Infrastructures — Open Access Journal

Prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground of railway tracks, as well as to secure rail gauge for safe train travels. Their design takes into account static and dynamic loading conditions. In spite of prestressed concrete crossties being most commonly used in railway tracks, there have always been many demands from rail engineers to improve the serviceability and functionality of concrete crossties. For example, signaling, fiber optic, equipment cables are often damaged either by ballast corners or by the tamping machine. There has been a need to re-design concrete crossties to incorporate cables internally so that they would not experience detrimental or harsh environments. Also, many concrete crossties need a retrofit for an automatic train control device and similar signaling equipment. In contrast, the effects of holes and web openings on the structural capacity of concrete crossties have not been thoroughly investigated. This paper accordingly highlights the experimental investigations into the effect of holes and web openings on the toughness and ductility of concrete crossties. The key outcome of this research is to enable a better decision making process for retrofitting prestressed concrete crossties with holes and web openings in practice. Full article

Australia’s 560 Councils are responsible for assets worth approximately $270 billion, many of which have a life span >50 years and so will be affected by climate change. Maintenance and replacement of Council infrastructure is guided by principles, models and tools in the International Infrastructure Management Manual that currently do not allow for climate change impacts or the likely flow-on effects to asset and financial management. This paper describes a financial simulation model developed to calculate the financial impacts of climate change on three major asset classes of importance to Australian Councils: hotmix sealed, spray sealed and unsealed roads. The research goes beyond previous studies of climate change impacts on roads in that it provides a location specific toolkit that is designed to assist councils in their asset management and planned maintenance programmes. Two categories of inputs are required for the model: climate inputs, relating specifically to baseline temperature and rainfall distributions and climate change parameters for temperature and rainfall; and engineering inputs, relating specifically to the three road types and the key parameters of their performance and useful lives over the scenario period. The baseline distributions are then shifted mathematically within the model by the mean change as projected by a selected Global Climate Model (GCM) scenario. Outputs of the model are the historical baseline climate variable distributions and the climate change (CC) impacts on road performance are in the form of changes to the useful life of the asset and associated changes in asset resurfacing and rehabilitation costs. Ten case study local councils in southern Australia are examined. Using IPCC AR4 scenarios, the results suggest that the incremental impact of climate change on all three types of road infrastructure modelled will be generally low. There are small cost reductions over the period for all road types as a result of the expected drying and warming trends in the climate. Full article

Although the generation of large points clouds from geomatic techniques allows us to realize the topography and appearance of the terrain and its infrastructures (e.g., roads, bridges, buildings, etc.), all these 3D point clouds require an unavoidable step to be conveniently treated: the definition of the surface that connects these points in space through digital surface models (DSM). In addition, these point clouds sometimes have associated attributes and geometric constraints such as breaklines and/or exclusion areas, which require the implementation of efficient triangulation techniques that can cope with a high volume of information. This article aims to make a comparative analysis of different Delaunay triangulation libraries, open or with academic versions available for the scientific community, so that we can assess their suitability for the modeling of the territory and its infrastructures. The comparison was carried out from a two-fold perspective: (i) to analyze and compare the computational cost of the triangulation; (ii) to assess the geometric quality of the resulting meshes. The different techniques and libraries have been tested based on three different study cases and the corresponding large points clouds generated. The study has been useful to identify the limitations of the existing large point clouds triangulation libraries and to propose statistical variables that assess the geometric quality of the resulting DSM. Full article

A Mobile Mapping System (MMS) equipped with laser scanners can collect large volumes of LiDAR data in a short time frame and generate complex 3D models of infrastructure. The performance of the automated algorithms that are developed to extract the infrastructure elements from the point clouds and create these models are largely dependent on the number of pulses striking infrastructure in these clouds. Mobile Mapping Systems have evolved accordingly, adding more and higher specification scanners to achieve the required high point density, however an unanswered question is whether optimising system configuration can achieve similar improvements at no extra cost. This paper presents an approach for improving MMS performance for infrastructure surveys through consideration of scanner orientation, scanner position and scanner operating parameters in a methodology referred to as Geometry Aided Design. A series of tests were designed to measure point cloud characteristics such as point density, point spacing and profile spacing. Three hypothetical MMSs were benchmarked to demonstrate the benefit of Geometry Aided Design for infrastructure surveys. These tests demonstrate that, with the recommended scanner configuration, a MMS, operating one high specification scanner and one low specification scanner, is capable of comparable performance with two high-end systems when benchmarked against a selection of planar, multi-faced and cylindrical targets, resulting in point density improvements in some cases of up to 400%. Full article

The shield tunnel of the Kunming subway crosses beneath the Kun-Shi Railway. Due to the high requirements of railway track for settlement control, this article proposes the following technical measures for controlling the settlement based on the analysis of risks arising from the shield crossing railway: (1) Reinforcing the stratum of the region crossed by the shield in advance to achieve high stability; (2) Using a reinforced segment for the shield tunnel and increasing reserved grouting holes for construction; (3) Reasonably configuring resources, optimizing construction parameters, strengthening monitoring and information management during the shield crossing. In strict accordance with the construction plan, the shield successfully and safely crossed beneath the Kun-Shi Railway; this provides experience that can be used in similar projects in the future. Full article

The Philippines is located in the typhoon belt region in the western side of the Pacific Ocean. Every year, an average of twenty typhoons pass through the country, resulting in the loss of life and property. As the design of the roofing is an important factor in the structural integrity of the detached structures and the survival of the occupants, an evaluation of different roofing designs for the detached structure is needed. Different roofing designs, typical in Philippine detached structures were investigated using the computation fluid dynamics (CFD). The developed CFD model was validated based on the data from full scale and wind tunnel results. The different roofing designs were evaluated in the developed and validated model based on the flow field, pressure coefficients and streamlines at different wind angles. The results show that different roofing designs affect the flow field velocity, flow field pressure coefficient and the structure’s surface pressure coefficients. The pyramidal and domed roofing designs have a smoother flow field velocity, flow field pressure coefficient and house surface pressure coefficient. The eaves overhang, which is common in Philippine detached structures, has a large effect on the surface pressure coefficient and the velocity streamlines, as compared to structures with no eaves overhang. The results of this study show the importance of the roof design in Philippine detached structures. Full article

Rural roads represent an important part of the economy in the Great Plains and Midwest of the United States. As oil exploration in North Dakota increases, the number of vehicles travelling on these roads is also increasing, resulting in significant needs for infrastructure maintenance and upgrades, including the construction of new bridges. The lifecycle benefit–cost analysis of bridge construction is the overall objective of this research. This paper investigates the benefits of combining travel demand modeling and lifecycle benefit–cost analysis, and demonstrates traffic forecasting using geographic information systems (GIS) and network flow problem. The paper also shows a comparison of the alternative scenarios. The authors demonstrate a method of integrating geographic information systems, operations research, and data analytics to estimate future traffic by evaluating infrastructure needs. The travel demand modeling is essential for the lifecycle benefit–cost analysis. This study would help government agencies and construction companies evaluate and prioritize new bridge construction projects. The agencies should consider adding the environmental costs. Full article

Infrastructures are crucial components in the development of a country, enhancing the country’s productivity, improving the efficiency of production, transportation, and communication. The journal considers the term infrastructures in a broad sense. In recent decades, the advances in infrastructures have been enormous. They include the application of new construction materials, improvement of computer tools, and the development of machinery that allows us to embark on ambitious construction projects, in a safe, efficient and sustainable manner. Therefore, the future and scope of infrastructures is very promising and exciting; the concept of Smart Infrastructure is key in the development of the countries and their cities. From the old concept of infrastructure as a passive element, arises the new idea of infrastructure as active component that interacts with the users, people or machines.[...] Full article