Luis F. Alarcón

Assessing the impacts of implementing lean construction

Over the last 10 years an increasing number of companies have implemented lean construction practices in an attempt to improve performance in construction projects. Most companies, and also some researchers, have reported satisfactory results from their implementation. However, there is still a need to provide more extensive analysis of the empirical evidence available to assess the impact of the implementation of lean construction. The authors have researched the implementation of the Last Planner System and other Lean Construction techniques in over one hundred construction projects over the last five years. They have also developed strategies and support tools for implementation. This paper analyses some of the main impacts observed in the studied projects, and some of the lessons learned from implementations. The paper discusses difficulties and barriers for implementation, productivity improvements, variability reduction and effectiveness of implementation strategies. The paper also provides recommendations for future implementation and research.

Construction process improvement methodology for construction projects

Abstract A methodology developed for construction improvement and waste reduction is presented. This methodology has been successfully applied during the last 3 years to several construction sites in Chile, through consulting services and research studies. The approach includes a set of structured activities and tools that are performed and applied for the identification and evaluation of the problems that produce construction waste, and the causes associated to them. A second stage of the approach corresponds to the development of both short and mid-term solutions in order to act on the factors that produce these problems with the purpose of reducing or eliminating their effects. A summary of the major improvements achieved through the application of this framework is also included to show the potential of this approach, specially in countries where the construction industry is characterized by the low educational level of its workers and the many technological limitations that still pervade some construction sectors, particularly the housing construction sector.

Investigating the relationship between planning reliability and project performance

Variability is a well-known problem in construction projects, which leads to the general deterioration of project performance. During the last decade, the Last Planner System (LPS™), a production planning and control system based on lean production principles, has been increasingly applied in the construction industry to improve planning reliability reducing the negative impacts of variability. LPS™ promotes actions to increase planning reliability, monitoring the percentage of plan completed (PPC) in a short-term period. However, there is limited research evidence about the relationship between planning reliability and project performance. In this paper, the authors report on a detailed research analysing this relationship during the construction phase of a home building project at activity and project levels. By doing so, two indexes are proposed: an activity planning reliability index called the process reliability index (PRI), and a project aggregate labour productivity index, called the project productivity index (PPI). Statistical analyses using the proposed indexes were conducted showing positive and strong relationships between planning reliability and performance at activity and project levels. Finally, the research findings provide the guidelines of a preliminary methodology to forecast the impacts of planning reliability over project performance, when lean production methodologies are applied in project planning and control.

Improving Planning Reliability and Project Performance using the Reliable Commitment Model.

Commitment planning reliability at an operational level is a key factor for improving project performance. In the last 15 years, the Last Planner System, a production planning and control system based on lean production principles, has improved commitment planning reliability in the construction industry. However, many construction decision makers continue to rely on their experience and intuition when planning their commitments, which hinders their reliability. The reliable commitment model (RCM) is proposed to improve commitment planning reliability at the operational level by using statistical models. RCM is an operational decision-making tool based on lean principles that supports short-term forecasting commitment planning using common-site information such as workers, buffers, and plans. RCM was tested in several case studies, demonstrating its production forecasting capabilities and its ability to help increase commitment planning reliability and improve project performance. RCM also supports worklo...

Organizational Improvement Through Standardization of the Innovation Process in Construction Firms

Abstract: The purpose of this article is to identify the drivers, success factors, benefits, and barriers to innovation in a medium size construction firm with a standardized innovation management system. The case study method is used to compare theory to reality from different perspectives, building explanations from a Spanish contractor observed over a three year period. Findings suggest that innovation management can be standardized, which leads to an organizational improvement for the company, and at the same time this improvement facilitates organizational problem-solving on a regular basis, increasing technical capabilities, knowledge management, business profit, and client satisfaction. The framework described in this research aims to provide guidance for managers, thus they can innovate in a systematic way; however, this exploratory study has still to be validated by empirical investigations on a larger scale through a significant number of certified companies, which is currently not yet the case in the Spanish construction industry.

Model for Systematic Innovation in Construction Companies

AbstractThe reasons that drive construction companies to innovate, as well as the processes they use, have not yet been fully explored in the construction management literature. This paper describes the “hows” and “whys” behind the push for innovation in a construction company. The research method is founded on the validation of a model developed by a case study; this is focused on a medium-sized construction company which implemented and certified an innovation management system, as established by a Spanish standard. The studies conducted by the authors over a five-year period generated a set of 18 propositions reflecting an explanatory model of innovation management. This paper reports on the external validation of this model by means of a set of interviews; the results fully corroborate 15 of these propositions. The strongest drivers of innovation in construction companies are technical problems in construction projects, client requirements, and upper management. Innovation opportunities are identified...

Implementing Lean Production Strategies in Construction Companies

This paper describes a joint effort of twelve Chilean construction companies to introduce improvements in their project management processes. These companies participate in a collaborative research project to improve construction project performance developed by the Universidad Catolica de Chile. The strategies followed for implementation include some key elements such as: training for action, collaborative sharing among companies, coaching and action research. All these aspects are part of an overall strategy to introduce principles of lean construction and better practices in the organizations. This paper describes a computer system developed to support implementation of improved management practices. The system uses the core concepts of the “Last Planner” system of production control, to develop a knowledge framework for management decision making. This framework, implemented in a computer system, provides the means to capture and manage data collected during project planning meetings and from the project information systems. The system provides valuable information for continuous improvement of the project. Three stages are identified during the implementation of the improved planning process: Stage I, initial status of the companies, Stage II, one year after the beginning of implementation in each company and Stage III, implementation of the strategy supported by A computer system. The paper reports continuous improvements in all the stages, with a notorious increase in speed of improvements in the third stage.

Project management decision making using cross-impact analysis

Abstract This paper presents a methodology to evaluate the impact of management decisions on project performance outcomes. This decision-theory based methodology consists of a conceptual qualitative model structure and a mathematical model structure. The conceptual component is a simplified structured model of the variables and interactions that influence the decision being analysed. Influences and interactions assessed by experts or members of the management team are stored in a knowledge base. The mathematical component of the methodology uses concepts of cross-impact analysis and probabilistic inference as the core of the analysis procedure. The paper describes how the cross-impact concepts have been adapted and extended. Among the extensions, a method to combine probabilistic evidence is applied in this model to perform probabilistic inference. The result is a powerful but easy to use modelling and decision making methodology.

Risk Planning and Management for the Panama Canal Expansion Program

In April 2006, the Panama Canal Authority formally proposed a major expansion of the canal to increase its capacity and make it more productive, safe, and efficient. This proposal included cost and schedule estimates for completing the expansion and was supported overwhelmingly by the citizens of Panama in an October 2006 public referendum. Given the conceptual level of design at the time of the proposal and the inherent uncertainty in a project of this magnitude at the early stages of engineering, a comprehensive risk analysis was performed to develop a contingency model for the total expansion program cost and schedule. This contingency model is based on a Monte Carlo simulation of the cost and schedule estimates, taking into account the most significant risks identified for the project. The resulting model provides contingency assessments for duration and total cost and sensitivity analysis of the risks; it also allows for multiple scenario planning and ultimately supports overall risk management. This paper presents a project case study that focuses on the contingency model development and the resulting risk management and contingency resolution processes.

Integrated Methodology to Design and Manage Work-in-Process Buffers in Repetitive Building Projects

An integrated methodology to design and manage buffers in repetitive building projects using work-in-process at conceptual level is proposed. The buffer design framework employs the Multiobjective Analytic Model and Simulation-Optimisation techniques, applied at strategic and tactical scheduling levels. The buffer management framework uses a statistical model to predict work progress, the Reliable Commitment Model, applied at operational scheduling level. The integrated methodology provides a new buffering approach for scheduling repetitive building projects, which considers: (1) a general production framework covering all the production levels from top to bottom; (2) a general modelling structure suitable to any type of repetitive building project; and (3) a sound theoretical and practical framework describing different production scenarios. The benefits of using this methodology are illustrated through a hypothetical project application.