Journal of Construction Engineering and Management

The development of construction equipment has followed the major changes in global transportation. In 1420, Giovanni Fontana was dreaming of and diagramming dredging machines. Development of the steam shovel was driven by a demand for an economical mass excavation machine to support the era of railroad construction. The Cummins diesel engine was developed in the early 1900s as the road-building phase of transportation construction began. In the short term, the basic machine frame will not change, but productivity, accuracy, and utility should improve because of enhancements. Machines will evolve into a mobile counterweight driven by an energy-efficient powerplant. This mobile counterweight will serve as a work platform for an array of hydraulic tools, and it will have synthesized computers that instantly communicate by satellite with distant management teams reporting diagnostics, production, and position.

Numerous workers, equipment, material, temporary facilities, as well as permanent structures share the limited space during construction. Since space constraints may affect productivity and the critical path, it is essential to organize the available space efficiently and minimize space conflicts. This study considers space availability due to time and scheduling, productivity loss due to space constraints and path interference, as well as the possibility of alternative space to resolve these conflicts and optimize space usage. Herein, computer-aided design is integrated with scheduling software for the dynamic identification of space conflicts on the jobsite. Follow-up supplemental decision criteria are then provided for conflict analysis and resolution. A prototype decision support system that combines the criteria was developed to solve this significant and complex problem more efficiently and precisely. A case study demonstrates the use and development of this system, which is very helpful to engineers and project managers.

Construction activities require a set of work spaces to be executed safely and productively. The locations and volumes of these spaces change in three dimensions and across time, according to project-specific design and schedule information. Previous research on construction space management requires users to specify the spatio-temporal data necessary to represent each project-specific space needed for construction. Since a construction schedule consists of hundreds of activities requiring multiple types of spaces, this approach is practically infeasible. There is a need for a generic (project-independent) representation of work spaces, from which the project-specific instances of spaces can be derived automatically based on project-specific design and construction schedule information. This paper formalizes such a generic space description as a computer-interpretable ontology. This ontology is general, reusable, and comprehensive. A prototype system developed uses this ontology to capture the spatial requirements associated with construction methods and to automate the generation of project-specific spaces represented in three dimensions and across time.

To provide a safe and productive environment, project managers need to plan for the work spaces required by construction activities. Work space planning involves representing various types of spaces required by construction activities in three dimensions and across time. Since a construction schedule consists of hundreds of activities requiring multiple types of spaces, it is practically impossible to expect project managers to specify manually the spatiotemporal data necessary to represent work spaces in four dimensions. This paper presents mechanisms that automatically generate project-specific work spaces from a generic work space ontology and a project-specific IFC (industry foundation class) based 4D production model. The generation of these work spaces leads to a space-loaded production model. Within this model, work spaces are represented as being related to the relevant construction activities and methods and as having attributes that describe when, where, and how long they exist, and how much volume they occupy. These space-loaded production models enable richer 4D CAD simulations, time-space conflict analysis, and proactive work space planning prior to construction.

Material waste has been recognized as a major problem in the construction industry that has important implications both for the efficiency industry and for the environmental impact of construction projects. Moreover, waste measurement plays an important role in the management of production systems since it is an effective way to assess their performance, allowing areas of potential improvement to be pointed out. This paper describes the main results of two research studies carried out in Brazil that investigated the occurrence of material waste at 74 building sites located in different regions of that country. Some typical figures for the waste of some key construction materials are provided, and the main causes of waste in the sector are discussed. The results indicate that the waste of materials in the Brazilian building industry is fairly high and that a large variability in waste incidence is found across different projects. Most of this waste can be avoided by implementing inexpensive preventive measures, mostly related to managerial improvements.

This paper develops an alternative concession model for build operate transfer (BOT) infrastructure projects. The concession period is a measure for deciding when the project ownership will be transferred from the investor back to the government concerned; it also demarcates the benefits, authorities, and responsibilities between the government and private investors. Previous studies have developed various techniques and methods, mainly suggesting proper organization structure, contracting procedures, methods of project financing, and risk allocation strategies when BOT-contract projects are implemented. These works have provided effective methodologies for the development of BOT contracts. Nevertheless, it appears that little has been undertaken in studying the way to determine the concession period in a BOT contract. This paper critically reviews the principles of establishing the concession period in a BOT contract. Such a review leads to developing a quantitative model for determining a proper concession period that can protect the interests of both the government concerned and private investors. An example is given that indicates how the alternative model can be applied to determine the concession periods of BOT infrastructure projects.

Labor-intensive industries such as the electrical and mechanical trades are considered high risk due to the high percentage of labor costs. Because of this high risk, it is important for contractors in these industries to closely track labor costs on projects and compare these costs to industry benchmarks. In this paper, benchmark indicators for these industries are established on the basis of actual project data. These benchmarks include the relationship between the percent complete or percent time and cumulative work hours or cost, project size and duration, project size and average man power, project size and peak man power, and average versus peak man power. These relationships were developed using regression analysis. Man power loading charts and the related S-curves were developed from actual project data. The man power loading charts and the related S-curves are useful for resource planning and for tracking progress on a construction project. They can be used to show the cause-and-effect relationship between projects impacted by outside factors and normal labor productivity.

The state of Utah has experienced problems in the procurement of construction. Similar to other states using low-bid, Utah historically has not had construction projects delivered on time and within budget. Faced with critical projects to prepare for the 2002 Olympics, overworked construction project managers, and construction litigation caused by low-bidding contractors, the Division of Facilities Construction and Management tested the Performance Information Procurement System (PIPS) in the fall of 1998 on the University of Utah Housing Project Phase II for the 2002 Olympic Housing. Five other tests were conducted. This article analyzes the differences between the PIPS and the Utah low-bid procurement system, the results of the state of Utah tests, problems, and modifications to the PIPS, and recommendations to future users of the PIPS. Major contributions of this article include the PIPS, Kashiwagi’s Information Measurement Theory, and Zeleny’s Displaced Ideal Model. The objective of this article is to use an information-based business process to procure contractors who deliver on time and on budget and meet quality expectations.

This paper presents a case study of the applications and nonapplications of constructability concepts to illustrate, in a practical way, the impact that these concepts can have on a project’s success. This case study, which conveys an important message with regard to the application of constructability concepts, was purposely chosen from among prestigious projects in peninsular Malaysia. The basic message, as viewed by the interviewees, is that applying these constructability concepts will enhance a project’s constructability, consequently optimizing the schedule, cost, and quality of the project for the benefit of all the parties involved. The interviewees for the case study agreed that the applied constructability concepts were derived from their own experience and not based on any existing formal program. The absence of a systematic technique for transferring construction experience and knowledge to all the participants in all phases of a construction project is the reason behind the lack of constructability in our construction industry today.

The change in productivity is studied for six different pieces of earthmoving equipment over a period of 15 years. It is shown that the production rate of this group of equipment has increased 1.58% on average per year. During the same period, without adjusting for inflation and making specific assumptions, the unit price of production has increased at an average rate of 1.77% per year. The results of this analysis may be used in modeling obsolescence costs in equipment replacement analysis. The equipment considered includes two models of wheel-type loaders, one track-type loader, one scraper, and two track-type dozer models.