Lean construction

This paper describes a lean productivity strategy for a firm that is not currently the overall cost leader in a mature market segment. It uses the analysis of the Chartered Quantity Surveying Practice (CQSP), a service provider in the United Kingdom construction industry as the focus of such analysis. A CQSP that is not currently the cost leader can, using lean productivity philosophy, reconfigure the value chain to find new cost curves which may actually be lower than the overall market low cost producer for certain clients and certain services. A viable strategy can thus be created for a firm that could not otherwise compete.

LEAN PRODUCTION PRODUCTIVITY IMPROVEMENTS FOR CONSTRUCTION PROFESSIONS.

David Eaton Department of Surveying, University of Salford, United Kingdom.

Lean productivity is seen to be a possible methodology for addressing many of the fundamental faults in traditional service provision for the construction industry professions of the United Kingdom. The increasing globalisation of construction activity will require all the construction service professions to change and adapt or they will wither and die.This paper will explore the origins of lean productivity as exemplified by manufacturing industries world-wide. It will trace the potential development of lean productivity into the construction industry professions. It will then explain why and how lean production can be of benefit and offer predictions for its exploitation within the professional services associated with the industry.

TOOLS FOR THE IDENTIFICATION AND REDUCTION OF WASTE IN CONSTRUCTION PROJECTS

Luis F. Alarcón C.

Departamento de Ingeniería y Gestión de la Construcción, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, CHILE

A discussion of the importance and impact of introducing the new production philosophy in the field of construction is carried out, based on experiences in other industries and recent applications in construction companies. The importance of the heuristic principle of reducing non value-adding activities is emphasized, as the fundamental focus for achieving improvement. Different definitions and classifications of waste are compared which extend this concept beyond its traditional meaning. Within this context, examples are presented of tools which can be used to identify and reduce waste, such as: work sampling, resource balance charts, and a waste diagnostic survey.

IDENTIFICATION OF CRITICAL FACTORS IN THE OWNER-CONTRACTOR RELATION

Luis Fernando Alarcón C. , Patricio Venegas C. and Mario Campero Q .

Departamento de Ingeniería y Gestión de la Construcción, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, CHILE

This article presents a modeling exercise in which the effects of certain characteristics of risk in owner-contractor relations are evaluated in relation to the results of construction projects. It uses a conceptual model based on contractors' experience in public works and a mathematical model which integrates the assessments of the modeling participants. Characteristics of the relation such as good faith, the quality of design received by the contractor, the inspection regime stipulated by the owner, and the quality of payments, among others, were analyzed to predict the effects that different scenarios would have on cost, schedule and overall quality of projects. The authors' analysis of the results, indicates that contractors' efforts to understand and solve problems should focus on those aspects which are of major importance to the desired results, namely: 1) contract flexibility should reflect the quality of design, i.e. flawed design requires greater flexibility; and, 2) increased confidence in owner-contractor relations forms a work team with better inspection values.

IMPLEMENTING LEAN CONSTRUCTION: IMPROVING DOWNSTREAM PERFORMANCE

Glenn Ballard

Construction Engineering & Management Program, Department of Civil Engineering, 215 McLaughlin Hall, University of California, Berkeley, CA 94720 USA

Greg Howell

Department of Civil Engineering, Tapy Hall, Room 209, University of New Mexico, Albuquerque, NM 87131 USA

The conversion process model would have us attempt to achieve performance improvement on complex, fast track projects by separately reducing the cost and time of Engineering, Procurement and Construction, without regard to their interdependencies. The lean construction model facilitates performance improvement by revealing those interdependencies. This not only avoids suboptimization. The logic of lean construction implementation requires a certain sequence of initiatives, which progressively reveal additional opportunities for improvement. Ohno and Shingo, two of the principal architects of the Toyota Production System, argue persuasively that manufacturing be conceived in two complimentary but different ways: 1) As a process, i.e. the course of events through which material is changed into a product, and 2) As an operation, i.e. the course of events through which man and machine work on the product. They also argue that process must be balanced and managed prior to addressing operations. We are following Ohno and Shingo when we advocate implementation of lean construction in three phases, beginning with stabilization and reducing in-flow variation (process), and finally turning to operations.

IMPLEMENTING LEAN CONSTRUCTION: STABILIZING WORK FLOW

Glenn Ballard

Construction Engineering & Management Program, Department of Civil Engineering, 215 McLaughlin Hall, University of California, Berkeley, CA 94720 USA

Greg Howell

Department of Civil Engineering, Tapy Hall, Room 209, University of New Mexico, Albuquerque, NM 87131 USA

Lean construction has at least two foci that distinguish it from traditional construction management. One focus is on waste and the reduction of waste. Breaking from the conversion process model, and reconceiving production processes in terms of Koskela's flow process model reveals the time and money wasted when materials and information are defective or idle. Instead of simply improving the efficiency of conversion processes, the task is extended to the management of flows between conversions. Consequently, in addition to its focus on waste, lean construction also focuses on managing flows, and to do so, puts management systems and processes into the spotlight along with production processes. Flow management is a much more difficult task on complex, fast track projects such as refineries, chemical plants, food processing plants, paper mills, etc. These projects have long, complicated supply chains, many players, typically are under pressure to hit market windows for product, and are subject to multiple, extensive process design changes motivated by the opportunity to make much more money than is lost through disruption of construction. In this environment, traditional approaches to construction management fail miserably. The conversion process model conceals everything that needs to be revealed; particularly the design of systems and processes to manage work and work flow.

Implementing Lean Construction: Reducing Inflow Variation

Greg Howell

Department of Civil Engineering, Tapy Hall, Room 209, University of New Mexico, Albuquerque, NM 87131 USA

Glenn Ballard

Construction Engineering & Management Program, Department of Civil Engineering,215 McLaughlin Hall, University of California, Berkeley, CA 94720 USA

In many circumstances variety is the spice of life. But it is a bitter herb when you are trying to complete a complex and uncertain fast track project. Significant variations occur at every stage in the construction process. Plans change and materials are late. In compressed circumstances, variation becomes more apparent and critical as it exposes the interdependence between activities. Once the work environment is stabilized through modifying the planning system, it becomes possible both to reduce variation in flows and to work behind the shield to improve downstream operations. Suggestions for research and improved practice are offered specifically regarding the management and reduction of flow variation.

Lean Production Theory: Moving beyond "Can-Do"

Greg Howell

Department of Civil Engineering, Tapy Hall, Room 209, University of New Mexico, Albuquerque, NM 87131 USA

Glenn Ballard

Construction Engineering & Management Program, Department of Civil Engineering, 215 McLaughlin Hall, University of California, Berkeley, CA 94720 USA

Lauri Koskela identified the first task for academics "is to explain the new philosophy in the context of construction"and this is first objective here. The second is to provide a foundation to understand the contributions of Glenn Ballard which follow. The paper first discusses changes in the construction industry to suggest why a new (or for that matter any) production theory is required. The extent of the uncertainty experienced on projects leads to yet another comparison between manufacturing and construction. A new understanding of the construction process is offered. Next the concepts of flows and the role of Lean Production Theory (LPT) is examined. The paper closes with a reflection on the mental models which support current thinking. One caution, our perspective is drawn from experience in petrochemical and process piping projects. While there appear to be many parallels with experience in other project types, the specific thinking and applications occurred primarily in this industry segment.

WHAT DO WE MEAN BY LEAN PRODUCTION IN CONSTRUCTION?

Dr.ir. Bert Melles

Construction Management, Delft University of Technology, The Netherlands

Partner, INFOCUS Management Consultants BV, management consultant in construction companies

This paper will discuss lean production in construction. The primary goal of lean production is to avoid waste of time, money, equipment, etc. (Japanese: "muda") [Shingo 1992]. Everything is focused on productivity improvement and cost reduction by stimulating all employees. Koskela [Koskela-1993] gave an overview of waste in construction. He found results of 6 to 10% of the total project costs in Sweden and the USA. Investigations in construction companies in the Netherlands [source: INFOCUS Management Consultants] did give the same results. `Quick scans gave a result of failure costs (costs to restore failures) of at least 6% of the project costs! Lean production is a philosophy to decline the waste in production companies. Some elements of this philosophy are used already in construction. We discuss the principles and experiments.

FAST OR CONCURRENT - THE ART OF GETTING CONSTRUCTION IMPROVED

Pekka Huovila, Lauri Koskela, Mika Lautanala

VTT Building Technology, P.O. BOX 1801, 02044 VTT, Finland, tel. + 358 - 0 - 4561, fax. + 358 - 0 - 456 6251

Fast Tracking and Concurrent Engineering are approaches aiming at a shorter project duration. Fast Tracking is a method already practised in construction projects, while Concurrent Engineering comes from other industries' product development projects. Both have been emerged as an alternative for the sequential approach of project realisation.The purpose of this paper is to outline the essential features of Fast Tracking and compare them to those of Concurrent Engineering, and to study the applicability of Concurrent Engineering principles to construction. The work is based on a literature study. The main conclusions are:(1) Fast Tracking is a practically oriented approach, without solid conceptual or theoretical basis. The essence of Fast Tracking is overlapping of design and construction, which does not always lead to an optimal design solution.(2) Concurrent Engineering aims principally at reducing the duration of engineering time, increasing the value of the product and reducing the costs. Theoretically, this is achieved by reducing the share of those activities which do not directly contribute to the conversion of requirements to the final design, and by assuring that value is maximally added by those activities contributing to this conversion.(3) Concurrent Engineering emphasising at customer satisfaction, team approach, concurrent process for design of the product and planning of production, strategic relations with suppliers and continuous improvement is fully relevant for construction.

CONSTRUCTION MODELS: A NEW INTEGRATED APPROACH

Saied Kartam

Project Engineer, CH2M HILL Inc., Santa Maria, CA 93455.

Glenn Ballard

Lecturer in Civil Engineering, University of California, Berkeley, CA 94720 and President, Ballard Management Associates, Oakland, CA.

C. William Ibbs

Professor of Civil Engineering, University of California, Berkeley, CA 94720.

Modeling any system is a critical step for understanding it and improving its performance. The thrust of this research is the belief in the development of valid credible models as a logical precursor to automation. This article reviews the key models used to represent construction work processes. Through an examination of these models, this paper makes an important distinction between process and system modeling concepts. This distinction is the basis for the conclusion that no single tool, by itself, is accurately capable of fully modeling the construction system. This is why this research integrates a set of descriptive tools to allow the development of construction system models. This article presents one of these tools as a new system modeling concept, called "workmapping", that overcomes the deficiencies in the current modeling approaches. The power of this new model is illustrated in a detailed comparison among the key system modeling concepts.

Lean manufacturing of construction components

Lauri Koskela, VTT Building Technology, P.O. Box 18022, 02044 VTT, Finland

Telefax: +358-0-456 6251, e-mail: lauri.koskela@vtt.fi

Jukka Leikas, Mecrastor Corp., Kimmeltie 1, 02110 Espoo, Finland

Telefax: +358-0-4697 326

This paper is based on a research project undertaken by a consultancy company, a research institute, and six construction component manufacturing firms. The goal was to draw up a methodology for initiating lean production activities in construction component manufacturing, and to verify the potential of lean production in this industry through practical experiments.The resultant conceptual and methodological framework is outlined, and the implementation procedure is presented. Process improvement and redesign initiatives implemented by participating firms, along with related results and benefits, are analyzed. Finally, the feasibility and significance of lean production in construction component manufacturing is discussed.

ASSESSING QUALITY CONTROL SYSTEMS: SOME METHODOLOGICAL CONSIDERATIONS

David Seymour

School of Civil Engineering, University of Birmingham, Edgbaston, B15 2TT, UK.

The paper reports a study that was designed to establish the circumstances in which different levels of quality with regard to a feature of steel reinforced concrete structures were achieved. A procedure in the research process is discussed in order to consider ways in which the research paradigm used influences findings and the practical inferences that may be drawn from them. Four research paradigms are considered and contrasted, two of them are referred to as 'Applied' and two as 'Critical' . It is argued that if developments like that of Lean Construction are to realize their potential benefits, 'Critical' research has an important contribution to make.

APPLICATION OF QUALITY FUNCTION DEPLOYMENT TO THE DETERMINATION OF THE DESIGN CHARACTERISTICS OF BUILDING APARTMENTS

Alfredo Serpell and Rodolfo Wagner

Department of Construction Engineering and Management, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, Chile

A practical application of Quality Function Deployment (QFD) to the determination of the design characteristics of the internal layout of building apartments in Santiago (Chile) is described. The operational aspects of the analysis and the identification of client requirements are emphasized. The principal difficulties of the application of this method are also discussed. Finally, some results are presented to demonstrate the great potential of this tool for the solution of problems that combine demand and supply factors.

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Created 25.3.1996 by Lauri Koskela