3,386 research outputs found
Potentialities of a Highway Alignment Optimization Method in an I-BIM Environment
The BIM (Building Information Modeling) approach potential in the civil engineering field opened novel scenarios in the design idea concept, from planning to executive and constructive phases. The related advantages are numerous and not only limited to a real-time interaction among the involved subjects, that can actually operate in an optimized 3D shared environment. Owing to the sharing information philosophy and to the features of various "smart objects" combined in the project, this innovation reduces potential errors and increases the effectiveness of the design solution in terms of both functionality and cost. Despite these advantages, the highway alignment design problem remains very complicated and not easy to solve without appropriate supporting tools. In recent years, several efforts have been spent in defining highway optimization procedures for helping designers in the selection of an optimal solution in compliance with numerous different constraints. Introducing these procedures in a BIM environment may represent a crucial step in the improvement of the highway design procedures, exploiting the full representation and modelling potential of the approach. In this paper, the authors present the advantages of a 3D highway alignment optimization algorithm, based on the Particle Swarm Optimization method, and its possible implementation in a BIM platform. A proper I-BIM environment can exploit the potential of the alignment optimization algorithms, simplifying the analysis of the different solutions, the final representation and the eventual manual modifications
OPTIMIZATION OF STATION LOCATIONS AND TRACK ALIGNMENTS FOR RAIL TRANSIT LINES
Designing urban rail transit systems is a complex problem, which involves the determination of station locations, track geometry, right-of-way type, and various other system characteristics. The existing studies overlook the complex interactions between railway alignments and station locations in a practical design process. This study proposes a comprehensive methodology that helps transit planners to concurrently optimize station locations and track alignments for an urban rail transit line. The modeling framework resolves the essential trade-off between an economically efficient system with low initial and operation cost and an effective system that provides convenient service for the public. The proposed method accounts for various geometric requirements and real-world design constraints for track alignment and stations plans. This method integrates a genetic algorithm (GA) for optimization with comprehensive evaluation of various important measures of effectiveness based on processing Geographical Information System (GIS) data.
The base model designs the track alignment through a sequence of preset stations. Detailed assumptions and formulations are presented for geometric requirements, design constraints, and evaluation criteria. Three extensions of the base model are proposed. The first extension explicitly incorporates vehicle dynamics in the design of track alignments, with the objective of better balancing the initial construction cost with the operation and user costs recurring throughout the system's life cycle. In the second extension, an integrated optimization model of rail transit station locations and track alignment is formulated for situations in which the locations of major stations are not preset. The concurrent optimization model searches through additional decision variables for station locations and station types, estimate rail transit demand, and incorporates demand and station cost in the evaluation framework. The third extension considers the existing road network when selecting sections of the alignment. Special algorithms are developed to allow the optimized alignment to take advantage of links in an existing network for construction cost reduction, and to account for disturbances of roadway traffic at highway/rail crossings. Numerical results show that these extensions have significantly enhanced the applicability of the proposed optimization methodology in concurrently selecting rail transit station locations and generating track alignment
Multiobjective railway alignment optimization using ballastless track and reduced cross-section in tunnel
The increasing need for railway planning and design to connect growing cities in inland mountainous areas has pushed engineering efforts toward the research of railway tracks that must comply with more restrictive constraints. In this study, a multiobjective alignment optimization (HAO), commonly used for highway projects, was carried out to identify a better solution for constructing a high-speed railway track considering technical and economic feasibilities. Then, two different and innovative scenarios were investigated: an unconventional ballastless superstructure, which is more environment-friendly than a gravel superstructure, and a reduced cross-section in a tunnel, which enables a slower design speed and then, less restrictive geometric constraints and earthmoving. The results showed that the first solution obtained a better performance with a slight increase in cost. Moreover, both scenarios improved the preliminary alignment optimization, reducing the overall cost by 11% for the first scenario and 20% for the second one
Building demolition estimation in urban road widening projects using as-is BIM models
Building demolition caused by urban road widening projects can lead to engineering, economic, and environmental issues and should be planned at the design stage. Based on as-is BIM, this paper proposes a method to estimate the building demolition caused by urban road widening using online map data and statistics on government websites. The as-is BIM models of the existing old road and its surrounding buildings are created, and the BIM models of the newly widened road are built based on the as-is BIM models considering road components in accordance with road engineering expressions to assist building demolition estimation using clash detection. This paper presents a cost-effective building demolition estimation in urban road widening projects without field surveys. It was tested on the M4 Motorway project in London. It has been proved to be a very practical approach to facilitate urban road planning and decision making
Modification of the Highway Capacity Manual two-lane highway analysis procedure for Spanish conditions
[EN] The US Highway Capacity Manual (HCM) methodology is used in Spain to evaluate traffic operation and quality of service. The effect of passing manoeuvre on two-lane highway operational performance is considered through adjustment factors to average travel speeds and percent time spent following. The procedure is largely based on simulations in TWOPAS and passing behaviours observed during US calibrations in the 1970s. It is not clear whether US driving behaviour and vehicles' performance are comparable with Spanish conditions. The objective of this research is to adapt the HCM 2010 methodology to Spanish driver behaviour, for base conditions (i.e. no passing restrictions). To do so, TWOPAS was calibrated and validated based on current Spanish passing field data. The calibration used a genetic algorithm. The case study included an ideal two-lane highway with varying directional traffic flow rate, directional split and percentage of trucks. The updated methodology for base conditions is simpler than the current HCM 2010 and does not rely on interpolation from tables.The research was funded by the Spanish Ministry of Economy and Competitiveness (TRA2013-42578-P) and has been partially developed as a result of a mobility stay at the University of Florida funded by the Spanish Ministry of Economy and Competitiveness (EEBB-I-15-09970). The research was completed with the support of the FPI Research and Teaching Fellowship of the Spanish Ministry of Economy and Competitiveness (BES-2011-044612) and the TUM University Foundation Fellowship (TUFF) for international postdocs.
We would like to thank Dr Lemke from the Bundesanstalt fur Straaenwesen (Federal Highway Research Institute) for providing the book from Brannolte and Holz [13] and the final reports of the research projects FE-Nr. 02.155G92 [12] and FE 16.0015/2009 [11].Moreno Chou, AT.; Llorca García, C.; Washburn, S.; Bessa Jr., JE.; Hale, DK.; García García, A. (2016). Modification of the Highway Capacity Manual two-lane highway analysis procedure for Spanish conditions. Journal of Advanced Transportation. 50(8):1650-1665. https://doi.org/10.1002/atr.1421S1650166550
BIM for infrastructure: An overall review and constructor perspective
The subject of building information modelling (BIM) has become a central topic to the improvement of the
AECOO (Architecture, Engineering, Construction, Owner and Operator) industry around the world, to the point
where the concept is being expanded into domains it was not originally conceived to address. Transitioning
BIMinto the domain of infrastructure projects has provided challenges and emphasized the constructor perspective
of BIM. Therefore, this study aims to collect the relevant literature regarding BIM within the Infrastructure
domain and its use from the constructor perspective to review and analyse the current industry positioning
and research state of the art, with regards to the set criteria. The review highlighted a developing base of BIM
for infrastructure. Fromthe analysis, the related research gapswere identified regarding information integration,
alignment of BIM processes to constructor business processes & the effective governance and value of information.
From this a unique research strategy utilising a framework for information governance coupled with a
graph based distributed data environment is outlined to further progress the integration and efficiency of
AECOO Infrastructure projects
Image Based Modeling Technique for Pavement Distress surveys: a Specific Application to Rutting
Image-based modeling (IBM) is a well-known
technique to obtain high quality 3D models based on multi view
images. IBM started being used in several applications such as
inspection, identification of objects and visualization, due to the
user-friendly approach, the low cost and highly automated
technique.
This paper focuses on the investigation of the potential
application of IBM in the diagnosis of road pavement distresses
and in particular rutting. Indeed, the evaluation of the rutting
distress is a fundamental step to define the whole state of a
pavement as demonstrated by the calculation of Present
Serviceability Index (PSI). Currently, the permanent
deformation is measured monitoring visually the rut depth with
the approximations that this procedure involves. Nevertheless,
the exact measure of the rut depth is necessary to evaluate
precisely the cause and the severity of this distress and be
effective in the maintenance and rehabilitation of the pavement
structure.
The objective of this study is to apply the IBM technique on a
laboratory rutted sample, in order to verify the accuracy of the
method in determining the rut depth. To achieve this, a
comparison has been made between the 3D model obtained with
IBM and the one obtained with blue led 3D scan (Artec Spider)
of the same rutted asphalt concrete. The metric accuracy of the
model is then defined and its validity is assessed, in terms of
distress diagnosis
- …