Infrastructures, Volume 6, Issue 3 (March 2021) – 17 articles

This study aimed to explore the use of additives in soil–cement mixtures that have undergone a wetting-drying cycle. In total, two types of soil were used, granitic and lateritic, which are widely used in road base construction in the Katingan area, Central Kalimantan, Indonesia. The cement used was the ordinary Portland type I, while the additive utilized was for commercial purposes, and predominantly contained CaCl₂. This research was conducted by testing the optimum cement content for each soil to determine the shear strength according to Indonesian standards (i.e., minimum Unconfined Compressive Strength of 2400 kPa). The optimum cement contents of granitic and lateritic soils were deduced to be 5.5% and 5% on a dry weight basis, respectively. The utilization of 0.8% additive resulted in a 0.5% reduction in the optimum cement content of granite-like soil. The results showed that the optimum additive content for granitic soil was higher than that without supplementation, while for lateritic, no changes occurred. The advantage of using supplements, however, was more pronounced in the samples when they had been subjected to wetting–drying cycles. Additionally, at the optimum additive level, the moisture content and soil-cement loss during wetting was always lower than without supplements. Full article

Geographically, at the center of Mississippi is a concentration of High Plastic Yazoo Clay Soil (HPYCS). Shallow landslides frequently occur in embankments constructed with HPYCS caused by rainfall-induced saturation of the embankment slope. The traditional methods are becoming expensive to repair the shallow slope failure. The use of Recycled Plastic Pins (RPPs) to stabilize shallow slope failures offers a significant cost and construction benefit and can be a useful remedial measure for these types of failures. The current study investigates the effectiveness of RPP in slopes constructed with HPYCS, using the Finite Element Method (FEM). The FEM analysis was conducted with the PLAXIS 2D software package. Three uniform and varied RPP spacings were investigated to reinforce 2–4H:1V slopes. Reinforced slope stability analyses were performed to investigate the applicability of RPP in HPYCS. The FEM analysis results indicated that RPP provides shear resistance for the sloping embankment constructed of HPYCS. Uniform spacing of RPP provides sufficient resistance that increases the Factor of Safety (FS) to 1.68 in 2H:1V slopes with deformation of RPP less than 15 mm. The uniform spacing and varied spacing combination of RPP increase the FS to 2.0 with the deformation of RPP less 7 mm. Full article

Industrialization, urban development, and population growth in the last decades caused a significant increase in congestion of transportation networks across the world. Increasing congestion of transportation networks and limitations of the traditional methods in analyzing and evaluating the congestion mitigation strategies led many transportation professionals to the use of traffic simulation techniques. Nowadays, traffic simulation is heavily used in a variety of applications, including the design of transportation facilities, traffic flow management, and intelligent transportation systems. The literature review, conducted as a part of this study, shows that many different traffic simulation packages with various features have been developed to date. The present study specifically focuses on a comprehensive comparative analysis of the advanced interactive microscopic simulator for urban and non-urban networks (AIMSUN) and SimTraffic microsimulation models, which have been widely used in the literature and practice. The evaluation of microsimulation models is performed for the four roadway sections with different functional classifications, which are located in the northern part of Iran. The SimTraffic and AIMSUN microsimulation models are compared in terms of the major transportation network performance indicators. The results from the conducted analysis indicate that AIMSUN returned smaller errors for the vehicle flow, travel speed, and total travel distance. On the other hand, SimTraffic provided more accurate values of the travel time. Both microsimulation models were able to effectively identify traffic bottlenecks. Findings from this study will be useful for the researchers and practitioners, who heavily rely on microsimulation models in transportation planning. Full article

A holistic understanding of the correlations between supply and demand in buildings forms the basis for their performance assessment. This paper aims to reinterpret a set of Key Performance Indicators (KPIs) that influence users’ satisfaction from different perspectives. Fieldwork was carried out in an office building following a detailed review on KPIs by conducting user surveys. This study highlights the need to organize specific indicators to focus on the usability of workplaces and, where and when required, through an iterative process, understand the user perception of performance indicators in usage conditions. This methodology is applicable for organizations to understand the main existing in-service problems, and could improve the building’s performance over time. Survey results showed that hygiene was the most recognizable influence on users’ satisfaction and indoor air quality was the less well-known in the assessment results. User perception results can be compared to other office buildings results to benchmark good practices and should also be investigated for the post-COVID-19 period. Full article

A common concern for bus operators is efficiency measurement in order to monitor transit performance. The purpose of this paper is to propose a series two-stage data envelopment analysis (DEA) approach integrated with bootstrapping in order to evaluate the performance of electric trolley bus routes of Athens and Piraeus, Greece. Production and sales efficiency were measured in the first and second stages, respectively. In the light of the results, the routes assessed have a comparable higher DEA-based efficiency in both stages when compared to the perfect possible performance, but production and sales efficiency are not associated. Nevertheless, arterial bus routes have a marginally better performance in the production process on average, whereas the feeder–local bus routes produce a slightly better sales performance. The proposed modeling approach is an addition to the current literature, and can be employed by managers and operators. Full article

Europe’s aging transportation infrastructure requires optimized maintenance programs. However, data and monitoring systems may not be readily available to support strategic decisions or they may require costly installations in terms of time and labor requirements. In recent years, the possibility of monitoring bridges by indirectly sensing relevant parameters from traveling vehicles has emerged—an approach that would allow for the elimination of the costly installation of sensors and monitoring campaigns. The advantages of cooperative, connected, and automated mobility (CCAM), which is expected to become a reality in Europe towards the end of this decade, should therefore be considered for the future development of iSHM strategies. A critical review of methods and strategies for CCAM, including Intelligent Transportation Systems, is a prerequisite for moving towards the goal of identifying the synergies between CCAM and civil infrastructures, in line with future developments in vehicle automation. This study presents the policy framework of CCAM in Europe and discusses the policy enablers and bottlenecks of using CCAM in the drive-by monitoring of transport infrastructure. It also highlights the current direction of research within the iSHM paradigm towards the identification of technologies and methods that could benefit from the use of connected and automated vehicles (CAVs). Full article

Tunnelling and underground construction operations are often characterized by critical safety issues mainly due to poor visibility and blind spots around large vehicles and equipment. This can lead to collisions between vehicles or between vehicles and pedestrians or structural elements, causing accidents and fatalities. To improve the OS&H conditions, it is important to investigate the possible introduction of innovative techniques and technologies to reduce the occurrences and consequences of shared spaces (spaces used by both vehicles and pedestrians). For this reason, research was conducted to investigate the possible use of different technologies of anti-collision systems in tunnelling operations. First, to achieve this goal, an extensive review of the literature was carried out in accordance with the PRISMA statement to select the current techniques and technologies used by general anti-collision systems in civil and mining construction sites. Then, the operating principles, the relative advantages and disadvantages, combinations, and costs were examined for each of these. Eight types of systems and many examples of applications of anti-collision systems in underground environments were identified as a result of the analysis of the literature. Generally, it was noted that the anti-collision techniques available have found limited application in the excavation sites of underground civil works up to the present day, though the improvement in terms of safety and efficiency would be considerable. Full article

As cities grow in size, traffic also increases, thus making the population more exposed to road noise and traffic accidents. It is therefore important to study and understand which properties of the pavement influence its acoustic impact and skid resistance performance. The pavement texture plays a major role in generating noise and friction, and it can be engineered in order to control both of them at the same time. The phenomena regulating skid resistance are well understood today. The same applies for noise generation and propagation; the literature contains methods of designing the pavement surface layer to achieve consistent results. Several types of solutions can be found for asphalt mixtures, most of them derived from decades of studies and research. They use different approaches to be effective for noise and friction, but all have in common the control of the surface’s macro and microtexture. Finally, some considerations are made regarding novel paving solutions with artificial aggregates instead of natural ones to address noise and skid resistance. Full article

The seismic response of five cultural heritage towers erected between the 10th and 19th century AD are investigated herein. Firstly, their architectural and modal characteristics were studied in the light of seismic events that hit the monuments. There exist several historical reports of strong earthquakes, as well as damaged structures and collapses. The limit analysis is adopted to examine the post-elastic behavior of the towers up to collapse due to out-of-plane failure. Recurrent damage modes were collected from recent earthquakes and a classification of four possible collapse mechanisms in towers and slender masonry structures is here proposed: overturning, separation of perpendicular walls, diagonal cracking, and dislocation of the belfry. A thorough examination of the towers under investigation verified the proposed damage classification. The capacity curves were derived combining the capacity curves of each of the collapse mechanisms. Damage thresholds were defined on these curves in correspondence with damage states. The studied group of structures is representative of a wider typology. A statistical approach was adopted to describe damage with seismic intensity, and vulnerability curves were generated. The results of this study will improve the understanding of the performance and the collapse mechanisms of slender masonry structures under seismic loading and provide a characterization of seismic vulnerability for the studied cultural heritage types of towers. Full article

Recent collapses and malfunctions of European bridges threatened the service conditions of road networks and pointed out the need for robust procedures to mitigate the impact of material degradation and overloading of existing bridges. Condition assessment of bridges remains a challenging task, which could take advantage of cost-effective and reliable inspection strategies. The advances in sensors as well as Information and Communication Technologies (ICT) ensure a significant enhancement of the capabilities in recording and processing physical and mechanical data. The present paper focuses on the paradigm of indirect vibration measurements for modal parameter identification in operational conditions. It is very attractive because of the related opportunities of application of dynamic tests as a tool for periodic inspections while significantly mitigating their impact on the traffic flow. In this framework the instrumented vehicle acts as a dynamic measurement device for periodic inspections and provides valuable information on the structural response of the bridge at a low-cost. Vehicle-bridge interaction models are here applied to realistically simulate the traffic-induced vibration response of bridges and assess the accuracy of modal parameter estimates obtained from indirect vibration measurements characterized by different noise levels. Full article

The paper takes an analysis of traffic conditions in a developing country, namely, India. India is a country with a rapidly growing economy and a large market, and it has the second largest population in the world, which was 1.3 billion in 2018. India also suffers from environmental problems, such as air pollution and global warming that is contributed by traffic CO₂ emissions from transportation. In order to analyze this problem, a particularly challenging issue in developing countries like India, is the collection of traffic data. In general, developing countries do not often have well established infrastructure such as installations of small traffic signals, they lack new road construction and public transportation, etc. This study is the first real traffic congestion analysis in India and introduces unique traffic flow analysis such as: (1) Collecting over a month of recent traffic data in a major city in India, (2) defining traffic congestion from occupancy parameter based on traffic flow theory and observation data, and (3) using geographical special analysis (GIS) for identifying traffic congestion location. These three combination analysis enables one to identify the most congested area in the city with quantitative congestion condition. This study becomes useful to other countries that have similar issues. Full article

A key driver of Australia’s economic development is through promoting migration. A strong bottleneck to achieve the targets is a disproportional concentration of population in the metropolitan cities. To avoid congestion in these cities, emphasis is being given at the government level to promote the regional cities. With different city ranking systems, this study tries to identify linkage between the city ranking and people’s preference to live there. The proposed ranking system uses six components, namely, economy, mobility, environment, people, living, and governance. A comparison is done between the ranking systems by first assigning the same weightage to the six components and then assigning different weightages based on people’s preferences. This study considered 112 Australian cities, which were ranked by considering their performance based on the non-weighted and weighted parameters. Analytical Hierarchy Process is then used to assign the priorities/preferences of the components, factors, and indicators. The study also incorporates clustering technique to address the issue of missing data/information that is a typical problem with small cities where missing data is a common issue. The results of the comparison demonstrate that assigning weightage to ranking parameters makes the city ranking closer to the preference of people to live in a city. It is also recommended that the city ranking system and urban governance should have closer connection to each other. The lowest performing city ranking parameter should be given higher preferences in urban management and development plans. Full article

Smart mobility is becoming an alternative technology of transportation development for today and the future. Thailand has applied the intelligent transport system (ITS) to improve traffic and transport services. The success of the project is generally dependent on collaboration between private, public, and governmental agencies in policymaking and planning, coupled with an inclusive agreement and technological knowledge in the field. This study argues that Thailand’s automatic transportation has been successful because of cooperative-ITS (C-ITS). This study explores the evidence-based cases of ITS development from six areas, Singapore, South Korea, Japan, China, the European Union, and the United States of America, to explain how the C-ITS conditions support the success of ITS. The study uses the SWOT (Strength, Weakness, Opportunity, Threat) and TOWS (Threat, Opportunity, Weakness, Strength) analysis matrix to identify influential factors from the six-area cases and compare them to Thailand. The authors identified seven components that relate to the success of Thailand’s C-ITS. These include: (1) Pragmatic policy for pilot project implementation; (2) close cooperation among stakeholders; (3) working criteria for C-ITS development; (4) architecture of standard and framework; (5) share of lessons learned about current technology; (6) capability of C-ITS deployment; and (7) a clear statement of data exchange and sharing. These findings represent both the threat and opportunity for traffic and transport improvement in Thailand through the C-ITS approach. Full article

The use of waste materials in road construction is becoming widely spread due to economic and environmental needs. Construction and demolition waste materials and mining residues have been studied for a long time. However, the use of fine materials, mainly from mine tailing and mining residue, is still complex, as they can be used as inert materials into the mix or can become a reactive agent in geopolymer mixes. In the present paper, an experimental application of basalt powder is proposed in the geopolymerisation reaction to produce artificial aggregates. In order to understand the input and output variables’ interactions used in the mix design, a statistical method called Design of Experiments was applied. With this design approach, it was possible to optimize the mix design of the experimental geopolymer mortars. The study evaluated several mixes with respect to their workability, compressive strength, and success rate of aggregates production. Finally, a model for predicting compressive strength is proposed and evaluated. Full article

Cycling for transportation is an important resource to reduce urban traffic congestion, enhance personal health, reduce energy consumption, and improve air quality, and the safety of cyclists in the cities is becoming a topic of growing interest. As shown in the literature, an important number of cyclist fatalities is due to road crashes occurring at urban intersections. This study combines a probabilistic and a damage model to perform a risk analysis for the collisions between motor vehicles and bicycles in the merging and diverging conflict points of a single-lane conventional roundabout with four arms, characterized by a permanent traffic flow. The probabilistic model is based on Poisson’s law and is aimed to measure the probability of a collision between bikes and motor vehicles within the elementary unit of exposure in each conflict point of the roundabout. The damage model exploits the reaction time of a road user to avoid a collision and has been built to develop a danger classification for the conflict points. The goal of this study is then to estimate the so-called risk of collision at the roundabout, to compare different possible layouts for various traffic volumes with increasing bike flows and geometric configurations, and to identify the most effective solutions to improve safety for cyclists. The results demonstrate the risk reduction given by a roundabike compared to a standard layout where cyclists and motor vehicles share the circulatory roadway. Therefore, the study here presented could help road managers to implement mitigation strategies taking into consideration both geometric and functional constraints. Full article

Municipal solid waste (MSW) landfills near a metropolitan area are renewable energy resources to produce heat and methane that can generate electricity. However, it is difficult to use those sources productively because disposed MSW in landfills are spatially and temporally heterogeneous. Regarding the prediction of the sources, the analysis of in situ MSW properties is an alternative way to reduce the uncertainty and to understand complex processes undergoing in the landfill effectively. A hydraulic profiling tool (HPT) and membrane interface probe (MIP) test measures the continuous profile of MSW properties with depth, including hydraulic pressure, temperature, electrical conductivity (EC), and the relative concentration of methane at the field. In this study, we conducted a series of the tests to investigate the MSW characteristics of active and closed landfills. MIP results showed that the methane existed closer to right below the top cover in the active landfill and several peak concentrations at different layers of the closed landfill. As the depth and age of the waste increased, the hydraulic pressure increased for both landfills. The average EC results showed that the electrical conductivity decreased with the landfill age. The results of hydraulic properties, temperature, and EC obtained from active and closed sites could be used to estimate the waste age and help designing energy recovery systems. Full article

Overconsolidated (OC) soils may develop a low or negative pore pressure during PCPT. Thus, it is challenging to develop an “on-the-fly” estimation of hydraulic conductivity from PCPT results. This study presents a method to estimate the hydraulic conductivity of OC soils from PCPT results based on a previously developed method for normally consolidated (NC) soils. To apply the existing method, PCPT pore pressure in OC soils is adjusted by using a correction factor. An equation for the correction factor is derived based on the concepts of critical state soil mechanics, cavity expansion, and consolidation theories. Then, it was reformulated so that traditional cone indices could be used as input parameters. It is shown that the correction factor is mainly influenced by the cone tip resistance, pore pressure, and the rigidity index. The comparison of predicted, which is based on corrected pore pressure and measured hydraulic conductivity showed a good match for four well documented data sets. With the findings of the study, it is expected that an “on-the-fly” estimation of hydraulic conductivity of overconsolidated soils is possible. Full article