chakraborty/ Structural Integrity Procedia 00 (2019) 000 – 000

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The main goal of this study is to transfer the change and degradation detection technologies from the laboratory size specimens to the routine field application. In this research novel ultrasonic transducer developed by Bundesanstalt für Materialforschung und Prüfung (BAM) was used. Its primary part is a hollow piezo ceramic cylinder (Niederleithinger et al. (2015)). These ultrasonic sensors and vibrating wire strain gauge sensors embedded in the bridge located in Gliwice (Poland) during construction in 2015. Since acquired signals from the mentioned ultrasonic sensors are the raw signals, their additional processing is needed. Therefore, the signal processing algorithm is developed for ultrasonic sensors array to detect changes in the reinforced concrete structure and compare the detection capability with traditional strain gauge sensors. These signal processing methods being used for denoising, DC offset compensation, and the feature extraction. The rest of the paper is organized as follows. In Section 2, the test object and experimental setups are described, then signal acquisition is explained. In Section 3, the proposed features are defined. In section 4, the comparison of these features is evaluated and compared with traditional strain gauge sensors. The whole paper is summarized in Section 5.

2. SHM Methodology

2.1. The test object The Gliwice bridge on the Kłodnica river has great importance in the daily life of the neighboring populations since they ensure vital communication in the highly urbanized Upper Silesia region.

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Fig. 2 (a) Location of Gliwice bridges. (b) Monitored bridge span at southeast end. (c) Static scheme of the bridge.

The bridge is located along the Katowice - Gliwice route within Silesian Central Motorway. It was built to overcome an obstacle, which is the Kłodnica river with the flooding area. The location of the bridge is illustrated in Fig. 2a. It consists of twelve-span continuous beam made of prestressed concrete supported by two girders and the total length of the bridge is 552 m (Fig. 2c). There are two steel pot bearings on each support. The 36 meters long span at the southeast end of the bridge (Fig. 2b) was selected as a research object.