This issue of Bridge Engineering brings the second part and the conclusion to the theme of deterioration and structural performance of ageing concrete bridges. Unfortunately, just over the few past months, there have been a couple of bridge collapses, which serves as a dire warning of the risk and associated dangers when things go wrong.
Around the world, bridges in general form the backbone of transport networks while connecting communities and enabling economic activity. Concrete bridges have become increasingly more popular over the past 50 years due to the significant reduction in cost, strength, versatility, offsite and precast manufacturing opportunities, and limited maintenance requirements.
However, concrete is an inhomogeneous material with numerous natural constituents that can vary in composition and quality, which can give rise to pretty much an infinite number of combinations and outcomes. At the same time, concrete bridges can be exposed to numerous harsh environmental conditions that can lead to significant wear and structural deterioration.
In this issue, we are travelling across the world from Italy to Iran and India to investigate a variety of mathematical and empirical performance and assessment tools. The paper by Bergami et al. (2022) discusses the development of a procedure for the seismic assessment of reinforced concrete bridges that have suffered from chloride-induced corrosion. It utilises an alternative approach to the computationally intensive requirements of non-linear analyses to evaluate the effects of chloride-induced corrosion on reinforced concrete and thereafter their seismic performance.
The paper by Asghshahr and Rahai (2022) investigates the seismic performance of bridges in Iran, who has an extensive asset portfolio of circa 330 000 structures, with a third of them being exposed to aggressive environmental conditions. Those in the Bandar Abbas region are also highly susceptible to major seismic occurrences. Using a probabilistic seismic hazard analysis, they investigate the performance of a typical two-span concrete bridge, associated seismic fragility and improvements required in peak ground acceleration design parameters to meet service life requirements.
The paper by Afsar Dizaj (2022) takes us on an interesting mathematical journey to articulate the varying results arising based on the modelling strategy adopted for the structural assessment of deteriorated concrete bridge columns and associated outcomes. The work demonstrates that the chosen modelling strategy and assumptions made will significantly affect the predicted time-variant structural performance of a deteriorated structure.
The paper by Das and Sil (2022) presents the results of numerical analysis of bridges using time-variant and time-invariant reliability models, in which both load and resistance are considered as time-dependent parameters, with the work being focused in the Barak Valley region in Assam, India. The proposed framework enables the simultaneous assessment of structural resistance to deterioration to enable improved asset management outcomes.
We hope that you will sincerely enjoy this themed issue of Bridge Engineering and you will find the papers intellectually stimulating while giving a broader perspective of the asset management challenges experienced around the world.
