Rybka, Iwona, Bondar-Nowakowska, Elżbieta, Połoński, Mieczysław
Abstract:This paper analyses the causes and consequences of stoppages due to cuts in the water supply and sewage systems installations. The bases for the article are direct observations conducted on 8 building projects.
Abstract:This paper presents development of the earned value concept regarding forecasting project duration time. On the basis of the calculations carried out for an implemented investment project, consisting of development of the sanitary sewage and municipal water supply system, individual methods and their assumptions were presented and discussed.
Abstract:Construction scheduling deals with the decisions which can affect the feasible sequence of construction activities, the selection of alternative execution modes for the activities and the positioning of the construction in time. Effects of these decisions can be evaluated by means of specific schedule evaluation criteria. However, the peculiarity of construction in civil engineering causes that the real effects of the construction also depend on the influence of the surrounding environment. For example, construction processes are sensitive to adverse weather. Poor weather influences the actual performance of construction activities. The performance of the activities influences the performance of the whole construction project. Thus, the performance of whole construction project is also influenced by bad weather. Considering the influence of adverse weather is therefore indispensable when preparing a reliable construction schedule. Note, that the effects of poor weather on actual construction performance can be limited by the careful choice of the activity sequence, construction time lines, and the execution modes for various activities. The approach is presented, in this paper therefore provides the appropriate sequence of construction activities, related starting date and the allocation of execution modes to the activities in order to make construction schedule less sensitive to inclement weather.
Abstract:Construction schedule optimization generally deals with the identification of the feasible sequence of activities and allocation of modes that provide the most efficient construction performance according to the assumed evaluation criteria. The specific technological order of activities results in the numerous feasible sequences of activities and availability of alternative modes results in the numerous mode combinations. Construction scheduling becomes, therefore, a difficult combinatorial problem that is usually underestimated by the planners. This is the main reason for obtaining schedules that result in construction implementation lasting too long and costing too much. It is, nevertheless, possible to identify the construction schedules that provide excellent results. A simple, simulationbased approach is presented in this paper. Its originality results from nature of applied model and a way the calculations are made. The effectiveness of the approach is illustrated by means of a sample analysis based on data provided by . The approach also proved useful for solving scheduling problems in engineering practice.
Abstract:On the basis of traditional methods for the technical normalization of working time, this present paper presents the use of probabilistic models of working processes for use when estimating the execution time for selected building processes.
Abstract:The paper describes the comparison of different approaches to reconstruction and the problems in the selection of implementation for a historic bridge over the Vistula River in Tczew. A compromise reconstruction is shown, taking technical, historical and aesthetic aspects into account, as well as the needs of the local community.
Abstract:Planning the course of construction works is complex and complicated, requiring reflection on many aspects related to the implementation of the project. High importance is placed on duration and cost of the project, as well as the separation of necessary resources. This article deals with the subject of planning the size of the workforce for a project, presenting widely available workforce planning methods, in accordance with academic approaches. A survey was conducted among Polish construction contractors – with differing scopes and ranges of activities, regarding practical methods for determining the size of the workforce. Factors that influence the size of a construction team were also investigated. The results obtained will develop with further research in this area.
Abstract:This paper presents the elements, the goals and the functions as well as the rules for the elaboration of a property management plan. The authors analyzed its importance in the decisionmaking process (the immediate and long-term decisions) concerning property management. Particular attention has been paid to the multifaceted character of this problem.
Abstract:The assignment problem consists of allocating renewable resources (construction equipment, crews, or contractors) of limited availability to a set of activities. The classical model for this problem minimizes the total time or cost of completing all activities with the assumption that each activity is assigned to one particular resource. This paper systematizes and describes extensions of these assumptions, considering the effects of task sequence: parallel, serial and hybrid (modeled by means of network methods). This study proposes algorithms for the solution of presented models, which can be used in construction project scheduling.
Abstract:Production downtime results from the technological regime of production processes, established in production diagrams as network nodes. Their direct cause in the lack of harmonization between working teams, diversity of performance of hardware units – working in mixed systems, and different labor construction processes, performed on the same working plots. Time and costs analysis lies in optimizing the downtime of production resources using the “by-pass” production, which allows production labor (R) and hardware measures (S) for the implementation of part of the process. This tool is defined in network nodes, slowing down the production and binding the run of the production front with a two criteria network plan: technologically and organizationally. The technique is based on an algorithm of the limitations of renewable resources of means of production, which assumes the full availability of construction materials, available from storage sites. The paper presents an analysis of fixed and variable investments costs in terms of compensating for downtime.