Journal of Construction Engineering and Management

Public road agencies are currently evaluating hot mix applications of PlusRide™ and Arm‐R‐Shield™ modified asphalt pavements. The processes use reclaimed rubber from ground automotive and light truck tires to reduce reflective and thermal cracking, suppress traffic noise, increase resistance to studded tire wear, and reduce the environmental impact of tire disposal. The projects constructed to date have primarily been experimental because the capital cost for this surfacing alternative ranges from 1.5 to 2 or more times the cost of conventional asphaltic concrete. A literature review of the construction practices and a questionnaire survey of contractors are used to determine why the construction costs of the modified mixes have been so high. One of the factors is the increase in financial risk perceived by contractors who bid on these types of pavements. Another cost factor, especially with the PlusRide™ system, is the unusual aggregate gradation required by the process. Still another concern is the increased mixing temperatures and times required by both rubber‐modified products. For Arm‐R‐Shield™, the high cost of the mix primarily reflects the cost of the asphalt‐rubber binder supplied by the manufacturer. These costs could be reduced by development of specifications which limit the contractor's risk, such as the use of conventional aggregate gradings, requiring minimum increases in mixing temperature and time, and allowing competition between rubber‐modified asphalt suppliers.

The objective of this paper is to predict the tunnel advance rate in the construction of a several‐mile‐long, small‐diameter (3–3.5 m) tunnel in soft rock. For this purpose, the CYCLONE simulation system is used. Several simulation models are developed to investigate the effect of different variables on the tunnel advance rate. At first the suitable tunneling method, including the tunnel support and material handling system, is selected by reviewing similar projects completed in recent years. Various cycle times and durations, e.g., TBM penetration rate and train travel time, are carefully calculated, based on previous tunneling jobs. After specifying the construction method and duration times, the developed simulation models are described. The impact of each major variable on the tunnel advance rate is studied by sensitivity analysis. These variables include the TBM penetration rate, the train travel time, the number of muck trains, the type of rock, and the rock standup time. Simulation models quantify the effect of each of these variables on the tunnel advance rate.

Geologic uncertainty in underground construction often leads to design and construction conservatism and thus to inflated costs. This paper presents a general model for the probabilistic prediction of tunnel geology as a basis for developing more effective tunnel design and construction decision support systems. The geologic conditions along the tunnel alignment are modeled by a set of geologic parameters (e.g., rock type, joint density, degree of weathering, etc.), each following a continuous‐space, discrete‐state Markov process. The state probabilities for each geologic parameter are initially based on general geologic information and are later updated to reflect the outcomes and reliability of the location‐specific, nondeterministic observations provided by exploration programs. The resulting posterior geologic parameter profiles are aggregated into a single probabilistic ground class profile that can be used for determining optimal tunnel design and construction strategies. The model is illustrated by an example application.

The time allowed for construction project performance is usually an important consideration for both the project owner and the project contractor. Yet, it is typical for construction projects to be delayed. Delays may be caused by the owner (compensable delay), by the contractor (nonexcusable delay), by acts of god, or a third party (excusable delay), or several different kinds of delays may happen concurrently. Because of the many sources and causes of construction delays, it is often difficult to analyze the ultimate liability in delay claims. The original schedule (as‐planned) is known, and, likewise, the actual schedule (as‐built) is known. What is unknown is the appropriate schedule when all allowable adjustments to the schedule are taken into account; this schedule is often called the as‐adjusted schedule. This paper presents a tool to aid in analysis of delay claims. The procedure set forth will handle delays and accelerations and will help in determination of the as‐adjusted schedule.

Contemporary use of integrated package programs in construction management has centered on financial and accounting analyses. A method is described in this paper that uses an integrated package in the design and optimization of concrete formwork. The formwork design method consists of three modules, the input data, the data bank, and the calculations.

A specialty conference on earthmoving and heavy equipment was held on February 5–7, 1986, at Tempe, Arizona, under the sponsorship of the Committee on Construction Equipment and Techniques, Construction Division of ASCE. The objective of the conference was to foster an exchange of ideas concerning the economical field utilization of earthmoving and heavy construction equipment. The presentations by a number of knowledgeable speakers, and the resulting discussions among these individuals and the audience, provided an effective forum for summarizing the status of the industry and examining new developments which may be expected in the near future. The purpose of this paper is to summarize the primary topics of discussion and to conceptualize the future development of the earthmoving and heavy equipment industry.

The factor model for evaluating the productivity of labor‐intensive construction activities is described. The theory underlying the model is presented. The model states that many factors cause disturbances to crew performance. If these can be quantified and discounted from actual productivity data, one is left with an ideal productivity curve, which can be used to forecast future performance. Methods for collecting and combining data from various projects are presented and illustrated using actual productivity data from three commercial construction projects. Insight into the validity of the factor model is demonstrated by considering the effect of temperature and relative humidity on productivity. Multiple regression techniques are used to mathematically explain approximately 40% of the variability in the daily productivity data. Other statistical parameters are also described. The results of the weather model are compared to similar relationships reported by other researchers. The relationship developed by the writers is consistent with those reported in the literature. The factor model and the methods used to develop the weather model appear to be valid because the discounted productivity curve has less variability than the original productivity data. Lastly, an example is presented that illustrates the way in which the impact of weather on productivity can be evaluated.

The standard documents of the American Institute of Architects and the Associated General Contractors of America for construction management projects imply processes and operational procedures that have become customary if not standard since publication in 1975. Adjustments must be made to accommodate the particular form and variation of construction management specifically required by the contract. However, construction management firms have a tendency to customize processes and procedures for their own convenience. This is especially true on projects where a firm is contractually assigned other service responsibilities such as design, contracting, or construction. When a CM process and its procedures exactly match the intent of the project delivery system, owners are positioned to gain from the use of the system. When convenience intervenes, the system cannot function effectively, and the owner may experience negative results. This paper argues that convenient customizing of the CM process and its procedures, especially customizing that mitigates the checks and balances specifically built into the construction management system and implied by established CM practice, represents a detrimental divergence from the fundamental reasons CM is. selected for use by owners on their projects.

Changing needs of owners, changing designs of constructed facilities, and increased foreign competition for domestic construction markets provide new incentives for advanced construction technology. This paper describes a process for innovation in the construction firm, based on an investigation of several new construction methods. This process includes recognizing forces and opportunities for innovation, creating a climate for innovation, developing the necessary capabilities, providing new construction technologies, experimenting and refining, and implementing. The paper also develops practical applications to assist industry professionals attempting to increase innovation within their firms and implications to structure further investigations of construction innovation.

In order to ensure that graduate‐level construction engineering project‐management education programs best serve the needs of the construction industry, it is deemed essential that a continuing dialogue between university professors and practitioners be maintained. Based upon three surveys conducted among the top 400 contractors as listed by ENR 1978, 1982, and 1984, six‐year trends in educational needs are covered. They represent the shifting in the priorities among graduate courses and show the reflection of the evaluation of construction management in the USA. Construction industry expectations should be translated at the university level into a variety of new regular courses offered by various programs in the country. Short courses for practitioners should be offered by both universities or professional societies to complement their college education.