Maintenance Yards Research Articles

Rigid inclusions performance as ground improvement for lacustrine clays

The Bogotá urban railway system involves constructing a rail maintenance yard covering 33 ha near the Bogotá River. It requires the construction of a 4.1 m embankment to overcome flood risks. Approximately 57,000 rigid inclusions (RI) were installed because of poor soil conditions to control excessive settlement. The embankment and RI were placed on a lacustrine deposit comprising layers with high organic matter content and soft clays that extended up to 200 m below ground surface. The effects of RI installation were reviewed using an inclinometer and benchmark data. Proof static load tests (SLT) and CPT were performed after RI installation to verify RI performance. CPTs were completed in the soil adjacent to the RI, as tested by the SLT. Different time spans were considered after RI installation for the CPT to assess the evolution of soil properties. The SLT uses the estimated working loads factored in by at least 20%. The CPT results showed that after a relatively short period of RI installation, the soil properties were similar to the initial properties. SLT results showed that RI capacity and head displacements were within the admissible ranges, considering that they had no competent bearing stratum, demonstrating the effectiveness of the ground improvement method. The results of both tests demonstrate the effectiveness of RI as a ground improvement technique for lacustrine soft clay in Bogotá.

Financial performance-based assessment of companies’ competitiveness: Evidence from the Norwegian Shipbuilding Industry

The Norwegian maritime industry is at the forefront of green technology development, with shipyards playing a crucial role in testing, verification, and development. However, the industry faces challenges such as high personal costs, increasing competition from abroad, and cyclical market trends. This study aims to assess financial performance as indicator of firm-level competitiveness based on a set of 12 financial measures and test the hypothesis of the positive impact of portfolio diversification on shipyards’ competitiveness.The analysis utilizes data from four large construction yards and four medium-sized construction, repair, and maintenance yards in the Møre region. The methodology involves constructing a Shipyard Competitiveness Index with sub-indices for liquidity, profitability, solvency, and efficiency. Regression analysis is conducted to investigate the impact of ship variety, as a diversification parameter, on the competitiveness level.The obtained results reveal that during the analyzed period (2009–2020), companies in the group of large shipyards had better financial performance until 2017, while on the contrary, the second group of shipyards in the same period showed an increase in their competitiveness index. Moreover, the findings proved the presence of the positive relationship between diversification of portfolio and competitiveness index.This study contributes valuable insights for the Norwegian shipbuilding industry, highlighting the importance of financial performance assessment in measuring competitiveness. The study provides a foundation for future discussions on fostering sustainable growth and innovation within the maritime sector.

Potential Availability of Wood Biomass from Urban Trees: Implications for the Sustainable Management of Maintenance Yards

The current energy situation requires the effective utilization of all available resources, and residual wood biomass from urban forestry may represent an excellent opportunity for increasing the presence of short-range energy sources. In urban forestry management, two main operations can provide large amounts of wood biomass: The felling and pruning of trees. These operations are carried out with two principal techniques that differ in terms of mechanization intensity (i.e., accessing the trees’ crown with mechanized aerial lifts or utilizing ropes—tree-climbing). This study has investigated 18 felling and 15 pruning yards, carried out with aerial lifts (17 yards) or tree-climbing (16 yards), most of them located in the city of Rome (Italy), one of the greenest European capitals. The operations were sampled with time studies, and five elements of work time were measured from the beginning of work to the transport of the residual biomass to the loading point, using centesimal stopwatches and video recording. The total observation time amounted to 152.0 h. The total residual biomass was assessed. The cost calculation for each yard took into account fixed, variable, and labor costs. A set of variables for each yard (including several site characteristics, trees’ size, fuel consumption, carbon dioxide (CO2) emissions, energy consumption, costs of yards, biomass, and work times) was analyzed. This study can contribute to enhancing tree maintenance sustainability in urban sites and estimating the quantity of residual wood biomass obtainable from urban forestry maintenance in the city of Rome.

An analysis on the domestic fish marketing of south Andaman

The domestic fish marketing of fish landing centre of south Andaman was analysed. The study has undertaken between January and February, 2022 in two fish landing centres (FLCs) of South Andaman namely Wandoor and Junglighat. Around 9 fishery cooperative societies marketing personnel were interviewed by adopting semistructured interview method and daily visit to landing centre has been done to analyse the structure and pattern of fish marketing system in both the FLCs (Table 1). This exercise has undertaken to meet different marketing personnel nearby portblair region and ideate about the interventions which could be planned for improving the infrastructure facilities and innovations in the marketing system (Table 2). It is observed that the marketing costs incurred by each of the intermediaries has been increasing day by day in Junglighat fish market and less involvement in Wandoor landing centre. Lack of proper communication facility with the island while fishing, inadequacy of maintenance yards for crafts and gears, lack of launching and landing facilities for crafts and gears in many areas, lack of processing factories and inadequate training for fishermen by the fisheries department are the infrastructural constraints pointed out by the fishermen at landing centre.

Optimization Models for Snowplow Routes and Depot Locations: A Real-World Implementation

This study developed a series of strategies to reassess the service level of winter road maintenance (WRM) operations on the road network in Perth County, Ontario, Canada. These strategies include rearranging plow routes by sharing the material storage yards and optimizing their numbers and locations while considering operational and legislative constraints such as total circuit time, operating speeds, and the number of available trucks. A methodological framework was then formulated and solved by tackling four practical, yet challenging, tasks in a sequential manner. The first task was to identify existing plow routes and construct a detailed GIS database that was later used for benchmarking the current WRM operations. The second task involved the optimization of existing plow routes, while the third task focused on the optimization of plow routes and depot locations by amalgamating WRM operations of different municipalities within Perth County. The final task was to conduct a clean slate optimization to see the benefits of combining depots and route sharing. The optimization models developed were implemented to transform the existing maintenance operations networks to an optimized, integrated, and unified network of routes, with improved land use utilization for road maintenance yards. The framework then captured the impact of the service order of maintenance routes and arranged routing priority efficiently using the tabu search algorithm. The findings also revealed that, by sharing depots, the county could retire three depots and eight trucks while still meeting legislative requirements, thereby suggesting the potential for substantial monetary savings.

Ship Repair and Maintenance Management: Application of PERT Analysis on a Tanker Vessel

The costs in shipbuilding and ship repair and maintenance activities are massive and need several materials in the same production phase. Construction without planning is not rational, and any mistake in the planning phase will cause major loss of time, quality, and financial resources. Planning in ship repair and maintenance yards is more complicated than new building shipyards because the duration time is limited. In this study, 200-m-long tanker’s repair and maintenance period has been planned by program evaluation and review technique analysis in light of the data acquired from X shipyard in Turkey to reflect critical activities that affect the total duration time.

Optimization of the Shunting Operation Plan at Electric Multiple Units Depots

The number of standard electric multiple units (EMUs) in China has increased from 1003 in 2013 to 3256 in 2018. For maintaining all EMUs in time, the high-speed rail system with the fast-developing number of EMUs is facing growing pressure. The maintenance and cleaning capacity of an EMU depot can be improved by a better shunting operation planning (SOP). This paper considers an SOP problem at EMU depots, which may have two types of yards, namely, stub-end and through. Every track at an EMU depot has two sections and can accommodate two short standard EMUs of 8 railcars or one long EMU of 16 railcars. As the SOP is currently handled manually by dispatchers, this paper proposes two integer linear programming models for two types of yards for daily planning and dispatching, which aim at minimizing the total delay time of all EMUs during the planning horizon. A Reduced Variable Neighborhood Search (RVNS) algorithm is designed to improve the solution efficiency. The results of the numerical experiment show that the RVNS algorithm can yield an optimal maintenance plan in a few seconds for depots of different layout types and can be applied to a computer-aided planning system. The track utilization rate of the maintenance yard with the stub-end type is higher than that of the through type. The stub-end type may be more suitable for the current schedule, as its total track utilization rate is much lower than the through type.

Continuous Monitoring and Evaluation of Railway Tracks: System Description and Assessment

A R&D Project was completed in Portugal that aimed at designing, developing and demonstrating the applicability of an innovative and integrated approach to assess the performance and condition of railway tracks. This approach is also expected to contribute to identify the specific causes of some track performance degradation, namely those that are related to the characteristics of the layers and the geomaterials that compose the substructure of the track. A system prototype was developed and installed on board of a self-propelled railway maintenance vehicle. The system is designed to continuously evaluate the vertical stiffness of the track and to detect disturbances on the dynamic contact interface between the wheelsets and the rails, some of which can be related to defects on the tracks. The system is also able to post-process the acquired data.This paper includes an overall system description of the prototype implemented based on the discussed approach and the first experimental tests performed with said prototype, regarding the system assessment. These tests were performed on a railway track, adjacent to a maintenance yard. The track was instrumented with additional on-site equipment to serve as reference for the prototype’s assessment. The data obtained from the preliminary tests suggest that the proposed approach is adequate in this context.

Optimal track utilization in electric multiple unit maintenance depots

The Chinese high-speed rail network has a fast-growing number of electric multiple units (EMU) in service and is facing increasing pressure of maintaining all EMUs on-time. The capacity at an EMU maintenance depot is relevant to its track utilization rate, which can be improved by a better EMU-to-track assignment in various areas, such as the maintenance yard, temporary storage yard, and washing yard. Most tracks at EMU depots have two sections that can accommodate one long EMU of sixteen railcars or two short EMUs of eight railcars. The two yard types, stub-end and through, further add complexity to the assignment problem, which is currently handled manually. To make the assignment process more efficient, this paper proposes a simple optimization model for yards with either type and with any combination of long and short EMUs. The numerical results based on a real-world case show that the proposed solution method can yield an assignment plan with the optimal track utilization in a small amount of computational time and can be implemented in a computer-aided planning system easily. The case also discusses potential changes in practice to improve the track utilization rate, such as changing the maintenance schedule and connecting two short EMUs into a long EMU. After comparing the track utilization rates between the two yard types, the paper suggests that the through type is more appropriate for the current schedule at EMU depots, especially for the maintenance yard.

Criticalities on highway maintenance yards: some suggestions to improve the effectiveness of OS&H supervision/inspection activities

Research work results on Occupational Safety and Health -OS&H- aspects of highway maintenance yards in normal operative conditions and special situations - typically potential interferences from heavy traffic - stressed the diversification of yards typologies and criticalities. The European Directive 92/57/EEC on the implementation of minimum Safety and Health requirements at temporary or mobile construction sites concentrates on the improvement of Risk Assessment and Management from the very first steps of the design, and introduces coordinators charged of a safe project preparation and of the execution phase supervising. In particular, in the case of highway maintenance yards, the Coordinator for and health matters at the project execution stage should manage both routine situations, and situations requiring high expertise and capacity of judgment. In such complex scenarios, Safety inspection activities become a demanding task also in terms of time and resources for both the Company and the National Inspectorate supervisors. The paper discusses an original approach for the optimization of supervision / inspection activities, based on the appropriate use of Fellow Supervisors to support the Coordinator in the routine activities, with the added benefit of an increased presence of safety people at the yard. The setup of an appropriate data gathering, recording and mining system, organized in interlinked cards in logical sequence, contributes to the efficiency and thoroughness of the work of the both the Coordinator and the Fellow Supervisors. The results of ex post tests on a real case -input data provided by the Prosecutor Office which proposed the study- can be considered significant.

LEGISLATIVE DEVELOPMENT AND MANAGEMENT HEALTH AND SAFETY IN MAINTENANCE CONSTRUCTION SITES

When considering the maintenance of buildings, the implementation of legislative codes for health and safety requires particular attention as early as in the design approach. Statistics indicate that accidents often occur during maintenance operations. The organization of the maintenance yard requires specific safety measures, which often depend on the choices related to the design and construction of a building. European Directive 57/1992 indicates that “the architectural and/or organizational measures are not enough. A poor design frequently causes work-related accidents in construction sites with significant damage to the community.” This statement, dating back 22 years, is still valid in Europe today. The introduction of the obligation to draw up the Safety File, to manage safety in the maintenance tasks of the building life cycle, is still valid. This paper refers to the maintenance tasks programmed by ensuring safety conditions. Particular focus is on the individuation of the types of risks in relation to design. The design choices, likewise, are made in order to have an effective plan of health and safety for the workers. The preventive identification of the most common natural risks, and the application of practice codes related to maintenance programs, are the most important strategic choices to ensure safety in interventions deferred over time.

Fleet size estimation for spreading operation considering road geometry, weather and traffic

Abstract: Extreme weather conditions(i.e. snow storm) in winter time have caused significant travel disruptions and increased delay and traffic accidents. Snow plowing and salt spreading are the most common counter-measures for making our roads safer for motorists. To assist highway maintenance authorities with better planning and allocation of winter maintenance resources, this study introduces an analytical model to estimate the required number of trucks for spreading operation subjective to pre-specified service time constraints considering road geometry, weather and traffic. The complexity of the research problem lies in dealing with heterogeneous road geometry of road sections, truck capacities, spreading patterns, and traffic speeds under different weather conditions and time periods of an event. The proposed model is applied to two maintenance yards with seven road sections in New Jersey (USA), which demonstrates itself fairly practical to be implemented, considering diverse operational conditions.

Development of Mechanistic–Empirical Design Procedure for Fully Permeable Pavement under Heavy Traffic

Fully permeable pavements are those in which all layers are intended to be permeable and the pavement structure serves as a reservoir to store water during storm periods to minimize the adverse effects of stormwater runoff. Fully permeable pavements are currently used primarily for light traffic (e.g., parking lots that only allow cars, not trucks). The development of fully permeable pavement designs as a potential best management practice for stormwater management in areas that carry heavy truck traffic is of significant interest. Results are presented from one phase of a project to develop mechanistic–empirical design procedures for fully permeable pavement designs that will carry heavy vehicles operating primarily at slow speeds (e.g., in maintenance yards, parking lots, streets, and highway shoulders). Mechanistic–empirical computer modeling of the structural designs was performed for three types of surface material (open-graded asphalt, open-graded concrete, and concrete slabs with cast drainage), considering different traffic loading based on typical California highway truck traffic, different traffic speeds, and several typical California climate regions, as well as materials properties developed from laboratory testing. A preliminary design method and preliminary design charts that considered both hydraulic and structural performance were developed; some examples of their use are provided. The mechanistic–empirical approach used in this project for the development of fully permeable pavement designs could increase the speed of development and implementation of this technology.

Anthropogenic sources and environmentally relevant concentrations of heavy metals in surface water of a mining district in Ghana: a multivariate statistical approach

The levels of heavy metals in surface water and their potential origin (natural and anthropogenic) were respectively determined and analysed for the Obuasi mining area in Ghana. Using Hawth's tool an extension in ArcGIS 9.2 software, a total of 48 water sample points in Obuasi and its environs were randomly selected for study. The magnitude of As, Cu, Mn, Fe, Pb, Hg, Zn and Cd in surface water from the sampling sites were measured by flame Atomic Absorption Spectrophotometry (AAS). Water quality parameters including conductivity, pH, total dissolved solids and turbidity were also evaluated. Principal component analysis and cluster analysis, coupled with correlation coefficient analysis, were used to identify possible sources of these heavy metals. Pearson correlation coefficients among total metal concentrations and selected water properties showed a number of strong associations. The results indicate that apart from tap water, surface water in Obuasi has elevated heavy metal concentrations, especially Hg, Pb, As, Cu and Cd, which are above the Ghana Environmental Protection Agency (GEPA) and World Health Organisation (WHO) permissible levels; clearly demonstrating anthropogenic impact. The mean heavy metal concentrations in surface water divided by the corresponding background values of surface water in Obuasi decrease in the order of Cd > Cu > As > Pb > Hg > Zn > Mn > Fe. The results also showed that Cu, Mn, Cd and Fe are largely responsible for the variations in the data, explaining 72% of total variance; while Pb, As and Hg explain only 18.7% of total variance. Three main sources of these heavy metals were identified. As originates from nature (oxidation of sulphide minerals particularly arsenopyrite-FeAsS). Pb derives from water carrying drainage from towns and mine machinery maintenance yards. Cd, Zn, Fe and Mn mainly emanate from industry sources. Hg mainly originates from artisanal small-scale mining. It cannot be said that the difference in concentration of heavy metals might be attributed to difference in proximity to mining-related activities because this is inconsistent with the cluster analysis. Based on cluster analysis SN32, SN42 and SN43 all belong to group one and are spatially similar. But the maximum Cu concentration was found in SN32 while the minimum Cu concentration was found in SN42 and SN43.

Vehicle/Steel Guideway Interaction When the Maglev Train is Hovering

Aiming at the problem of unstable hovering of the maglev train on the steel guideway, tests were made on the natural vibration frequencies of this maglev system. Moreover, the authors make the strength calculation, the modal analysis and the interaction analysis between vehicle and the steel guideway. The result shows that the designed pseudo-static loadings of the steel guideway are not enough for the actual dynamic vehicle-guideway interaction. The system stability is related to the second suspension's frequency and damping the controlling system's frequency and damping the track's frequency and damp, and the system's basic parameters (specified balance position, the ratio of vehicles to the guideway, the electrical resistance and the induction of the coil). With the modified stiffness of the guideway frame column, the vehicle/steel guideway system can be stable when the maglev trains are hovering on the steel guideway in the maintenance yard.

A guideline for prediction and control of noise in railroads maintenance activities

In railroads routine maintenance as well as emergency maintenance can be represented by the acoustic point of view as a system of classified yard activities, including catalogued single and grouped noise sources, that is moved along the tracks areas. RFI (Rete Ferroviaria Italiana), the Italian National Railway Company, has provided a guideline for the correct evaluation of noise impact on receivers surrounding the yards, which can be adapted to many situations fitting the specific national law and local regulations disposals about noise assessment, prediction and reduction in temporary activities. Starting from their long term experience, the authors have developed a method for the production of local reports on maintenance railroad yard activities based on the modelling of standard scenarios. Each machinery employed in yards (for superstructure laying or repairing, electric traction, etc,) has been measured and characterized as noise source or as part of a noise sources system (emission box). The noise propagation scenarios are then build using an MS Excel based adaptation software. This methodology represents the technical and procedural architecture of the guideline which provides materials for the management of all the different typologies of maintenance yards operating on the RFI railroad network.

Evaluation of Storm Water Catch Basin Inserts for Transportation Facilities

Transportation facilities such as parking lots and maintenance yards often do not have provisions to treat storm water before discharge. Catch basin inserts can provide a retrofit alternative as a method to meet the new National Pollution Discharge Elimination System Phase II storm water pollution prevention regulations. Inserts produced by four manufacturers were evaluated for removal of suspended solids and petroleum hydrocarbons by using a pilot scale catch basin and synthetic storm water. In addition, the inserts were placed at operating transportation facilities and monitored for operational problems. At a flow rate of approximately 0.013 m3/s (200 gal/min) and pollutant concentrations for total suspended solids (TSS) and total petroleum hydrocarbons (TPH) of 225 mg/L and 31 mg/L, respectively, the inserts were capable of removing 11% to 42% of TSS and 10% to 19% of TPH.

Performance, Cost, and Maintenance Requirements of Austin Sand Filters

Five Austin-style sand filters were constructed by the California Department of Transportation (CALTRANS) as retrofit projects for maintenance yards and park-and-ride facilities in the Los Angeles and San Diego metropolitan areas. Each of these filter systems included storm-water monitoring equipment for collection of flow weighted composite samples. In addition, detailed records were compiled of the design elements, construction costs, and type and amount of maintenance required at each of the sites. The construction costs were relatively high because of the retrofit nature of the project and the integration of the CALTRANS storm-drain system with those of the adjoining metropolitan areas, which eliminated any opportunities for economies of scale. An analysis of performance using linear-regression techniques indicated that for sediment and almost all particle associated constituents, effluent concentration was independent of influent concentration. For instance, the average suspended solids concentration in treated runoff was 7.8–1.2 mg/L (at the 90% confidence level) regardless of observed influent concentration. The constant effluent quality produced for the particulate constituents indicates that the calculation of a percent reduction is more indicative of the influent concentration rather than the performance of the filter itself. Rejuvenation of the filter bed was required at three sites after 3 years of operation when the solids loading to the system was between 5 and 7.5 kg/m² of filter area. However, the clogging may have been accelerated by problems with the pumps that resulted in standing water on the filter for extended periods. Other maintenance activities consisted mainly of inspections, pump repair, and activities to reduce mosquito breeding. The main impediment to widespread implementation is the initial construction cost; however, modifications of the filter configuration and media may reduce these costs and increase effectiveness, thereby making the technology more attractive.

Lung Health Consequences of Reported Accidental Chlorine Gas Exposures among Pulpmill Workers

The long-term consequences of accidental chlorine gas exposure have been investigated, mainly in the community setting, among persons exposed as a result of a nearby chlorine spill. This circumstance is not analogous to the more frequent chlorine or chlorine dioxide gas overexposures that occur commonly in pulpmills over a background of a low level of gas exposure. To investigate the respiratory health consequences of these accidental exposures ("chlorine gassing") in the industrial setting, we carried out a cross-sectional respiratory health survey among workers at a British Columbia coastal pulpmill and a nearby rail maintenance yard. A greater proportion of pulpmill workers were unavailable for study because of illness (10.5% versus 2.4% in the railyard, p less than 0.01). Procedures involved simple spirometry, respiratory symptom assessment, and measurement of average levels of air contaminants. Average chlorine levels in the pulpmill were below 1 ppm; however, 60% of the pulpmill workers reported one or more accidental "chlorine gassing" incidents. Pulpmill workers who reported being "gassed" were significantly more likely to report wheezing on occasion than were other pulpmill workers and railyard workers (rate for these three groups: nonsmokers: 8, 2, 1%; ex-smokers: 17, 11, 7%; current smokers: 42, 21, 19%; p less than 0.05). No significant lung function differences were found between the overall pulpmill group and the railyard workers; however, nonsmoking and formerly smoking pulpmill workers who reported being "gassed" had significantly lower average midmaximal flow rate and FEV1/FVC ratio than did their counterparts in the remainder of the pulpmill population (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A NEW SPECTROGRAPH TESTING TECHNIQUE, ESTABLISHED AT PEARL HARBOR NAVY YARD

The Industrial Department of the Pearl Harbor Navy Yard has recently installed a grating spectrograph in the general testing laboratory to be used in increasing the technical efficiency of ship overhaul work.The Pearl Harbor spectrograph is of a relatively new type to be manufactured for general industrial analysis. There are features in its installation of original design. The uses to which such a piece of equipment may be put in a purely repair and maintenance yard may not be self‐apparent. Therefore, its description will be of interest as an adjunct to the control and inspection of materials.