Infrastructure Engineering - Research Publications

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    Structural Health Monitoring of Bridges Using Advanced Non-destructive Testing Technique
    Maizuar, M ; Zhang, L ; Miramini, S ; Mendis, P ; Duffield, C ; Wang, CM ; Ho, JCM ; Kitipornchai, S (Springer, Singapore, 2020-01-01)
    This paper presents an integrated framework for structural health monitoring of bridges by using advanced non-destructive testing (NDT) technique in conjunction with computational modelling. First, the structural characteristics of the Eltham Trestle Bridge under train loading were monitored using the combination of the 3D optical measurement system and IBIS-S. The results demonstrate that, in conjunction with computational modelling, the NDT can capture the structural health conditions of the bridge by analysing the natural frequencies and deformation profiles of the critical members of the bridges. Then, the developed framework also takes into account the impact of extreme events (e.g. truck impacts and earthquakes) by using a reliability-based model. Finally, using the Montague Street Bridge as a case study, it shows that proposed framework has the capability of predicting the residual life of a bridge subject to both progressive deterioration and extreme events throughout its service life.
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    Automation in structural health monitoring of transport infrastructure
    Zhang, L ; Herath, N ; Raja, BNK ; Chen, S ; Miramini, S ; Duffield, C (Springer Singapore, 2021-01-01)
    Roads are among the most important assets in the world. Road structure improvements make a crucial contribution to economic development and growth and bring important social benefits. Automation in structural health monitoring allow the accurate prediction of ongoing damage caused by long-term traffic loading. This permits optimal road structure management and ensures the longevity and safety of road structures. This chapter discusses a variety of advanced automation techniques in structural health monitoring of road structures, such as data acquisition, data processing, and life-cycle assessment. It demonstrates that the implementation of automation in road asset management can increase the productivity and extend the service life of road structures, and enhance the durability of crucial road structures and increase transport infrastructure sustainability.
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    Infrared thermography detection of delamination in bottom of concrete bridge decks
    Raja, BNK ; Miramini, S ; Duffield, C ; Sofi, M ; Zhang, L (JOHN WILEY & SONS LTD, 2022-03)
    Infrared thermography (IRT) has been widely used in detecting the subsurface delamination of bridge deck. However, IRT inspection on delamination zones of the bridge deck which have limited exposure to direct solar radiation (e.g., the bottom surface of the bridge deck) is rather challenging due to the relatively low thermal contrast (∆T) development in these zones. Therefore, the purpose of this study is to conduct a series of experimental studies in conjunction with numerical modeling for investigating the effectiveness of IRT in delamination detection of bridge deck components which are normally not exposed to direct solar radiation. Specially, the effects of different environmental conditions, thickness of bridge deck, and defect characteristics on the absolute thermal contrast (∆T) development were systematically investigated. The results show that IRT can effectively detect the subsurface delamination of concrete bridge deck located in regions that are not exposed to the direct solar radiation. In addition, the development of detectable thermal contrast (>0.5°C) is much dependent on the rate of change in ambient temperature with a suitable detection period between 8 am and 4 pm. Furthermore, it shows that the value of ∆T increases with the increase of bridge deck thickness and delamination size.
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    A Simplified Methodology for Condition Assessment of Bridge Bearings Using Vibration Based Structural Health Monitoring Techniques
    Raja, BNK ; Miramini, S ; Duffield, C ; Chen, S ; Zhang, L (WORLD SCIENTIFIC PUBL CO PTE LTD, 2021-09-01)
    The mechanical properties of bridge bearings gradually deteriorate over time resulting from daily traffic loading and harsh environmental conditions. However, structural health monitoring of in-service bridge bearings is rather challenging. This study presents a bridge bearing condition assessment framework which integrates the vibration data from a non-contact interferometric radar (i.e. IBIS-S) and a simplified analytical model. Using two existing concrete bridges in Australia as a case study, it demonstrates that the developed framework has the capability of detecting the structural condition of the bridge bearings in real-time. In addition, the results from a series of parametric studies show that the effectiveness of the developed framework is largely determined by the stiffness ratio between bridge bearing and girder ([Formula: see text], i.e. the structural condition of the bearings can only be effectively captured when the value of [Formula: see text] ranges from 1/100 and 100.
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    Infrared Thermography for Detecting Subsurface Defects of Concrete Structures
    Khan Raja, BN ; Miramini, S ; Duffield, C ; Zhang, L ; Wang, CM ; Ming, C ; Kitipornchai, S (Springer Singapore, 2020-12-23)
    Delamination is one of the serious types of deterioration in reinforced concrete structures. It could cause concrete spalling, exposed steel bars, and ultimately affects the structural integrity of concrete structures. Infrared thermography (IRT) is a non-destructive technique which could potentially detect the delamination by capturing thermal contrast (∆T) on concrete surface caused by the heat flow disruption within the concrete due to subsurface anomalies. However, the optimum time and environmental conditions for IRT data collection are still unclear. In this study, an experimentally validated numerical model was developed to investigate the effect of a range of environmental conditions and defect characteristics on the IRT inspection outcomes. The results show that, under direct solar irradiation, the total heat flux input plays an important role in the development of thermal contrast ∆T instead of flux rate. Furthermore, delamination depth and size are two critical parameters that affect IRT results.
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    Life-cycle modelling of concrete cracking and reinforcement corrosion in concrete bridges: A case study
    Chen, S ; Duffield, C ; Miramini, S ; Nasim Khan Raja, B ; Zhang, L (Elsevier BV, 2021-06-15)
    The development of effective life cycle management strategies for transport infrastructure assets is of importance for meeting the defined public policies and levels of service. In the last decades, much progress has been made in assessing the life-cycle performance of bridges using reliability-based approaches. However, the goal of developing a comprehensive life-cycle performance assessment framework for bridges has not been fully achieved. This is due to the uncertainties surrounding model parameters as well as the correlation between these parameters (e.g. the complex correlation between the reinforcement corrosion and the concrete cracking). It becomes more challenging due to the limited access to bridge inspection data by bridge research communities resulting from confidentiality issues. Using a typical highway concrete bridge as a case study, the present study systematically investigated the impact of concrete crack induced reinforcement corrosion on the serviceability of concrete bridges by developing an engineering reliability-based approach involving an auto-regressive crack propagation model and a steel corrosion prediction model. The model parameters were calibrated using the eight-year inspection data of an operating bridge. The influence of different external environments in the reinforcement corrosion, ultimately the residual life of the bridges, was also investigated through conducting a series of parametric studies. Based on the collected bridge inspection data, the model results predict that, although the surface crack of a RC bridge is repairable through periodic maintenance, the corrosion of the steel bars in the bridge still continues over time with a corrosion rate which depends on different maintenance intervention cycle periods (Tcycle). For example, reducing Tcycle from 12 years to 4 years could potentially prolong the service life of the bridge by around 15 years. The developed model could assist bridge managers to estimate the optimal Tcycle to prolong the service life of bridges.
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    The influence of ambient environmental conditions in detecting bridge concrete deck delamination using infrared thermography (IRT)
    Raja, BNK ; Miramini, S ; Duffield, C ; Sofi, M ; Mendis, P ; Zhang, L (Wiley, 2020-04-01)
    Delamination is a serious form of deterioration in concrete bridge decks. Infrared thermography (IRT) is an advance non‐destructive testing method for concrete bridge deck delamination detection by capturing the absolute thermal contrast (ΔT) on the concrete surface caused by the disruption in heat flow due to subsurface defects. However, as the ambient environmental conditions (e.g. wind velocity and solar radiation) of a bridge could significantly affect the measurement outcomes of IRT, the optimal times for infrared data collection are still unclear. In this paper, a series of experimental and numerical studies were carried out to investigate the effects of the rate of heat flux and wind velocity on ΔT on the surface of bridge decks with the aim of identifying the optimal inspection times for different geometry characteristics of delamination (i.e. size and depth). The developed model is firstly validated by the experimental data and then a series of parametric studies were carried out. The result shows that the heat flux rate plays an important role in the development of ΔT on concrete surface, especially for a relatively shallow and small size delamination. However, the influence of heat flux rate gradually diminishes with the increase in size and depth of delamination. In addition, it demonstrates that there is a positive linear correlation between the total heat energy (external irradiation) and square of the delamination depth. The current research represents an important step towards the development of an effective and efficient way for defect detection using IRT.