269 publications from this institution
The effects of construction delays are not confined to the construction industry but influence the state of the overall economy of a country. This is particularly so in Turkey where construction investments account for almost half of all investments and where delays have reached significant magnitudes in the 1970–80 decade. A Iurge number of public agencies that are construction owners and a large number of contractors that undertake construction work for public agencies in Turkey were surveyed to identify and rank in an order of importance the causes for such delays. The results indicate that shortages of some resources; public agencies' and contractors' fincincial dfiiculties; organizational deficiencies and delays in design work, frequent chunge orders and considerable extra work are the most important sources of delay. While some of the causes are dependent on national economic policies, others may be overcome by measures to be taken by public agencies and contractors.
Abstract: The type and number of activities involved in highway construction, the precedence relationships between them, and their estimated durations depend on a multitude of factors. When considered under different conditions, the number of options available in this regard is found to be very high. Computerized support for the generation of construction schedules is currently limited to creating networks for manually defined and sequenced activities. This paper describes a system called ROAD PLANNER that generates activity networks and computes estimated activity durations. Eleven main activities that are present in the majority of highway construction projects have been defined at the root level. Based on information provided by the user, the system generates the precedence relationships between these main activities. It then generates subactivities and estimates their duration by interacting with 14 rule bases. Lead and lag times between activities are also calculated by the system. The rule bases contain expert information on various construction methods and different technologies. They interface with 27 databases that contain productivity information regarding a multitude of construction equipment.
Although a few studies have considered financing cost in the construction project, no research has been conducted to select the optimal financing alternatives out of those offered by financial institutions. This study presents a model that minimizes financing cost by considering different financing alternatives and a work schedule with normal activity durations. The proposed model creates a cash flow forecast based on a work schedule generated by the critical path method (CPM). The output includes optimized schedules of financing inflow (borrowed money) and outflow (repayments of principal and interest). The proposed model has advantages compared to models developed in previous studies because the contractor: (1) pays less financing cost, (2) avoids extending the project duration and avoids liquidated damages, (3) provides an optimal financing schedule, and (4) reduces the risk of ending up with a work schedule composed of more critical activities. The model has been tested in three cases and sensitivity analysis has been performed.
Abandonment of rail branches and secondary lines with low traffic density is an effective means of maintaining railway company profitability in many countries such as Britain, Canada, Australia, and Japan. In the United States, it was not until passage by Congress of the Stagger's Act in 1980, that the industry's abandonment vigor became fully manifested. This is because the Stagger's Act substantially reduced the time required for the Interstate Commerce Commission to act upon abandonment applications. An economic model is developed to predict losses in a railroad branch line without going through the cumbersome and lengthy calculations normally undertaken, thus reducing the time necessary for the decision‐making process. To this purpose, regression analysis has been performed between losses incurred in 50 railroad branch lines and independent variables extracted from the abandonment applications made for these lines to the Interstate Commerce Commission. The resulting statistically significant model indicates that losses can confidently be predicted by making use of cost and revenue data that are readily obtainable by railway companies freight revenues, maintenance costs for way and structures, rehabilitation costs and equipment maintenance costs.
Collusive bidding is regarded as one of the most socially harmful, anticompetitive, and illegal practices in the construction sector. The process of collusion is hidden from public sight, making it difficult to calculate its cost. A model was developed in this study for calculating the embodied cost of the convenor in collusive bidding cases using the regression analysis technique. The model was tested using 254 publicized collusion cases in China, and the results were verified by online interviews with a fair number of experts with extensive experience. It was found that the embodied collusion cost composed of side payments and administrative penalties has a positive relationship with awarding price. Also, from a box plot, it was found that the embodied collusion cost has a low growth trajectory for lower awarding prices, but remains stable for higher awarding prices. This study provides an effective tool for antitrust authorities to detect the existence of additional cartel members by comparing the difference between the reported and calculated values of side payments.
Purpose The purpose of this paper is to explore the relationship between civil engineers’ demographics (e.g. age, marital status, education, work experience) and their personal values. The objective was to predict civil engineers’ personal values based on their demographics. Design/methodology/approach A questionnaire survey was administered to civil engineers to collect data on their demographics and their personal values. Statistical analysis was performed to verify whether a significant statistical relationship exists between civil engineers’ demographics and their personal values. Findings The most important and the least important personal values were identified for civil engineers. Statistical analysis indicated that civil engineers’ values do vary based on their demographics. Research limitations/implications The results of this study cannot be generalized, because individuals’ personal values and demographics are, by definition, local. Location and culture may affect the personal values of civil engineers. Practical implications Team leaders normally have access to information about the demographics of the engineers they employ; based on the results of this study, they should be able to predict their personal values, and to make more informed decisions when appointing them to particular positions on project teams. Originality/value The research presented in this paper, establishes for the first time, that a linkage exists between civil engineers’ personal values and their demographics, and makes it easier for team leaders to make assignment decisions.
A sectoral analysis of the construction industry in Indonesia indicates that it has grown considerably in recent years. Efforts are under way to adapt to this new situation, including exploring ways to increase productivity. A survey of top contractors indicates that certain functions including procurement practices, cost control, scheduling and management integration need much improvement. A survey of top design professionals indicates that they are concerned about design practices, computer utilization in planning and scheduling activities, and goal setting techniques. There seem to be conflicting opinions regarding the construction management project delivery system. Both contractors and design professionals are willing to cooperate in any productivity enhancement programme but neither are willing to fund such activities.
