Life-cycle structural performance assessment framework for concrete bridges

The aim of the project was to develop a framework for assessing the structural performance life-cycle of concrete bridges, based on environmental and loading conditions. Bridges have a vital financial, environmental and social role. The service life of bridges depends on various factors, including concrete mix design, quality control during construction, and environmental and loading conditions. In extreme conditions, bridges may deteriorate more rapidly. This could lead to serious consequences, including for freight distribution that depends on ground transport. This project aimed to fill the information gap on the effects of traffic load on progressive deterioration of concrete bridges, and to develop innovative bridge inspection techniques for the detection of structural degradation. The findings of this study are targeted to ensure the longevity and safety of bridges and assist in the optimisation of their management.

Assessing the condition of a bridge involves continuously monitoring changes to material properties, support conditions and system connectivity. It is known that the structural integrity of bridges can be monitored by measuring their vibration responses. However, the relationship between frequency changes and structural damage is still not fully understood. This study presents a bridge condition assessment framework that integrates computational modelling and noncontact radar sensor techniques (IBIS‐S) to predict changes in the natural frequencies of a bridge girder as a result of a range of parameters that govern its structural performance.


The research found several key factors affected the natural frequencies of a girder. In addition, an integrated bridge health monitoring framework was developed using advanced modeling in conjunction with weight-in-motion technology and interferometric radar sensors.

This project led to the development of a fully integrated reliability model in conjunction with advanced non-destructive testing (NDT) techniques for ageing bridges that require significant maintenance and rehabilitation. The outcomes from this project will provide significant benefits to both the economy and society by ensuring the longevity and safety of ageing bridges.

This project aimed to develop a validated life-cycle performance model for bridges consisting of a traffic load prediction model, a damage prediction model and a reliability-based assessment model. First, information on the parameters governing current bridge structural conditions (e.g. crack width) was obtained by on-site inspection using advanced NDT techniques developed in this project, while the loading on the bridge was characterised by traffic load prediction model in conjunction with IBIS-S and WIM data analysis.

Using the information on bridge characteristics and traffic loading obtained in step one as input data, we quantified damage accumulation in bridge structures through a damage prediction model. This was calibrated and validated using field test data. The changed structural capacity of the bridge over time was predicted using the damage prediction model, and this was also validated by the field test results over the three years of the project. Finally, the probability of structural failure at a given time was estimated using the reliability-based assessment models.


Currently, road authorities face numerous challenges in maintaining bridges. These include the inability to predict the effect of increased heavy truck loads on damage accumulation in bridge components (e.g. creep, cracking and corrosion), and the difficulty of knowing when to to intervene. In practice, decisions about bridge structures are based on uncertain and incomplete information. Uncertainties arise due to the variability in environmental factors, methods of inspection and data collection, lifetime traffic load prediction and so on.

For these reasons, the improving accuracy of deterministic models and computational tools does not solve the problem of identifying the uncertainties of the model parameters. In this project, a theoretical model has been developed to predict the residual service life of bridges, with consideration of progressive deterioration resulting from daily traffic loading and extreme events such as earthquakes and truck impacts.



Journal articles

Kafle, B., Zhang, L., Mendis P., Herath, N., Maizuar M., Duffield, C., Thompson R. (2017). Monitoring the dynamic behaviour of the Merlynston Creek bridge using interferometric radar sensors and finite element modelling. International Journal of Applied Mechanics 2017; 9(1)

Maizuar, M., Zhang, L., Miramini, S., Mendis, P., Thompson, R. (2017). Detecting structural damage to bridge girders using radar interferometry and computational modelling. Structural Control and Health Monitoring, 24(10).

doi: 0.1002/stc.1985


Raja N. K. R. (2018). Delamination detection of concrete structures using infrared thermography. AIC Infrastructure Cluster Conference. Four Point Sheraton, Surabaya.

Zhang, L. (2018) Life-cycle structural performance assessment of bridges. 2018. AIC Conference, The University of Melbourne, Australia.

Zhang, L. (2017). LEAN in practice; from Government projects to drones and all things LEAN in between. Lean Construction Institute Australasia, The University of Melbourne

Zhang, L. (2017) Bridge health monitoring using non-destructive testing techniques. Victorian Infrastructure Investment Forum, Melbourne, Australia

Zhang, L. (2017). NDT techniques used for delamination detection between FRP fabric and concrete substrate. FRP Workshop, VicRoads, Melbourne, Australia

Zhang, L., P. Mendis. (2017). An innovative condition assessment approach for concrete bridges under heavy truck loading. Proceedings of 1st Australia-China Conference on Science, Technology and Innovation, Perth, Australia

Zhang, L., P. Mendis. (2016) An innovative condition assessment approach for concrete bridges under heavy truck loading. The 11th RMS Annual Bridge Conference, Sydney, Australia

Zhang, L., P. Mendis. (2015). Life-cycle Performance Assessment of Bridges. 10th RMS Annual Bridge Conference, Sydney, Australia