Special Issue "Resilience of Critical Infrastructures: Risk Reduction and Maintenance"

Dear Colleagues,

The large majority of our infrastructure network dates back to the 20th century. Structures such as bridges and tunnels are experiencing ageing phenomena that reduce their structural safety. The increase of traffic loads and environmental stressors are reducing the expected working life of infrastructures, as proven by recent bridge collapses. Maintenance is required in order to prevent and control the ageing and degradation of structures, and to reduce the associated risk. We are pleased to invite you to contribute to a Special Issue devoted to the recent advances and technical solutions for the resilience of critical infrastructures, with a special focus on the reduction of the risk of failure, as well as the preventive maintenance and health monitoring of transportation infrastructures. In this Special Issue, original research articles, review articles and case studies are welcome. Research areas may include (but are not limited to) the following:

• Critical infrastructure resilience;
• Maintenance of critical infrastructures;
• Benefit–cost assessment of maintenance;
• Infrastructure management;
• Degradation of constructional materials;
• Ageing of transportation infrastructures;
• Extreme loading for aged concrete;
• Alkali–aggregate reaction;
• Fatigue life assessment of corroded steel;
• Structural failure of bridges;
• Bridge inspections;
• Tunnel fire safety;
• Structural health monitoring for maintenance;
• Risk mitigation strategies;
• Uncertainty related to transportation networks.

We look forward to receiving your contributions.

Dr. Foad Kiakojouri
Dr. Valerio De Biagi
Guest Editors

Manuscript Submission Information

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• critical infrastructures
• transportation infrastructure
• bridge
• tunnel
• resilience
• structural failure
• maintenance
• collapse
• risk assessment
• aging and degradation

1. Numerical Evaluation of Lateral Torsional Buckling of PFRP Channel Beams under Pure Bending

Elahe Zeinali¹*, Ali Nazari², Hossein Showkati³ and Shapol Fotuhisara⁴

Abstract: The use of pultruded fiber reinforced polymers (PFRPs) in strengthening existing structures and also in the design of infrastructures that are exposed to corrosion and other resistance reduction factors is growing rapidly, however, the structural behavior of these materials under different loadings should be completely and comprehensively examined and evaluated in order to provide a wider field of use of these sections in various structural and industrial fields. Pultrusion profiles can be also used as beams in bridges. When a beam with thin-walled open cross sections is not restrained laterally along its span, the probable instability mode can be lateral torsional buckling. For this reason, research on buckling behavior of PFRP materials is very important. In this study, analytical responses through the equation in the Eurocode 3 regulation are calculated for channel shaped beams of bridges under pure bending. Then, in numerical modeling with the selection of appropriate elements, linear and nonlinear structural failure of these beams is investigated with finite element package, Abaqus. A total of 75 specimens of PFRP channel profiles with different thicknesses in various spans and lateral restraint conditions are studied for lateral torsional buckling behavior. The difference between the values obtained from the software and the analytical results for the PFRP beams shows that the analytical equations used for these beams need to be modified to be able to estimate the buckling loads of FRP beams under the conditions studied in this paper more accurately.

Keywords: bridge; PFRP beams; structural failure; lateral-torsional buckling; pure bending; channel beams; FE analysis

Planned submission date: 30 March 2023

2. Probability Assessment of Seismic Risk of Highway Bridges with Various Structural Systems (Case Study: Tehran City)

Meisam Mogheisi¹, Hamid Reza Tavakoli^2*, Elnaz Peyghaleh³

Abstract: Considering the development of urban transportation systems and the importance of highway bridges in the resilience of cities against earthquakes, it is necessary to pay special attention to this issue. The most important thing that should be taken into account before an earthquake is the evaluation of the direct and indirect possible damage to the bridges, which would cause to have the best performance of the bridge rehabilitation plan and the least amount of losses. For this purpose, this article discussed the seismic risk assessment of all highway bridges in Tehran province (the capital of Iran), which included 713 highway bridges. At first, these bridges were divided into 6 categories according to the type of structural system and the year of construction, each category has two cases with and without seismic design. Then it was subjected to a scenario from a ten thousand years catalog of earthquakes and with the help of fragility curves for all 6 categories of bridges were drawn in two states of less than 10 years and more than 10 years in four states of slight, medium, high and complete damage. The amount of risk as well as possible direct and indirect damage caused by the failure of each bridge system was calculated and its damage functions were drawn. According to which, necessary decisions can be made regarding prioritizing the optimization of bridges according to the defined budget.

Keywords: Seismic Risk Assessment; Bridge; Damage Function Evaluation; Optimization

Planned submission date: 30 March 2023

3. Impact of Slip of Elastomeric Bearings on Seismic Resilience of a Typical Highway Bridges

Mohammad Barkhordary¹, Saeed Tariverdilo² , Afshin Movafaghi³

Abstract: Ordinary highway bridges are one of the most important urban infrastructures; the majority of them have benefited from thermal elastomeric bearings from decades ago. Elastomeric bearings are widely used in bridges to accommodate thermal displacements. In typical highway bridges, these bearings are employed with no positive connections to the superstructure or substructure, facilitating the installation of bearings with larger construction tolerances. As a result, friction at the interfaces between the bearings and the superstructure and the substructure is the only mechanism of lateral force transfer between the superstructure and substructure. This boundary condition seems to have a significant impact on the bridge's structural safety during a seismic event. Currently, the seismic design of typical ordinary bridges does not account for the possibility of slip at these interfaces of elastomeric bearings. However, the real behavior of these bridges showed large deck displacement due to bearing slip. Therefore, this study investigates the seismic resilience of ordinary bridges, accounting for this slip, and also proposes a design strategy considering the possible use of this slip to choose an economical retrofit strategy. A three-dimensional model of a typical bridge with no positive connection between the elastomeric bearing and super- and sub-structure was developed, and the effect of possible uncertainty in the determination of the coefficient of friction at the interface was evaluated. Finally, a design methodology accounting for this slip was proposed, which could be used in the retrofit of older bridges and for the design of new ones in order to make them more resilient.

Keywords: bridge; elastomeric bearing; slip; resilience; retrofit

Planned submission date: 1 October 2023

4. Assessment of the Impact of Structural Degradation on the Resistance of a Secured Drapery System through DEM Analyses

Maddalena Marchelli ^1*, Antonio Pol ²

Abstract: Anchored mesh systems are often located in an aggressive environment and hardly accessible areas (high mountain or coastal areas) and thus are exposed to both weathering and ageing. Maintenance interventions are therefore fundamental but at the same time should be reduced to a minimum due to the hard accessibility of the area where the structure is located. In this perspective, it is crucial to understand the relative importance of the different consequences of structural degradation on the mesh system. In this paper, this problem is addressed numerically using a simple rather effective description of the mesh system based on the discrete element approach. The effect of weathering and ageing phenomena is account for by introducing some defects in the numerical model of the mesh. The results are rationalized in order to assess the role of different consequences of structural degradation in terms on the mechanical response of the entire system.

Keywords: secured drapery mesh; maintenance; ageing effects.

Planned submission date: 31 October 2023