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Infrastructures (ISSN 2412-3811) is an international scientific peer-reviewed open access journal on infrastructures published quarterly online by MDPI. The journal collaborates with the Spanish Road Technology Platform /Plataforma Tecnológica Española de la Carretera (PTC). Infrastructures is affiliated to International Society for Maintenance and Rehabilitation of Transport Infrastructures (iSMARTi).
- Open Access free for readers, free publication for well-prepared manuscripts submitted in 2018.
- Rapid publication: manuscripts are peer-reviewed and a first decision provided to authors approximately 24 days after submission; acceptance to publication is undertaken in 3.8 days (median values for papers published in the first six months of 2018).
- Recognition of reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
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Latest Articles
Monitoring the Impact of Groundwater Pumping on Infrastructure Using Geographic Information System (GIS) and Persistent Scatterer Interferometry (PSI)
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Infrastructures 2018, 3(4), 57; https://doi.org/10.3390/infrastructures3040057 - 15 December 2018
Abstract
Transportation infrastructure is critical for the advancement of society. Bridges are vital for an efficient transportation network. Bridges across the world undergo variable deformation/displacement due to the Earth’s dynamic processes. This displacement is caused by ground motion, which occurs from many natural and
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Transportation infrastructure is critical for the advancement of society. Bridges are vital for an efficient transportation network. Bridges across the world undergo variable deformation/displacement due to the Earth’s dynamic processes. This displacement is caused by ground motion, which occurs from many natural and anthropogenic events. Events causing deformation include temperature fluctuation, subsidence, landslides, earthquakes, water/sea level variation, subsurface resource extraction, etc. Continual deformation may cause bridge failure, putting civilians at risk, if not managed properly. Monitoring bridge displacement, large and small, provides evidence of the state and health of the bridge. Traditionally, bridge monitoring has been executed through on-site surveys. Although this method of bridge monitoring is systematic and successful, it is not the most efficient and cost-effective. Through technological advances, satellite-based Persistent Scatterer Interferometry (PSI) and Geographic Information Systems (GIS) have provided a system for analyzing ground deformation over time. This method is applied to distinguish bridges that are more at risk than others by generating models that display the displacement at various locations along each bridge. A bridge’s health and its potential risk can be estimated upon analysis of measured displacement rates. In return, this process of monitoring bridges can be done at much faster rates; saving time, money and resources. PSI data covering Oxnard, California, revealed both bridge displacement and regional ground displacement. Although each bridge maintained different patterns of displacement, many of the bridges within the Oxnard area displayed an overall downward movement matching regional subsidence trends observed in the area. Patterns in displacement-time series plots provide evidence for two types of deformation mechanisms. Long-term downward movements correlate with the relatively large regional subsidence observed using PSI in Oxnard. Thermal dilation from seasonal temperature changes may cause short-term variabilities unique to each bridge. Overall, it may be said that linking geologic, weather, and groundwater patterns with bridge displacement has shown promise for monitoring transportation infrastructure and more importantly differentiating between regional subsidence and site-specific displacements.
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Integration of Thermoactive Metro Stations in a Smart Energy System: Feedbacks from the Grand Paris Project
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Infrastructures 2018, 3(4), 56; https://doi.org/10.3390/infrastructures3040056 - 10 December 2018
Abstract
During the next 15 years, around 200 km of tunnels and 68 new metro stations will be built around Paris to increase the capacity of the existing metro and the transport efficiency. The Société du Grand Paris—the public entity in charge of the
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During the next 15 years, around 200 km of tunnels and 68 new metro stations will be built around Paris to increase the capacity of the existing metro and the transport efficiency. The Société du Grand Paris—the public entity in charge of the design and the execution of this new network—is also highly concerned by the development and the use of renewable energy within this project, especially the integration of thermoactive metro stations in a smart energy system. This paper discusses some issues related to this strategy within the “Grand Paris Project”. The first part presents how smart technology could help to the integration of thermoactive metro stations into the urban energy system, while the second part addresses the following issues: assessment of the geothermal potential, estimate of the energy demand, ground investigations, thermal design, and finally system monitoring. The mechanical design is not considered in this paper. The paper shows the pertinence of the smart energy system for the integration of the thermoactive metro stations energy and the procedure for its implementation.
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Fit-for-Purpose Infrastructure Asset Management Framework for Water Utilities Facing High Uncertainties
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Infrastructures 2018, 3(4), 55; https://doi.org/10.3390/infrastructures3040055 - 4 December 2018
Abstract
Traditional infrastructure asset management is about maintaining the status quo of service levels in a resource-restricted, sometimes risk-increasing environment. Infrastructure asset management (IAM) is effective in addressing resource-deprived situations and in maximizing the benefits of the utility in these contexts. This makes IAM
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Traditional infrastructure asset management is about maintaining the status quo of service levels in a resource-restricted, sometimes risk-increasing environment. Infrastructure asset management (IAM) is effective in addressing resource-deprived situations and in maximizing the benefits of the utility in these contexts. This makes IAM a very appropriate and useful approach for developing countries. Hence, this paper focuses on developing a fit-for-purpose integrated asset management (IAM) framework that is suitable for situations where there are risks to assets, significant uncertainties, and resource deficits, and where improvements to the current service levels are needed. To be comprehensive in the application in these contexts, there is a need to supplement IAM with a new perspective—critical necessities, next to the risks to the status quo (current levels of service). This gap was evident during application of IAM principles to the drinking water system of Al-Mafraq, Jordan. It was overcome by framing questions on adaptation deficits and future needs that are to be answered together with risk matrix-based prioritization of asset management actions. The fit-for-purpose IAM framework comprising asset management, adaptation deficit, and future needs can ensure the continuity of service levels in emerging cities when supported through expert inputs and stakeholder consultations.
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Graphical abstract
An Assessment of Sustainable Airport Water Management: The Case of Osaka’s Kansai International Airport
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Infrastructures 2018, 3(4), 54; https://doi.org/10.3390/infrastructures3040054 - 29 November 2018
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Airports are an essential infrastructure to facilitate aviation. The substantial growth of aviation has led to a significant increase in water usage by airports. Airports also generate large volumes of wastewater that may include contaminants. Hence, understanding sustainable water management practices is essential
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Airports are an essential infrastructure to facilitate aviation. The substantial growth of aviation has led to a significant increase in water usage by airports. Airports also generate large volumes of wastewater that may include contaminants. Hence, understanding sustainable water management practices is essential in the aviation industry. In this study, an exploratory research design was utilized in the examination of the sustainable water management strategies and systems at Kansai International Airport from 2002 to 2016. The qualitative data were examined using document analysis as part of a case study. The quantitative data were analyzed using regression analysis as part of a longitudinal study. The airport has been able to reduce the total water consumption, water consumption per passenger, and water consumption per aircraft movement, even with increased traffic in recent years. The airport sources water from the municipal authorities and reclaims water for non-potable water uses. The airport conducts regular water quality tests which measure the Chemical oxygen demand, total nitrogen, and total phosphates. The airport’s onsite wastewater processing centre processes all wastewaters, which discharges non-reclaimed water into Osaka Bay. With a decrease in water consumption, there has similarly been a decrease in the need to treat wastewater, while the reclaimed water ratio has increased over the period of the study.
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Will Updated Electricity Infrastructure Security Protect the Grid? A Case Study Modeling Electrical Substation Attacks
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Infrastructures 2018, 3(4), 53; https://doi.org/10.3390/infrastructures3040053 - 20 November 2018
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As targeted attacks continue to threaten electricity infrastructure, the North American Electricity Reliability Corporation (NERC) and private utilities companies are revising and updating the physical and cybersecurity standards for grid infrastructure in the United States (U.S.). Using information collected about past physical attacks,
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As targeted attacks continue to threaten electricity infrastructure, the North American Electricity Reliability Corporation (NERC) and private utilities companies are revising and updating the physical and cybersecurity standards for grid infrastructure in the United States (U.S.). Using information collected about past physical attacks, feasible physical and cyber-physical attacks are modeled against the proposed updated security standards for a U.S.-based generic electric substation. Utilizing the software program Joint Conflict and Tactical Simulation (JCATS), a series of increasingly sophisticated physical attacks are simulated on the substation, as are a set of cyber-enabled physical attacks. The purpose of this study is to determine which of the security upgrades will be most effective at mitigating damages to the electrical infrastructure from an attack. The findings indicate that some of the utility and agency-proposed security measures are more effective than others. Specifically, additional barriers around the substation and physical armored protection of transformers are most effective at mitigating damages from attacks. In contrast, increased lighting at the substation and reducing the surrounding foliage are not as effective. This case study demonstrates a modeling analysis approach to testing the efficacy of physical security measures that can assist in utility and agency decision-making for critical infrastructure security.
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Experimental Analysis of the Strengthening of Reinforced Concrete Beams in Shear Using Steel Plates
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Infrastructures 2018, 3(4), 52; https://doi.org/10.3390/infrastructures3040052 - 16 November 2018
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In some situations, it is necessary to strengthen or rehabilitate a structure in the short term, but before doing so, a critical analysis of the underlying causes is required to find the best technique to solve the problem. The structural strengthening is used
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In some situations, it is necessary to strengthen or rehabilitate a structure in the short term, but before doing so, a critical analysis of the underlying causes is required to find the best technique to solve the problem. The structural strengthening is used to increase an element’s ability to resist a stress when it no longer meets the original conditions or new necessities of use due to faults, deterioration, thermal variations, and lack of maintenance. The present article aims to evaluate the strengthening of reinforced concrete beams with 0.75 mm thick SAE 1020 steel plates bonded with epoxy-based structural adhesive. The steel plates were attached to the sheared area before and after the beams were taken to the breaking point load. According to the results, it was possible to conclude the effectiveness of the strengthening applied to healthy beams that had its bearing capacity increased up to 50%. The beam that was strengthened after the shear, with a fissure that was restored with epoxy-based structural adhesive, had its load bearing capacity increased by 49.2%. The beams with fissures that were filled with mortar had their bearing capacity decreased by 58.70% if compared with the reference beams, and thus they presented an unsatisfactory performance.
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Challenges and Opportunities of Crowdsourcing and Participatory Planning in Developing Infrastructure Systems of Smart Cities
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Infrastructures 2018, 3(4), 51; https://doi.org/10.3390/infrastructures3040051 - 14 November 2018
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The concept of Smart City aims to provide its citizens with infrastructure systems that make cities safer and more livable. One of the methods for doing so is collecting data from the crowd itself—termed crowdsourcing—and incorporating their ideas to improve the existing facilities,
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The concept of Smart City aims to provide its citizens with infrastructure systems that make cities safer and more livable. One of the methods for doing so is collecting data from the crowd itself—termed crowdsourcing—and incorporating their ideas to improve the existing facilities, as well as build new ones to cater to their arising needs. This paper aims to inspect the attributes that govern crowdsourcing, evaluating its feasibility in attaining solutions in the present scenario. A systemic review of the existing literature on crowdsourcing platforms was conducted and major findings have been summarized adequately. The areas of environment, disaster management, public safety, innovation, transportation and health have been explored in connection to the existing crowdsourcing platforms and selected examples have been mentioned. Next, the attributes that affect crowdsourcing have been discussed in detail under three broad categories: (1) human characteristics; (2) data characteristics and (3) system characteristics. In the end, some recommendations for improvement in the implementation of the crowdsourcing platforms have been proposed for their enhanced applicability and effectiveness.
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Implementation of Advanced Demand Side Management for Microgrid Incorporating Demand Response and Home Energy Management System
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Infrastructures 2018, 3(4), 50; https://doi.org/10.3390/infrastructures3040050 - 13 November 2018
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To facilitate the possible technology and demand changes in a renewable-energy dominated future energy system, an integrated approach that involves Renewable Energy Sources (RES)-based generation, cutting-edge communication strategies, and advanced Demand Side Management (DSM) is essential. A Home Energy Management System (HEMS) with
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To facilitate the possible technology and demand changes in a renewable-energy dominated future energy system, an integrated approach that involves Renewable Energy Sources (RES)-based generation, cutting-edge communication strategies, and advanced Demand Side Management (DSM) is essential. A Home Energy Management System (HEMS) with integrated Demand Response (DR) programs is able to perform optimal coordination and scheduling of various smart appliances. This paper develops an advanced DSM framework for microgrids, which encompasses modeling of a microgrid, inclusion of a smart HEMS comprising of smart load monitoring and an intelligent load controller, and finally, incorporation of a DR strategy to reduce peak demand and energy costs. Effectiveness of the proposed framework is assessed through a case study analysis, by investigation of DR opportunities and identification of energy savings for the developed model on a typical summer day in Western Australia. From the case study analysis, it is evident that a maximum amount of 2.95 kWh energy can be shifted to low demand periods, which provides a total daily energy savings of 3%. The total energy cost per day is AU$2.50 and AU$3.49 for a house with and without HEMS, respectively. Finally, maximum possible peak shaving, maximum shiftable energy, and maximum standby power losses and energy cost savings with or without HEMS have been calculated to identify the energy saving opportunities of the proposed strategy for a microgrid of 100 houses with solar, wind, and a back-up diesel generator in the generation side.
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Risk and Resilience at the Oroville Dam
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Infrastructures 2018, 3(4), 49; https://doi.org/10.3390/infrastructures3040049 - 6 November 2018
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Existing analyses of the February 2017 Oroville Dam Crisis identify maintenance failures and engineering shortcomings as the root cause of a nearly catastrophic failure of the tallest dam in the United States. However, the focus on technical shortcomings largely overlooks the role of
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Existing analyses of the February 2017 Oroville Dam Crisis identify maintenance failures and engineering shortcomings as the root cause of a nearly catastrophic failure of the tallest dam in the United States. However, the focus on technical shortcomings largely overlooks the role of adaptive decision-making that eventually averted the crisis. Understanding the decisions that both created the circumstances leading up to the crisis and saved the dam from collapse requires that risk analysis be complemented by a resilience perspective. This paper presents a case study on the Oroville Dam Crisis to develop a timeline of failures and successes in the resilience processes of sensing, anticipation, adapting, and learning throughout the history of the dam. Three factors that drove poor operational and engineering decisions include: (1) misalignment of technical nomenclature and design requirements for the ungated spillway, (2) overconfidence in original engineering designs, and (3) conflicting pressure from diverse stakeholders. These factors contributed to unrealistic perceptions of dam capabilities and promoted decisions to forgo maintenance and design efforts that may have mitigated the danger.
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Structural Safety Analysis of the Aqueducts “Coll De Foix” and “Capdevila” of the Canal of Aragon and Catalonia
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Infrastructures 2018, 3(4), 48; https://doi.org/10.3390/infrastructures3040048 - 5 November 2018
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The Canal of Aragon and Catalonia (CAC) is 134 km long and irrigates 105,000 ha (131 irrigation user communities) and it is owned by the River Ebro’s Water Agency. The aqueducts are located between km 67 and 71 of the canal and were
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The Canal of Aragon and Catalonia (CAC) is 134 km long and irrigates 105,000 ha (131 irrigation user communities) and it is owned by the River Ebro’s Water Agency. The aqueducts are located between km 67 and 71 of the canal and were designed by the civil engineer Félix de los Ríos Martín in 1907. The cross-section of both aqueducts, Coll de Foix and Capdevila, was extended within the framework of the project by Fernando Hué Herrero in 1962 in order to reach design flows of 26.1 m3/s and 25.7 m3/s, respectively. The structural performance of the aqueducts has been satisfactory; nevertheless, the hydraulic capacity has reduced over the years. As a result, the irrigation user communities have expressed the need to extend the cross-section of the aqueducts to meet the irrigation demands. Given the age of the structure and the different design considerations at the time, it is paramount to verify the structural reliability of the aqueducts in the new load configuration. Therefore, the objective of this contribution is to present the structural safety analysis conducted and to describe the new extended cross-section for both aqueducts (maintaining the original structural typology).
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A Comparative Study of Laser Doppler Vibrometers for Vibration Measurements on Pavement Materials
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Infrastructures 2018, 3(4), 47; https://doi.org/10.3390/infrastructures3040047 - 1 November 2018
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A laser Doppler vibrometer (LDV) is a noncontact optical measurement device to measure the vibration velocities of particular points on the surface of an object. Even though LDV has become more popular in road engineering in recent years, their signal-to-noise ratio (SNR) is
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A laser Doppler vibrometer (LDV) is a noncontact optical measurement device to measure the vibration velocities of particular points on the surface of an object. Even though LDV has become more popular in road engineering in recent years, their signal-to-noise ratio (SNR) is strongly dependent on light scattering properties of the surface which, in some cases, needs to be properly conditioned. SNR is the main limitation in LDV instrumentation when measuring on low diffusive surfaces like pavements; therefore, an investigation on the SNR of different LDV devices on different surface conditions is of great importance. The objective of this research is to investigate the quality of two types of commercially available LDV systems—helium–neon (He–Ne)-based vibrometers and recently developed infrared vibrometers—on different surface conditions, i.e., retroreflective tape, white tape, black tape, and asphalt concrete. Both noise floor and modal analysis experiments are carried out on these surface conditions. It is shown that the noise floor of the He–Ne LDV is higher when dealing with a noncooperative dark surface, such as asphalt concrete, and it can be improved by improving the surface quality or by using an infrared LDV, which consequently improves the modal analysis experiments performed on pavement materials.
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Hotels as Critical Hubs for Destination Disaster Resilience: An Analysis of Hotel Corporations’ CSR Activities Supporting Disaster Relief and Resilience
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Infrastructures 2018, 3(4), 46; https://doi.org/10.3390/infrastructures3040046 - 18 October 2018
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Disaster management has begun to examine the unique role of the private sector in disaster relief. The hotel and lodging industry is an especially critical infrastructure for community disaster relief and resilience, providing many lifeline services in addition to core skills and competencies
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Disaster management has begun to examine the unique role of the private sector in disaster relief. The hotel and lodging industry is an especially critical infrastructure for community disaster relief and resilience, providing many lifeline services in addition to core skills and competencies contributing to the community’s social and human capital. Social and human capital empower the community to better cope with disturbance, and companies’ efforts to build social and human capital are often tied to their corporate social responsibility (CSR) management systems. A framework was developed to evaluate the management system maturity of the hotel and lodging industry’s CSR management for disaster relief and resilience. An analysis of three hotel and lodging corporations was performed to understand the current state of the industry. While many hotel properties are engaging in CSR activities during disaster relief, the analysis revealed that corporate management systems have room for maturation and growth to support the resilience of their community.
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Infrared Thermography for Weld Inspection: Feasibility and Application
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Infrastructures 2018, 3(4), 45; https://doi.org/10.3390/infrastructures3040045 - 9 October 2018
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Traditional ultrasonic testing (UT) techniques have been widely used to detect surface and sub-surface defects of welds. UT inspection is a contact method which burdens the manufacturer by storing hot specimens for inspection when the material is cool. Additionally, UT is only valid
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Traditional ultrasonic testing (UT) techniques have been widely used to detect surface and sub-surface defects of welds. UT inspection is a contact method which burdens the manufacturer by storing hot specimens for inspection when the material is cool. Additionally, UT is only valid for 5 mm specimens or thicker and requires a highly skilled operator to perform the inspections and interpret the signals. Infrared thermography (IRT) has the potential to be implemented for weld inspections due to its non-contact nature. In this study, the feasibility of using IRT to overcome the limitations of UT inspection is investigated to detect inclusion, porosity, cracking, and lack of fusion in 38 weld specimens with thicknesses of 3, 8 and 13 mm. UT inspection was also performed to locate regions containing defects in the 8 mm and 13 mm specimens. Results showed that regions diagnosed with defects by the UT inspection lost heat faster than the sound weld. The IRT method was applied to six 3 mm specimens to detect their defects and successfully detected lack of fusion in one of them. All specimens were cut at the locations indicated by UT and IRT methods which proved the presence of a defect in 86% of the specimens. Despite the agreement with the UT inspection, the proposed IRT method had limited success in locating the defects in the 8 mm specimens. To fully implement in-line IRT-based weld inspections more investigations are required.
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Evaluation of the Bond-to-Concrete Properties of GFRP Rebars in Marine Environments
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Infrastructures 2018, 3(4), 44; https://doi.org/10.3390/infrastructures3040044 - 8 October 2018
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Increased traffic in combination with growing environmental impacts have led to the accelerated degradation of built infrastructure. In reinforced concrete structures, the corrosion of steel reinforcement is the predominant cause of deterioration. Thus, over the last years the use of glass fiber reinforced
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Increased traffic in combination with growing environmental impacts have led to the accelerated degradation of built infrastructure. In reinforced concrete structures, the corrosion of steel reinforcement is the predominant cause of deterioration. Thus, over the last years the use of glass fiber reinforced polymer (GFRP) composites as internal reinforcement bars (rebars) for concrete structures has been evaluated, and has been proved to be a viable alternative to traditional steel reinforcement mainly due to its tensile strength and non-corrosive nature. However, thus far, the GFRP rebar market is diverse and manufacturers around the world produce GFRP rebar types with different surface enhancements to improve the bond to concrete characteristics. In this study, the bond performance of three dissimilar GFRP rebar types (sand coated, helically grooved and with surface lugs) was evaluated over time in seawater environments, with a focus on the bond strength. Accordingly, specimens were exposed to seawater in circulating chambers at three different temperatures (23 °C, 40 °C and 60 °C) for multiple time periods (60 and 120 days). To evaluate the bond performance, pullout tests were conducted according to ASTM D7913. The results showed that the bond strength varied with the surface enhancement features. However, the bond strength did not vary significantly with exposure time and temperature for all three evaluated rebar types.
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Smart Libraries
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Infrastructures 2018, 3(4), 43; https://doi.org/10.3390/infrastructures3040043 - 29 September 2018
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Can the smart city provide a new perspective for public and academic libraries? How does the smart city impact the libraries as cultural and scientific assets? And how can libraries contribute to the development of the smart city? An overview of recent library
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Can the smart city provide a new perspective for public and academic libraries? How does the smart city impact the libraries as cultural and scientific assets? And how can libraries contribute to the development of the smart city? An overview of recent library models, like the learning center or the green library, reveals affinities with the concept of the smart city, especially regarding the central role of information and the integration of technology, people, and institutions. From this observation, the paper develops the outline of a new concept of the smart library, which can be described in four dimensions, i.e., smart services, smart people, smart place, and smart governance. However, the smart library concept does not constitute a unique model or project, but a process, a way of how to get things done, that is less linear, less structured, and more creative and innovative. Also, smartness may not be a solution for all library problems.
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Beneficial Uses of Dredged Material in Green Infrastructure and Living Architecture to Improve Resilience of Lake Erie
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Infrastructures 2018, 3(4), 42; https://doi.org/10.3390/infrastructures3040042 - 27 September 2018
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To maintain the navigational depth, 1.15 million cubic meters (1.5 million cubic yards) of sediment is dredged out from the federal harbors every year from Lake Erie, Ohio Coast. Treating this huge amount of dredged material is a major challenge due to the
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To maintain the navigational depth, 1.15 million cubic meters (1.5 million cubic yards) of sediment is dredged out from the federal harbors every year from Lake Erie, Ohio Coast. Treating this huge amount of dredged material is a major challenge due to the mobilization of potential contaminants causing depreciation in water quality and depletion of valuable land. Rather than treating the dredged material as a waste, we suggest investigating alternative ways to recycle and reuse the material within Green Infrastructure (GI) and living architecture applications. This study identifies potential applications of the dredged material in bioretention and vegetative roof systems, and examines the role of dredged material in these edaphic conditions. The paper discusses the beneficial uses of dredged material in GI by investigating the quality of dredged material and performances of GI built using dredged material through laboratory and field-testing. Preliminary results of a growth media using dredged material for the vegetative roof have been developed in lab/field studies that possess the performance values comparable to the current commercial product. The growth media containing lightweight aggregate, made from the dredged material, is observed to have high water retention capacity and high unit weight in comparison to a commercial product. The growth media leachate water test demonstrated the water quality to be comparable to the drained water from the commercial product. The growth media overwintered and advanced a rare plant species, Viola pedatifida, which is similar to conventional media. The beneficial uses of dredged material in the GI will help maintain the economic viability of harbors and ports along the shoreline of Lake Erie in Ohio and GIs, which were built using dredged material that can help address storm water management issues in urban areas due to extensive impervious surfaces.
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Graphical abstract
Behavior of Geogrid-Reinforced Portland Cement Concrete under Static Flexural Loading
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Infrastructures 2018, 3(4), 41; https://doi.org/10.3390/infrastructures3040041 - 26 September 2018
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Geogrids have been investigated by a limited number of studies as a potential alternative to steel reinforcement for Portland cement concrete (PCC), especially in situations where using steel reinforcement may not be suitable due to constructability and durability limitations. This study aims to
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Geogrids have been investigated by a limited number of studies as a potential alternative to steel reinforcement for Portland cement concrete (PCC), especially in situations where using steel reinforcement may not be suitable due to constructability and durability limitations. This study aims to investigate the flexural behavior of simply-supported concrete beams reinforced by geogrids, which would aid in assessing the potential use of geogrids for concrete structures such as overlays and other thin sections. Another objective of this study is to examine the potential benefits of embedding geogrids in PCC, and to investigate the mechanism and effectiveness of geogrid reinforcement in PCC. Plain and geogrid-reinforced concrete beams were fabricated and tested under a static four-point flexural bending load. The midspan deflection and crack mouth opening displacement (CMOD) of the beams were recorded during loading. Additionally, for geogrid-reinforced beams, strain gages were attached on the geogrids to monitor the strains that developed in geogrids. Results reveal that the geogrid primarily contributes to improving the ductility of the post-peak behavior of plain concrete and to delaying the collapse failure of concrete beams. Strain measurements of the geogrids indicate that the geogrids were activated and mobilized instantly upon the application of the flexural load. Both the strain measurements and observations of the geogrids post failure suggest that there was no slippage between the geogrids and the concrete.
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Developing an Open Space Standard in a Densely Populated City: A Case Study of Chittagong City
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Infrastructures 2018, 3(3), 40; https://doi.org/10.3390/infrastructures3030040 - 19 September 2018
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In densely populated settings like Chittagong, Bangladesh cities facing rapid urbanization and economic growth are challenged to provide open space for its citizens. For example, the population of this port city is 14,200 people per square kilometer and there is a struggle to
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In densely populated settings like Chittagong, Bangladesh cities facing rapid urbanization and economic growth are challenged to provide open space for its citizens. For example, the population of this port city is 14,200 people per square kilometer and there is a struggle to provide open space. Again, the planning proposal did not set any open space standard to achieve its open space aspirations Hence, the objectives of this paper are four-fold: (i) Develop an understanding of open space standards to establish relative benchmarks for potential use in Chittagong. (ii) Examine existing formal open space in Chittagong. (iii) Document the existing informal open space areas in Chittagong according to the planning direction. (iv) Recommend an approach that can be used to realize open spaces in Chittagong. To achieve these, this paper documents the existing open space scenario in the city, examines the recommended open space standards developed by organizations such as the World Health Organization (WHO) and the Dhaka Structural Plan (2016–2035) (the planning document of the capital city of Bangladesh) to identify to what extent these ‘benchmark’ standards are appropriate for use in the city. A discussion on open space in Chittagong and the criteria used to ‘frame’ open space calculations in the city is then conducted to provide a foundation to reflect upon the world’s various open space recommendations. Ultimately, by analyzing existing open space recommendations and their associated well-being aspirations, the research suggests that a new standard relating to the unique characteristics of the city should be used when developing open space standards in Chittagong.
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Structural Behavior of the General Archive of the Nation (AGN) Building, Mexico
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Infrastructures 2018, 3(3), 39; https://doi.org/10.3390/infrastructures3030039 - 18 September 2018
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This article presents a study on the structural behavior of the Government Building that is part of the old Lecumberri Palace and which currently houses the Mexican General Archive of the Nation. This building was inaugurated in 1900 and closed in 1976, after
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This article presents a study on the structural behavior of the Government Building that is part of the old Lecumberri Palace and which currently houses the Mexican General Archive of the Nation. This building was inaugurated in 1900 and closed in 1976, after serving as a prison for 76 years. It was reopened in 1982 after it had undergone several remodeling works. The construction is made of brick masonry with lime mortar. It is supported by a deposit of overly compressible high-plasticity clays. The main problems of this building are the appearance of cracks in both interior and exterior walls, and moisture in the ground floor, caused by differential settlements. The study entailed a geometric and a damage survey as well as ambient vibration tests in order to determine the dynamic properties of the construction. The data obtained was used for the making of a model that, using the finite element method, was analyzed under different load conditions. This study has focused on the overall response with the assumption of smeared crack damage. According to the results, the building’s safety was deemed as acceptable. It has the capability to withstand seismic actions as established by the Mexican Building Code due to the high density of its walls and the resulting stiffness, which infer that the fundamental vibration period of the building would be distant from the predominant vibration period of the soil. This highlights the idea that the building’s critical condition is constituted by the differential settlements, which cause damage in the construction.
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Experimental Study of the Mechanical Behaviour of Bricks from 19th and 20th Century Buildings in the Province of Zamora (Spain)
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Infrastructures 2018, 3(3), 38; https://doi.org/10.3390/infrastructures3030038 - 16 September 2018
Abstract
Interventions in historic brick buildings require an exhaustive analysis of the current characteristics of bricks in order to establish the role performed by these elements in the buildings. This study presents the results of an experimental analysis of the compressive strength of brick
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Interventions in historic brick buildings require an exhaustive analysis of the current characteristics of bricks in order to establish the role performed by these elements in the buildings. This study presents the results of an experimental analysis of the compressive strength of brick specimens extracted from different buildings built in the 19th and 20th centuries in the province of Zamora (Spain). The study analyses specimens with very different characteristics to compare results from different masonry units and manufacturing processes. Specimens are classified into four groups according to their macroscopic and microscopic analyses. Compressive strength results are correlated to the above classification and to the results of density, absorption and open porosity of the samples. The compressive strength results present high variation between clay bricks (9.2–64.4 N/mm2) and between samples extracted from the same brick due to the heterogeneity of the material. Correlations between compressive strength and open porosity, absorption and dry density values are observed, with less dispersion in the case of high sintering level, up to 1000 °C. Finally, the compliance with the current Spanish Technical Building Code with respect to their compressive strength is checked.
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30 October 2018
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