Infrastructures, Volume 6, Issue 1 (January 2021) – 12 articles

Even though landscape quality is largely a subjective issue, the integration of infrastructure into landscapes has been identified as a key element of sustainability. In a spatial planning context, the landscape impacts that are generated by infrastructures are commonly quantified through visibility analysis. In this study, we develop a new method of visibility analysis and apply it in a case study of a reservoir (Plastiras dam in Greece). The methodology combines common visibility analysis with a stochastic tool for visual-impacts evaluation; points that generate high visual contrasts in landscapes are considered Focus Points (FPs) and their clustering in landscapes is analyzed trying to answer two questions: (1) How does the clustering of Focus Points (FPs) impact the aesthetic value of the landscape? (2) How can the visual impacts of these FPs be evaluated? Visual clustering is calculated utilizing a stochastic analysis of generated Zones of Theoretical Visibility. Based on the results, we argue that if the visual effect of groups of FPs is positive, then the optimal sitting of FPs should be in the direction of faint clustering, whereas if the effect is negative, the optimal sitting of FPs should be directed to intense clustering. In order to optimize the landscape integration of infrastructure, this method could be a useful analytical tool for environmental impact assessment or a monitoring tool for a project’s managing authorities. This is demonstrated through the case study of Plastiras’ reservoir, where the clustering of positively perceived FPs is found to be an overlooked attribute of its perception as a highly sustainable infrastructure project. Full article

The construction sector is responsible for one third of the total wastes produced in the EU. Finding solutions for the reuse or recycling of these wastes is one of the major environmental concerns of modern times. The replacement of sand or cement in specific construction materials, such as concrete or mortars, is a possible solution for these wastes’ management. By using construction and demolition wastes in construction materials, namely on buildings, the cycle of circular economy is closed, increasing the life cycle of the wastes in the same sector. In this research, a reduction of cement content in rendering mortars is analysed. This reduction is achieved by a decrease of the cement/aggregate ratio simultaneously with the incorporation of very fine recycled aggregate from construction and demolition waste. Two recycled aggregates were studied: recycled concrete aggregate (RCA) and mixed recycled aggregate (MRA). The fresh and hardened state properties of the mortars were analysed. Several tests were carried out to evaluate the mortars’ performance, such as mechanical strength tests, water absorption tests, drying tests and shrinkage. It was noticed that the incorporation of RCA led to a better behaviour than in the reference mortar, in terms of mechanical strengths and protection against water. Full article

It is well-known that the ultra-peripheral territories as Islands present several limitations such as the lack of resources, restricted land, mass tourism, and barriers to movement, and connectivity between urban centers. These obstacles make ultra-peripheral regions suitable case studies considering their territorial governance and consequently, sustainable development and growth. Thus, transportation and infrastructure sustainability in these regions are not an exception. Considering all the obstacles present in these regions, the accessibility and connectivity patterns that the local population has in these territories should be assessed and monitored. Thereby, through exploratory tools, the present research assumes to examine, using accessibility and connectivity indicators, the consequences across the social-economic dimension that the regional transportation and infrastructure should convey to the Azores Islands Archipelago populations. Therefore, this article allows us to set the present situation regarding this region’s accessibility and connectivity patterns, creating an additional tool for supporting the main actors’ design and implementation of these territories’ future plans and strategies. Besides, this study enables us to recognize that Pico, Flores, and São Miguel are the ones with better accessibility patterns within the Azores Archipelago. Full article

To ensure the sustainable development of the water and wastewater (WSS) sectors, new and more investments are needed. However, private financing in these sectors has not been successfully leveraged. This study conducted a systematic literature review of peer-reviewed papers in this field, to provide an overview of how researchers have been studying the financing endeavors of the WSS sectors. A three-part framework was carried out: retrieval of papers from search engines (Scopus and ASCE Library), focused on the title, abstract, and keywords; process of elimination of papers; and analysis of the selected papers based on the hybrid method combining a systematic quantitative review, a semantic network analysis, and a narrative analysis. This research resulted in the identification of four most studied areas: sustainable development; water management and public finance; project financing; and public policy. Future research should focus on existing financing instruments and how these can specifically be applied in the WSS sectors successfully. This paper makes several contributions to the literature because it addresses and emphasizes the most important financing issues in WSS, reviews the insights found, and discusses the future research needs. In addition, it demonstrates the benefits of using a hybrid methodology that could be adopted in other literature review studies. Full article

The city of L’Aquila (Italy) includes a significant amount of masonry palaces erected from the middle of the 13th century up to the first half of the 20th century. This paper focuses on the seismic response of a masonry palace built during the first half of the 20th century and characterized by regularity in plan and elevation. The authors investigate the seismic response by varying a suite of modelling parameters that express the actual scatter of the mechanical properties typical of the masonry palaces erected in L’Aquila. The authors discuss the seismic performance exhibited by this building during the 2009 earthquake. Then, they assess the sensitivity of the selected building’s seismic performance via non-linear static analysis to the mechanical properties of masonry, the in-plane stiffness of the floors, and the mechanical resistance of the spandrels. The parametric analysis shows that the three variables markedly affect the shear resistance, the ultimate displacement, and the behavior factors. The fragility functions were then estimated from the results of non-linear static analysis. A significant scatter of the probability of collapse for the considered limit states reveals the limitations of typological approaches for masonry palaces. Full article

Road networks are disseminated of bridge structures whose typology reflects the time of design and construction of the transportation infrastructure and its relevance in the reference geographical area. Among others, masonry bridges are still widely operational, especially in those regions affected by a limited urbanization and a very high landscape value. As a consequence, the maintenance and the reliability of existing structures is a key issue for owners and managers of road and railway infrastructures. This circumstance leads to the development of an integrated approach able to cover the needs of knowledge of the technological and structural features of the bridge along with its history and current conditions. The main contribution of the study lies in the implementation of such an interdisciplinary approach through the application of archaeological stratigraphic method and 3D data management to historical masonry bridges. The survey and inspection protocol, whose first results are here presented, aims to improve the knowledge of the assets, and facilitate the visual inspection. The results refer to a road infrastructure located along the Aterno River in the surroundings of L’Aquila (Central Italy) and point out promising perspectives in terms of feasibility and scalability of the approach to large stocks of assets. Full article

The primary focus of this study is to evaluate the nonlinear response of reinforced concrete (RC) frames with two types of brick infills viz., unreinforced brick masonry infill (URM) and semi-interlocked brick masonry infill (SIM) together with lintel beams, subjected to seismic loads. The seismic response is quantified in terms of response reduction factor and base shear. Infill walls are modeled using double strut nonlinear cyclic element. Nonlinear static adaptive pushover analysis is performed in the finite element program SeismoStruct. The response reduction factor (R) is computed from adaptive pushover analysis and performance for all models is obtained. The results showed that the average R factor of the RC framed structure with semi-interlocked masonry (SIM) is 1.31 times higher than the RC frame with unreinforced masonry (URM) infill. The R value of the bare frame with the lintel beam is found to be less than the corresponding value recommended in the Indian Standard Code. The results obtained in this study highlight that if the impacts of lintel beams and various brick infill scenarios are considered in the RC frames then the R values used for the design of RC frame buildings with infills would be underestimated (i.e., the evaluated R values are greater than the R values used for the design purpose). Full article

Mild temperature fluctuation of a material sitting on a slope may only cause a small slip, but a large number of the repeated temperature changes can amplify the magnitude of the overall slip and eventually bring an issue of structural instability. The slip accumulation starts from the minor magnitude and reaches the extensive level called “slip ratcheting”. Experimental evidence for such thermally-induced slip ratcheting is first provided in this work. It is implemented with an acryl sheet placed on an inclined wood with a mild angle; it is found that the temperature fluctuation of the acryl sheet causes the sheet to slide down gradually without any additional loading. The numerical model is then attempted to emulate the major findings of the experiments. From the simulation work, the location of a neutral point is found when the acryl plate is heated, and another neutral point is observed when cooled down. The shift of the neutral point appears to be a major reason for the unrecovered slip after a temperature increase and decrease cycle. Finally, a parametric study using the numerical model is carried out to examine which parameters play a major role in the development of residual slips. Full article

Contactless structural monitoring has in recent years seen a growing number of applications in civil engineering. Indeed, the elimination of physical installations of sensors is very attractive, especially for structures that might not be easily or safely accessible, yet requiring the experimental evaluation of their conditions, for example following extreme events such as strong earthquakes, explosions, and floods. Among contactless technologies, vision-based monitoring is possibly the solution that has attracted most of the interest of civil engineers, given that the advantages of contactless monitoring can be potentially obtained thorough simple and low-cost consumer-grade instrumentations. The objective of this review article is to provide an introductory discussion of the latest applications of vision-based vibration monitoring of structures and infrastructures through an overview of the results achieved in full-scale field tests, as documented in the published technical literature. In this way, engineers new to vision-based monitoring and stakeholders interested in the possibilities of contactless monitoring in civil engineering could have an outline of up-to-date achievements to support a first evaluation of the feasibility and convenience for future monitoring tasks. Full article

This article describes the development and demonstration of a non-intrusive method for the quantitative determination of speed of air movement along the ground and inside an isolated subsurface structure, a type of confined space. Natural ventilation occurs continuously and reduces risk to entrants from contact with a hazardous atmosphere. One of the most important parameters still undetermined was the speed of air movement during the process. Small puffs of artificial “smoke” were used to visualize air movement. Tracker, an open-source physics program, provided the capability to analyze this movement. Measurement of air speed requires access to individual frames in the video, capability to move forward and backward, and the means to manipulate the image to highlight the “smoke”. Background subtraction, control of brightness and contrast, and conversion of color to greyscale were essential for obtaining these measurements. Measurements for a single opening indicated that flow along the ground was borderline turbulent (Reynolds number ~3000) and in the opening and inside the airspace, within the bounds of laminar flow (Reynolds number <2250). Video obtained during this work showed behavior observable in laboratory studies of Helmholtz resonators. Results provide the basis for a larger study of the ventilation process to facilitate design improvements. Full article

The aim of this research is to look for an automated, economical and fast method able to identify the elements of an existing road layout, whose original geometric design could date back to distant ages and could have undergone major modifications over the years. The analysis has been directed towards the Italian two-lane rural roads; the national public company ANAS made available its graph, obtained from high-performance surveys, that represents about 90% of these roads’ network. The graph is made up of a collection of georeferenced points but does not recognize or describe the geometric elements making up the roadway. Consequently, it has been necessary to design and develop an original procedure, subsequently implemented in a programming platform, able to identify the characteristics of the several parts, which constitute the reference axes of the existing roads. This research focuses on the horizontal geometry assessing the coherence, consistency and homogeneity of the roads’ layout, through the ex post application of the regulatory model for the design verification. If road sections are identified in which some conditions are not significantly met, further investigation should be conducted in order to ensure road safety and to plan any road upgrading activities. Full article

Liquid-containing structures are used for various municipal and industrial applications. The functionality of these structures in seismic regions is crucial. The main purpose of this study is to investigate the behavior of liquid under seismic excitations using numerical modelling. For this purpose, experimental and numerical studies are conducted. In the experimental tests, a ground-supported rectangular tank is excited on a shaking table. The tests are videotaped from two directions and subsequently analyzed frame-by-frame. Four different orientations are tested to investigate the effect of bilateral excitation. In the numerical simulations, the same tank is modeled in OpenFOAM—a computational fluid dynamics program—and the same excitations are applied. The results from the numerical and the experimental studies are compared, and reliability of the numerical model is discussed. Furthermore, using the numerical model, the pressure on the roof of the tank is obtained at various locations and examined for different excitations. Full article