Civil Comp - RFID in Construction Submission 2009-2008-000127

8/8/2019 Civil Comp - RFID in Construction Submission 2009-2008-000127

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Radio Frequency Identification (RFID) and Building Information Modeling(BIM); Integrating the Lean Construction Process

J. Mark Taylor, Ph.D., JDAuburn UniversityAuburn, Alabama

Stephen A. Coady, MBC CandidateAuburn University McWhorter School of Building Science

Jon ChesserAtlas RFID Solutions, Inc.

Birmingham, Alabama

Abstract

Radio Frequency Identification (RFID) is an emerging technology that is beginning

to receive attention in the construction industry. From asset and progressmanagement, to the locating of underground and in-wall utilities/objects, to theintegration of RFID with building information modeling (BIM), the potentialbenefits of RFID to the construction industry will be a topic that receives more andmore attention in the future. RFID, in conjunction with BIM, shows great promisein the promotion of lean construction techniques in the construction industry. As thetechnology becomes more readily accessible and the cost of implementationdecreases, this will be used on more and more construction projects. Oncecontractors start adventuring into the potential that RFID has, the greater theconstruction industry will benefit.

Keywords: Radio Frequency Identification, RFID, Building InformationModeling, BIM, Lean Construction, Technology, Construction Technology.

1 Introduction

Profitability in the construction industry takes exceptional execution at everystage of a construction project, from the initial planning and design phases, to theclosing out, and signing of the final contracts. The unique complexities and



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unpredictable nature of projects in the construction industry make successfulmanagement a very valuable asset, but an extremely difficult chore. According tostatistics in 2006, more than half of construction firms fail within their first four

years in business [1].The importance of productivity improvements within the construction industryhas been generating a significant amount of interest [2]. Efficient management of assets may be considered a serious contributor to profit margins in almost everyform of business. Technological advancements have provided companies in manydifferent industries with more effective means for tracking and managing theirassets. One such technology is Radio Frequency Identification (RFID). Among themany possible uses, it can be used for identification and data storage of objects,animals, and people.

1.1 Radio Frequency Identification (RFID)

Radio Frequency Identification (RFID) refers to an automatic identificationtechnology which utilizes radio frequencies, or waves, to capture and transmit data[3]. Data can be gathered and stored regarding an array of tagged items such asobjects/components, people, and animals. There is currently a vast range of uses forthe technology outside of construction including, but not limited to, product trackingfor retail chains, library usages, inventory and supply chain management, animaltracking, health care, access and security systems, postal environment, airportbaggage management, usages in automobile keys, and toll-collection (EZ-Pass).

RFID technology uses a tag (also known as a transponder), and a reader(sometimes referred to as an interrogator), to successfully communicate and transmit

data. The data gathered through tag and reader communication is transferred to ahost system, such as a personal computer, or connected to a business’s enterprisesystem. The tag is attached to, or embedded into the object for which data is beinggathered. Tags are comprised of a micro-chip and an antenna, which areencapsulated in a protective covering. RFID tags can have many different shapes,sizes and protective housings. Generally RFID transponders are considered eitherpassive, or active. Active tags are those that have an internal power supply (abattery). Passive tags, on the other hand, do not contain a battery [4]. Some generalcharacteristics of passive and active tags, as well as some pictures of each, areshown in Figures 1 and 2.

Since passive tags do not have an internal power supply, they can only

successfully transmit data when they absorb the power emitted by a reader. Sinceactive tags have an internal battery source, they can actively emit a signal to thereader in order to communicate and transmit data. Active tags, therefore, havelonger reading ranges. Active tags can also be “always on”, or programmed to“wake up” at determined time increments (every minute, 5 minutes, 10 minutesetc.), in order to communicate with a reader. However, long term use of the activetag is limited by the life of its battery, a problem that can limit its usefulness infacilities management.



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Passive Tag Characteristics:No internal power supply

Mostly read only (data cannot be re-written)Unlimited lifeUsually smaller/lighter than active tagsGenerally cheaper than active tagsLimited read rangeLess data storage capability than active tags.

Figure 1. Examples and Characteristics of Passive RFID Tags

Active Tag Characteristics:Contains internal power supply (battery)Typically read/write (data can either befixed or changed)Limited life (can be up to about 10years)Usually larger/heavier than passive tagsGenerally more expensive than passivetagsLonger reading range than passiveIncreased data storage capability

Figure 2. Examples and Characteristics of Active RFID Tags

Electronic reading devices are used to communicate with tagged objects andacquire data regarding those items. RFID readers or scanners can be portable(handheld) or stationary. The readers also contain an antenna for transmittingsignals to the desired tags. The distance that a reader can read a tag will vary fromone system to another. The reading range depends more so on the reader than thetag [5]. Some sample pictures of RFID readers are shown in Figure 3.



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Figure 3. Examples of RFID Readers

The frequency level at which an RFID system operates is also a key contributorto a system’s characteristics and performance. Higher frequency levels will increasethe system’s reading range, as well as increase the speed at which data is transmittedfrom the tag to the reader and the host computer. On the other hand, lowerfrequency levels will decrease the reading range, as well as the speed of data transferto the reader and rest of the system [5]. The frequency bands in which RFIDsystems operate is determined by each country’s respective regulatory body. TheRadio Frequency (RF) section of the electromagnetic spectrum generally spans from3Hz (Very Low Frequency) to 300GHz (Extremely High Frequency) (Table 1).

Generic Band Name Frequency Range Comment

Low Frequency (LF) 120 - 135 kHz Short range inductiveapplications.

High Frequency (HF) 13.56 MHz Worldwide commonfrequency, smart cards andlabels.

Ultra High Frequency(UHF)

433 MHz Active low power tags.

860 - 960 MHz Band with major supply chaindevelopment activity.

Microwave 2450 MHz Active tag technology givesrange and fast data rates.

Table 1. Radio-Frequency Identification Device Frequency Ranges

There are many different varieties of RFID readers and tags which havedifferent performance levels for certain criteria and purposes of use. This makes itdifficult to analyze costs and historical trends. However, Niemeyer, Pak, andRamaswamy [6] analyzed and forecasted the downward trend in average RFID tagsand readers in a McKinsey Quarterly Report (Figure 4.) This downward trendshould help facilitate increased adoption in the future.



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Figure 4. Average cost per RFID tag and reader, Niemeyer et al, 2003

1.2 Lean Construction

Lean construction results from the application of a new form of productionmanagement to construction. Essential features of lean construction include a clear

set of objectives for the delivery process, aimed at maximizing performance for thecustomer at the project level, concurrent design of product and process, and theapplication of production control throughout the life of the product from design todelivery [7].

The highly competitive nature, combined with stringent time and cost budgetsthat are common in construction, require participants within the industry toconstantly seek improvements in productivity [2]. Productivity can be measured inmany ways, but is often defined as a measurement of the quality and/or quantity of output, in relation to the input required to produce that output. Among the manyaspects critical to achieving better productivity, is a company’s ability to manage itsassets and resources successfully. The efficient allocation, supervision, and

motivation of on-site employees may be an important aspect of management forconstruction companies that employ a large number of craft workers. Effectivemanagement of building materials both throughout the supply chain, and while on-site, may be considered another important task for construction projects. Theknowledge regarding the whereabouts of important tools and equipment on large-scale projects can affect productivity.

The demand for increasing productivity and safety throughout project deliveryhas stimulated the exploration of new technologies that may be implemented toimprove productivity of construction work. Many other industries have utilized



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RFID technology for multiple purposes, perhaps most often for the tracking of products, and inventory systems management [8]. Currently, the prospectiveopportunities for RFID within construction are quite vast. Areas of lean

management that can potentially utilize RFID technology and implementationinclude:Tracking and tracing of components vehicles, parcels etcInventory ManagementProduct ID - using the right component and deviceMaintenance of service systemsTrack recording of componentsIncorporating RFID into design

The number of studies and experiments that have looked at different uses of thetechnology has significantly increased recently. From asset and progressmanagement, to the locating of underground and in-wall objects and utilities, theoutlook for potential benefits in productivity through the implementation of RFID inthe construction industry is starting to look positive [9].

Organizations such as FIATECH, CICA, ERA Build, and the ConstructionIndustry Institute (CII), ha ve analyzed the technology’s potential within theconstruction industry through various pilot studies, demo applications, journalarticles and papers, in an attempt to map out key processes and functions that couldpossibly benefit from RFID. ERA Build’s Final Report on RFID in Construction [8]noted the following as the main drivers for the construction industry:

Tracking and tracing of components, vehicles, parcels etc.Supply Chain Management and Logistics - efficiencyProduct ID - using the right component and deviceMaintenance of service systemsTrack recording of components

Although interest in RFID in the construction industry has increasedsignificantly over the past decade, the number of companies that have adopted thetechnology for continued use within their operations remains somewhat stagnant.According to the same ERA Build Report [8], some of the main preventers of widespread construction industry adoption include:

Immature application of advanced logistics systems and the absenceof information and identification systems in the construction industry.Lack of awareness of RFID's potential in the construction industry.Low RFID-knowledge and awareness in the construction sectorLack of robust RFID-initiatives in the construction industryLack of successful RFID-implementation cases that thoroughlyshows its potentialsThe traditionally less industrialized construction industry and itsrelatively negative attitudes toward new innovations and technology

A National Institute of Standards and Technology (NIST) white paper entitledSmart Chips in Construction, noted recommendations for further research that isneeded before advances are to be made in implementing RFID in the construction



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project life cycle. Among other requirements, the paper calls for increases in RFIDpilot studies within construction. For increased promotion of RFID solutions in theconstruction industry, ERA Build’s final report [8] stated that “the primary need is

for exchange of knowledge and project RFID sampling to increase contractor andowner awareness of the potential savings.” It will become increasingly important tocontinue to evaluate different reasons for RFID adoption, and the implementationprocesses that are undertaken by those companies which utilize the technology.

2 Background

Literature on RFID and its potential within the construction industry has mainlyarisen within the last decade or so. The Construction Industry Institute (CII)conducted a workshop regarding RFID and possible implementations in constructionin 1998 [3]. The workshop divided into four groups consisting of materialmanagement, engineering/design, maintenance, and field operations. Each groupidentified many potential RFID applications within their delegated areas of concentration. A lengthy report was written in 2006 regarding RFID andconstruction [8]. Contents of that report include: a brief introduction into RFIDtechnology; the uses and benefits found in other industries; Applications to theconstruction industry, as well as a list of cases and pilot studies that have beenperformed globally; and the driving forces for RFID, and challenges faced that maydeter or delay industry-wide acceptance. There have also been a number of brief articles written recently which express RFID’s lurking presence within theconstruction industry. The prospects for improved productivity through itsimplementation, and some problems that have hindered its adoption into

construction are also addressed in those articles [9, 10]. The positives and potentialnegatives of RFID uses for supply chain management are assessed in articles byWang [11] and Santosh [12], which explore new management processes, as well asthe legal aspects and concerns for confidentiality of supply chain processesinformation, resulting from uses of RFID.

Actual data producing research and experimental testing of RFID utilizationsfor improved efficiency in construction processes have been performedpredominantly over the last few years. One significant study has been done througha collaborative research method performed jointly by Samsung Corporation,Sungkyunkwan University, and Doalltech Corporation [13]. The study concentratedon RFID and 4D CAD (Computer Aided Design) technologies for improved

progress management of structural steel work on high-rise buildings in Seoul,Korea. RFID was implemented from the beginning steel manufacturing phase, andtracked throughout the delivery and receiving of materials phases. Invoicingpractices and on-site management of the steel inventory, from receiving and storing,to the actual erection of the pieces, were tracked and analyzed for three projects.Two of the three projects implemented the new technologies, whereas the otherfollowed current methods and practices for managing the supply chain andconstruction processes of structural steel components. Although there were plentyof positives resulting from the study, some apparent signs of the immaturity of the



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technology were reported. A lack of confidence in the technology was expressed bythose who were unfamiliar with RFID. Manufacturers of the steel were the mostreluctant to adopt the process because of the added work of attaching the RFID tags

and a lack of benefits on their end. On the positive side, increases were reported inproductivity for time spent inputting data, unloading steel, time spent in stockyardsof factory and construction site, and the general contractor and subcontractor’s dailyreports. An overall process time with the new technologies was shown to have 17%more time efficiency than the conventional process for supplying and erecting thesteel [13].

A materials tracking field test that was sponsored by the Construction IndustryInstitute was performed by professors and graduate students from The University of Texas at Austin, University of Kentucky, and University of Waterloo, along with thecollaborative help of local industry partners, and RFID solutions vendors. Thestudies were done on two projects: A $750 million power plant in Rockdale, TX,

constructed by Bechtel; and a 550 megawatt Portlands Energy Center in Toronto,Canada, contracted by SNC-Lavalin Constructors Inc. Both of these studies alsoproduced positive data and worker feedback regarding RFID implementation [9].Through comparing the time it took to locate materials with the old method, to theautomated method with RFID/GPS technology, the study found that the averagetime to locate materials with the manual method was 36.8 minutes, and the time ittook with the automated method was 4.6 minutes. In an ENR article, Paul Murray,the site manager on the Canadian project noted “Instead of having a $75 -per-hourpipefitter go out and look for [a component], we had a $14-per-hour student internID it, and then they would go out and get it” [9]. Murray also commented on the

performance of the technology and implementing it full time: “We had two identical

boilers…Once we saw the use of it we weren’t going to let one boiler fall behind”[9].Research on the use of RFID in the concrete curing processes has also

developed over the past fifteen years. In 1995, an article in the Journal of Construction Engineering and Management proposed three potential uses for thetechnology within the construction industry [5]. The concepts developed in thatarticle pertained to concreting operations; cost coding for labor and equipment; andmaterial control. The article mentioned the potential ability of RFID to takeincremental temperatures, but for the most part concentrated on proposed systemsfor tags to be externally applied to concrete trucks and concrete test cylinders inorder to locate and identify them. Another article discusses external applications of

RFID to concrete was recently written in the past two years [14]. The articleanalyzes the tracking of engineered-to-order components such as precast concretemembers throughout the supply chain with RFID. The article harps on theautomated data collection that RFID provides which workers try to avoid, as well asthe durability of the technological equipment, but still only mentions externalattachment to objects, as the cheaper passive tags better suited their budget.

A study regarding the implementation of RFID tags inside concrete specimenswas performed by Wang et al. [11]. One goal of the study was to develop a web-based quality inspection and management system for improving the availability and



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communication of inspection data results to those involved in the constructionprocess. The quality management system that developed was designed to quicklygather data in material test lab areas and relay that data, via the internet, to other

parties of interest such as the owner, consultant firm, customers, suppliers andcontractors. Another important goal of the study was to determine through fieldtests, whether the insertion of an RFID tag inside concrete would influence thestrength of a specimen. Proper placement within a specimen was also discussed.Conclusions regarding the web based system claimed that it “enhanced theconstruction quality inspection and managem ent performance in…workingefficiency, reduction of operation cost, customer satisfaction enhancement, and timesaving in inspection operation and management progress” [11]. The study alsofound that the placement of RFID tags inside concrete specimens did not influencethe strength of those specimens. An important note to add is that the researchexpressed the importance of the insertion position of the tags within the concrete

because if the tag were too deep, it would be unreadable [11].The Michigan Department of Transportation (MDOT) performed another studyand Dr. Andrew J. DeFinis wrote a white paper on the research entitled “ConcreteMaturity Testing in Michigan”, in February of 2004 [15]. The test was performedbecause the MDOT wanted to develop a provision that would allow contractors inMichigan to use maturity testing to approximate the strength development of concrete pavements. The maturity concept estimates the strength development of concrete by taking into account the combined effects of temperature, and the time aspecimen was poured. Data on time and temperature, gathered through RFIDwireless tags located within the concrete, was entered into an equation known as theNurse-Saul equation. The Nurse-Saul equation is used to estimate the strength of

concrete in pounds per square inch. Standard concrete cylinders were also testedand the compressive strength was compared to the maturity estimates. The studyconcluded that the Concrete Maturity Monitoring System measurement results werewithin 4-11% of the concrete cylinders. Differences in results were expected to bereduced if adjustments could be made to the method of curing the concretecylinders. Every RFID tag placed on the project worked.

Currently a study is underway which will utilize RFID tags for concrete curinginformation on the construction of the Freedom Tower in Manhattan, which is beingerected on the location where the World Trade Center towers once stood [16]. Thetags are being utilized on almost every major concrete pour including footings, corewalls, elevator shafts, stairs wells, and all mechanical spaces. Identec Solutions AG,

Lustenau, Austria is providing the tags, and the article reports that approximately20,000 active RFID tags will be used throughout the 1,776-foot tall tower and itssurrounding structures.

Research regarding the monitoring of labor inputs, and uses of new technologiesto compose real-time assessments and make necessary adjustments to labor forceallocations, has become an increasingly attractive topic in construction [17]. Studiesperformed by Navon and Goldschmidt in 2002 explored possible technologies thatcould be used for automated location measurement. RFID played a significant rolein their design of a performance measurement system, which proposed to determine



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worker’s locations at certain time intervals, and then measure the amount of work completed at those locations, or “work stations”, to establish a metric of productivity[17]. In 2003, Navon and Goldschmidt put their performance measurement system

through a series of smaller, preliminary field experiments, in order to analyze thesystems accuracy in measuring worker efficiency. The results determined that the“prototype successfully measured the time workers spent perform ing their tasks withan accuracy level of plus or minus 10- 20%” [18]. The study also mentioned the usesof RFID technology for determining employee locations after accidents haveoccurred on a site.

The amount of literature pertaining to RFID and the employments to theconstruction industry has significantly increased since the year 2000. There arenumerous reports that explain the current uses in other industries, and anticipate thatpossible applications within construction will increase in the future. A handful of data producing experiments have been performed for asset tracking and

management, particularly for materials, equipment labor and concrete curing, withhopes of determining potential improvements in the project delivery process.

3 Case Study

This specific case study pertaining to RFID applications within the constructionindustry was performed on a power plant expansion project being constructed byBechtel Corporation in the Northern United States. The expansion project consistsof two coal-fired steam-turbine generating units, as well as supporting facilities, andrelated civil work. The contractor’s scope of work consists of engineering,procurement, construction, and start up. The project will cost an estimated $2.15

billion dollars, with construction scheduled from 2005 to 2010. Of the two units,one is scheduled to begin operation in 2009, and the second is scheduled to beginoperation in 2010.

3.1 Site Layout and Material Lay-Down Yard

The original project site utilization plan for the project delineated one large areaof the site to act as the lay-down yard for construction materials as they werebrought onto the site. A substantial amount of site work was necessary in order toprepare the land for construction of the new expansion facilities. The earth removedfrom the shoreline area where the new expansion project was to be constructed wasplaced on the proposed materials lay-down area. Afterwards, it was found that therewere issues with the underpinning soils and the majority of the land would notsuffice for material storage. Approximately 60 acres of land intended for materialstorage was determined to be unusable.

As the original material lay-down yard was unsuitable, the constructionmanagement team was forced to reorganize and utilize alternative land for thenecessary material storage for the project. Through arrangements with landholdersto the south of the construction site, additional land was acquired for material



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Figure 5. Material ID code

storage needs for the duration of the project. The yards now stretched from North toSouth and the distance between the two farthest most yards was approximately threemiles.

3.2 Materials Management Process without RFID

The materials management process for the project is comprised of a series of activities or processes that ultimately lead to the installation of a component into thefacility. A majority of the steel and piping for the project was received on site viatruck. Some components for the project were shipped by boat.

As materials are delivered to the site, they came with a packing list, whichdetailed the contents of the shipment, including where it came from, contactinformation, date of shipment, etc.Each component of material comes

with its own specific materialidentification code for the project.The material ID codes are writtenon the surface of the components,and are comprised of a series of numbers and letters (Figure 5).The entire receipt process and theentry of items into the materialsmanagement database wasperformed with a paper basedmanual method. The materials areaccounted for and manually entered into the materials management database system,so that construction activities could be coordinated depending on the availability of materials.

The components are then taken to the lay-down yards and placed within aspecific grid. Caldas et al. [19] r efer to this stage as “Sorting.” The components aregrouped within grids according to characteristics and material identification code.Different groups of materials are assigned a color scheme. Specific colors andtwisted combinations of colored flags are attached to the respective groups of materials for future identification and locating purposes.

Materials are stored in the lay-down yard until needed for installation. When aconstruction crew or trade is prepared to construct a certain section of the facility,the necessary materials have to be retrieved from the lay-down yard. For this, asuperintendent coordinated with a field engineer and communicated the plans forassembling a certain area of the facility. The field engineer would generate amaterial withdrawal request (MWR), which listed all of the necessary materials thatthe superintendent’s crew need ed in order to complete the specified scope of work.The MWR is sent to the Materials Management staff, where they develop a “pick ticket”. The pick ticket lists the materials needed, along with the respective lay-



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down yard and grid location of the component. The Materials Management teamthen gives the pick ticket to the respective staff so that they can locate the materials.

Workers would take the pick ticket to the lay-down yards and visually locate the

materials that were needed for installation. Once located, the components wereflagged, organized, and staged so that the pick-up process of those materials wouldbe easier and more efficient. The materials would be loaded and taken to theconstruction area where they were turned over to the construction team. Once thematerials had been turned over to the construction team, the receiving foremenwould sign off on the materials to assure that they have received them.

The sequence of activities in the materials management process for this projectwas similar to the one described in the pilot test performed by Caldas et al. [19], inwhich the impacts of utilizing Global Positioning Systems (GPS) for the locating of materials was measured (Figures 6 and 7).

Figure 6. Material Management Process [2].

3.2.1 Problems Presented With the Manual System

The issues presented for materials management on Bechtel’s power plantexpansion revolve around the ability of personnel to locate and flag specific materialitems (Flagging), so they may be organized for convenient pick-up and transporting.When materials required for installation are not ready at the time they are needed,installation crews may become idle and nonproductive, which can increase craftlabor hours up to 16-18% [20].

The sheer volume of materials required on the construction site presented the

materials management team with several problems. The $2.15 billion power-plant



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Figure 7. Responsibilities and Paperwork for On-site Material Management Process

project is comprised of an incredibly large number of intricate components of steel,piping, and other structural and functional components. Individual piping pieces canbecome very difficult to identify when they are closely stacked together in areas of what can be thousands of square meters per lay-down grid. Additionally, there is alimited number of colors that flagging comes in, and it can become difficult for thepicking crew to decipher which materials are for their specific load if there aremultiple loads marked with the same colored flagging (Figure 8).

Figure 8. Piping and structural steel lay-down yards

Superintendent• Ready to construct

Field Engineer• Develops MWR (list of

needed materials)

MaterialsManagement

• Develops pick ticket

Trade Workers• Take ticket and locate,flag, and organize/stage

materials for pick-up

Communicates toField Engineer.

Sends MWR toMaterials Mgmt.

staff.

Sends pick ticket torespective trade staff.

Materials are loaded

up, taken to site, andworkers sign off on receipt



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The arrangement of the material yards is also a factor which can contribute todecreased efficiency in the flagging process, as well as the rest of the materialmanagement process. The farthest lay-down yard was almost three miles from the

construction site. Therefore, minimal time spent at the storage yard was desiredsince it took a significant amount of travel time to get there and back.Another factor affecting the material management process was the weather

conditions. Extremely cold temperatures, combined with rain and snowfall, werethe main areas of concern regarding severe weather that could affect constructionproductivity. The flagging process was made much more difficult after heavysnowfall for the obvious reason that the materials would get covered in snow and thematerial ID codes must be uncovered, with shovels or by hand, in order to properlyidentify. Snowfall could complicate and delay the delivery of materials to theconstruction site further if a significant amount of snow was received after theflagging crew had already located and flagged the necessary materials. The flagging

process must essentially be repeated by either the flagging crew or by the pickingteam when they come to load the items for transportation to the construction site.

3.3 Experience with Automated Systems, Lean Construction, SixSigma, and Decision to Implement

Due to the problems associated with the manual tracking system, the decisionwas made by management to implement a full scale RFID/GPS based system for theentire on-site materials management process. ERA Build [8] noted that longimplementation time and difficulty in obtaining the skills and knowledge on thetechnology can be key operational and technical barriers that face companies inadopting the technology. This was the company’s first full scale application of thetechnology. The big decision to invest and employ the technology on a large scalewas made less difficult, in large part, due to the company’s previous participation and involvement in pilot tests. Bechtel hosted an academic study pertaining to RFIDtechnology on one of its construction sites in 2005.

Bechtel’s field test was performed over approximately three months on a twin-boiler project in Rockdale, Texas. Chief sponsors of the pilot were the ConstructionIndustry Institute (CII) and FIATECH, and the research team was comprised of about two dozen individuals representing universities, construction firms, institutes,and technology vendors [9]. The field tests compared the times of the typical paperbased manual method of locating steel items, to the RFID/GPS based automatedmethod for tracking down components in the lay down yards. The trial results foundthat the average time taken to locate a specific component with the manual processwas 36.8 minutes. The average time taken to locate materials with the automatedmethod was 4.6 minutes. Also, when using the manual method, 9.52% of materialcomponents “were not immediately found,” compared to the 0.54% of theautomated method. The research team regarded the success rate of the automatedsystem to be quite significant considering the fact that the failure to locate criticalitems can lead to costly slowdowns, and sometimes even re-procurement [9].



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3.3.1 Six Sigma Management Strategies

Bechtel utilizes Six Sigma management strategies throughout their business

processes and construction projects. Six Sigma is a quality based business strategywhich aims to decrease the amount of defects, or errors, or failures that a companymight encounter throughout its business processes. Defects are known as anythingthat may lead to customer dissatisfaction. Six Sigma aims to develop quantifiablebusiness improvements via statistical analysis of data. The process can be describedas: “Six Sigma methodology of problem solving integrates the human elements(culture change, customer focus, belt system infrastructure, etc.) and processelements (process management, statistical analysis of process data, measurementsystem analysis, etc.) of improvement.”

The experience gained through the field study proved to be valuable forBechtel, in regards to developing future applications. Not only did the field studies

produce valuable data for statistical analyses, but the relationship that was gainedwith the technology vendor during the field tests, was able to be continued, anddeveloped into a business relationship for their full scale implementation.

3.3.2 Technological Specifications: Tags and Readers

The tags utilized in this full scale implementation were active RFID tags. Theseactive tags continually “wake up” and send out their ID information at pre -configured intervals (i.e. every 1 second, every 2 seconds, every 10 seconds, etc.).The active tags are Ultra High Frequency (UHF), and they operate on a 915MHzfrequency level. The lifespan of the tags is generally five years. The physical

dimensions of the tags measure about 5 x 1 x .85 inches and weigh about 50 grams.Tags with these characteristics and reading ranges cost approximately $25(US) each.The reading units utilized in this application were a combination of RFID reader

and Global Positioning System (GPS) receiver. The readers were mobile, handheldcomputers, or personal digital assistants (PDA), suitable for field readings. Thereaders’ operate with Microsoft Windows. Approximately six handheld readerswere utilized on the entire project; usually a team (i.e. iron-workers) would have itsown reader which was designated for them each day. RFID/GPS readers such asthose utilized in this study currently cost approximately $5,000(US).

The automated materials management process also used barcode scanners forassociation purposes. The scanners were mobile, handheld devices that utilize

Bluetooth technology. The scanners operate on High Frequency (HF) radio wavesat a 13.56 MHz frequency level. The scanners are rechargeable. The physicaldimension of the barcode scanner is about 4.8 x 2 x 1.3 inches and weighs 132grams (about 0.3 pounds). These barcode scanners currently cost around $450-$500(US). (Figure 9).

Server software is also required for the system and it can cost approximately$35,000 - $50,000(US) depending on the software and the vendor.



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Figure 9. System Hardware

3.4 Implementing the RFID/GPS Based System

The RFID/GPS based materials management process was not implementedfrom the beginning of the project. It was only after the problems mentioned abovearose, that the decision to implement the automated tracking system was made. Atthat time, around 65-75% of the materials for construction had already beendelivered to the site. Having the majority of the materials on site meant that thematerials management process would have to be retro-fitted with the technology.Roughly 6-10 employees were assigned the task of attaching tags to materials in thelay down yards, and associating those tags to the specific material piece in themanagement system. This project tagged 20,000+ unique material components withRFID. Approximately 12,000 tags were utilized for this project, as tags arereusable.

3.4.1 Attaching and Associating RFID Tags to Materials

RFID tags were attached to the material components with plastic zip ties. Theholes present on the RFID tags make this a simple process and the tags can attach tomaterials through anchor bolts in the materials, or by simply wrapping two tiesaround the materials and pulling tightly (Figure 10.).

Once the tags are attached, they must be associated with the respective materialto which they are attached, for future tracking purposes. Some materials arrived onsite with a barcode label that indicated the component’s material ID . Others did nothave barcodes attached, and their material ID would be written on the exterior of thecomponent.

If the material component had been delivered with a barcode label, then theassociation process becomes very simple and almost instant. The barcode label onthe material component is simply scanned along with the barcode label on the RFIDtag attached to it. The barcode scanner is able to instantly transmit the material IDand RFID tag’s ID in to the RFID reading device wirelessly via Bluetoothtechnology. Once the material ID and tag ID had been input into the RFID reader,



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the worker could hit “ associate ” on the RFID reader to initiate communication withthe tag while next to it , and that specific RFID tag’s ID would then be linked to thematerial component on which it was attached. Once the tag was associated, the

workers would hit the “locate” button on the RFID/GPS reader, and thecomponent’s latitude and longitude is stored in the reader. The tag had beenassociated to the specific material component and now that specific materialcomponent was ready to be tracked. When items arrived with barcode labels, theassociation process, after the tag had been attached, was very simple, andcompletely automated. The association process takes approximately 10 seconds.

Figure 10. Associating materials with and without barcodes ID

When material components did not have an attached barcode label, theassociation process was changed slightly. Workers would still scan the barcode onthe tag to input the tag ID into the RFID reader, but had to type in the material’sunique material ID, which was stamped or written on the exterior of the item, intothe RFID reader. The worker hits “associate ” on the RFID reading device so thatthe material component would now be linked to the tag (Figure 10). Again, theworker would hit “locate” to assign the material a latitude and longitudinal position.When employees typed the material ID into the handheld devices manually, theelements of human error become possible. Problems such as entering the materialproduct ID incorrectly were more prone to happen in this case.

3.4.2 GPS Mapping and RFID Tag Locations

Before the system was implemented, the lay-down yards throughout the sitewere geo-coded, mapped and entered into a geographic information system (GIS),which divides the yards into their respective coordinated grids. As Torrent andCaldas [20] explained, GPS receivers can be set to transform collected systems intoa coordinate system. The default latitude and longitude degrees for a global system



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can be transformed into a “local projected system” so that it “simplifies theimplementation of the localization mechanisms by providing coordinates infundamental units of length, such as meters [20]. An image of the digital lay down

yard on an office desktop easily identifies the material and its location in the lay-down yard (Figure 11).

Figure 11. Digital map of lay down yards with grids

3.4.3 Tag Item Location with RFID/GPS System

Because of costs and other issues, attaching individual GPS receivers to eachpiece of material, when there are mass amounts of material items, has been deemedan infeasible option for the purposes of locating construction materials [20].Therefore, the project in this study utilized six RFID reading devices that wereequipped with GPS receivers, and the material components were tagged with RFIDtags. The GPS receivers are able to determine their own location at any given time.The active RFID portion of the reader could then be utilized with localizationmethods, which are algorithmic based location projections based on strength of signal and reader location, as described by Torrent and Caldas [20], for the projectedlocations of the RFID tagged components that were within reading range of thereader. Periodic updates are made in order to update the projected locations of materials. To perform a periodic update on a lay down yard, an employee wouldeither walk or drive around the perimeter of the lay down yards with an RFID/GPShandheld very slowly, in order to allow the reader to pick up all tags within the yard.Once the updates are complete, the RFID readers are brought back to the materials



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management of fice and placed in their “dock” (Figure 12). When placed in a dock,the handheld reader automatically transfers new data, gathered by field activity, intothe main materials management database.

Figure 12. Docked RFID/GPS Readers in Office

3.4.4 Automated Locating Process

With the RFID/GPS system in place, the goal is to make the material locating(flagging) process much easier and faster. With the automated system in place, afterthe Engineer has developed a material withdrawal request (MWR), the materialsmanagement office staff generates a pick ticket packet which included a list of therequired materials and each item’ s specific yard and grid, as well as a supplementalimage, which would give the workers the approximate location of each componentwithin their respective grid, assigned by the GPS/RFID localization methods (Figure13). The workers go to the correct lay down yard and grid, and go approximately towhere the printed map had indicated the material’s location to be within that grid.

Once in the area, the workers utilize the RFID/GPS reader to narrow in and findthe component. The reader could pull up two different modes for finding the items.The map view utilizes the GPS portion of the reader. The digital map of the yardcan be displayed on the handheld screen and the GPS receiver will show where the



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Figure 13. Pick ticket list and map of projected locations

employee is standing, and the projected location of the material. The employee’spositioning on the screen is represented by a blue dot, and the material component isrepresented by a red dot (Figure 14). Another method was to set the reader intowhat was referred to as the Geiger counter mode. A Geiger counter is an instrumentthat can detect and measure radioactivity [21]. The Geiger counter mode of thereader allows the worker to communicate only with the specific tag that is desired.The Geiger counter can be utilized within 150ft proximity from the taggedcomponents. As the worker moves with the reader, the GPS receiver determines andgathers information on the location of the reader. The RFID portion communicateswith the desired tag, and the reader utilizes localization methods based on thepositions of the reader (gathered by GPS), and the received strength of signal fromthe desired tag at those positions (gathered by RFID). A compass pointed theemployee in the direction of the tag with which the reader was communicating(Figure 14). The reader also emits audible “beeps” that becomes more rapid and incloser intervals as the reader gets closer to the tag, and the signal strength increases.When the reader is within a couple of meters from the tag, the compass wouldchange to a cross- hair and display the words “WITHIN RANGE” (Figure 14).

Once the reader is held next to the correct tag/material, the blue column bars fillthe graphing area displayed on the screen (Figure 14). The worker then examinesthe material and the material ID, which is written on the exterior of the component,to assure that the material ID on the item matched the material ID listed in the pick ticket. As before, once the materials had been located, they could be organized,



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prepared for loading and transported to the construction area. The construction crewwould sign off on the materials to assure that they had been received for installation.After materials were delivered, the tags would be removed from the material and

placed in a steel bucket. The tags could then be recycled back to the materialmanagement office, where they would be disassociated from the material to whichthey were originally attached, and stored for possible reuse.

Figure 14. Reader in Geiger, Map, and Within Range

3.4.5 Performance of the System

The performance of the technology was satisfactory and it was noted that therewere very few malfunctions. One issue of concern was whether or not thetechnology would perform in very cold temperatures. They found that the systemworked down to -26 degrees Fahrenheit. Also, it was mentioned that at extremetemperatures below that mark, the readers were affected by the cold before the tags,so workers would warm the readers by means such as holding the readers insidetheir coats. Tags could easily be read through a couple of feet of snow.

Although the tags were durable, moving materials or placing heavy materials ontop of each other can sometimes damage the tags. It was proven that if the outershell of the tag has been damaged, but the internal battery and antenna device hadnot been affected, the tag maintained its readability function. For assurancemeasures on this project, tags that were damaged in any way were replaced, and newtags were attached and associated to the material.

During the initial stages of implementing the RFID system, a few tags were leftattached to their respective material components after the materials were installed inthe facility. When readings were attempted on the installed materials from insidethe facility, workers found that the surrounding structure, which was comprised of mass amounts of steel, did not facilitate successful communication between tag andreader. Therefore, management decided to remove the tags for recycling once thematerials had been received and signed for by the receiving foreman.



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3.4.6 Results and Future Plans

Jim Rogers, the Six Sigma Black Belt for the project, commented on the current

standing of the automated system and the effects that Six Sigma and RFID/GPShave had on the project: “We used all the (RFID) tools, and the application of LEANto eliminate a wasteful flagging step…We now send the loading crew straight to thematerial rather than having another pair of people go ahead to make sure they canfind the material, flag or identify it with colored ribbon, in order to optimize theloading crew’s time, and that of the crane. The quantified savings were centered oneliminating the flaggers, although many other benefits are known, e.g. schedule,supply chain risk, staging space savings.”

The RFID/GPS based system utilized on the project described in this case studywill continue to be used by the company for upcoming projects of similar type. Twonew projects will utilize the same technology are recently getting underway in Ohio

and Illinois. In this case study, the automated system was retrofitted to the existingmaterials already on site and in the lay down yards, however, future applicationswill aspire to implement the system so that the materials will be tagged with RFIDbefore they arrive on the project site. When commenting on further developments of RFID based solutions, and the processes that will be impacted and changed, Rogersnoted: “The whole supply chain, from engineering through procurement, fieldmaterial management, construction, and some selected components (that needmaintenance) by the customer. We started with the greatest need, with a compelling

business case, and we will build from there.” T he future goals will be to track different components throughout the entire supply chain, as well as while on site,and selected components that will need maintenance in the future, could also remain

tagged with RFID after installation to facilitate easier identification for maintenance.To do this, it will require increased cooperation and coordination with suppliers,customers, and others involved in the supply chain process.

4 Conclusions

Although RFID technology solutions for the construction industry are still in theearly stages of development, case studies are showing that custom solutions can beproven beneficial for some construction companies ’ processes . Solid business casesfor RFID based solutions that can be uniformly applied across the constructionindustry remain to be seen. This may be in large part due to the fact that each

construction project will be unique to a certain degree, whether it is by size,complexity, life-cycle, geographic location, etc. Also, depending on the size andstructure of a construction company, it may or may not be able to accommodate, andassign overseers for the adoption of a new technological system. Those companiesthat remain curious and open minded towards the technology will be more likely torealize potential benefits. If construction companies are willing and able to put forththe effort and investment of time that might be necessary to familiarize themselveswith the technology (different variations and combinations), then those companieswill be the ones that begin to realize the potential for applications within their own



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processes and project delivery methods. The experience a company gains with thetechnology through sponsored academic studies proves to be valuable for bothstatistical data, as well as for developing a working relationship with the technology

vendor. These experiences, combined with the companies’ excellent ability to self-analyze and pinpoint weaknesses within their current processes, ultimately led to afull scale implementation of an RFID/GPS automated system, which was aimed atcompletely eliminating an entire step within the materials management process.

Another technology that may facilitate the transition from tracking fieldmaterials to in-place materials is in the area of building information modeling(BIM). As more and more projects are becoming BIM based, a natural progressionwill be to link the RFID solution to the BIM solution. This would mitigate theproblems currently encountered with reading tags of in-place materials and the lossof data once a battery ceases to operate. If the owner receives an as-built model, thefacilities management process can eventually be streamlined. This is truly in line

with the lean construction philosophy.

References

[1] Ganaway, N. (2006). Construction Business Management: A Guide toContracting for Business Sources. Butterworth-Heinemann

[2] Park, H. (July, 2005). Benchmarking of Construction Productivity. Journalof Construction Engineering and Management, 131(7), 772-778.

[3] Jaselskis, E., El-Misalami, T. (2003). Implementing Radio Frequency

Identification in the Construction Process. Journal of ConstructionEngineering and Management. 129(6), 680-689.

[4] Roberts, C.M. (2006). Radio Frequency Identification (RFID). Computersand Security, 25(01), 18-26.

[5] Jaselskis, E., Anderson, M., Jahren, C., Rodriguez, Y., Njos, S. (1995, June).Radio-Frequency Identification Applications in Construction Industry.Journal of Construction Engineering and Management. 06(1995), 189-196.

[6] Niemeyer, A., Pak, M. H., Ramaswamy, S. E. (2003). Smart tags for your

supply chain. The McKinsey Quarterly, 4. Retrieved May 1, 2009 fromhttp://www.mckinseyquarterly.com

[7] Howell, Gregory A. (1999). What is Lean Construction. IGLC-7Proceedings, University of California, Berkeley, CA, July 26-28, 1999.

[8] ERA Build. (2006). Review of current state of radio frequency identification(RFID) technology, its use and potential future use in construction.

http://www.mckinseyquarterly.com/

http://www.mckinseyquarterly.com/



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[9] Sawyer, T. (2008, August). Test Projects Show Great Potential For Tracking

Technology. ENR: Engineering News Record. McGraw-Hill Construction.

[10] ENR Staff. (2008, April 28) Behind a murky name lurks an amazing little tag.ENR: Engineering News-Record. 260(14), 80-80.

[11] Wang, L., Lin, Y., Lin, P. (2007). Dynamic Mobile RFID-Based SupplyChain Control and Management System in Construction. AdvancedEngineering Informatics, 17 (2008), 377-390.

[12] Santosh, B., & Smith, L. (2008, October). RFID in the Supply Chain: Panaceaor Pandora's Box?. Communications of the ACM, 51(10), 127-131.

[13] Chin, S., Yoon, S., Choi, C., & Cho, C. (2008, March). RFID+4D CAD Forprogress management of structural steel works in high-rise buildings. Journalof Computing in Civil Engineering, 22(2), 74-89.

[14] Ergen, E., Akinci, B., Sacks. (2006, September). Life-cycle data managementof engineered-to-order components using radio frequency identification.Advanced Engineering Informatics. 21 (2007), 356-366.

[15] DeFinis, A. (2004, February). Concrete maturity testing in Michigan. TonyAngelo Cement Construction Company. Novie, Michigan, 2004.

[16] Gaudin, S. (2008, March). RFID tags at the base of NYC’s Freedom Tower.Retrieved November ,2008, from, Computer World Website:http://www.computerworld.com/action/article.

[17] Navon, R., Goldschmidt, E. (2002, April). Monitoring labor inputs:automated-data-collection model and enabling technologies. Automation inConstruction. 12(2), 185-199.

[18] Navon, R., Goldschmidt, E. (2003, July). Can labor inputs be measured andcontrolled automatically? Journal of Construction Engineering and

Management. 129(4), 437-445.[19] Caldas, C., Torrent, D., Haas, C. (2006). Using Global Positioning System to

Improve Materials-Locating Processes on Industrial Projects. Journal of Construction Engineering and Management. 132 (7), 741-749.

[20] Torrent, D., & Caldas, C. (2009). Methodology for Automating theIdentification and Localization of Construction Components on IndustrialProjects. Journal of Computing in Civil Engineering, 23(1), 3-13.

http://www.computerworld.com/action/article

http://www.computerworld.com/action/article



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[21] Iovine, J. (2000, March). Amazing Science: Geiger counter. Poptronics, 1(3),57.

Documents

Civil Comp - RFID in Construction Submission 2009-2008-000127