Formalization of the Flow of Component-Related Information in Precast Concrete Supply Chains

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Formalization of the Flow of Component-Related Informationin Precast Concrete Supply Chains

Esin Ergen1 and Burcu Akinci2

Abstract: Information flow in precast concrete supply chains should be streamlined to simplify complexities in tracking highly custom-ized components and related information. Currently, information created, exchanged, accessed, updated, and stored in a precast supplychain is not formalized. Consequently, even though various advanced technologies are available to streamline information flow, there isno formal way to identify the requirements and appropriate mechanisms for utilizing these technologies. This paper describes some majorpatterns in information flow related to precast components through postdesign phases in precast supply chains, based on observationsmade in the United States. It specifically proposes several propositions that characterize the information flow and tests those propositionsin descriptive case studies. It also depicts an information flow framework for formalizing information flow patterns in supply chains. Theresults include a list of information groups and major patterns of information flow observed in precast supply chains. It is expected thatthese results will enable researchers to develop formalisms and automated approaches to streamline information flow and help practitio-ners identify information flow patterns in their companies and corresponding supply chains to develop approaches and technologies tostreamline the flow accordingly.

DOI: 10.1061/�ASCE�0733-9364�2008�134:2�112�

CE Database subject headings: Information; Information management; Performance characteristics; Concrete, precast; Procurement;Construction industry.

Introduction

Within the architecture/engineering/construction �AEC� industry,more than 50% of problems observed in design, construction, anddevelopment are associated with poor information flow �Oloufa etal. 2004�. Two main attributes of an effective information flow areavailability and timeliness of information �Galliers 1987�. Un-availability of information or inability to access information on atimely basis can lead to project cost and time overruns, reducedquality and maintainability, or even complete failure of a project�Halfawy and Froese 2005; Hendrickson 2003�. Problems associ-ated with poor information flow are more pronounced for custom-ized prefabricated components because prefabrication projects arecomplex in terms of project organization, planning, monitoring,coordination, and communication and thus involve higher de-mand for information among the parties involved in the supplychain �Arbulu and Tommelein 2002; Elfving et al. 2002; Song etal. 2005; Wegelius-Lehtonen and Pahkala 1998�.

An engineered-to-order �ETO� component is a type of prefab-ricated component that is highly customized �Elfving et al. 2002�.

1Assistant Professor, Dept. of Civil Engineering, Istanbul TechnicalUniv., Istanbul, 34469, Turkey. E-mail: [email protected]

2Associate Professor, Dept. of Civil and Environmental Engrg.,Carnegie Mellon Univ., Pittsburgh, PA 15213 �corresponding author�.E-mail: [email protected]

Note. Discussion open until July 1, 2008. Separate discussions mustbe submitted for individual papers. To extend the closing date by onemonth, a written request must be filed with the ASCE Managing Editor.The manuscript for this paper was submitted for review and possiblepublication on April 10, 2006; approved on July 3, 2007. This paper ispart of the Journal of Construction Engineering and Management, Vol.134, No. 2, February 1, 2008. ©ASCE, ISSN 0733-9364/2008/2-112–
121/$25.00.
112 / JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT

J. Constr. Eng. Manage. 2

Because of the customization involved, status and location infor-mation of ETO components should be tracked individually foreach component and accessed especially by lower management toprevent any delays during production, delivery, and installation.High customization also results in large amounts of product andprocess information—e.g., drawings and handling and installationinstructions for each component—that need to be exchanged in asupply chain. Hence, to effectively manage the flow of ETOcomponents in a supply chain, each piece needs to be trackedindividually and component-related information needs to be ex-changed and be readily available or easily accessible.

The term “readily available” is used to define information thatcan be accessed without any delay at the time it is needed by thepeople who need that information. The term “easily accessible” isused to define information that is in a convenient format andlocation for access but that is not necessarily readily available.Readily available and easily accessible information about compo-nents enable timely access to the required information, minimizeadditional time spent and labor used for retrieving information,and reduce ineffective decisions made in the absence of informa-tion �de la Garza and Howitt 1998; Ergen et al. 2003; Kondratova2004; Meissner et al. 2003; Tenah 1986�.

This paper focuses on determining information flow patternsobserved for precast concrete components, commonly used ETOcomponents in building construction �Eastman 1999�. Current in-dustry practice lacks formalization of component information forprecast components that need to be created, stored, transferred,and accessed through a supply chain, once a design is complete.Component information for precast concrete includes informationrequired for effective flow of components in a supply chain �e.g.,identification information, handling instructions, coordinationinformation� and for effective maintenance of components in op-
erations and maintenance �O&M� phase �e.g., product history
© ASCE / FEBRUARY 2008

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consisting of production, inspection, handling, and maintenanceinformation� �Ergen et al. 2003; Goodrum 2003�.

Various information technologies �e.g., barcode, RFID, GPS,wireless LAN� that can enable effective component informationflow in a supply chain exist. Information collected and accessedthrough these information technologies can be exchanged amongdifferent parties using standard data model specifications andstandards, such as IFC �IAI 2003� and AEX �FIATECH 2005�,and made readily available or easily accessible across a supplychain. However, to deploy such technologies and standards foreffective information flow, major information items and their flowpatterns need to be formalized so that requirements for data col-lection, access, transfer, and storing can be derived and appropri-ate mechanisms and technologies to support such processes canbe identified.

The objective of the research presented in this paper is toidentify a set of major information flow patterns related to precastcomponents and used by workers and lower management throughpostdesign phases in a supply chain. Specifically, this paper de-scribes groups of information items that flow across a precastsupply chain in the United States, major actors and parties whoact on �create/collect, transfer, receive, access, update, and store�these information groups, and the frequency of those actions. Inthe AEC domain, the business and operational factors cause in-formation flow patterns to be dynamic and fuzzy; therefore, thefrequency assigned to actions are not fixed numbers but a timerange �e.g., every day, every week�. Formalization of informationflow will assist in determining technologies for enabling effectiveinformation flow and provide a basis on which to assess the ef-fectiveness of existing standard data exchange models in stream-lining the observed information flow patterns in the U.S. precastsupply chains.

To identify some major information items that are related tocomponents and that flow in a precast supply chain during post-design phases, five precast concrete supply chains in the UnitedStates were investigated with a focus on manufacturing, construc-tion, operations, and maintenance phases. Interviews and sitevisits were performed in three large-scale precast companies asexploratory case studies. Based on those exploratory case studies,a set of propositions that describe the characteristics of informa-tion flow was developed. The propositions were used in the fol-lowing two descriptive case studies, which were conducted at twolarge-scale precast manufacturing companies. Propositions werevalidated via the information flow matrices created for each case.A framework for developing an information flow matrix proposedby Wix and Liebich �2000� was modified and used to model theobserved information flows.

Background Research

This research study builds on and extends previous research oninformation modeling efforts within the AEC domain and generalapproaches and tools for modeling information flow.

Previous Research on Component Information

Previous research on ETO component supply chains in the AECindustry mostly focuses on modeling processes along supplychains to identify and reduce waste �Arbulu and Tommelein 2002;Elfving et al. 2003; Ballard et al. 2003; Tommelein and Weissen-berger 1999� or on comparing push and pull scheduling tech-
niques �Tommelein 1998�. While these process models provide an
JOURNAL OF CONSTRUCTION EN


overview of the characteristics and complexity of processes indifferent portions of various ETO supply chains, they fail tomodel the underlying information flow in detail.

Researchers agree that for a project to be completed success-fully, accurate and relevant information should be available to theright people at the right time �Abou-Zeid et al. 1995; de la Garzaand Howitt 1998; Hiremath and Skibniewski 2004�. Informationneeds for the industry were defined broadly by several researcherswith different perspectives. For example, jobsite informationneeds �de la Garza and Howitt 1998� and information needs forprecast components �Messner and Sanvido 1993� have been stud-ied. Among these studies, Messner and Sanvido �1993� focusedon precast components through the planning, design, manufactur-ing, and construction phases and provided a broad classificationof information items for precast components �e.g., constructioninformation, site equipment-related information�, without provid-ing details on the information flow patterns.

Most of the studies related to modeling of information flowwithin the AEC industry focused on activities at early design andengineering phases �Baldwin et al. 1999; Castro-Lacouture 2003;Oloufa et al. 2004�. Among such studies, Sacks et al. �2002�specifically focused on formalizing the information flow from en-gineering to erection phases within 13 precast companies. Thisstudy provides a good basis for the research described in thispaper. While a detailed list of information items were not pro-vided, this study concluded that information items that are used todescribe precast pieces and related components are essentially thesame in all companies.

Standard data models are being developed to store and ex-change product and process information. Examples of such effortsare the industry foundation classes �IFC� �IAI 2003�, ifcXML�IAI 2003�, and automating equipment information exchange�AEX� �FIATECH 2005�. In IFC 2x2, some design- andtransportation-related properties common to precast concrete ele-ments, such as identification information and weight, are repre-sented. However, production information �e.g., quality controlinformation� is not represented and most of the material informa-tion items, such as the composition and strength of materials,need to be represented by extending current IFC classes.

The AEX project focuses on formalizing transactional dataexchange across organizational boundaries through the engineer-ing, procurement, construction, and O&M phases. Currently AEX2.0 supports the exchange of information required within thequote, purchase order, and as-built and bill of materials docu-ments and provides in-depth descriptions of such information forcentrifugal pumps and shell and tube heat exchangers. Such for-malism can potentially help to streamline the information flow ina precast supply chain.

Previous Research on Approaches for ModelingInformation Flow

To formalize information flow in supply chains, the authorsneeded to select an approach that could clearly depict a set ofactions taken on information groups by a set of actors. First,component information flow interwoven with the production pro-cesses needed to be described. Second, the information flowneeded to be isolated from the production process model andelaborated in terms of information items, actors, and actions sothat one could clearly represent the flow patterns for each infor-mation group.

Many process- and data-modeling approaches in which graphi-
cal annotations are used to represent information flow within dif-
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ferent process activities are available. Examples of suchapproaches include standard approaches, such as IDEF0 andIDEF1 �Chen et al. 2004�, UML activity and sequence diagrams�Booch et al. 1998�, data flow diagrams �DFD� �Abou-Zeid et al.1995�, and a customized process modeling approach called GT-PPM, which focuses specifically on precast supply chains �East-man et al. 2002�. The process-oriented nature of the IDEF andGT-PPM approaches might make it hard to extract the flow pat-tern for information groups because the actors and the types ofactions performed on data groups �e.g., create, update, transfer�are interwoven in multitier process-based graphic models. Al-though UML activity and sequence diagrams provide a detailedview of actors and their actions on specific information items, oneof UML diagram can represent information flow between only asmall number of actors. Hence, the diagrams might not be suit-able to represent the information flow across a chain in which alarge number of actors are involved.

Instead of using these process-modeling methods, the authorsbuilt on a framework �Wix and Liebich 2000� that is capable ofrepresenting information groups, actions, and a set of actors in asimple matrix format without graphically showing specific pro-cesses. This framework enabled a compact view that shows theflow of information within one matrix, and correspondingly, itbecame easier to identify the patterns of information flow. Theauthors have extended the framework to include additional ac-tions and frequencies of actions and have applied it to precastsupply chains. Details of application of this framework are givenin the following sections.

Overview of Precast Supply Chains

A typical precast concrete supply chain is composed of suppliers,a precast manufacturer, a general contractor, an erector, and anowner. Suppliers provide materials or hardware needed for pre-cast production. A precast manufacturer produces precast pieces.An erector, who is either working for a manufacturer or hired asa subcontractor by general contractor, erects precast pieces at con-struction sites.

In a precast supply chain, materials flow unidirectionally fromupstream parties �e.g., the material suppliers� to downstream par-ties �e.g., the erector� while information flows bidirectionally.Component related information is most commonly transferredusing paper documents. Other communication means utilized arefax, phone, and structured or unstructured electronic data �draw-ings, e-mails, MS Word or Excel files�.

Challenges in accessing component information at the timeneeded using existing approaches are twofold:1. Information items related to components are collected by dif-

ferent companies and departments in a supply chain; thus,some information items are not easily accessible becausethey reside in different databases.

2. Even if some component-related information items are storedand transferred to downstream parties/departments upon re-quest, they are delivered in a format that is most convenientfor the creator’s own purposes and are typically embedded inpaper-based reports and drawings. In these cases, eventhough the information items are transferred to thedepartment/company that needs the information, they mightnot always be readily available or easily accessible. It cantake additional time to extract the pertinent information items
from multiple available documents.


Research Scope

The focus of this paper is to identify some major information flowpatterns that are associated with precast components and that arecreated, exchanged, accessed, and stored mostly by workers andlower management through the life cycle of precast components.The stages that were investigated included both construction/production stages and business/transactional stages, i.e., planning,quality control, material order, precast production, handling, stor-age, shipping order, shipping, erection, operations, and mainte-nance. Since workers and lower management are responsible forplanning, execution, and control of daily activities, availability ofcomponent information to these personnel has a direct effect onthe flow of components and the performance of related activities.

The authors investigated routine component information flow,and information flow observed in case of a structural problemamong different departments in precast manufacturing companiesand through precast supply chains. All synchronic �i.e., phone,regular meetings� and asynchronic �i.e., paper-based report trans-fer, fax, structured or unstructured electronic data� communica-tion means, except irregular, informal oral communications, wereexamined. The authors focused on the departments that produceand handle materials/components and support production andhandling by providing quality and schedule information. Theproject manager, who acts as the primary contact for all parties ina project, is also included. Each party, besides the precast manu-facturing company, is represented as a single actor �i.e., materialsuppliers, owner, erector/general contractor�.

Case Study Design and Research Methodology

To determine some major information flow patterns in a typicalprecast supply chain, exploratory and descriptive case studieswere performed at large-scale precast concrete manufacturingcompanies that produce architectural and structural precast com-ponents in the United States. The case study method was chosenbecause in-depth investigation was needed to identify the charac-teristics of information flow in the supply chain context. Thefocus was on large-scale companies because they are more orga-nized and have more departments; thus, the corresponding infor-mation flow is expected to be more structured and complex.

The research entailed five in-depth case studies. The first threecase studies were exploratory in nature to generate a set of propo-sitions related to information flow patterns. Two descriptive casestudies followed the exploratory case studies to validate thepropositions that were developed. All case studies were conductedat major large-scale structural and architectural precast manufac-turers located in the United States. These companies had Precast/Prestressed Concrete Institute �PCI� certification for quality assur-ance. PCI certification ensures that information flow related to thequality of components is performed according to PCI procedures.Because the companies shared the similar characteristics, similarinformation flow patterns were expected.

Yin �2003� identified the major components of the descriptivecase studies as study’s questions, study’s propositions, unit ofanalysis, linking data to propositions, and criteria for interpretingthe findings. For this research, the case study question has been,what are some major patterns of information flow that are relatedto precast components and that contain information used by work-ers and lower management through postdesign phases in a supplychain? To answer the study’s question, propositions were gener-
ated, each of which depicted an aspect to be investigated in the

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study �Yin 2003�. The generated propositions aimed to investigatethe most frequently accessed and exchanged information items,the information items that were utilized by a large number ofparties, and information items that needed to be readily availablewith the components. These propositions of the descriptive casestudies were generated in the initial exploratory case studies.

In these descriptive case studies, the unit of analysis was theprecast supply chain, specifically information flow in a precastmanufacturing company. To link the data to the propositions, datacollected during the case studies were formalized by creating usecases, an information flow matrix, and UML diagrams, which willbe explained in the following section. To interpret the findings,the information flow patterns in the information flow matrix werecompared to the information flow patterns described in the propo-sitions. Conclusions were drawn based on the similarities anddifferences among different information flow patterns.

The descriptive case studies were conducted sequentially.Hence, an information flow matrix was developed individually foreach case and the matrices were then compared and consolidatedto validate the generated propositions. To ensure the constructvalidity of each descriptive case study, multiple sources of evi-dence �i.e., interview, documentation review, and direct observa-tion� were used for data collection in each case to triangulate theresults. The information matrix for each case was also validatedby practitioners who were interviewed prior to the generation ofthe matrix.

External validity of the study determines the domain to whichstudy’s findings can be generalized �Yin 2003�. Unlike surveyresearch, which uses statistical generalization in which a samplegeneralizes to a larger universe, the case study approach usesanalytical generalization in which a set of results are generalizedto a broader theory �Yin 2003�. To generalize the propositions viaanalytical generalization, literal replication method was used, inwhich findings of the first descriptive case study were replicatedwith another case study conducted in a company within a similarsupply chain. In addition, three initial exploratory case studieswere also performed at three large-scale precast manufacturingplants. The results of the study do not claim that propositions areapplicable to all precast supply chains, since, unlike survey tech-nique, it is not feasible to conduct detailed case studies in a largeset of companies. However, it is reasonable to claim that theinformation flow patterns described in the propositions are ob-served in the U.S. precast supply chains that include large-scaleprecast manufacturing companies that have a PCI certificate. Theresults of this study provide steps toward understanding the infor-mation flow in precast supply chains and can provide a basis forexamining other cases �i.e., for replicating the results� that canlead to further generalization of the results.

Propositions

Initial exploratory case studies resulted in the development of thefollowing four propositions depicting some major informationflow patterns observed in precast supply chains:

Proposition 1: Up-to-date status information for componentsis frequently created, transferred, accessed, and updated bymany actors/parties in a supply chain. Departments in a precastcompany and downstream parties in a precast supply chain needto know the up-to-date status of precast pieces to monitor thestatus of a work order and to replan if necessary. For example, ashipping group within a material handling department needs to
know if specific pieces are produced and if quality is assured by


the quality control �QC� department before pieces are shipped.Similarly, a project manager needs to know the status of pieces toplan ahead and to report possible problems.

If this proposition is validated, activities completed to create,transfer, receive, update, and access up-to-date status informationneed to be investigated for opportunities for improvement. If suchopportunities are identified, advanced data collection and trackingtechnologies and data exchange standards can be utilized tostreamline the collection and exchange of up-to-date informationand to make this information readily available and easily acces-sible to the relevant actors in a supply chain.

Proposition 2: Material information and QC reports for ma-terials and components are not accessed unless a significantstructural problem exists. Material information �e.g., mill certifi-cates� and QC reports are sent with the materials by the materialsuppliers. A precast manufacturer does not access these reportsbecause each actor/party is supposed to meet the QC requirementsbefore he or she sends material to downstream parties. Similarly,the QC reports of precast components are not transferred andaccessed by the downstream parties. Only the results of QC testsor inspections, not the reports themselves, are transferred todownstream actors/parties via verbal communication or by mark-ing the pieces with different colors. QC reports for materials andcomponents are accessed only if there is a structural problemaffecting a component’s strength. In such a case, QC reports areaccessed either by a manufacturer or by an owner �or a consultanthired by an owner� to detect the cause of the problem.

If this proposition is true, in case of a problem, informationrelated to materials and components needs to be easily accessibleto the participants of a supply chain. This information does notnecessarily need to be readily available in a supply-chain since itis not accessed frequently.

Proposition 3: Order and shipping information for materialsand components is exchanged frequently between material sup-pliers and the precast manufacturer and between the precastmanufacturer and the erector. The purchasing department andthe batch plant at a precast manufacturing company need to fre-quently contact material suppliers to order materials, to getconfirmations on orders, and to coordinate the arrival of the ma-terials. Similarly, an erector and the shipping department at aprecast manufacturing company need to be in contact continuallyto coordinate the on-time delivery of components. Informationexchange is mostly performed via phone, fax, or e-mail.

If this proposition is validated, information exchanges betweenmaterial suppliers and the precast manufacturer and between theprecast manufacturer and erector need to be investigated to iden-tify opportunities for improvement to streamline the informationflow.

Proposition 4: Information items that need to be readilyavailable and stored with a precast component are its identifi-cation information, weight, handling instructions, and QC re-sults. Some criteria to use in deciding which information itemsneed to be readily available and stored with a precast componentare identified based on the frequency with which the informationneeds to be accessed and the number of actors that are accessingthe information at the field. As the frequency of access and/or thenumber of actors increase, the information should be readilyavailable on the component to save time by minimizing the timespent on looking for information.

It was observed that components need to be uniquely identifiedto streamline tracking and to enable easy access to component-related information frequently accessed by several actors in the
supply chain. This suggests that identification information needs

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to be readily available at the field. In addition, weight and han-dling instructions need to be readily available for the workerswho handle the components throughout the supply chain. Sincesome pieces are large in size, workers often need to know whetherthe components’ weight exceeds the capacity of a crane. Finally,the QC inspections results need to be available because workersneed to know if a piece was approved by the inspector before itwas moved to a storage yard or shipped to a construction site.

If this proposition is validated, component identification infor-mation, weight, handling instructions, and QC results need to bereadily available, with on the component. Advanced tracking andstorage technologies, such as RFID, can be used to track thecomponents and store such information items so that they will bereadily available in the field, where access to databases throughLAN can be limited.

In the descriptive case studies, these propositions were vali-dated via an information flow matrix developed using a frame-work. The details of the framework, its implementation, andanalysis for evaluating the propositions are discussed in the fol-lowing sections.

We extended the second step of this framework by elaboratingthe initial set of actions represented in the information matrix andby including the frequency of those actions. In the constructionindustry processes and actions are a fuzzy and dynamic in nature.Therefore, it was not possible to identify and assign a static fre-quency value to each information item and instead, the frequencyof actions was broadly defined as daily, weekly, monthly, or quar-terly. The extended information matrix is called CTRAUS andreceives its name from the first letters of actions performed oninformation items: create, transfer, receive, access, update, andstore.

We also included a fourth step in the initial framework. Infor-mation flow represented in the previous steps was analyzed todetermine the characteristics and patterns of information flow interms of actions on information groups, frequency of actions, andnumber of actors. The following four sections describe each stepof the framework and explain how it was used for characterizinginformation flow in precast supply chains.

Developing Use Cases

The first step of the framework is to develop use cases to capturescenarios of component information flow between departmentsand parties, with a focus on information groups, actors who actupon those information groups, and their actions. A use case tem-plate �aexXML 2003� is used to gather and describe componentinformation flow scenarios in which a group of information itemsis transferred at least once between two actors for each scenario.

To implement this step of the framework, 30 use cases weredeveloped based on the case studies, representing informationcreation, exchange, access, and storage activities observedthroughout precast supply chains. These use cases were related toinformation flow during planning, material procurement, produc-tion, material handling and shipping, erection, and maintenance.Details of these use cases can be found in Ergen �2005�.

Creating an Information Flow Matrix

In the second step, use cases are mapped to an information flowmatrix �CTRAUS matrix� to exclude context described in usecases and to focus only on the key characteristics of all informa-tion flows identified. In CTRAUS matrix the following key char-
acteristics are represented: �1� information groups; �2� actions that


are performed on information groups by participants of supplychain; �3� corresponding actors that act on the informationgroups; and �4� the frequency of each action. The rows of thematrix show the information groups representing the sets of in-formation items associated with a specific process and/or amaterial/component �e.g., a daily concrete order� and exchangedthrough a supply chain at the same time, mostly within the samedocument �e.g., QC reports, mill certificates�. The columns of thematrix represent actors who participate in information flow �e.g.,departments in a precast manufacturing plant�.

The CTRAUS matrix builds on the CRUD matrix that is usedmostly by database designers to check the completeness of datamodels and on the information matrix that was developed to de-scribe process communications in building construction �Wix andLiebich 2000�. In this research the CRUD matrix was extended toinclude additional actions related to data manipulation and stor-age �i.e., transfer, access, and store� in addition to actions de-scribed in the original CRUD matrix �i.e., create, receive, andupdate�. The authors did not include the delete action that wasoriginally in the CRUD matrix because any information that isnot shown as stored in the matrix is assumed to be deleted. Theinformation matrix was extended by replacing “activities” in thematrix with “information groups” and by including frequencies ofactions. Frequencies of actions indicate how often an informationgroup flows in a supply chain. Frequencies are defined as daily,weekly, monthly, quarterly, and once and are shown with differentshadings and pattern fillings.

The actions that are represented in the matrix are explainedbelow:1. Create �C�: forming a group of information items.2. Transfer �T�: moving a group of information items from one

actor to another by phone, fax, mail, e-mail, or personal de-livery. If an information group is made available for access�e.g., uploaded on a server� without being specifically trans-ferred to an actor, then the transfer action is not assigned tothat actor.

3. Receive �R�: acquiring a group of information items trans-ferred by an actor. If an information group is not transferredto the actor�s� but made available for access, then the receiveactivity is not assigned to any of the actors.

4. Access �A�: looking up a group of information items andusing it to accomplish a task. The access action indicates theactor who frequently accesses each information group. If anactor rarely �e.g., only in the case of a minor problem� ac-cesses an information group, the access activity is not as-signed to the actor.

5. Update �U�: replacing a group of information items createdpreviously with a new group of information items.

6. Store �S�: keeping each information group for archival pur-poses. These information groups will not be accessed unlessstructural problems or damages to a piece occur.

To implement this step of the framework, first, the actors in theuse cases were identified. The actors included a project manager,all departments in a precast company that handled a component orsupported the handling of a component in a precast manufacturingcompany �i.e., purchasing, weld shop, batch plant, production,shipping and material handling, planning, and QC�, and otherparties in a precast supply chain �i.e., upstream material suppliers,the erector, the general contractor, the owner�.

Second, information groups were extracted from the use cases.These information groups were classified into four categoriesbased on their contents:
�1� Design information included piece, detail, and erection draw-

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ings, specifications, design calculations, weight, and han-dling instructions.

�2� Material information included material and mill certificates,material QC reports, material tracking reports and mix designcalculations. Material and mill certificates show the contentsof a material and the results of the tests performed by sup-pliers. Material QC reports describe the results of the QCtests performed by a precast manufacturer on some materials.Material tracking reports are used to track the number andtype of materials used in each precast piece, and mix designcalculations are used to specify the ratio and the types ofmaterials used in each type of concrete produced.

�3� Component QC reports included reports for QC tests andinspections performed on components by the manufacturer.

�4� Coordination information included schedule, material order,and component delivery information and status informationabout drawings, materials, and components.

Finally, two CTRAUS matrices were created for each casestudy to show the actions taken on the information groups catego-rized above by the actors in a precast supply chain. Since thesetwo matrices turned out to be similar, they were merged into oneaggregate matrix, and few differences between two cases werehighlighted by numbers “1” and “2,” which referred to the corre-sponding case studies. Details of the observations made using theCTRAUS matrix are provided in the “Analysis” section of thispaper.

Developing UML Activity Diagrams

The CTRAUS matrix is limited in representing a complicatedinformation flow because each communication step cannot beshown in the table. In cases where the same actions are associatedwith an information group or performed by multiple actors orwhere an information group provides an input for creating another

Fig. 1. UML activity diagram for

information group, a detailed UML activity diagram was created



to show the sequence. Such a diagram allows all of the instancesof activities/interactions of actors with information groups de-picted in a use case to be modeled.

Two instances of information flow were further detailed withUML activity diagrams. Information flow for “mix design calcu-lation submission and approval �Fig. 1�, and for red-tag reportscreated for defective components were represented with UMLactivity diagrams because the same actions were performed bymultiple actors �e.g., QC office, batch plant, project manager�.UML activity diagrams showed the direction of flow, and thesequence of actions for the selected information flows, and theseUML activity diagrams are used in the analysis of the informationflow, which is explained in the following section.

Analysis

In the last step of the framework, the CTRAUS matrix and UMLactivity diagrams were analyzed to determine existing patterns inthe information flow. The analysis can be performed from differ-ent perspectives depending on the objectives of the investigation.If the objective is to validate some propositions developed forspecific information flow patterns, the CTRAUS matrix and UMLactivity diagrams are analyzed to determine if those patterns ex-ists in the current information flow. Another objective could be toinvestigate opportunities for improvement in the informationflow. In this case, patterns that indicate opportunities for improve-ment are defined �e.g., high frequency of information exchangebetween two parties, multiple access to an information item bymultiple parties�, and then existence of these patterns is investi-gated in the CTRAUS matrix and UML activity diagrams. If aninformation group is transferred and received by several parties,for example, the current information flow should be analyzed toidentify whether the interactions can be streamlined.

esign calculation information flow
mix d
To implement the last step, the CTRAUS matrix and UML


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activity diagrams developed for precast supply chains were ana-lyzed to determine whether the patterns defined in the proposi-tions existed in the current information flow.

Evaluation of Proposition 1: The first proposition proposesthat up-to-date status information for components is frequentlycreated, transferred, and accessed by many actors/parties in a sup-ply chain. The information flow depicted in CTRAUS matrixshown in Fig. 2 validates this statement. Every day, status infor-mation about materials, drawings, and components is created,transferred, received, accessed and updated by many actors. Theowner receives status information for components on a biweeklyor monthly basis depending on the contractual requirements.

Knowing that status information is frequently created, trans-ferred, and accessed by many actors/parties in a supply chain, wefurther investigated the existing situation depicting the flow ofup-to-date status information in precast supply chains. It is ob-served that component status data collection is performed manu-ally or using barcode scanners, both of which require workers’input. Since current component status data is mostly collectedmanually, many times a day for all of the components, it is con-sidered a time-consuming task by workers and is neglected. Thus,there is a need for collecting up-to-date status information in amore effective way with minimum human input.

In addition, in certain cases, status information is exchanged inan ad hoc way, usually upon requests from upstream or down-stream parties. For example, an erector typically does not confirmthat the hardware used for erection is received at a constructionsite. When certain hardware cannot be located, the erector callsthe manufacturer to report the problem. Such ad hoc exchanges ofstatus information result in delays at the construction site. If up-to-date status information is exchanged effectively in precast sup-ply chains using data exchange standards and is made readilyavailable, it will be accessed more frequently and used more ef-fectively for planning and coordination.

Evaluation of Proposition 2: The second proposition claimsthat material information and QC reports for materials and com-

Fig. 2. CTRAUS matrix f

ponents are not accessed unless a significant structural problem



exists. The analysis of the CTRAUS matrix demonstrates thatmaterial mill certificates are received frequently �every day orevery week� with the materials �i.e., cement, aggregate, admix-tures, reinforcement, and hardware�. However, neither materialmill certificates nor the reports for the tests performed on thesematerials by the manufacturer are accessed by actors. These docu-ments are merely transferred to the QC department for archivalpurposes. A similar flow is observed for QC reports prepared formaterials, hardware, and individual components. These reportsare not accessed, and only the results of the reports are transferredand accessed as part of the status information explained in theprevious section. An exception to this flow pattern is the red-tagreport prepared for defective pieces, and such reports are receivedby seven departments in a precast company. However, red-tagreports are also not accessed by those departments unless a struc-tural problem is identified.

The process of accessing archived material and QC documentswas further investigated to determine whether the current ap-proach was effective to streamline the information needed in caseof a significant structural problem. The current process was ob-served to be less than optimal, requiring up to several weeks tolocate and search through the unstructured information groupsand to identify and integrate the relevant information in relationto defective components. In addition, some of the relevant infor-mation was missing. These observations show that although ma-terial information and component QC reports are not accessedfrequently throughout the life cycle of a component, they need tobe easily accessible upon a participant’s request to assist in solv-ing problems related to components. This points out a need forstructuring material and component QC test and inspection re-ports and integrating them with the history of the component toenable easy access when needed. To meet this need, data stan-dards need to be used.

Evaluation of Proposition 3: The third proposition proposesthat order and shipping information for materials and componentsare exchanged frequently between material suppliers and a pre-

to-date status information
or up-
cast manufacturer and between a precast manufacturer and an


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erector. The information flow depicted in the CTRAUS matrixshown in Fig. 3 validates this statement. Every day, the batchplant department contacts cement and aggregate suppliers to re-quest materials, and similarly the purchasing department is incontact with rebar and hardware suppliers to order materials, toget confirmation, or to arrange a delivery. A similar informationexchange is observed between the erector and manufacturer’sshipping department. The erection sequence of components issent approximately every three months to the manufacturing com-pany, and a load list, which shows a list of pieces to be deliveredby each trailer, is created by the shipping department and is sentmonthly to the erector. Every day, a daily load list is exchangedbetween the manufacturer and the erector and a daily deliveryschedule is exchanged between shipping and storage. Finally, aninvoice �waybill� is sent with each trailer and received back witherector’s signature.

Further investigation of current approaches for exchangingorder and shipping information for materials and componentsshowed that these processes are completed via phone, fax, ore-mail. Thus, information received from another party needs to bemanually entered to a material tracking, material order, or projectmanagement system. Order and shipping information for materi-als and components should be integrated with the current softwaresystems used in precast manufacturing companies. Transactionaldata exchange standards can enable the integration of the dataexchanged with the related software systems.

Evaluation of Proposition 4: The fourth proposition proposesthat information items that need to be readily available with thecomponent are its identification information, weight, handling in-structions, and QC results. The information flow depicted in theCTRAUS matrix shown in Fig. 4 validates this statement. The

Fig. 3. CTRAUS matrix for order and shi

handling instructions and weight need to be accessed every day



by storage and shipping personnel, who perform their jobs at thestorage yard, and by the erector who works at the constructionsite. The receive action is not assigned to weight information inthe CTRAUS matrix, which suggests that weight information isreadily available for access in the current practice. Similarly, thereceive action is not assigned to handling information in one case�case 2� because handling instructions were readily available withthe component. QC inspection results are accessed daily by patch-ers, who fix mostly aesthetic problems. The identification infor-mation is not included separately in the matrix because it isneeded by all actors to associate any information with thecomponents.

Currently, the weight information and handling instructions aretransferred with the component by including them on metal orpaper identification tags attached to the components. This ap-proach is not reliable or convenient because tags can be damagedand it is hard to read the tags attached to pieces that are placed onthe tops of precast stacks. In addition, QC results are made avail-able with the components by marking the components with dif-ferent colors, and this approach was observed to be unreliablesince markings can be easily altered by other personnel. Ad-vanced tracking and data storage technologies, such as RFID, canbe used to store this information with the component and to up-date the QC information as the component is being inspected,fixed, and approved. The same group of technologies can be usedto automatically determine if QC results allow a piece to be storedor shipped.

Conclusions

In this study, a framework was developed for researchers and

information for materials and components
pping
practitioners to capture and analyze the characteristics of infor-


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mation flow in supply chains. The main steps of the frameworkare developing use cases, creating an information flow�CTRAUS� matrix, developing UML activity diagrams to furtherdetail complex information exchange scenarios of interest, andanalyzing the information flow described. This framework can beuseful in formalizing and characterizing complex informationflows within companies or supply chains. The CTRAUS matrixprovides a clear depiction of information flow, including interac-tions with information items, actors who act upon informationitems, and the frequency of interactions, and yet it is brief enoughto fit into a table. Such an information matrix allows for theidentification of patterns of information flow that can be used todecide which technologies can be used to enable effective infor-mation flow across a supply chain.

By utilizing the CTRAUS information flow framework, themain information groups that flow in a precast concrete supplychain are identified as design information, material information,component QC reports, and coordination information. The pat-terns of the flow of these information groups were identified. Itwas shown that up-to-date status information for components isfrequently created, transferred, and accessed by many actors/parties in a supply chain, and material and component QC testsand inspection reports are not accessed unless a significant struc-tural problem exists. In addition, order and shipping informationfor materials and components were identified to be exchangedfrequently between material suppliers and the between the precastmanufacturer and the precast manufacturer and between the erec-tor. Finally, the identification and the weight information, han-dling instructions, and the QC results need to be readily availableand stored with a component.

The observations in the case studies coupled with theCTRAUS matrix suggest that some opportunities for improve-ment exist in the current information flow processes of precastsupply chains. The future work for researchers includes develop-ing requirements and reasoning mechanisms for utilizing ad-vanced data collection, component tracking, and data storagetechnologies to improve information flow in precast supplychains. Practitioners can utilize the framework to identify infor-mation flow patterns in their companies and supply chains.

Acknowledgments

The research reported in this paper is partially supported by the

Fig. 4. CTRAUS matrix for handling instruct

Pennsylvania Infrastructure Technology Alliance �PITA�, the



Precast/Prestressed Concrete Institute �PCI�, and High Concrete,Inc. The writers would like to thank High Concrete, Inc., ShockeyPrecast, and CTI, Inc. for their assistance and support. Any opin-ions, findings, and conclusions or recommendations expressed inthis material are those of the writers and do not necessarily reflectthe views of PITA, PCI, High Concrete, Shockey Precast, or CTI.

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Documents

Formalization of the Flow of Component-Related Information in Precast Concrete Supply Chains