The purpose of this article is to present the preparation of Project Risk Assessment Methodology and its mitigation in complex construction projects. The main text provides a summary of the approach, the method used and the findings. The conclusions have been drawn that the proper tools for quantifying risks have to be based on the criteria specific for mathematical statistic and probability or at least fuzziness. Function, which makes possible to categorize any risks into one of the five categories, is a combination of probability and the impact on one of the items: people and their safety or budget, cost, schedule and planning or quality and performance. An attempt was made to express numerically the relationship between risks impacts and their level of likelihood. Also, a method of associating the influence of projects risks impacts on the extent of the likelihood of project risk occurrence which makes possible to determine the direction and the strength of this relationship was presented.
In Poland, it often happens that construction objects are subject to demolition work for different reasons. Demolition, according the Construction Law, is defined as a type of construction works and, as such, represents a particular type of construction project. As in other construction projects, a very important phase, in addition to execution of the works, is to prepare, design and plan demolition works. Some demolition activities are covered by appropriate regulations and can be described as typical. On the other hand the technical side of demolition works depends on many factors such as: the type of building, its age, technical condition, type of construction, etc. This article covers the analysis of the stages and tasks in the preparatory phase of the building demolition. This work will also present a description of the tasks carried out during the demolition works based on the example of a historic tenement house located in Krakow. This analysis aims to identify implementation problems and sources of risk that may occur during this type of construction work.
The concept of a general average is the oldest institution of maritime law. Its usefulness in modern shipping relations has long been criticized. Nevertheless, the general average, despite the fact that it is not the subject of any international agreement, occupies a prominent place in the internal legal systems of maritime states, and the international community continues to show great interest in it, regularly changing the principles of accounting established in the second half of the 19th century in York and Antwerp. During the work on the draft of the new Polish Maritime Code, the Maritime Law Codification Commission made some changes in the regulations concerning the general average, adapting the provisions of Polish law to new solutions proposed by participants of international maritime trade and non-governmental organizations, including Comité Maritime International.
The article presents the use of the Mamdani fuzzy reasoning model to develop a proposal of a system controlling partnering relations in construction projects. The system input variables include: current assessments of particular partnering relation parameters, the weights of these parameters’ impact on time, cost, quality and safety of implementation of construction projects, as well as the importance of these project assessment criteria for its manager. For each of the partnering relation parameters, the project’s manager will receive controlrecommendations. Moreover, the parameter to be improved first will be indicated. The article contains a calculation example of the system’s operations.
Article deals with the problem of technology selection for construction project. Three criteria were proposed: cost, time and technological complexity. To solve the problem, fuzzy preference relations were used. Authors present an algorithm supporting multi-criteria decision-making process. The algorithm creates fuzzy preference relations on the basis of the fuzzy comparison: “xᵢ is better than xj”.Then, with the use of criteria weights it creates general fuzzy preference relation, finds all non-dominated (admissible) alternatives and the best one among them. The algorithm consists of 7 steps. Authors show application of the proposed algorithm – example calculations.
Production rates for various activities and overall construction project duration are significantly influenced by crew formation. Crews are composed of available renewable resources. Construction companies tend to reduce the number of permanent employees, which reduces fixed costs, but at the same time limits production capacity. Therefore, construction project planning must be carried out by means of scheduling methods which allow for resource constrains. Authors create a mathematical model for optimized scheduling of linear construction projects with consideration of resources and work continuity constraints. Proposed approach enables user to select optimal crew formation under limited resource supply. This minimizes project duration and improves renewable resource utilization in construction linear projects. This paper presents mixed integer linear programming to model this problem and uses a case study to illustrate it.
This paper presents a model of scheduling of multi unit construction project based on an NP-hard permutation flow shop problem, in which the considered criterion is the sum of the costs of the works' execution of the project considering the time of the project as a constraint. It is also assumed that each job in the units constituting the project may be realized in up to three different ways with specific time and cost of execution. The optimization task relies on solving the problem with two different decision variables: the order of execution of units (permutation) and a set of ways to carry out the works in units. The task presented in the paper is performed with the use of a created algorithm which searches the space of solutions in which metaheuristic simulated annealing algorithm is used. The paper presents a calculation example showing the applicability of the model in the optimization of sub-contractors' work in the construction project.
Decision-making processes, including the ones related to ill-structured problems, are of considerable significance in the area of construction projects. Computer-aided inference under such conditions requires the employment of specific methods and tools (non-algorithmic ones), the best recognized and successfully used in practice represented by expert systems. The knowledge indispensable for such systems to perform inference is most frequently acquired directly from experts (through a dialogue: a domain expert - a knowledge engineer) and from various source documents. Little is known, however, about the possibility of automating knowledge acquisition in this area and as a result, in practice it is scarcely ever used. lt has to be noted that in numerous areas of management more and more attention is paid to the issue of acquiring knowledge from available data. What is known and successfully employed in the practice of aiding the decision-making is the different methods and tools. The paper attempts to select methods for knowledge discovery in data and presents possible ways of representing the acquired knowledge as well as sample tools (including programming ones), allowing for the use of this knowledge in the area under consideration.