Infrastructures, Volume 7, Issue 6 (June 2022) – 11 articles

Urbanization causes major changes in environmental systems, including those related with radiation balances and other meteorological conditions because of changes in surfaces and the physical environment. In addition, cities generate specific microclimates as a consequence of the diverse conditions within the urban fabric. Industrial parks represent vast urban areas, often neglected, contributing to the degradation of the urban environment, including poor thermal comfort as a result of soil sealing and low albedo surfaces. Nature-Based Solutions (NBS) can promote the mitigation of the anthropic effects of urbanization using nature as an inspiration. The present study, aimed at estimating the microclimate conditions in a fraction of the Argales industrial park in the city of Valladolid (Spain), with the use of the ENVI-Met software, assesses the current situation and a planned NBS scenario. Base scenario simulation results demonstrate different conditions across the simulations, with higher temperatures on sun-exposed surfaces with low albedo, and lower temperature spots, mostly associated with shadowed areas near existent buildings. After the simulation of the NBS scenario, the results show that, when compared with the base scenario, the projected air temperature changes reach reductions of up to 4.30 °C for the locations where changes are projected from impervious low albedo surfaces to shaded areas in the vicinity of trees and a water body. Full article

With the ever-increasing number of well-aged bridges carrying traffic loads beyond their intended design capacity, there is an urgency to find reliable and efficient means of monitoring structural safety and integrity. Among different attempts, vibration-based indirect damage identification systems have shown great promise in providing real-time information on the state of bridge damage. The fundamental principle in an indirect vibration-based damage identification system is to extract bridge damage signatures from on-board measurements, which also embody vibration signatures from the vehicle and road/rail profile and can be contaminated due to varying environmental and operational conditions. This study presents a numerical feasibility study of a novel data-driven damage detection system using train-borne signals while passing over a bridge with the speed of traffic. For this purpose, a deep Convolutional Neural Network is optimised, trained and tested to detect damage using a simulated acceleration response on a nominal RC4 power car passing over a 15 m simply supported reinforced concrete railway bridge. A 2D train–track interaction model is used to simulate train-borne acceleration signals. Bayesian Optimisation is used to optimise the architecture of the deep learning algorithm. The damage detection algorithm was tested on 18 damage scenarios (different severity levels and locations) and has shown great accuracy in detecting damage under varying speeds, rail irregularities and noise, hence provides promise in transforming the future of railway bridge damage identification systems. Full article

Sleeper spacing has been a taboo subject throughout the railway’s history. Safety concerns related to the structural integrity have been the main causes of not addressing this matter. There are no specific and clear recommendations or guidelines in relation to this matter and the distances do not go more than 0.8 m. In order to go beyond this current situation, the following research paper analyses the influence of the spacing between sleepers on the behaviour of ballasted tracks by performing a dynamic simulation with finite elements in two dimensions for different track configurations, different elements, geometries, and separations within the frame of the ODSTRACK project. The variables studied are the vertical displacements, the forces and stresses on the most important elements of the superstructure, as well as the vertical accelerations in the sleepers and the train. The values obtained from the numerical simulations were compared with the maximum permitted values according to the guidelines. To limit this distance to the most restrictive variable among those analysed, it is necessary to make important assumptions, such as the permissible values and effective support contact areas between the sleepers and the ballast. The preliminary analyses carried out shed light on a possible increment of the spacing between sleepers’ axes up to more than 0.8 m. This suggests that important savings in railways construction costs can be achieved, and they will help to develop the next stage of the ODSTRACK project. Full article

With the aging of bridges, the efficiency of periodic inspections has become a problem. As issues with the continuing close visual inspection of bridges are surfacing, remote imaging systems are expected to become a new inspection method that replaces close visual inspection. The objective of the study is to develop a classification model of countermeasure categories using the results of past periodic inspections of bridges conducted by skilled inspectors. Focusing on concrete slabs, a model was constructed to classify the countermeasure categories based on the characteristics of the damage maps by random forest classification. As a result, it was possible to classify two classes of countermeasure categories with a macro-average precision rate of about 88%. It became clear that the degree of crack development and the number of cracks are the most important factors in the classification of judgment categories. Full article

The development of transport infrastructure is associated with risks, expressed in the likelihood of harm to the road users’ health during road accidents and their consequences. The risk management process is aimed at reducing the influence of factors that contribute to the occurrence of an accident and increase the consequences’ severity after it. This article proposes a risk management methodology within five stages: identification, analysis and evaluation, processing, development of recommendations, and monitoring. For each step, we describe the methods and models that allow us to effectively solve the problem of risk management. We proposed a risk management algorithm based on feedback. We tested the adequacy of the methodology on a specific example: we conducted an analysis, an assessment, and proposed risk management measures in the field of ensuring road safety in a small town. Full article

Management of nonurban road network maintenance is a complex management process that requires the inclusion of many technical, economic, and other characteristics of the problem, as well as the continuous application of new knowledge and approaches, to maintenance management. To effectively manage the maintenance of the road network in conditions of limited financial resources, maintenance is examined through three interrelated management functions of planning: implementation, monitoring, and maintenance control. This paper includes an analysis of current and relevant papers on this topic. Based on the conducted analysis, the paper gives a theoretical framework and proposes a management model for road network maintenance between urban areas. This model supports the previously mentioned management functions using Multicriteria Decision-Making Methods. The AHP method and the TOPSIS method are engaged in the process of generating a priority road maintenance plan and Earned Value Analysis in maintenance monitoring and control. The AHP method is used to determine the criteria weight vector as a key role in defining the rank of alternatives and in identifying the optimal maintenance rank of nonurban roads using the TOPSIS method. All of the above aim to ensure the safe flow of traffic and the permanent preservation of the construction, traffic, and economic value of roads between urban areas. Full article

Photovoltaic (PV) energy systems are considered good renewable energy technologies due to their high production of clean energy. This paper combines a PV system with wastewater treatment plants (WWTPs), which are usually designed separately. For this, a recent methodology was adopted, which provides direct steps to estimate the peak powers of PV plants (PVPs) by using the airflow of blowers. The goal was to reduce the energy consumption of aeration tanks in WWTPs. Analytical equations and parameters based on the air temperature, solar irradiation, biological kinetic, dissolved oxygen, and mechanical oxygenation are adopted. The key parameter in this methodology is the air temperature variation that represents an approximated temperature in the WWTP’s oxidation tanks. It is shown, through the analysis of small WWTPs, that since the temperature changes for each season, there is a peak in the function of the quantity of oxidation, which is high in the summer season. Further, the curve trends of temperature for WWRPs are similar to PVPs. Therefore, it could be possible to design the PV system with the WWTPs well. The results show that the air temperature curves increase in a directly proportional way with the consumption of energy from oxidation blowers; this could induce a more conservative PVP design. Furthermore, the results show that the mean trend of the energy consumption of the analyzed aeration systems reaches about 8.0% at a temperature of 20–25 °C, covering a good part of the oxidation tank consumption. Full article

As everyone spends much time traveling, engaged in leisure or work activities, travel time represents one of the largest costs to transportation. The main objective of the study is to investigate travelers’ perceptions related to value of travel time saving with the help of a questionnaire survey. The survey was conducted online with the help of Google forms. The required data were collected through a self-reported questionnaire that consisted of five parts. A total of 312 useable sample responses were collected. The collected data were analyzed using conventional and statistical methods. In conventional methods, frequency distribution was carried out, and bar and pie charts were prepared. In the statistical methods, the exploratory factor analysis method (EFA) was conducted to extract useful factors affecting the travelers’ perceptions about travel time saving attitude. The survey results showed that more than 73% of people use a car for transport, which implies that most of them do not like to wait for public transport modes. It means that their travel attitudes are more inclined towards private transport seeking travel time saving. Most people do not like to share space with others while traveling, amounting to 44% of respondents using private cars alone, and placing high importance on flexibility, reliability, and time and cost saving in traveling, which implies that they are more likely to travel alone to save travel time. In addition, most of the respondents use short routes; this propensity is positively related to time and cost saving factors. Similarly, the time and cost savings and car-oriented attitudes are positively associated with the choice of a short route to save travel time. They also believe that the service quality level of transportation facilities affects the travel time saving and its value. This study proposes to improve travel time and cost in Oman. Full article

In modern transportation projects, the demand for skewed bridges is increasing. Restrictive site constraints, particularly in urban infrastructure projects, yield severely skewed bridges that demand specific design and construction considerations. In particular, the acute corners have reinforcement details that are challenging to construct and often perform poorly. Although the Federal Highway Administration has recognized this problem, to date a simplified detail has not been suggested and evaluated. To tackle this challenge, the Connecticut Department of Transportation partnered with the University of Connecticut to propose a simplified reinforcement detail for acute corners that replaces the normal transverse reinforcement with reinforcement placed along the skew with specific detailing to avoid congestion. An analytical study was conducted using CSiBridge to evaluate the performance of the detail with different skew angles. A series of pushover analyses were performed to capture the flexural yielding of the parapet and measure the stresses in the reinforcing bars in the slab. Based on these findings, a simplified detail for the acute corner of skewed bridge decks is provided. Full article

A procedure for assessing and monitoring the response of critical infrastructures when subjected to natural hazards is proposed in this paper, with a particular focus on bridges and viaducts, which are very peculiar and strategic assets of transport networks. The proposed procedure is characterized by three levels of analysis (L1–L3) with increasing reliability and complexity. The first level of analysis (L1) is carried out by evaluating a Class of Attention in line with the approach that is proposed by the Italian Guidelines for the safety assessment of bridges. The second level (L2) of analysis requires the definition of a numerical model of the bridge. The third level (L3) of analysis relies on the seismic response data from a seismic monitoring network. For all the three levels of the proposed procedure, data are collected in the CIPCast Decision Support System (CIPCast-DSS), a WebGIS platform developed by ENEA to support the decision-making process related to risk prevention and the management of impacts induced by natural hazards on critical infrastructures. The real-time analysis of the data collected and processed in the CIPcast-DSS in post-disaster circumstances provides a quasi-real-time prediction of the impacted infrastructures, and the extent of damages they could have suffered before a local inspection and analysis could take place. The continuous static and dynamic monitoring in periods without seismic events enables the planning of preventive and effective maintenance interventions. Full article

There is an obvious tendency towards increasing the information content of surveys of hard-to-reach objects at high altitudes through the use of remote-controlled robot crawlers. This can be explained by the reasonable desire of industrial objects owners to maintain their property: pipelines, containers, metal structures in operating technical condition, which contributes to reducing accident risks and increasing the economic efficiency of operation (optimization of repair planning, etc.) This paper presents the concept of a robotic device equipped with LIDAR and EMAT which can move over pipes from a diameter of 100 mm by using a special type of magnetic wheel. The robot uses convolutional neural networks to detect structural elements and classify their defects. The article contains information about tests held on a specially developed test rig. The results showed that the device could increase the information level of survey and reduce the labour intensity. In this work, we consider a prototype of the device which has not started mass operation at industrial facilities yet. Full article