Survey technologies, GIS software and consulting services in compliance with the changing regulations

The product suite for the airports comes from the competence of Siteco in survey technologies and software development, a consolidated experience collected and matured in the road environment in over 10 years and with more than 40,000 km of surveys.

The Mobile Mapping System Road-Scanner has been expressly integrated with new equipment targeted to satisfy and implement the requirements of the airport regulations.

The most interesting innovative factor of the solution is the integration in the ESRI ArcGIS system, which allows a complete control of all inspections and maintenance activities in their mapping context. Thanks to this, it is possible to have a view of the infrastructure as a whole and obtain an immediate consultation of the state of repair and of the interventions planned and carried out. With specific functions, the user can plan the maintenance interventions and therefore efficiently optimize both operating costs and pavement life cycle.

The solution proposed by Siteco includes:

• The sophisticated technology of the MMS Road-Scanner, expressly equipped to allow surveys also at night time thus avoiding  interferences with the air traffic;
• The Road-SIT PMS application, fully integrated in the powerful ESRI ArcGIS mapping system, providing monitoring and decision support features for the analysis of Maintenance Programs related to Status Indicators;
• Bearing capacity surveys and structural and design analyses.

MODULES SYSTEM

The features of Road-SIT PMS can be classified as follows:

Distress Analysis - This module allows the consultation of the data collected with Road-Scanner, namely high-resolution images, laser scans, scans obtained with the Ground Penetrating Radar, longitudinal roughness data obtained with the profilometer. This module allows the survey of all functional pavement defects that have been registered in the relational database of the system, and carries out monitoring activities, also using "mobile" equipment such as PDA, tablets, etc. The Pavement Condition Index is calculated in accordance with the ASTM D 5340 standards, and output values are updated on the base of the maintenance activities carried out and the results of the inspections.

Data Management System - Road-SIT PMS is designed to acquire all the data collected with the different sensors mounted on the MMS and also other types of data deriving from tests carried out on the airport pavements (e.g. data of friction and bearing capacity). According to the available data, the system calculates specific status indices for the various homogeneous sections of the airport. The sections are divided into areas of constant surface. The GIS views allow the  immediate control of the different parameters.

Decision Management System - The system incorporates the maintenance technologies used by different airports allowing the creation of customized maintenance programs. Every activity can be associated with the results that can be achieved in terms of resolution of structural surface defects and relating costs as well. Through the simulation of different maintenance strategies, the user can choose the best interventions to make. Then the system allows the management of all the activities to be carried out and the re-calculation of the various indices as a result of the interventions implemented.

 WORK METHODOLOGY

Road-SIT Airport PMS is based on the organization of specific information layers of the GIS system, that represent all the PMS data:  routes of the vehicle surveys, survey key points and areas considered in the bearing capacity inspections, PCI areas, relating survey data, and processing. The GIS system also provides the definition of the areas which the airport infrastructure is divided into, according to a precise hierarchical organization.

Subdivision and hierarchical organization of the infrastructure
For a rational management of the pavements, the whole paved surface is split into different areas, based on a hierarchical principle at different levels, also known as Pavement Grid Map. The first level consists of the zones of operations (branches), with different functions: runway, taxiway, links, parking, service roads, etc. These areas are divided again into Homogeneous Sections, i.e. sections with similar design features:

• Period of construction,
• Thickness of the pavement and its status of load capacity
• Traffic or strain level in general.

This division is essential to define the decay curves of each section, and take a decision on the most appropriate maintenance activities to be carried out.

Each section is further split into an adequate number of elementary zones of constant surface area (300-400 m²), defined according to the different indices associated with them (PCI, roughness, load capacity, friction, etc.). For each zone, the indices of degradation are sampled with respect to several structural or functional aspects.

Road-Scanner Survey
The trajectories made by the MMS Road-Scanner are reported on an extra layer, thus facilitating the consultation of the collected data. These trajectories allow the identification on the cartography of the route visible in the imagery that is being consulted and, vice versa, it is also possible to select the most appropriate imagery and examine the area to be checked. The airport surface is covered by the Road-Scanner vehicle in parallel routes at a distance of 4-5 meters. As for runways and taxiways, the survey direction is controlled with a special software that helps the driver to maintain a constant direction.

Survey of the Status of Surface Degradation
The defects are classified in a catalog according to the ASTM D6433/2003 specifications, with the aid of special menus that assist the user to assess the level of severity. One of the more interesting components of the proposed methodology is the visual detection of defects, assisted by the consultation of the data obtained with the profilometer and the laser-scanners.

The environment of imagery consultation, integrated in the GIS ArcView, allows an optimal navigation on all surveyed  data and also in the defect database. At all stages, the operator can check the activities carried out in the mapping system.

All the detected surface defects are represented on an extra layer, which contain the related geometries (for example: points for holes, polylines for cracking, polygons for alligator cracking, depressions, rutting). On the basis of the defects that completely or partly belong to PCI areas, it is possible to calculate the corresponding indices, and represent them according to the thresholds of the ASTM specifications. The application also allows the consultation of the surface defects of each single PCI area.

Consultation of the Maintenance Status
All the survey results are represented in ArcGIS and can be immediately displayed on the map, or consulted numerically. It is possible in this way to represent the characteristic bearing values (PCN /ACN, elastic modules, layer thicknesses), PCI indexes, longitudinal roughness, etc. Thanks to this type of representations, the intervention activities can be carried out quickly and effectively.

Management of the Intervention Catalog
With this application it is possible to define different maintenance catalogs. The available databases can be integrated with the Tender Specification. Each catalog allows the user to organize interventions by type, for instance structural or functional interventions, rehabilitation or localized interventions. This organization has the double goal of improving the organization of the interventions and, at the same time, of providing the system with methods for calculating the cost of each intervention. For each intervention, users can define the cost per unit and specify the list of defects that the intervention can solve as well as any residual defect after the maintenance.

Assignment of the Interventions to the Pavement
In order to analyze the cost and extend the residual life of the airport paved surfaces, it is necessary to select the areas and/or the homogeneous sections to which a specific intervention must be assigned. This assignment can be done with a graphic selection directly in the GIS software or filtering areas and sections through appropriate queries to the database according to priority criteria. In this way it is possible to create a Maintenance Plan containing the maintenance interventions selected from the catalog. If the same intervention belongs to different planes, the PMS operator can define different maintenance plans, and compare them in terms of cost, time distribution and useful lifetime of the infrastructure.

Decision Support Tools and Decay Curves
The system also provides tools for the decision support, by simulating different maintenance strategies, the calculation of the PCI and the derived curves of decays. Special functions allow the users to assign the decay curves to the homogeneous sections and therefore to define the timing diagram. Then it is possible to compare the theoretical decay curves with those derived from the observations performed during the monitoring phase. On the basis of these results it will be possible to calibrate the specific curves of the different homogeneous sections.