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Experience and business intuition of a contractor are often insufficient to ensure that tender procedures will provide a good trade-off between the cost of bid preparation and the benefit of a high probability of winning a money-making contract. The authors put forward a set of decision-support models: a multi-criteria analysis for assessing the desirability of a potential new contract, and two linear programming models: one for calculating the total price, and the other for distributing the bid amount among the items of the bill of quantities to maximize the contractor's cash flows. Application of the models is illustrated with a numerical example. [ABSTRACT FROM AUTHOR]

Estimates of the construction time are of key importance in the early phases of the project -- they serve as a basis for the decision whether to commence with planning or not, and are used as input for budgets and programmes. Usually, such estimates base on experience with similar projects completed in the past. This experience may be recorded in the form of mathematical models that relate project characteristics to construction time. The aim of the research was, basing on real-life cases, to develop a model of public road building projects duration. The research comprised collection of input for the analyses, preselection of project features correlated with duration, and construction of three models: a simple statistical regression, a multifactor regression and a regression tree. The models were then compared to each other and to the models presented in the literature with respect to their predictive ability. With the assumed set of potential predictors of construction duration, the regression models were found statistically correct, though not precise enough be used as decision-support tools. [ABSTRACT FROM AUTHOR]

Material supply-related decisions strongly affect economic performance of construction projects. To facilitate planning, the authors put forward a mixed integer linear programming model for optimizing supplies of materials or components that are consumed irregularly. The model's objective function is minimizing the total inventory management cost. As material prices change over time and cannot be predicted with certainty, they are expressed as fuzzy values with triangular membership functions. The planning horizon is divided into units of time to allow for seasonal changes and scope variations that affect consumption of materials. The model enables the user to determine economic order quantities for consecutive periods of construction works and to select most economical supply channels of a particular material/component. The model allows for material/component substitution. Substitutes may differ in level of prefabrication and thus in costs of on-site processing. To solve the problem the fuzzy model is converted into a three-objective linear program with crisp coefficients. An example illustrates benefits of using the proposed approach in reducing the total inventory cost. [ABSTRACT FROM AUTHOR]