Damage Detection of a Concrete Column Subject to Blast Loads Using Embedded Piezoceramic Transducers.

Kai Xu,Qingshan Deng,Siuchun Ho,Lujun Cai,Gangbing Song

doi:10.3390/s18051377

Kai Xu, Qingshan Deng + Show 3 more

Open Access

https://doi.org/10.3390/s18051377

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Abstract

Some of the most severe structural loadings come in the form of blast loads, which may be caused by severe accidents or even terrorist activities. Most commonly after exposure to explosive forces, a structure will suffer from different degrees of damage, and even progress towards a state of collapse. Therefore, damage detection of a structure subject to explosive loads is of importance. This paper proposes a new approach to damage detection of a concrete column structure subjected to blast loads using embedded piezoceramic smart aggregates (SAs). Since the sensors are embedded in the structure, the proposed active-sensing based approach is more sensitive to internal or through cracks than surface damage. In the active sensing approach, the embedded SAs act as actuators and sensors, that can respectively generate and detect stress waves. If the stress wave propagates across a crack, the energy of the wave attenuates, and the reduction of the energy compared to the healthy baseline is indicative of a damage. With a damage index matrix constructed by signals obtained from an array of SAs, cracks caused by blast loads can be detected throughout the structure. Conventional sensing methods such as the measurement of dynamic strain and acceleration were included in the experiment. Since columns are critical elements needed to prevent structural collapse, knowledge of their integrity and damage conditions is essential for safety after exposure to blast loads. In this research, a concrete column with embedded SAs was chosen as the specimen, and a series of explosive tests were conducted on the column. Experimental results reveal that surface damages, though appear severe, cause minor changes in the damage index, and through cracks result in significant increase of the damage index, demonstrating the effectiveness of the active sensing, enabled by embedded SAs, in damage monitoring of the column under blast loads, and thus providing a reliable indication of structural integrity in the event of blast loads.

Highlights

Recent years have seen a rise in terrorist activities, and the number of bombing incidents in particular have risen across the globe
Figure shows the maximum response of all the strain gauges during all blasts
Since the smart aggregates were embedded in the concrete column, the stress waves waves propagate inside the column, and the damage index value reflect the internal damages to the propagate inside the column, and the damage index value reflect the internal damages to the structure

Summary

Introduction

Recent years have seen a rise in terrorist activities, and the number of bombing incidents in particular have risen across the globe. Terrorists have been known to indiscriminately target civilian populations, exposing civil structures to dangerous blast loads [1,2]. With the use of vehicles and suitcase bombs against critical elements in city centers, the potential for greatly increased blast magnitudes have intensified [3,4]. Progressive collapse is a chain reaction of failures initiated by instantaneous loss of at least one load carrying element [6]. Such a mode of structural failure occurred during several actual explosion events [7,8,9,10,11]. Izzuddin et al [12]

Results

Discussion

Conclusion