PEC have developed a number of innovations aimed at improving road transport infrastructure, making safer transport in Europe.
Every day our intensively connected society uses and depends on transport infrastructure. The sensitivity on any disturbance is obvious for us. Transport is a major component of economic activity influencing other activities. Road transport dominates compared to other transport modes; the volume of road traffic depends on the demand for transport (largely determined by economic activity and transport prices) and on transport supply (e.g. the development of road infrastructure).
Transport infrastructure is divided into civil work and the intelligent traffic system. The focus is laid on construction itself, more precisely bridges. The usage and climate impacts change the structural condition subsequently and challenges administrations to react upon changes and schedule timely predictive measures. There is no time to lean back and be satisfied with previous work.
What are the benefits of a consultation company in the transport infrastructure industry?
We focus on construction itself, the basis of infrastructure. Even this is a big topic and the decision was to support maintenance in order to save investments and reduce pollution, acting to fight against climate change.
At the beginning PEC developed an infrastructure database for Austria. The necessity was given due to fragmented data storage and many different simple data models to describe building infrastructure at transport networks. The main motivation doing such basic work was, and is, to provide data for optimising investments and to elongate the operational time of transport infrastructure. The boundary conditions for decision makers is traffic intensity. Reduced place for extensions, limited budgets, combined with limited potential in industry and administration to run a bigger number of projects are further cornerstones.
The development of database BAUT (Buildings Austria) was pioneered 15 years ago. It was at that time a leading database in D-A-CH region was the singular provider of information. Nowadays, new developments have taken place, resulting in a fragmented environment once again.
The ageing of infrastructure and the ever-reducing capacity to withstand loadings from trucks is the process we are faced with. Therefore, inspections locating shortcomings, as well as ratings of structural elements, is the most important data – generated every six years during detailed inspections by our experts. The timely data is used to develop statistical descriptions of infrastructural lifetimes.
Ten years ago, PEC developed a simulation tool for predicting ageing and maintenance strategies for the near future. The idea comes from findings from inspection input and an adapted cohort survival method, which is mainly used in forecasting future population. Cohorts are groups of people of a certain age and we all move from one cohort to another before finally dropping out of the system; a similar approach has been employed to bridges, whereby it becomes multi-dimensional, reflecting different behaviour. The simulation artificially ages components of each element, resulting in a worse rating and thus movement into another cohort. The good thing for bridges is that ageing can be partly compensated due to rehabilitation work, therefore managing the costs and producing reports summarises our approach.
With such tools, actual and predicted asset value of transport infrastructure is evaluated. The value is constantly changing, positively due to retrofitting, or the other way around by ageing correlated to traffic usage, and in some manner by climate change. The questions which arise are: will we able to hold actual asset value in the future and what is the optimal condition level? A badly rated bridge describes only its operability not its safety.
The term availability led PEC to a new very specific area, the analysis of stochastic nets, for example a road net in a simplified form. The term stochastic introduces a probability on elements describing the yearly availability. Due to ageing, this probability decreases. The effect of one element like a long bridge may be tremendous on net availability. PEC has done pioneer work on that field for Austrian highway starting with a course model and investigating its resilience.
The motivation to compete in the offered services and the need to have a tool in hand to make an effective stress test for bridges has led to a development process, whereby Bridge Weigh In Motion systems came out. We call it iBWIM in order to underline the IoT paradigm.
It is a measuring system for bridge and structure surveillance which holds a patent in several Member States of Europe and the USA. It measures expansions while heavy goods vehicles cross bridges. The big advantage is that the system does not require sensors to be installed on the road surface. Measurement data is collected and sent online to a central server, the customer is able to monitor the data from the bridges via web-browser in real-time and with a simulation-function for past data. The system’s hardware consists of a measurement amplifier called iBWIM Spider (data collector). The Spider is an electronic unit which collects data from different types of sensors and transmits it via LAN to the computer.
iBWIM system enables integration of third party sensors such as acceleration and inclination sensors, lasers or IP cameras of various suppliers. After having chosen a suitable bridge, a wiring diagram is prepared in order to define sensor layout. Subsequently, it is necessary to accurately measure the road width in order to determine where the sensors have to be installed underneath the bridge. Once the system has been installed and the parameters appropriately set, data collection starts.
The first step in this context is calibration, trucks whose weight have previously been determined cross the bridge several times and the measurement results are accurately recorded, a detailed calibration plan has to be chosen out of COST 323 specification. This phase is particularly important as it plays a key role for the quality of the subsequent measurement results. Generally, measurement accuracy ranges between 5-10%.
Measurement duration is between one day and several years – in case of long-term measurements. The power consumption of an iBWIM unit has been reduced to a minimum during past development steps. On completion of the measurement phase, the recorded data is further processed and an iBWIM report is prepared. Information relating to the real load data is important as it may be used as a decision-making criterion for further tests in order to determine repair, refurbishment or renewal requirements. As a heavy goods vehicle crosses the bridge, iBWIM measures its loads throughout the entire crossing period, which produces highly accurate measurement results. With these facts it enables determination of the bridge’s residual service life.
How data is collected and stored using iBWIM
The sensors installed underneath the bridge produce data which must be immediately compressed and sent to a local database. In this context, a compression algorithm is of key importance and substantially influences the work process. Other factors that have a direct influence on this process are waiting period, memory space and quick filtering of noises. The data in the database is analysed by the iBWIM algorithm using raw signal parameters such as speed, axle spacing and axle weight. In combination with other sensor information it is possible to obtain a complete picture of the heavy goods vehicle crossing the bridge.
The goal is to define information without impacting quality. Following evaluation of every single recording, raw data in gigabytes is turned into megabytes for each individual heavy goods vehicle. Such data is nevertheless still difficult to handle. To facilitate data processing, traffic-flow and axle-load models have been developed, enabling a reduction in the entire volume of measured data down to just a few kilobytes of data.
iBWIM is successfully working in different countries in Europe and Asia; the system can be rented in units or sold completely with hardware and software. All parts of iBWIM are in further development, such as evolving new sensors and photovoltaic or further increasing the accuracy of the whole system with new hardware and software components.
Dr Markus Petschacher
PEC – Petschacher Consulting,
+43 4276 33780