«USE OF EMBEDDED RFID TAGS IN CONCRETE ELEMENT SUPPLY CHAINS REVISED: February 2013 PUBLISHED: April 2013 EDITOR: Robert ...»
www.itcon.org - Journal of Information Technology in Construction - ISSN 1874-4753
USE OF EMBEDDED RFID TAGS IN CONCRETE ELEMENT SUPPLY
REVISED: February 2013
PUBLISHED: April 2013 http://www.itcon.org/2013/7
EDITOR: Robert Amor
Jouni Ikonen, Associate Professor,
Lappeenranta University of Technology, Finland;
Antti Knutas, MSc.,
Lappeenranta University of Technology, Finland;
email@example.com Harri Hämäläinen, MSc., Lappeenranta University of Technology, Finland;
firstname.lastname@example.org Marko Ihonen, MSc., Miradore Ltd, Finland;
email@example.com Jari Porras, Professor, Lappeenranta University of Technology, Finland;
firstname.lastname@example.org Tommi Kallonen, MSc., Lappeenranta University of Technology, Finland;
email@example.com SUMMARY: Precast concrete components are basic element of modern construction industry. Their lifecycle involves many steps, in which the element's progress is usually tracked on paper. Similarly construction projects do not often have a formal information management process. Increased traceability and information management could address issues related to duplicated information management work, lack of real-time information, information delays and access issues. A study of how an information system can be integrated to the construction process and what kind of services can be implemented with the unique tracking of precast concrete elements is reported here. The tracking and data management is implemented with embedded RFID chips in each of the elements. The viability of building information modelling, traceability, management, gathering of quality management data and logistics location management services are shown to work with a series of pilot projects. The information system increases the amount and the detail of data, providing more tools for data management and reduces the amount of human errors involved in information management.
KEYWORDS: mobile technology, radio identification, logistics, supply chain, construction, information technology.
REFERENCE: J. Ikonen, A. Knutas, H. Hämäläinen, M. Ihonen, J. Porras, T. Kallonen (2013) Use of embedded RFID tags in concrete element supply chains. Journal of Information Technology in Construction (ITcon), Vol. 18, pg. 119 - 147, http://www.itcon.org/2013/7 COPYRIGHT: © 2013 The authors. This is an open access article distributed under the terms of the Creative Commons Attribution 3.0 unported (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ITcon Vol. 18 (2013), Ikonen, et.al., pg. 119
1. INTRODUCTION Precast concrete elements are building blocks of various building projects. They come in different shapes and can form the entire supporting structure of a building. During its life cycle, presented in Fig. 1, a precast element will pass through many stages, e.g. planning, manufacturing, storage, transportation, pending installation queue, and installation. Current state information is important so that the construction site can confirm that parts have been received in correct order and they can proceed on schedule.
FIG. 1: Supply chain for precast elements.
Traditionally, status updates, defects in construction objects and quality inspection records are marked on paper by a construction worker. Workers collect this information during the workday and deliver it to the project manager at the end of the shift. Knowledge management of construction projects is often formed on an ad-hoc basis and does not serve the project’s needs as well as a designed system could (Carrillo et al., 2000). The traditional approach has problems and challenges related to information management, which have been
recognized by researchers (Kimoto et al., 2005; Ergen et al., 2007; Lin et al., 2007; Leskinen, 2008), namely:
Lack of real-time information;
Information access issues.
A current drawback to information management in construction logistics is that the traceability of the elements through the logistics chain is often poor, because the elements are not tracked in detail and might be grouped with other elements of a similar model. The details available from the construction site storage might be just on the level of recently arrived deliveries and beyond that, the manager has to do phone-based queries. Additionally, many reports from the construction site have to be gathered manually and input to the information systems. In a worst-case scenario, the produced reports, such as daily defect reports, remain in paper form and are not shared efficiently or are lost. A recent study by Torrent and Caldas (2009) noted that construction labor hours can increase by up-to 16-18% if required materials and components are not ready when needed. If potential problems can be detected at an early stage, there are better opportunities to react and reallocate resources.
Traceability is not the only problem present in construction, but rework costs are a major element of total construction project costs, with the cost of rework being as high as 6% to 25% of contract price (Josephson, 1999; Barber et al., 2000). However, in construction projects where a quality management system was implemented, the cost of rework can be only 1% of contract price (Love and Li, 2000). Effective quality management requires accurate and current information about the quality issues for improving the processes and planning the rework (Love, 2002). The lack of information or poor information can lead to needless rework and increased construction costs (Love, 2002). This means that accurate information tracking and quality management can lessen the need for repeated work, because quality issues can be caught in time.
The poor management of knowledge about the precast logistics chain leads often to delays and repeated input work, which might discourage workers from entering exact data all the time. This means that the information available in information systems and shared with partners is not necessarily up to date or as accurate as possible.
Logistics and production decision-making would benefit from exact and up-to-date information about the status of precast components, allowing decisions to be made earlier and based on more accurate data about what is happening in the field.
Traditional forms of information dissemination, such as phone, email or SMS, are ineffective and timeconsuming. Better tracking of the elements through the logistics chain would enable the automation of information management and the implementation of services that utilize the more accurate tracking data, like ITcon Vol. 18 (2013), Ikonen, et.al., pg. 120 automatically collected and targeted quality management data. The collected data can be gathered and processed automatically for computerized presentation in BIM (Building Information Modelling) programs, which have been found effective in construction management (Yusuf Arayici, 2012).
The nature of information storage at construction sites has been perceived as a problem and different kinds of information management systems have been developed for it, each addressing a different issue from logistics tracking (Song et al., 2007) to quality inspection (Dong et al., 2009). RFID (Radio Frequency Identification) is a heavily researched and a quickly maturing technology as well (Ngai et al., 2008). However, these problems are still often examined from separate aspects, with the field lacking a system that combines automatic identification, tracking, mobile quality management and measuring into one cohesive whole.
The aim of the research presented in this paper is to improve construction project logistics processes by
improving information handling and increasing traceability. The main research questions are:
Which kind of changes does a construction logistics chain require in order to support accurate traceability of elements through the entire chain?
What services can be provided with the help of improved traceability?
The research approach is design science, in which a solution is designed to address a specific problem and the solution’s validity is confirmed by its utility (Hevner et al., 2004). In this case the first step is to first examine the current state of construction element logistic chains, the existing implementations of tracking and the suitability of different machine-readable identification systems for the transported elements. After examining the problem a new construction project information management system is designed and implemented based on the lessons learned in earlier research. Finally, the validity of the chosen approach is tested by using the information management system services in a series of pilots.
This paper analyzes the logistics chain of precast concrete elements, from manufacturing in the factory to installation and post-control on site, and details an approach to implementing a computerized real-time quality management for precast elements. An approach is presented where mobile devices are used to provide access to a centralized project information system and RFID (Radio Frequency Identification) is used to guarantee permanent and efficient identification of elements. The aim is to present an approach to construction logistics management systems where information can be shared more efficiently among the participants of a project and overall in the project the information is more available and up-to-date.
The presented application of design science research method (DSRM) consists of six steps (Peffers et al. 2007).
The Table 1 shows how they are applied in this study and how each step of the activity corresponds to a step of the research presented in the paper. With the problem defined earlier in the introduction section, the following sections present the steps from two to five: The design, demonstration and evaluation of the design science artifact. In this study the artifact is the tracking process and the information management system for precast concrete elements in construction.
The paper is constructed as follows. Following the introduction and motivation for the study, element identification is addressed in section 2. Accurate element identification is seen as essential for effective management of construction industry processes. Section 3 covers the proposed solution for project management through a centralized management server. The system architecture and its components are explained. Section 4 presents the research plan, the performed case study, examines the construction process supply chain and how the proposed solution can be utilized. The paper concludes by presenting conclusions and discussing future development ideas for the construction industry.
2. CONCRETE ELEMENT IDENTIFICATIONEach precast concrete element has to be identifiable throughout the whole supply chain and, therefore, is labeled during production. Elements may be identified in sets by their type or by their unique serial number. During interviews with construction industry representatives, it became apparent that there is a need to identify each element uniquely using some type of serial number to ensure tracking. This is important because identical looking pieces may have different attributes, e.g. steel reinforcements that are not necessarily visible after casting. These identifiers have to remain the same through the whole supply chain or be linked to each other so that all the cooperating companies can identify the elements.
Identification methods can be divided into visual- and radio-based methods. Visual identification can be carried out with human readable characters or different types of machine-readable bar codes. Radio-based identification makes possible advanced types of identification scenarios compared to visual identification.
2.1 Visual element identification Most identification systems in the construction industry are currently based on visual identification.
Identification marks and codes are typically printed on external labels that are attached to the elements in the factory, or in some cases, painted on the element.
One of the limitations with using external labels is that they are attached to the element in a factory and removed during or after installation, and therefore, the traceability of a single element ends at this point, unless precise information about each element and its location is brought to the as-built building information model and is accessible afterwards. Since these labels are attached to the outside of the element, they can occasionally become detached or be destroyed during transportation. This always causes additional examination work in the construction yard to ascertain the type and identity of an element. Visual element identification can be divided into human readable and machine-readable methods.
ITcon Vol. 18 (2013), Ikonen, et.al., pg. 122 2.1.1 Human readable identification Visual element identification is typically done using coated paper or plastic labels which are human interpretable and attached to the elements. The elements are mostly handled by humans and there is little automation in the identification process. Labels typically contain specific information such as dimensions, weight and possibly acknowledgements of passed inspections. An example of a plastic identification label can be seen in Fig. 2.
FIG. 2: Example of manually filled in label used for identification of precast concrete elements (front and back).
2.1.2 Barcode identification In addition to human readable information, precast element labels can include visual machine-readable information such as barcodes. Machine readable identification has gained popularity as the identification process can be speeded up and human based keystroke errors can be avoided. If the reader devices are able to communicate directly with company databases, they can update status information of the inspected object.