Application of PZT Technology and Clustering Algorithm for Debonding Detection of Steel-UHPC Composite Slabs.

Banfu Yan,Xudong Shao,Qiqi Zou,You Dong

doi:10.3390/s18092953

Abstract

A lightweight composite bridge deck system composed of steel orthotropic deck stiffened with thin Ultra-High Performance Concrete (UHPC) layer has been proposed to eliminate fatigue cracks in orthotropic steel decks. The debonding between steel deck and UHPC layer may be introduced during construction and operation phases, which could cause adverse consequences, such as crack-induced water invasion and distinct reduction of the shear resistance. The piezoelectric lead zirconate titanate (PZT)-based technologies are used to detect interfacial debonding defects between the steel deck and the UHPC layer. Both impedance analysis and wave propagation method are employed to extract debonding features of the steel-UHPC composite slab with debonding defect in different sizes and thicknesses. Experimental tests are performed on two steel-UHPC composite slabs and a conventional steel-concrete composite deck. Additionally, an improved Particle Swarm Optimization (PSO)-k-means clustering algorithm is adopted to obtain debonding patterns based on the feature data set. The laboratory tests demonstrate that the proposed approach provides an effective way to detect interfacial debonding of steel-UHPC composite deck.

Highlights

The lightweight steel-Ultra-High-Performance Concrete (UHPC) composite bridge deck, composed of steel deck and a thin reinforced UHPC layer through stud shear connectors, is an effective way to eliminate bridge defects, such as preventing pavement cracking and reducing fatigue cracking of the orthotropic steel deck [1,2,3,4]
The thickness modes (Yang et al [22], Park et al [23]) of piezoelectric lead zirconate titanate (PZT) patches are employed for debonding detection of the steel-UHPC composite slab
In order to select suitable excitation frequency bands, the PZT patches on the test specimen are scanned over a wide frequency range of

Summary

Introduction

The lightweight steel-Ultra-High-Performance Concrete (UHPC) composite bridge deck, composed of steel deck and a thin reinforced UHPC layer through stud shear connectors, is an effective way to eliminate bridge defects, such as preventing pavement cracking and reducing fatigue cracking of the orthotropic steel deck [1,2,3,4]. The thickness of the UHPC layer in the composite bridge is relatively thin, i.e., 35–50 mm, and the composite slab requires a high-temperature steam-curing treatment. The steel-fiber volume ratio in the structure could be up to 3.5%, which may cause steel fiber clustering. The high-temperature steam curing can cause debonding between steel and the UHPC layer. The performance of the steel-UHPC composite deck system may degrade due to the effects of vehicle overloading, thermal action, and fatigue load action during operation

Methods

Results

Conclusion