Iris D. Tommelein's Publications

Contents

Refereed Journal Papers

  • Tsao, C.C.Y. and Tommelein, I.D. (2007). "Work Structuring in Lean Construction: Case Study of Assembled-to-Order Light Fixtures." ASCE, J. of Constr. Engrg. and Mgmt., submitted in Feb 2007, in review
    • ABSTRACT: ‘Work structuring’ is a term used in lean construction. In the delivery of a project, it refers to creating flow and value while minimizing waste by determining who is in the best position to do what, together with how and when each project participant is to apply their abilities and fulfill their commitments. Work structuring considers both internal and external customers while establishing a project’s production system design. This is essential to delivering a project while striving for the lean ideal, namely ‘to deliver what the customer wants, in no time, with nothing in stores.’ Principles of work structuring are presented through a case study on the delivery of light fixtures. A fabricator developed a product family of light fixtures and the associated production system while aiming for exceptional performance overall, including the supply chain. Examples help to articulate drivers for work structuring. Work structuring is conceptually broad and encourages innovation throughout project delivery, nevertheless, project participants may focus on one or several specific aspects thereof, devising different strategies towards achieving lean ideals. Work structuring is not a routine AEC practice, but it is an essential process to adopt when one sets out to design a lean production system.

  • Milberg, Colin T. and Tommelein, Iris D. (2007). "AEC Tolerance Management Theory." J. of Constr. Engrg. and Mgmt., CO/2007 submitted in October 2007, in review.
    • ABSTRACT: In architecture, engineering, and construction (AEC), the management of dimensional tolerances —a critical process for achieving product quality and performance— has left much to be desired. Suggestions for better tolerance management have met with little success which, the writers claim, is in part due to the absence of an AEC tolerance theory. To develop such a theory, the writers researched tolerance concepts in manufacturing and used them to analyze AEC cases. Their research question was: Can existing tolerance management concepts and tools be used or adapted for use in AEC? Using tolerance concepts to group the causes of problems found in the cases, the writers thus identified six Tolerance Failure Modes (TFMs). Furthermore, they identified tolerancing principles and mitigation strategies and associated them with these TFMs. TFMs help structure both evaluation of designs for potential tolerance problems and application of mitigation strategies, while tolerancing principles inform a designer how to specify tolerances to avoid such problems in the first place. The TFMs, tolerancing principles, and mitigation strategies form the basis of an AEC tolerance management theory.

  • Tuholski , S.J., Gursel , A.P., Tommelein, I.D., and Bomba, G. (2008). "'Lean' Comparison using Process Charts of Complex Seismic Retrofit Projects." ASCE, J. of Constr. Engrg. and Mgmt., resubmitted in May, in review.
    ABSTRACT: This paper compares the delivery of two retrofit projects where seismic isolation bearings were installed. The comparison is retrospective. The design teams on these projects did not implement 'lean' thinking to develop their approach, nevertheless, observed process differences are characterized using a 'lean' process evaluation and optimization tool, and then gauged and rationalized from that perspective. Cross-functional process charts identify functional parties with interrelated material or information hand-offs. They help to identify (un)necessary steps or complexity as measured by number of hand-offs and interacting parties. Analysis of these charts shows that project value may stem from the owner integrating design development with product procurement and construction method selection. On one project, integration was made possible by structural engineers evaluating the impacts of product procurement on overall project performance, expert consultants providing construction process reviews, and experienced contractors participating in installation sequence development. This paper illustrates the value of developing a symbiotic relationship between designers and suppliers in a niche market. It stresses the need for work structuring early on in the delivery process, integrating process with product development, to improve project delivery.

  • Gil, N., Beckman, S., and Tommelein, I.D. (2008). "Problem-Solving Base Building under Uncertainty and Ambiguity: A Multiple-Case Study on an Airport Expansion Program." ASCE, J. of Constr. Engrg. and Mgmt., CO/2006/023664, in press. 

  • Gil, N., Beckman, S., and Tommelein, I. (2008). "Upstream Problem-Solving under Uncertainty and Ambiguity: Evidence from Airport Expansion Projects," IEEE Transactions on Engineering Management, 10.1109/TEM.2008.922635, published online as of 10 June 2008
    • ABSTRACT: Environmental changes are common during development of large engineering (infrastructure) projects. To accommodate them when they occur, developers design and physically execute the upstream base building with preliminary information about the downstream business-critical fit-out. Base-building subsystems provide service space for occupancy, whereas fit-out subsystems make the space functional. We build theory on design under uncertainty and ambiguity from case study research, drawing on theory of preliminary information exchange in concurrent development. We find that the base-building subsystem shows low sensitivity to incremental changes in fit-out. However, it shows high sensitivity to radical changes, unless the two subsystems interact in a modular fashion. In the face of slow resolution of downstream uncertainty and difficulties in decoupling the physical interfaces (as is the case in modular design for example), upstream developers avoid starvation by making working assumptions at risk and exploring the space of possible design solutions through an early "optioneering" stage. Two patterns for problem-solving upstream stand out: 1) iterate design when preliminary information is either ambiguous or precise, but unstable and 2) build buffers in the design definition to absorb foreseeable changes when the preliminary information lacks precision but is not ambiguous. Buffers can be designed out if downstream uncertainties resolve favorably before the buffers are physically executed.

  • Alves, T. da C.L. and Tommelein, I.D. (2007). "Cadeias de suprimentos na construção civil: análise e simulação computacional." (original is in Portugese, title in English is "Construction supply chains: analysis and computational simulation.") Ambiente Construído, Porto Alegre, 7 (2) 31-44, abr./jun. ISSN 1678-8621; available online at http://www.antac.org.br/ambienteconstruido/: PDF | Abstract
    ABSTRACT: This paper discusses the importance of managing supply chains in the construction industry as well as concepts that may contribute for the improvement of their performance. In order to illustrate the concepts discussed and their importance, the authors present a simulation model developed using data from the HVAC sheet metal ductwork supply chain. Conducting experiments on supply chains can be rather costly and time consuming. Therefore, simulation tools can be employed to carry out low cost studies of supply chains. Those tools can be used for generating models that mimic a controlled environment in which experiments can be carried out. Four scenarios were studied to evaluate the impact that variations on activity durations and batching have on the project lead time. The conclusions highlight the use of simulation as a tool for supply chain and production system design, the need to improve communication channels between different parts of the supply chain aiming to reduce inventories, and the impact that variability and batching have on the project lead time.
    RESUMO: Este artigo discute a importância do gerenciamento da cadeia de suprimentos da construção civil bem como conceitos que podem contribuir para a melhoria de seu desempenho. De modo a ilustrar os conceitos discutidos e a sua relevância para o tema, as autoras apresentam um modelo de simulação desenvolvido com base em dados da cadeia de suprimentos de dutos de ar-condicionado. Experimentos com cadeias de suprimentos podem demandar muito tempo e esforço para serem realizados. Dessa forma, a simulação computacional tem grande potencial para o estudo de cadeias de suprimentos, pois pode ser empregada com baixo custo e gerar modelos e conclusões que representem uma realidade controlada na qual experimentos podem ser realizados. Quatro cenários foram simulados para avaliar o impacto que variações nas durações das atividades da cadeia de suprimentos e a definição de grandes lotes têm no tempo de entrega (lead time) de um projeto. Como conclusões, destacam-se o uso de simulação computacional para o projeto de sistemas produtivos e cadeias de suprimentos, a necessidade de melhorar a comunicação entre partes da cadeia como forma de reduzir seus estoques, e o aumento do tempo de entrega do projeto à medida que a variabilidade das durações e o tamanho do lote aumentam.

  • Gil, N., Tommelein, I.D., and Schruben, L.W. (2006). "External Change in Large Engineering Design Projects: The Role of the Client." IEEE Transactions on Engineering Management, 53 (3) 426-439, August.
    • ABSTRACT: A problem facing the management of large engineering projects is: Why do clients often adopt an early commitment strategy on design decision-making when they want to speed up project delivery, yet allow late changes to the project definition to accommodate the resolution of (un)foreseen external uncertainties? Empirical findings illustrate this problem and underpin a 2-stage model of the concept development process, in which conceptualization is followed by design, and stochastic pre-emption simulates asymmetric changes. Simulation experiments demonstrate that when clients make commitments early in conditions of high uncertainty, they increase the likelihood (upside risk) of speeding up the delivery if external events do not materialize; however, if these events do materialize, they increase the likelihood (downside risk) of causing design rework and losing process predictability— especially when the ability to reuse design work after a change is limited. We show that moderate design postponement is appropriate if clients strategically relinquish some of the upside risk of finishing the project sooner. Moderate design postponement does not increase the downside risk of overrunning the project completion date in relation to the risk clients incur when they commit earlier because it reduces expected variability in design. These insights highlight the client’s role in foreseeing external uncertainties and judiciously instructing changes to design teams. They also demonstrate the applicability of postponement to large engineering design projects where external uncertainty emerges as a fundamental contingency.

  • Elfving, J.A., Tommelein, I.D., and Ballard, G. (2005). "Consequences of Competitive Bidding in Project Based Production." Journal of Purchasing and Supply Management, 11:173-181.
    • ABSTRACT: This paper discusses the consequences competitive bidding have on lead time in project-based production, such as construction. Earlier studies argued that competitive bidding may significantly increase resource consumption and generate waste in the delivery process, which this paper supports. However, the relation between competitive bidding and lead time has been less discussed. Lead time reduction has long been considered a fundamental objective for overall business improvement. An objective of our study was to understand what contributes to long lead times. The reported findings are from a 4-year study on the delivery process of power distribution equipment, a type of engineered-to-order (ETO) product. The paper concludes by suggesting procurement practices that reduce lead times for ETO products.

  • Gil, N., Tommelein, I.D., Stout, A., and Garrett, T. (2005). "Embodying Product and Process Flexibility to Cope with Challenging Project Deliveries." ASCE, Journal of Construction Engineering and Management, 131 (4) 439–448, April.
    • ABSTRACT: Four factors make it challenging to manage semiconductor fabrication facility (“fabs”) projects: technical complexity of the product design, need to compress the project duration, need to reduce upfront costs, and unexpected project changes. The strategies employed by practitioners to cope with these challenges form an intricate puzzle. We empirically develop a framework that provides a structure for helping to solve this puzzle, which comprises two principles: investing upfront in a flexible product design and structuring a flexible process. Empirical findings reveal that project teams make commitments early on by overdesigning but also postpone critical decisions by differentiating the scope of their work. Project teams employ other strategies such as increasing communication, using modular architectures, engaging in four-dimensional computer-based modeling, and fabricating components and subsystems off-site. Our analysis yields understanding on the purposes and performance tradeoffs of these strategies, and on how they embody the two principles. Project managers may find the framework useful when deciding which strategies best suit other equally challenging projects.

  • Gil, N., Tommelein, I.D., and Beckman, S. (2004). "Postponing Design Processes in Unpredictable Environments." Research in Engineering Design, 15 (3) 139-154, December.
    • ABSTRACT: This work explores the effectiveness of design postponement in the concept development phase of large-scale engineering projects. Our empirical research shows limited use of postponement in semiconductor fabrication facility (fab) projects despite evidence that the customer inevitably requests design criteria changes in the projects life. We simulate fab concept development as a 2-stage process—conceptualization followed by design. We find that postponing the start of design in relation to the completion of conceptualization reduces the average resources spent on design and the variability in the concept development duration but increases the average concept development duration. A sensitivity analysis on the postponement lag duration indicates, however, that some degree of postponement may allow reducing design rework without increasing the risk of overrunning the project completion date, in comparison to the risk with early commitment. Further, simulation indicates that the effectiveness of postponement decreases as designers' capability to reuse work increases.

  • Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and Howell, G.A. (2004). "Work Structuring to Achieve Integrated Product-Process Design." ASCE, J. of Constr. Engrg. and Mgmt., Nov/Dec, 130 (6) 780-789.
    • ABSTRACT: This paper presents “work structuring,” a term used to describe the effort of integrating product and process design throughout the project development process. To illustrate current work structuring practice, we describe a case study involving the installation of door frames into walls in a prison. We analyze why various problems existed. To improve the work structuring effort, we apply the “five whys” to develop local and global fixes for the system of precast walls and door frames. The five whys is a technique to elicit alternative ways of structuring work without being constrained by contractual agreements, traditions, or trade boundaries. We discuss the importance of dimensional tolerances in construction and how these affect the handoff of work from one group of workers to the next. We argue that these constraints and tolerance management practices are so embedded that project participants can miss opportunities to better integrate product and process design. We propose shifting the focus of work structuring from maximizing local trade efficiency to improving overall performance in the delivery system of a capital project.

    This paper was reprinted by Doors and Hardware:

    • Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and Howell, G.A. (2006a). "Work Structuring to Achieve Integrated Product-Process Design, Part I." Doors and Hardware, June, pp. 42-48. 
    • Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and Howell, G.A. (2006b). "Work Structuring to Achieve Integrated Product-Process Design, Part II." Doors and Hardware, July, pp. 32-44 and 77.

  • Walsh, K.D., Hershauer, J.C., Tommelein, I.D., and Walsh, T.A. (2004). "Strategic Positioning of Inventory to Match Demand in a Capital Projects Supply Chain." ASCE, J. of Constr. Engrg. and Mgmt., Nov/Dec, 130 (6) 818-826.
    • ABSTRACT: Industrial buyers of capital facilities have experienced and continue to experience pressure to reduce facility design and construction lead time. This pressure arises both internally (due to successes in manufacturing lead time reductions) and externally (due to competitive forces including narrowing product delivery windows). This paper presents a case study detailing one owner’s efforts to reduce the length and variability of delivery time for long-lead construction materials in order to improve overall project lead time. The owner adopted a long-term multiproject perspective, procuring material in advance of specific projects and holding it at a position in the supply chain selected to allow flexibility for customization. Reduction in lead time of 75% from order to delivery of the material resulted for individual projects within the owner’s capital plan. As a result, the material was available at the construction site well in advance of its need for erection. To study if holding material at alternative locations in the supply chain could provide a better match between delivery quantities and the demand for erection, the supply chain was simulated. In this case study, demand information was imprecise, allowing only the quantity of material delivered to be considered rather than matching specific items to specific locations. Nonetheless, the results demonstrate the utility of simulation in the capital projects supply chain and the value of improving demand forecasts.

  • Gil, N., Tommelein, I.D., and Ballard, G. (2004). "Theoretical Comparison of Alternative Delivery Systems for Projects in Unpredictable Environments." Construction Management and Economics, 22 (5) 495-508, June.
    • ABSTRACT: A project delivery process simulation is presented based upon empirical studies in the design-build environment of semiconductor fabrication facilities ('fabs'). The model captures key tasks and decisions in design, procurement and construction, as well as design criteria changes along the delivery of a R&D fab utility system. Simulation shows that to involve the specialty contractor from the project start on average expedites project delivery since it prevents delays caused by bidding and by contractors' unfamiliarity with the design product definition. Yet, in unpredictable project environments - environments in which design criteria are likely to change irrespectively of the project progress status - simulation reveals that the averages of construction rework and waste increase if design is prematurely frozen. Assuming that work methods do not change and design criteria remain uncertain, results indicate that a system that combines early contractor involvement with judicious postponement of the design start reduces the average duration of the fab utility delivery in relation to the expected duration if competitive bidding was used, with limited increase in the averages of construction rework and waste. Additional efficiency is gained when specialty contractors relax conservative assumptions on anticipated site conditions. An economic model uses simulation results to assess the tradeoffs between alternative project delivery systems for the case of R&D fabs.

  • Choo, H.J., Hammond, J., Tommelein, I.D., Austin, S., and Ballard, G. (2004). "DePlan: Tool for Integrated Design Management." Automation in Construction, 13 (3) 313-326, May.
    • ABSTRACT: The iterative and information-intensive nature of the design process makes it hard to plan and schedule work using tools for conventional project management. The success of design projects depends on the quality of the available information. This paper proposes DePlan as a method for integrated design management during the detail design phase. DePlan integrates two techniques, namely ADePT and planning according to Last Planner™, each involving a software tool. ADePT implements the dependency structure matrix analysis method to identify iterative processes and the planning strategy for managing them. Planning according to Last Planner™ follows a production management philosophy that includes reliably scheduling and controlling design activities. Combined as DePlan, these techniques help planners generate quality plans, i.e., plans that express what is ready for execution by sequencing activities in the right order, identifying informational and resource requirements ahead of design execution, and by scheduling only activities that have met these requirements. This collaborative research has successfully developed the DePlan approach and associated computer software and tested them.

  • Dzeng, R.-J. and Tommelein, I.D. (2004). "Product Modeling to Support Case-based Construction Planning and Scheduling." Automation in Construction, 13 (3) 341-360, May.
    • ABSTRACT: Many human schedulers create schedules by reusing past similar schedules. The retrieval and reuse of similar schedules are subjective and experience-based. This paper explores different notions of similarity required when performing different scheduling tasks. It describes the CasePlan system that helps schedulers retrieve and reuse parts of existing schedules based on a generic product model, and apply case-based reasoning to generate new schedules. The validation experiment demonstrated CasePlan’s accuracy in determining individual subnetworks and activity durations, but weak performance in determining interlinks between subnetworks, which highly depends upon the availability of pertinent cases and the level of detail of project information.

  • Arbulu, R.J., Tommelein, I.D., Walsh, K.D., and Hershauer, J.C. (2003). "Value Stream Analysis of a Re-engineered Construction Supply Chain." J. Building Research and Information - Special Issue on Re-engineering Construction, Spon Press, 31 (2) 161–171.
    • ABSTRACT: A study is presented that documents the most common configuration of the supply chain for pipe supports used in power plants in the USA. This supply chain, like many others in construction, has numerous inefficiencies, many of which occur at the interfaces between processes, disciplines or organizations. Recognizing and understanding such inefficiencies, their causes and potential remedies provides a basis for process re-engineering. The study describes how today’s industry practices are changing to yield shorter supply chain lead times. To model the mechanisms that drive those changes, data are presented from industry practice in the form of value stream maps that span across organizational disciplines and company boundaries. Metrics commonly used in lean construction are introduced to gauge system performance. A current state map documents how work flows throughout the design, procurement and fabrication phases of pipe supports. Analysis of this current state map highlights value-added and non-value-added times and lead times. A future state map then illustrates process improvements that can be obtained by applying various supply chain management tactics. The methodology applied in this study could be applied to other construction supply chains equally well.

  • Whelton, M., Ballard, G., and Tommelein, I.D. (2002). "A Knowledge Management Framework for Project Definition." ITcon, Special Issue ICT for Knowledge Management in Construction, Vol. 7, pp. 197-212.
    • ABSTRACT: This paper proposes a knowledge management framework for project definition of capital facility projects. The conceptual framework emphasizes project-based learning and the creation of group knowledge in early phase project planning and design activity. The use of multi-disciplinary expertise in this phase of project development acknowledges the use of multiple decision frames by which stakeholders approach project solutions. This research views project definition as a collaborative decision-making process, and highlights the need for supporting group management techniques and technologies. Project definition is regarded as the phase of project development where exploration of alternatives creates innovative problem and solution definitions that allows maximum customer value generation to be developed. This paper proposes a management framework to support organizational and process interfaces within project definition. The model is based primarily on findings from recent research literature and on exploratory descriptive research. The model presents a process for project definition and supports group knowledge creation and management. The model bases its development on soft systems methodology to support group cognition, learning and creative solution generation. Collaborative group theory is incorporated into the model to support project definition. The framework builds on theoretical principles of lean design and construction.

  • Gil, N., Tommelein, I. D., Kirkendall, R.L., and Ballard, G. (2001). "Leveraging Specialty-Contractor Knowledge in Design-Build Organizations." Engineering, Construction, and Architectural Management (ECAM), October/December, 8 (5/6) 355-367.
    • ABSTRACT: Specialty contractors have knowledge to contribute to the early design of architecture, engineering, and construction (AEC) products. In current practice, however, they are seldom involved in early design, but evidence suggests that their early involvement is increasing. Lean construction theory advocates such involvement. The practice of involving suppliers in product development efforts and manufacturing has proven to be highly successful. The paper reports on empirical research that identified the contributions of specialty contractor knowledge to early design, which led to gains in process efficiency and improvements in product quality. These contributions are categorized and illustrated by means of examples that stem from current practice or present potential opportunities for improvement. Reasons are given why specialty contractor knowledge is often ignored in design. Changes in AEC practices nevertheless suggest that organizations are creating conditions to increase interaction between designers and specialty contractors. Such interactions will help AEC organizations to retain and share the knowledge of individuals as well as learn to develop new knowledge.

  • Zouein, P.P. and Tommelein, I.D. (2001). "Improvement Algorithm for Limited Space Scheduling." ASCE, J. of Constr. Engrg. and Mgmt., 127 (2) 116-124, March/April.
    • ABSTRACT: Selecting construction methods and scheduling activities along with planning the use of site space over time are key to constructing a project efficiently. Site layout and activity scheduling have traditionally been tackled as independent problems. Their interdependence is often ignored at the planning stage and may be dealt with-if at all-when construction is underway. Problems that may have had easy solutions if dealt with earlier, may then be expensive to remedy. This paper addresses the combined problem termed "space scheduling" and presents an algorithmic time-space trade-off model for adjusting activity durations and start dates to decrease the need for space over congested time periods. The model characterizes resource space requirements over time and establishes a time-space relationship for each activity in the schedule based on minimum, normal, and maximum resource levels. An example illustrates the presented algorithm that generates a feasible space schedule.

  • Zouein, P.P. and Tommelein, I.D. (1999). "Dynamic Layout Planning Using a Hybrid Incremental Solution Method." ASCE, J. of Constr. Engrg. and Mgmt., 125 (6) 400-408, Nov/Dec.
    • ABSTRACT: Efficiently using site space to accommodate resources throughout the duration of a construction project is a critical problem. It is termed the "dynamic layout planning" problem. Solving it involves creating a sequence of layouts that span the entire project duration, given resources, the timing of their presence on site, their changing demand for space over time, constraints on their location, and costs for their relocation. A dynamic layout construction procedure is presented here. Construction resources, represented as rectangles, are subjected to two-dimensional geometric constraints on relative locations. The objective is to allocate site space to all resources so that no spatial conflicts arise, while keeping distance-based adjacency and relocation costs minimal. The solution is constructed stepwise for consecutive time frames. For each resource, selected heuristically one at a time, constraint satisfaction is used to compute sets of feasible positions. Subsequently, a linear program is solved to find the optimal position for each resource so as to minimize all costs. The resulting sequence of layouts is suboptimal in terms of the stated global objective, but the algorithm helps the layout planner explore better alternative solutions.

  • Tommelein, I.D., Riley, D., and Howell, G.A. (1999). "Parade Game: Impact of Work Flow Variability on Trade Performance." ASCE, J. of Constr. Engrg. and Mgmt., 125 (5) 304-310, Sept/Oct.
    • ABSTRACT: The Parade Game illustrates what impact work flow variability has on the performance of construction trades and their successors. The game consists of simulating a construction process in which resources produced by one trade are prerequisite to work by the next trade. Production-level detail, describing resources being passed from one trade to the next, illustrates that throughput will be reduced, project completion delayed, and waste increased by variations in flow. The game shows that it is possible to reduce waste and shorten project duration by improving the reliability of work flow between trades. Basic production management concepts are thus applied to construction management. They highlight two shortcomings of using CPM for field-level planning: CPM makes modeling the dependence of ongoing activities between trades or with operations unwieldy and it does not explicitly represent reliability. The Parade Game can be played in a classroom setting either by hand or using a computer. Computer simulation enables students to experiment with numerous alternatives in order to sharpen their intuition regarding variability, process throughput, buffers, productivity, and crew sizing. Managers interested in schedule compression will benefit from understanding work flow variability’s impact on succeeding trade performance.

  • Tommelein, I.D. (1999). "Lean Construction Experiments using Discrete-event Simulation: Techniques and Tools for Process Re-engineering?" International Journal of Computer-Integrated Design and Construction, CIDAC, Special issue on Construction Process Re-engineering, 1 (2) 53-63, September.
    • ABSTRACT: The construction community concerned with process re-engineering needs formal techniques and modeling tools to support their efforts. This paper proposes that lean construction, a theory of production custom-tailored to suit the needs of construction, be embraced to drive re-engineering efforts. Several lean production techniques have already been adapted successfully to address construction needs. This paper specifically provides an example that illustrates a lean technique called ‘pulling.’ It also shows how computer-based discrete-event simulation can be used as a tool to model and experiment with alternative production systems, in order to study their characteristic properties such as buffer sizes and production rates. The provided example pertains to supply-chain materials-management in industrial construction. The systematic application of a production theory combined with computer experimentation prior to field implementation of a re-engineered system is bound to increase its likelihood of success.

  • Choo, H.J., Tommelein, I.D., Ballard, G., and Zabelle, T.R. (1999). "WorkPlan: Constraint-based Database for Work Package Scheduling." ASCE, J. of Constr. Engrg. and Mgmt., 125 (3) 151-160.
    • ABSTRACT: A database program called WorkPlan has been created to systematically develop weekly work plans. Such work plans are used by crew foremen in scheduling work packages and allocating available labor and equipment resources. WorkPlan adopts the Last Planner methodology, which implements several lean construction techniques. A week prior to conducting work, WorkPlan guides the user step by step through the process of spelling out work packages, identifying constraints, checking constraint satisfaction, releasing work packages, and allocating resources; then at the end of the week, collecting field progress data and reasons for plan failure. This systematic approach helps the user create quality work plans and learn from understanding reasons for failure. The lean planning philosophy underlying WorkPlan and the functionality of the computer program implementation are detailed in this paper. Various ways of displaying work package data are illustrated. WorkPlan's job-shop scheduling view complements the view traditionally adopted by project management, as is reflected in scheduling tools using the critical path method (CPM).

  • Tommelein, I.D. (1998). "Pull-driven Scheduling for Pipe-Spool Installation: Simulation of Lean Construction Technique." ASCE, J. of Constr. Engrg. and Mgmt., 124 (4) 279-288.
    • ABSTRACT: Many construction processes include installation of unique materials in specific locations in the facility being built: materials and locations must match before installation can take place. Mismatches due to delay and uncertainty in supplying materials or completing prerequisite work at those locations hamper field productivity. This is illustrated here using a model of a materials-management process with a matching problem that typifies fast-track process-plant projects. The uniqueness of materials and locations combined with the unpredictability in duration and variation in execution quality of various steps in the supply chain allow for different ways to sequence material delivery and work area completion. Several alternatives are described. Their impact on process execution is illustrated by means of probabilistic process models. One model reflects total lack of coordination between delivery and work area completion prior to the start of construction; a second one describes perfect coordination. The corresponding materials staging buffers and construction progress are plotted based on output from discrete-event simulation models. A third probabilistic model then illustrates the use of the lean construction technique called pull-driven scheduling. Real-time feedback regarding the status of progress on site is provided to the fabricator off site so process steps can be re-sequenced opportunistically. This yields smaller buffers and earlier project completion and, when properly accounted for, increased productivity.

    The Stroboscope source code file 'PipeSpool.STR' of the pipe-spool model described in this paper is available for download by clicking here. Please acknowledge the source when using this model in or as a basis for your work. You will need to get the STROBOSCOPE simulation engine to run this code.

  • Dzeng, R.J. and Tommelein, I.D. (1997). "Boiler Erection Scheduling Using Product Models and Case-based Reasoning." ASCE, J. of Constr. Engrg. and Mgmt., 123 (3) 338-347.
    • ABSTRACT: Contractors who repeatedly construct facilities designed by copying major parts from one project to the next find that previously developed schedules associated with those designs could be reused to schedule new work. To facilitate such reuse, project characteristics must be articulated and associated schedules described to include not only traditional, numerical scheduling data, but also scheduling constraints. In addition, knowledge about how to reuse schedules must be available. The CasePlan system, presented here, supports and augments the scheduling activity of people who reason about cases—each case describing the design and schedule of a completed project—to generate new project schedules. Specifically, CasePlan reuses annotated cases to automatically schedule the erection of power plant boilers. Because such boilers have a more-or-less standardized design, a generic boiler product model can serve as the basis for assessing similarities between designs. On this basis CasePlan selects schedules for reuse. A user can also interact with CasePlan to isolate fragments of case schedules and adapt them to better suit the variables of the new project at hand.

  • Tommelein, I.D., Carr, R.I., and Odeh, A.M. (1994). "Assembly of Simulation Networks using Designs, Plans, and Methods." ASCE, J. of Constr. Engrg. and Mgmt., 120 (4) 796-815.
    • ABSTRACT: An object-oriented and interactive computer system is presented that realistically models construction processes by matching resource properties with design component properties and operation durations. This system, named CIPROS, uses a modular representation to create discrete-event simulation networks, and to aid in relating simulation output back to the design and construction plan of a facility to be built. CIPROS users must identify and describe attributes of components to be constructed, based on the facility's design drawings and specifications, and they must develop a critical path method (CPM) plan. They must also select a construction method to perform each activity by retrieving the appropriate elemental simulation network from a library of networks that represent such methods. CIPROS then pieces together the networks based on sequential relationships from the plan and property values input from the drawing and specification data. The latter initialize the simulation network resources that make up the constructed facility. To complete the simulation network, users must specify the construction resources that are available to perform the work and which may be shared by activities. CIPROS comprises a fully operational discrete-event simulation engine that is called once a network is completed. Besides producing statistical reports that are instrumental in assessing the quality of the construction plan, CIPROS can also be used to check the degree of facility completion as the simulation progresses.

  • Balkany, A., Birmingham, W.P., Maxim, B.R., Runkel, J.T., and Tommelein, I.D. (1994). "DIDS: Rapidly Prototyping Configuration Design Systems." Journal of Intelligent Manufacturing, (5) 33-45.
    • ABSTRACT: This paper describes an object-oriented system, known as the Domain-Independent Design System (DIDS), for rapidly constructing design tools. DIDS supports a graphic-based development paradigm, where a tool builder assembles a design tool from a library of reusable software objects called mechanisms. Once configured, these objects are automatically converted to C++ code that implements the design system. This paper explores the issues involved in constructing DIDS, particularly the definition of objects to ensure that they capture the proper level of functionality and can be easily combined. An example of DIDS constructing a bicycle configuration system is given.

  • Tommelein, I.D. and Zouein, P.P. (1993). "Interactive Dynamic Layout Planning." ASCE, J. of Constr. Engrg. and Mgmt., 119 (2) 266-287.

  • Balkany, A., Birmingham, W. P., and Tommelein, I.D. (1993). "An Analysis of Several Design Systems." J. of Artificial Intell. in Engrg., Design, and Mfrg., AI EDAM, 7 (1) 1-17.

  • Tommelein, I.D., Hayes-Roth, B., and Levitt, R.E. (1992). "Altering the SightPlan Knowledge-based Systems." J. of Artificial Intell. in Engrg., Design, and Mfrg., AI EDAM, 6 (1) 19-37.

  • Tommelein, I.D., Levitt, R.E., and Hayes-Roth, B. (1992). "SightPlan Model for Site Layout." ASCE, J. of Constr. Engrg. and Mgmt., 118 (4) 749-766.
    • ABSTRACT: A model that uses artificial intelligence programming techniques is presented as a new tool for layout designers. This model, named SightPlan, represents the layout process as well as the layout product. A description of the knowledge and problem-solving method is given of the SightPlan system that mimics the actions of a human layout designer. SightPlan lays out temporary facilities, represented as rectangles, on a construction site, represented as a two-dimensional space. An early-commitment strategy and spatial constraint satisfaction techniques are used to find unique positions for facilities among those already in place. An example run in which SightPlan is applied to a case-study project illustrates how the program operates in stand-alone mode. SightPlan demonstrates that knowledge-based systems can successfully address problems not adequately modeled until now and, thus, opens up a new way of thinking about computer-aided decision support for the construction industry. The present system is a prototype, however. Additional work must be done before SightPlan will be ready for field use and useful to field practitioners.

  • Tommelein, I.D., Levitt, R.E., and Hayes-Roth, B. (1992). "Site Layout Modeling: How Can Artificial Intelligence Help?" ASCE, J. of Constr. Engrg. and Mgmt., 118 (3) 594-611.

  • Tommelein, I.D., Levitt, R.E., Hayes-Roth, B., and Confrey, T. (1991). "SightPlan Experiments: Alternate Strategies for Site Layout Design." ASCE, J. of Computing in Civil Engrg., 5 (1) 42-63, Jan.
    • ABSTRACT: SightPlan is a knowledge-based system that lays out temporary facilities on construction sites. Its implementation architecture calls for explicit representation of the problem-solving strategy used to construct a solution layout. Because this strategy can easily be modified we explore several alternate formulations. This paper describes the development and testing of strategies that two agents might adopt to match their cognitive capabilities. One strategy models the steps taken by a construction manager laying out the site; it reflects human cognitive strengths and weaknesses. Recognizing that such a strategy would not be well-suited for execution by a computer, we critique it, and craft a second strategy to make better use of the computer's storage and computational capabilities. Although more powerful in several ways, this second strategy falls short of some human strengths, such as the ability to discriminate between alternatives. After comparing these two strategies, we develop a third, combining human and machine strengths. This strategy augments the second strategy with graphics to allow for human-computer interaction. We argue that the resulting joint cognitive system can generate better solutions than either a person or a machine.

Discussions

White Papers

  • Tommelein, Iris D. (1999). "Life-cycle Design and Systems Engineering." White paper contributed to the Berkeley-Stanford CE&M Workshop: Defining a Research Agenda for AEC Process/Product Development in 2000 and Beyond, hosted by Stanford University and co-organized by U.C. Berkeley, 26-28 August 1999, 7 pp.

  • Tommelein, I.D. (1994). "Computer-Aided Engineering: Let's Formalize a Way." White paper presented at the International Workshop on the Future Directions of Computer Aided Engineering, held at Carnegie Mellon University, 18-19 June 1994. Appeared in Rehak, D. (ed)(1994). Bridging the Generations: Intl. Workshop on the Future Directions of Computer-Aided Engineering, Carnegie Mellon University, Pittsburgh, PA, 255-258. Reprinted in Garrett, J.H. Jr. and Rehak, D.R. (editors)(1999). "Bridging the Generations: The Future of Computer-Aided Engineering." Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, ISBN: 0966785908

Technical Reports

  • Tommelein, I.D. (2004). Tool and Material Management Systems. New Horizons Foundation, Chantilly, VA, www.newhorizonsfoundation.org, 46 pages.

  • Tommelein, I.D. (2004). The Value Chain: Adding Value to the Supply Chain, Mechanical Contracting Education & Research Foundation (MCERF), Chantilly, VA. Also see http://www.mcaa.org/news/pressreleases/2004-11-02ValueChain.cfm

    • ABSTRACT:This MCERF study defines the construction supply chain and highlights key concepts that will help you transform your supply chain into a value chain.

  • Tommelein, I.D., Walsh, K.D., and Hershauer, J.C. (2003). Improving Capital Projects Supply Chain Performance. Research Report PT172-11, Construction Industry Institute, Austin, TX, 241 pp.

  • Choo, H.J. and Tommelein, I.D. (1999). "Parade of Trades: A Computer Game for Understanding Variability and Dependence." Technical Report 99-1, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California, Berkeley, September.

    • Click here to download a fully executable copy of the Parade Game. Not-for-profit educational use of this program is hereby granted. If the program is used in any money-making instructional, commercial, consulting, or other setting, written permission to do so must be obtained in advance of such use by contacting Professor Iris D. Tommelein.

  • Tommelein, Iris D. and Ballard, Glenn (1997). "Look-ahead Planning: Screening and Pulling." Technical Report No. 97-9, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California. Berkeley, CA. Also invited paper that appeared in Proc. Second Intl. Seminar on Lean Construction, 20-21 October 1997, Sao Paulo, Brazil, organized by A.S.I. Conte, Logical Systems, Sao Paulo, Brazil.

  • Tommelein, Iris D. and Ballard, Glenn (1997). "Coordinating Specialists." Technical Report No. 97-8, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California, Berkeley, CA. Also invited paper that appeared in Proc. Second Intl. Seminar on Lean Construction, 20-21 October 1997, Sao Paulo, Brazil, organized by A.S.I. Conte, Logical Systems, Sao Paulo, Brazil.

  • Tommelein, I.D. (1997). "Discrete-event Simulation of a Pull-driven Materials-handling Process that Requires Resource Matching: Example of Pipe-spool Installation." Technical Report 97-2, Constr. Engrg. and Mgmt. Program, Civil and Envir. Engrg. Dept., U.C. Berkeley, March, 53 pages.

Papers in Refereed Conferences or Proceedings

2008

  • Feng, P.P., Tommelein, I.D., and Booth, L. (2008). “Modeling the Effect of Rework Timing: Case Study of a Mechanical Contractor.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester, UK.  

  • Hamzeh, F.R., Ballard, G., and Tommelein, I.D. (2008). “Improving Construction Work Flow - The Connective Role of Lookahead Planning.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .   

  • Nguyen, H.V., Tommelein, I.D., and Ballard, G. (2008). “Process-Based Cost Modeling to Support Lean Project Delivery.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .  

  • Parrish, K., Wong, J.M., Tommelein, I.D., and Stojadinovic, B. (2008). “Set-Based Design: Case Study on Innovative Hospital Design.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .

    ABSTRACT: This paper describes collaboration efforts of a project team that implemented lean concepts in the course of structural system selection during the design phase of a hospital project. Out-of-the-box thinking, contractual incentives for team work, early collaboration, and a set-based design approach led to the development of an innovative and cost-effective structural system that may set precedent for other medical facilities to be constructed in seismically active zones. The structural design team on this project rigorously explored the design space and tested design alternatives against project value propositions. When pushed by the owner to think more broadly, the structural engineer proposed using a new technology, namely viscous damping walls. This concept was developed in Japan but has not yet been tried on projects in the United States. Because it is a first, this solution requires not only rigorous analysis and testing by the structural engineer but also detailed investigation by the state's regulatory agency that issues building permits. This paper describes the team's efforts at defining the design space and the set-based design approach they used. A key lesson from this case study is that teams have a lot to learn about how to make requests and commitments while pursuing set-based design to be lean.

  • Parrish, K., Wong, J.M., Tommelein, I.D., and Stojadinovic, B. (2008). “Value Propositions for Set-Based Design of Reinforced Concrete Structures.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .  

  • Rybkowski, Z.R., Wong, J.M., Ballard, G., and Tommelein, I.D. (2008). “Using Controlled Experiments to Calibrate Computer Models: The Airplane Game as a Lean Simulation Exercise.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .  

  • Tommelein, I.D. (2008). “‘Poka Yoke’ or Quality by Mistake Proofing Design and Construction Systems.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .  

  • Tuholski, S.J., and Tommelein, I.D. (2008). “Design Structure Matrix (DSM) Implementation on a Seismic Retrofit.” In Tzortzopoulos, P. and Kagioglou, M. (Eds.) (2008). Proceedings of the 16th Annual Conference of the International Group for Lean Construction (IGLC 16), 16-18 July, Manchester , UK .  

2007

  • Wong, J.M., Parrish, K., Tommelein, I.D. and Stojadinovic, B. (2007). "Communication and Process Simulation of Set-Based Design for Concrete Reinforcement.” in Henderson, S.G., Biller, B., Hsieh, M.-H., Shortle, J., Tew, J.D., and Barton, R.R. (eds.) Proceedings of the 2007 Winter Simulation Conference, 9-12 December 2007, Washington, D.C.
    ABSTRACT: Two discrete-event simulations are developed to assess the feasibility of improving the delivery process of reinforced concrete structures. The simulations represent the resource and information flows necessary for supporting set-based design of reinforcing bars used in concrete. Setbased design enables the exploration of feasible solutions for longer in the design process than is otherwise affordable using point-based design, so as to allow for input from several project participants early on and at the same time. The simulations use the canonical example of selecting longitudinal reinforcement for a beam-column joint. The first simulation uses EZStrobe© to model the amount of time necessary to converge to a satisfactory design solution using set-based vs. point-based design methods. The second simulation uses XML data exchange and state machines in a service-based architecture to analyze the required information flows for communicating design sets. This enables the exploration of a meta-language to express design goals.

  • Hamzeh, F., Tommelein, I.D., Ballard, G., and Kaminsky, P. (2007). "Logistics Centers to Support Project-based Production in the Construction Industry." in Pasquire, C.L. and Tzortzopoulos, P. (editors)(2007). Proceedings of the 15th Annual Conference of the International Group for Lean Construction (IGLC 15), 18-20 July 2007, East Lansing, MI.
    ABSTRACT: With the advancement of information technology and increased market competition, construction companies are driven to employ supply chain management strategies to seek competitive advantage. Managing logistics is one component at the core of such strategies. An effective logistics system ensures delivery of the right products and services to the right customers at the right time while minimizing costs and rewarding all participants based on value added to the supply chain. As a component of a logistics system, logistics centres can serve the construction industry by offering services such as: storage, transport, distribution, assembly, kitting, consolidation, sorting, breaking bulk, cross-docking, and e-commerce. This paper focuses on the role logistics centres may play and the impact they may have on construction supply chains. Construction companies may configure their logistics centres in different ways to match their global and local supply chain strategy, while addressing challenges posed by variation in demand and supply for material, equipment, and services. A hypothesis is that logistics centres are underused in this industry, yet may offer considerable advantage. The ultimate aim of the research that is reported on here is developing a logistics system to support project-based production needs. The authors present a simulation model of a logistic centre that supports multiple site stores on different construction projects facing variations in supply lead times. The objective of the simulation is to find an approach to reduce material management costs while avoiding resource shortages, and enhancing both reliability and responsiveness of the supply chain.

  • Mikati, S., Roller, T., Tommelein, I.D., and Khanzode, A. (2007). "Priority Conversations: A Case Study On Priority Walls." in Pasquire, C.L. and Tzortzopoulos, P. (editors)(2007). Proceedings of the 15th Annual Conference of the International Group for Lean Construction (IGLC 15), 18-20 July 2007, East Lansing, MI.
    ABSTRACT: This paper presents and analyzes work structuring and collaboration efforts of the general contractor and specialty contractors working together as a team to implement lean practices during construction of a medical facility. We describe the team’s focus specifically on ‘priority walls’ as a driver for coordinating work among contractors. We then elaborate on the tools the team used to support their language (“priority conversations”) and action, as well as on the successes and failures of their approach. Success of this effort stems from the team’s willingness to experiment, collaborate, and learn; use of an owner-provided incentive sharing plan; and other lean practices including use of the ‘big room’ (‘oba’ or ‘oobeya’ in Japanese), development of a Building Information Model (BIM) that allowed for integration and coordination of trade-specific design details, promotion of reliable planning, as well as use of standardization combined with offsite fabrication and assembly. The paper illustrates how this combination of lean practices changed the nature of the conversation specialists have in the course of development of a project and yielded value to all project participants as well as to the project as a whole.

    This paper was shortened and then reprinted by Tradeline:

    • Mikati, S., Roller, T., Tommelein, I.D., and Khanzode, A. (2007). "Contractors Work as a Team to Implement Lean Construction Practices: 'Priority Conversations,' Use of 'Big Room,' and Willingness to Experiment Facilitate Efforts" Online at http://www.tradelineinc.com/content/28831/display/x70jgb, November.

  • Parrish, K., Wong, J.-M., Tommelein, I.D. and Stojadinovic, B. (2007). "Proof-of-Concept of Set-Based Design for Reinforced Concrete Structures." in Pasquire, C.L. and Tzortzopoulos, P. (editors)(2007). Proceedings of the 15th Annual Conference of the International Group for Lean Construction (IGLC 15), 18-20 July 2007, East Lansing, MI.
    ABSTRACT: To explore the feasibility of improving the delivery process of reinforced concrete, we focus in this paper on reinforcing bars (rebar) used in cast-in-place (CIP) concrete. Specifically, we describe the methodology for set-based design of rebar that we are pursuing in an ongoing research effort. Set-based design makes it possible to maintain feasible solutions for longer in the design process than is otherwise affordable using point-based design. It thereby allows for input from several project participants at the same time and early on, as well as throughout project delivery. Set-based communication helps participants avoid rework and through teamwork develop a more globally satisfactory design solution than would otherwise be the case. To illustrate the methodology, we examine the canonical example of reinforcement at a beam-column joint and study the relationships between those who design the joint and those who fabricate and install it: mainly the structural engineer, the fabricator, and the rebar placer. The set-based approach for concrete design is promising. It warrants further effort in characterizing sets at different levels of abstraction and in articulating what different participants value, both of which are needed for sets to be narrowed effectively and for the process to lead to a solution.

2006

  • Alves, T.D.C.L. and Tommelein, I.D. (2006). "Simulation as a Tool for Production System Design in Construction." Proc. 14th Conference of the International Group for Lean Construction (IGLC14), 25-27 July 2006, Santiago, Chile, 10 pages, 341-353.
    • ABSTRACT: In this paper, the authors discuss the concepts of variability, buffers, and batches, as well as the interactions between them. The discussion aims at contributing to the identification of factors that impact production systems design, which includes the definition of buffer locations, buffer profiles, batch sizes, etc. The authors use a simulation model developed using STROBOSCOPE to represent five different scenarios for planning, fabrication, shipping, and installation of sheet metal ductwork in order to illustrate how production system design choices may affect the lead time needed to deliver a project. The data used to develop the model was obtained from time studies performed by the authors as well as from interviews conducted with field superintendents. In order to develop the model, the authors needed basic information about activities pertaining to the delivery of sheet metal ductwork. Modeled durations and quantities are approximations based on the data collected. The model highlights the need for and importance of reliable data when designing production systems and simulation models thereof. Effort needs to be put in by the construction industry and researchers to gather more representative sets of data that can be used to design production systems. 

  • Alves, T.D.C.L. and Tommelein, I.D. (2006). "Investigation of Buffer Dynamics in Sheet Metal Ductwork Supply Chains." Proc. 14th Conference of the International Group for Lean Construction (IGLC14), 25-27 July 2006, Santiago, Chile, 10 pages, 309-315.
    • ABSTRACT: The model discussed in this paper represents the interactions between design changes, site work, and fabrication shop work for make-to-order products.  Being qualitative in nature, it serves as a basis for discussing how inventory and buffers are created in the Sheet Metal Ductwork Supply Chain due to changes in design and installation sequences.  The authors chose to model changes in schedule and design because industry practitioners indicated that these are the main causes for variations that disrupt contractors’ work flow.  The authors highlight selected feedback links between activities to discuss the implications of communication, timing of demand, and product standardization vs. customization.  A number of insights into the model can be abstracted to other supply chains in construction.  Other supply chains in construction (e.g., electrical systems, architectural components, precast concrete) can benefit from the analysis as presented.

  • Tommelein, I.D. (2006). "Process Benefits from Use of Standard Products - Simulation Experiments using the Pipe Spool Model." Proc. 14th Conference of the International Group for Lean Construction (IGLC14), 25-27 July 2006, Santiago, Chile, 177-189.

    • ABSTRACT: Construction materials management and supply chain management are challenging not in the least because of the sheer number and variety of types of materials being assembled in any one project. Uniqueness of materials increases system complexity. This raises the question addressed in this paper: How may the use of increasing numbers of a standard product affect production system performance? To answer this question, we build on the pipe-spool model with ‘matching problems’ that was presented at the IGLC in 1997 but we study parameters that are different from those studied previously to illustrate how management practices may affect a production system’s behavior. Specifically, we show how the use of standard products alleviates the matching problem. Computer-based discrete-event simulation is known to be a useful tool to describe how lean systems may be designed and metrics applied to analyze their performance. Accordingly, we use simulation experiments to illustrate the relationship between the use of various numbers of standard products and process execution. As shown, small numbers of standard products result in some reduction of the project duration, but increasing numbers benefit the system disproportionately more. Using lessons learned from this experiment combined with other observations based on theory and practice, we provide directions for follow-on research and recommendations for managers to design their project-based production systems by exploiting product standardization opportunities. 

2005

  • Alves, T.D.C.L. and Tommelein, I.D. (2005). "Investigation of the Sheet Metal Ductwork Supply Chain: Current Practices and Opportunities for Improvement." Simposio Brasileiro de Gestao e Economia da Construcao, Encontro Latino-americano de Gestao e Economia da Construcao, October 24-26, Porte Alegre, Brasil, 10 pages.

  • Alves, T.D.C.L. Tommelein, I.D., and Ballard, G. (2005). "Value Stream Mapping for Make-to-order Products in a Job Shop Environment." Proc. Construction Research Congress, held in San Diego, CA, 5-7 April 2005, published on CD ROM by ASCE, Reston, VA, 10 pages.

  • Graham, D., Smith, S.D., and Tommelein, I.D. (2005). "Cost of Concrete Placement for Contractors." Proc. 21st Annual Conference and Annual General Meeting of the Association of Researchers in Construction Management (ARCOM), Soas, London, UK, 7-9 September, 10 pages.

  • Graham, D., Tommelein, I.D., and Smith, S.D. (2005). "Cost Reduction through Vertical Integration of the In-situ Concrete Supply Chain." Proc. 21st Annual Conference and Annual General Meeting of the Association of Researchers in Construction Management (ARCOM), Soas, London, UK, 7-9 September, 10 pages.

  • Kaplan, H., Elburg, A., and Tommelein, I.D. (2005). "Analysis of Variability in Precasting and Installation of Pile Foundations." Proc. Construction Research Congress, held in San Diego, CA, 5-7 April 2005, published on CD ROM by ASCE, Reston, VA, 10 pages.
    • ABSTRACT: This paper presents a study on the use of pre-stressed precast foundation piles using data collected on a building project that comprised the installation of more than 340 piles. The objective is to assess the presence of product and process variability in demand and supply, and the impact it has on precast pile delivery. Sources of variability in precasting, transportation, and installation are described. As a step towards understanding the complexity of this production system and to show how production planning decisions affect execution, this paper elaborates on two deterministic scenarios and compares those with actual data from the project. Performance of the system is analyzed on the basis of inventory vs. work completed. From the perspective of ‘lean’ thinking the paper then identifies sources of waste and suggests means to eliminate them. It also presents questions for follow-on research.

  • Milberg, C. and Tommelein, I.D. (2005). "Application of Tolerance Mapping in AEC Systems." Proc. Construction Research Congress, held in San Diego, CA, 5-7 April 2005, published on CD ROM by ASCE, Reston, VA, 10 pages.
    • ABSTRACT: Tolerance maps are a tool for specifying, analyzing and allocating tolerances for both product and process design. This paper introduces the authors’ tolerance mapping system and the steps for creating and implementing the system to an existing design for evaluation and improvement, via a sample case. The paper addresses current industry limitations on tolerances, future mapping improvements, and mapping implementation challenges.

  • Tommelein, I.D. and Ballard, G. (2005). "Restructuring the Rebar Supply System." Proc. Construction Research Congress, held in San Diego, CA, 5-7 April 2005, published on CD ROM by ASCE, Reston, VA, 10 pages.
    • ABSTRACT: The rebar supply system includes all the organizations involved in the manufacturing, design, procurement, fabrication, transport, installation, inspection and regulation of reinforcing steel. It also includes their relationships and their processes. That system is highly fragmented and sub-optimized; it needs to be restructured. An industry task force, formed to support the authors’ research, characterized the current state of the system in terms of adversarial relations, low pay, and failure to learn from project-to-project. No one is making an adequate profit, low fees constrain designers from full exercise of their professional capabilities, and drawing quality and design constructability are declining. The task force also proposed a vision of the future state, identified obstacles to its realization and generated basic strategies for overcoming those obstacles. This paper describes these task force outputs and develops its strategies into a plan for reforming the rebar supply system.

2004

2003

2002

2001

2000

1999

ABSTRACT: Temporary facilities on construction sites are needed to support the labor force during the course of their work. Rules of thumb traditionally have been used to decide on the location and capacity of those facilities, but the demand for support is project dependent and changes as construction progresses at a rate specific to each trade discipline. This paper presents a more systematic method for facility location and capacity sizing based on travel-time simulation. Actual site circumstances, including the location of a temporary facility relative to the location of the workers as well as workers' needs, travel, and service time are taken into account. The objective is to identify the best location on site for temporary facilities on a project-by-project basis. When real-time data becomes available as construction progresses, it can be incorporated in the model to generate even more realistic output. Tool-room location is used as an illustration. The presented simulation model yields data to assess how much travel and wait time is tolerable compared to the cost of increasing the capacity of the support facility or providing service at additional locations.

1998

  • Choo, H.J., Tommelein, I.D., Ballard, G., and Zabelle, T.R. (1998). "WorkPlan Database for Work Package Production Scheduling." Proc. Sixth Annual Conference of the International Group for Lean Construction (IGLC-6), 13-15 August held in Guaruja, Brazil, 12 pp.

  • Tommelein, I.D., Riley, D., and Howell, G.A. (1998). "Parade Game: Impact of Work Flow Variability on Succeeding Trade Performance." Proc. Sixth Annual Conference of the International Group for Lean Construction, IGLC-6, 13-15 August held in Guaruja, Brazil, 14 pp.

  • Choo, H.J., Tommelein, I.D., Ballard, G., and Zabelle, T.R. (1998). "Constraint-Based Database for Work Package Scheduling." Proc. Computing Congress '98, ASCE, pp. 169-180; also Technical Report No. 98-1, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California, Berkeley, CA.

  • Sadonio, M., Tommelein, I.D., and Zabelle, T.R. (1998). " The LAST DESIGNER'S Database-CAD for Sourcing, Procurement, and Planning." Proc. Computing Congress '98, ASCE, pp. 364-375; also Technical Report No. 98-2, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California, Berkeley, CA.

  • Tommelein, I.D. and Chua, D.K.H. (1998). "Management of Design Detailing Process: Key to Specialty-Contractor Performance." Proc. Computing Congress '98, ASCE, pp. 61-72; also Technical Report No. 98-3, Construction Engineering and Management Program, Civil and Environmental Engineering Department, University of California, Berkeley, CA.

1997

  • Tommelein, I.D. (1997). "Using Palm-Top Computers in Teaching Materials Management." Proceedings Construction Congress V, Oct. 5-7 in Minneapolis, MN, ASCE, NY, NY, 405-413.

  • Tommelein, I.D. (1997). "Models of Lean Construction Processes: Example of Pipe-Spool Materials Management." Proceedings Construction Congress V, Oct. 5-7 in Minneapolis, MN, ASCE, NY, NY, 156-164.

  • Tommelein, I.D. (1997). "Discrete-event Simulation of Lean Construction Processes." Proc. Fifth Annual Conference of the International Group for Lean Construction, IGLC-5, 16-17 July 1997 at Griffith University-Gold Coast Campus, Gold Coast, Queensland, Australia, 121-135.

1996

  • Riley, D.R. and Tommelein, I.D. (1996). "Space Planning Tools for Multi-story Construction." Proc. 3rd Congress on Computing in Civil Engineering, Vanegas J. and Chinowsky, P. (eds.), ASCE, New York, NY, 718-724.

1995

  • Tommelein, I.D. (1995). "New Tools for Site Materials Handling and Layout Control." Proc. Construction Congress '95, Ibbs, C.W. (editor), ASCE, New York, NY, 479-486.

  • Dzeng, R.J. and Tommelein, I.D. (1995) "Case-based Scheduling Using Product Models." Proc. Second Congress on Computing in Civil Engineering, Atlanta, GA, 5-8 June 1995, ASCE, New York, NY, 163-170.

1994

  • Tommelein, I.D., Carr, R.I., and Odeh, A.M. (1994). "Knowledge-Based Assembly of Simulation Networks Using Construction Designs, Plans, and Methods." Proceedings 1994 Winter Simulation Conference, December 11-14, 1145-1152.

  • Tommelein, I.D. (1994). "MoveCapPlan: An Integrated System for Planning and Controlling Construction Material Laydown and Handling." ASCE, Proc. 1st Computing Congress, ASCE, New York, NY, 1172-1179.

  • Zouein, P.P. and Tommelein, I.D. (1994). "Time-Space Tradeoff Strategies For Space-Schedule Construction." ASCE, Proc. 1st Computing Congress, ASCE, New York, NY, 1180-1187.

  • Dzeng, R.J. and Tommelein, I.D. (1994). "Case Storage of Planning Knowledge for Power Plant Construction." ASCE, Proc. 1st Computing Congress, ASCE, New York, NY, 293-300.

  • Tommelein, I.D. (1994). "Materials Handling and Site Layout Control." Proc. 11th ISARC, 24-26 May in Brighton, U.K., in Chamberlain, D.A. (1994). Automation and Robotics in Construction XI, Elsevier Science Publishers, 297-304.

  • Tommelein, I.D. and Dzeng, R.J. (1994). "Automated Case-Based Scheduling for Power Plant Boiler Erection." Proc. 11th ISARC, 24-26 May in Brighton, U.K., in Chamberlain, D.A. (1994). Automation and Robotics in Construction XI, Elsevier Science Publishers, 179-186.

  • Zouein, P.P. and Tommelein, I.D. (1994). "Automating Dynamic Layout Construction." Proc. 11th ISARC, 24-26 May in Brighton, U.K., in Chamberlain, D.A. (1994). Automation and Robotics in Construction XI, Elsevier Science Publishers, 409-416.

1993

  • Tommelein, I.D. (1993). "Planning and Controlling On-site Materials Handling through Space Scheduling." EPRI 3rd International Fossil Plant Construction Conference, 26-28 Oct. 93 in Palm Beach, Florida (invited paper).

  • Tommelein, I.D. and Dzeng, R.J. (1993). "Product Modeling to Structure a Case Library for Case-based Construction Planning." Proc. 1st Intl. Conf. on the Management of Information Technology in Construction, Aug. 17-20, Singapore, CIB W-78.
ABSTRACT: The conceptual design of a case-based planner, named CasePlan, is presented to plan and schedule construction activities by comparing a new facility with those described in cases, and adapting the selected cases' plans to suit the new construction needs. For effective case retrieval and new case indexing, CasePlan relies on a product model, that describes a prototypical power plant facility. Each construction product in a project is a specialization of this product model. A library of construction techniques and methods is also related to this product model. This well-structured organization of detail enables CasePlan to construct executable project plans. This is in contrast to most other artificial-intelligence based planners that generate only least-commitment plans, which must be detailed further manually. CasePlan thus exploits the power provided by a well-structured model to capture human expertise in design and construction planning cases, and demonstrates how such a product model can effectively be used. A operational prototype of CasePlan is currently being developed.

  • Tommelein, I.D., Dzeng, R.J., and Zouein, P.P. (1993). "Exchanging Layout and Schedule Data in a Real-Time Distributed Environment." Proc. 5th Intl. Conf. on Computing in Civil and Building Engrg., June 7-9, Anaheim, Calif., ASCE, New York, NY, 947-954.
ABSTRACT: Unpredictable site conditions and unforeseen changes in construction work may result in inefficiencies due to a shortage of work space and difficult access to critical areas on site. This hampers productivity. Detailed advance planning of site space use over time and reorganization of the work may alleviate these inefficiencies.
An interactive decision support tool is presented that loosely integrates layout with r