Mohammed Abdussamad Siddiqui
Research Associate, Artificial Intelligence Center
College of Engineering Osmania University, Hyderabad
Highway Infrastructure Monitoring
In the last decade, great strides have been made all over the World, in the field of Highway infrastructure health monitoring. In particular, the application of latest technology, involving a variety of sensors – strain gauges, optical fiber sensors, data acquisition cards, computer based data analysis, has increased. This indeed is an advancement when compared to the conventional “Visual inspection method” commonly in use, for Highway infrastructure monitoring. However, in many a countries, the inability to adapt to modern technologies, has more to do with the available resources than, the inertia against a change.
In developing economies, technological advances may not go out of academic corridors, workshops and conferences, unless they are economical enough, to what ever prevailing methods that exist. Interestingly, in these countries, the only time a new technology is used is when ever it is indispensable and dictates the use, irrespective of the enormous costs involved.
The concept of zero – health monitoring, is useful to emphasise the widespread practice in the field. Zero-health monitoring of infrastructure is said to prevail when there is no monitoring of strength status of an infrastructure. In practice, the frequency of highway infrastructure monitoring may vary to a great extent. However, it tends to be more towards zero-health monitoring than total-health monitoring.
The risk factor in zero-health monitoring of infrastructure is high. The longer the deterioration, the more expensive will be the maintenance cost of a structure. An economical monitoring system would result in early detection of an impending structural damage, if followed up by preventive maintenance programme, it results in economical gains thus ensuring healthy and safe infrastructure.
Hence, any attempt, development, innovation, that raises the status of the prevailing infrastructure health monitoring system is bound to have a wider acceptance in developing and under-developed nations. Also, it adds to a lot of economic saving.
Status of Remote Infrastructure Health Monitoring
Remote infrastructure monitoring as a decision making tool exists. The term Geoengineering1 is applied to infrastructure life cycle monitoring. However, the aspects of infrastructure monitoring that are suggested in this concept, are what can be considered Macro, the different phases of an infrastructure construction project is one such example. As compared to Macro changes, infrastructure Health monitoring pertains with micro changes in a structure. – Part of an infrastructure. These micro changes are not so obvious unless they reach the stage of distress cracks or displacements. For micro changes to be documented very sensitive sensors are to be designed and installed at strategic locations. These sensors give us valuable information about the health condition of an infrastructure. If this is monitored regularly, helpful information is obtained. Functional anomalies and deviations from the designed parameters can be obtained. Thus, a more precise preventive maintenance programme can be taken up and, the infrastructure can sustain longer functional life.
In recent times, Infrastructure health monitoring has made great strides in North America and Europe. Immense progress has been made in this regard. Microelectronics and microptics playing a major role in these techniques, Japan and Korea too are very active in these innovations. However, the focus of these advancements is more towards gaining deeper knowledge about an infrastructure, than its potential economical application to a large set of infrastructure in a given domain. Developing and under-developed nations may embrace these innovative technologies, alien to their environs. However, without due consideration to their compatibility, they may not be able to make optimum gains with the use of these technologies.
In one of the present remote health monitoring methods presented in ACC20002 ,the data is logged and then is converted into RF modulation and transmitted after due amplification to a remote location. The remaining steps required to reach results are done basically at the remote location Another aspect is explored by D Inaudi 3 showing the application of Global Positioning System (GPS) to remote monitoring of a Highway bridge.
The mode and type of field data generated from a structure may vary depending on the method employed. Strain gauges, fiber optics, Natural Excitation Techniques (NExT) are some of the techniques that have been demonstrated to assimilate data from the field. Different sets of data are generated for different types of loads .viz. static loads, dynamic loads, thermal loads etc. The frequency of data collection is relative and may vary for different structures, depending upon the need to monitor it or the loading patterns of the structure.
These technologies can be adopted directly to apply for remote Highway infrastructure monitoring in developing and under-developed countries. For economical reasons the application of these technologies in these countries is limited, almost non-existent. As the saving of a fast deteriorating infrastructure – costing huge amounts – becomes imperative, cost of monitoring system takes a back seat.
To make infrastructure monitoring systems a part of routine infrastructure maintenance programme in developing and under-developed countries. We need to arrive at a solution that:
- is cost effective
- matches the skills of available staff
One possibility of arriving at an economical Highway infrastructure monitoring system is to use technology in an effective combination. This integrated approach is visible in a Remote infrastructure health monitoring System – MONIMASS™ 5. In this system technologies, as varied as Instrumentation, GIS, GPS, Communications, Networking, Structural Analysis and Graphic Display are used in combination seequialtially. This package comes with programmable Modules and can be programmed to be effectively used for Highway infrastructure monitoring. Some of the essential aspects of such a programmable, remote infrastructure monitoring system are as followings.
Essentials of Remote Infrastructure Health Monitoring
The processes involved in Remote infrastructure health monitoring are listed below.
- Data Sensing
- Data Logging
- Data Acquisition
- Data Transfer
- Data Reading
- Data Storage
- Data Analysis
- Data Interpretation
- Data Interpolation
A typical data set in a Remote Infrastructure health monitoring is made up of the following:
- Material Properties Data – Material used
- Engineered Properties Data – Dimensions and proportions
- Imposed Loads Data – Impending Loads
- Imposed Loads Data – Environmental
As the focus of this paper is the application of Web based GIS technologies, in Remote Health Monitoring of Highway Infrastructure, the engineering details of the stages involved are not being elaborated upon.
The Application of Integrated Remote Health Infrastructure Monitoring System to Highway Infrastructure is looked into by looking into the functionality of each of the modules that make the system. Module 1 – Infrastructure Clustering Module
Module 2 – Data Acquisition Module
Module 3 – Data Conversion Module
Module 4 – Data Communication Module
Module 5 – Data Receiving and Sorting and organising
Module 6 – Real-time Environmental Data Module
Module 7 – Mathematical Modeling Module
Module 8 – Algorithmic Module
Module 9 – Analytical Module
Module 10 – Graphic Display Module All the above modules go into making an integrated system of Infrastructure health monitoring. Module 1 and Module 10 are based on GIS and GPS technology. Module 1 and Module 5 are based on networking. Module 2 and Module 3 are based on Instrumentation. Module 4 is based on Internet technology. Module 7, Module 8 and Module 9 are based on Engineering principles. Module 10 is based on Graphic Design and Mapping.
As it can be seen in the following description of each of the above modules, some of these modules have been used in isolation for different purposes, including remote highway infrastructure monitoring. But the integrated approach envisaged here offers the following advantages when compared with an isolated use:
- Simultaneous monitoring of several units of an infrastructure.
- Widely spread out units of infrastructure can be monitored
- Single Command and Control Center
- Data from Real-time Environmental Satellite feed can be superimposed
- Environmental forecasts can be extended to influence on infrastructure as well.
- Good control on infrastructure behaviour in Disaster Management
Module-1: Infrastructure Clustering
This module involves incorporating all the basic information about the entire infrastructure within the region of a command center. The modes and types of infrastructure may vary over a wide range. A single command and control center may have several steel bridges, concrete bridges, tunnels, culverts, etc. Clustering of these units of infrastructure requires inputting their geophysical. In other words the global positioning of these units is defined here.
MODULE –2: Data Acquisition
This module involves identification of appropriate sensors, instrumentation of the infrastructural units, data logging. Again here no single technique is appropriate and universally applicable. The sensors attached to a reinforced concrete bridge may vary from the sensors attached to a cable suspended bridge, yet tunnels might have completely a different set of sensors. This module allows the option of selecting appropriate sensors and the data acquisition instruments.
MODULE –3: Data Conversion
This module involves conversion of data generated from sensors to a digitised form. Some Data recorders might directly convert the data into a digitised form. However, this module not only converts the data thus read, but also labels and packages the data for identifying it with and correlating it with the relevant mathematical and thus the graphical model displayed at the Infrastructure Monitoring Command Center.
In case of El Hormiguero Bridge-20011 remote monitoring, the instrumentation at the bridge comprised of a set of Accelerometers, Amplifiers filters and FM transmitters. These FM modulations are modified and converted and digitised by an A-D Converter.
MODULE –4: Data Communication
Once digitised, the data can be transferred to any point through internet or intranet irrespective of distance. Global Positioning System (GPS) techniques are applied to identify the data emanating from a given static location of an infrastructure. This principle of data collection from a single point can be applied to geographically dispersed locations to collect data from several locations simultaneously.
Communication or transfer of digitised data to the command center can be achieved in a combination of ways
- It can be directly transferred thru a modem, where available.
- Digitised data can be read into a Mobile data recorder and then transferred from the nearest web node.
- Radioed data from a set of remote infrastructure can be sequentially read through a FM receiver and then transferred to the command center after converting it to a digitised data.
MODULE –5: Data Receiving, Sorting and organising
Simultaneous accumulation of data is achieved by scheduling the events. Normal periodic data is collected as a routine. However, there are instances where data is generated upon an event. For instance, if an overloaded truck is passing over a bridge it can trigger a set of data, this in turn activates the communication receiving mode at the command center and data is instantaneously received. The data thus generated is a real-time data. However, the transfer of data may or may not be real-time depending upon the location of the infrastructure and the remote accessibility of the infrastructure. Multiple channels can operate at the command center to receive data as per the schedule. The size of the receiving module could match the volume of data generated in the given region.
MODULE –6: Real Time Environmental Data
Accumulation of real-time environment data is done to get the actual environmental conditions at a particular location where the infrastructure is being monitored. The environmental factors which can influence the behavior of an infrastructure are , Wind velocity, Temperature, Flood level, Tidal wave, Storm intensity ,Earth quake intensity, etc .This data can be obtained periodically for the locations at which the infrastructure is being monitored. This data is mostly collected through weather monitoring satellites globally.
MODULE – 7: Mathematical Modeling
In this module, a mathematical model which is built based on the data available on the condition of an infrastructural unit, a bridge for instance. This is done using standard available Structural Engineering Packages. The mathematical model represents behavior of the actual structure it represents. Hence when this module is made to interact with the external influences like loads, weather conditions etc, it reflects on the behavior of the actual structure. Any standard Structural package serves good for this purpose of Mathematical Modeling.
ODULE – 8: Algorithm
This module is an engine which lets the mathematical model of the structure and the external influences interact. It is built based on the engineering principles
MODULE – 9 Analysis
An analysis is said to have been done when the mathematical model is made to interact with the external forces as per the defined algorithm. The resultants are tabulated or translated to graphic displays. Normally, extreme loads cause distortion in the proportions of a structure, leading to cracks and then an automate failure, if no attention is paid to the deviations from the designed parameters in a structure.
MODULE: 10: Graphic Display
At the Infrastructure Health Monitoring Command Center, a display can be made on a wall mounted screen. The initial display could reflect the geographic location of the infrastructure in the region. GIS and GPS can be used for this display. As already demonstrated by Myung-Hee Jo 5
Subsequently, all the analysis and the effects of the loads on each of this infrastructure can be displayed, when all the modules function. Hence, all the changes in a given structure are visible through interactive modules. This gives an instantaneous insight into a structure system, which otherwise is not visible in a physical inspection of the actual location.
This graphic package when integrated with structural engineering software can zoom in on a specific structure and highlight the mathematical model of the structure as required.
It can be said that it is possible for the developing and the under developed countries to adapt latest technological innovations. However, a word of caution here, adaptation of new technologies is a costly affair. Adapting any new technology in isolation will not be beneficial. Due consideration must be paid to using these technology in combination with other available technologies around. As can be seen here in Highway infrastructure monitoring technology, when applied in combination with some of the other compatible technologies, it not only becomes cost effective, but also the scope of its application can be broad.
- Jean Baptiste Mounnier, David Keam “Internet GIS for the infrastructure lifecycle” MAPINDIA200 Proceedings (1)
- Juan M Caicedo, Johannio Marulanda, Peter Thomson and Shirley J Dyke, Monitoring of Bridges to detect changes in structural health – Proceeds of American control conference 2001 (2)
- Sandra LLoret, Daniele Inaudi, Samuel Virpillot , Static and Dynamic Bridge Monitoring with Fiber Optic Sensors, SPIE International Photonics China Symposium on eLaser Optoelectronics and Photoelectronics, Beijing, China, 1998 (3)
- MONIMASS©, is a Starmass Environment Technologies, www.starmass.net – infrastructure health Monitoring solution for developing countries. It is an integrated remote highway infrastructure health monitoring solution, presently undergoing rigorous tests at Artificial Intelligence Center, Osmania University, Hyderabad (4)
- Myung-Hee Jo · Sung-Joong Park · Mal-Suk Kim · Yun-Won Jo,” The Management System Development of Campus Facility Information using Web-based GIS” MAPINDIA-2001 Proceedings. (5)