M. Połoński

Management of Alterations to Project Documentation – a Case Study of Water Supply and Sewerage Works

Background . The implementation of alterations to project documentation is the modification of certain solutions, assumptions or requirements. It mostly involves the verification or the specification of project documentation with regard to the actual conditions of execution or the investor’s expectations. The management of alterations in a construction project is aimed at predicting any negative consequences caused by changes in the investment process and their prevention or mitigation. Previous experience indicates that alterations to project documentation introduced during the execution of the work are widespread. They contribute to loss of time and increase in the cost of the project. For this reason, it is necessary to develop and implement an effective model for the management of such alterations. Research aims . The project manager, before construction, should be aware of any alterations to the project documentation that may have occurred during its execution, and their possible consequences. The aim of the study is to identify the causes, the structure and the consequences of alterations to project documentation with regard to water supply and sewerage construction. Methodology . The basis of the research and analyses constitute a detailed review of documentation compiled from eight projects in water supply and sewerage. Among the documents concerned, the “Records of Necessity” and “Records of Negotiations” were especially valuable for conducting the analysis. Key findings . The research conducted indicated the crucial role of the investor in the process of managing alterations to project documentation. The research revealed that proper preparation of the investment process, i.e. recruiting the best designers to prepare the project documentation, tracking changes in the nearer and farther surroundings, may significantly contribute to reducing or even eliminating many alterations to project documentation during the execution of the work.

The influence of stoppages on productivity during construction of water supply and sewage systems

The influence of stoppages on productivity during construction of water supply and sewage systems

Impact of Baseline Terms on the Course of Critical Paths and Time Buffers in the Modified Goldratt’s Method

Abstract The introduction of a baseline term to the dependency network most often results in a change, break and/or generation of a new sequence of critical path, depending on the type of such a baseline term and the exact date selected. Each of those situations has an impact on the location or need to include new time buffers in the modified Goldratt’s method. The purpose of this article was to identify possible effects brought by declaration of each type of baseline term and to point out actions to be taken in each case. It must be noted that guidelines provided should in each individual case be adapted to the specific character of schedule changes caused by implementation of the relevant baseline term. The example presented herein exemplifies one of such solutions to be implemented as a result of break of the critical path and need to introduce new time buffers.

Risk of Contractors’ Claims On the Example of Road Works

The aim of the study is to analyse claims filed by building contractors during the project implementation. The work is divided into two parts. In the first part problems associated with the management of claims in the construction process were discussed. Bearing in mind that claims may result in prolongation of the investment or exceeding planned budget, possibilities of applying information included in documents connected with claims procedure to risk management was analysed in the second part of the study. The basis of the analysis is a review of 226 documents. They originate from 8 construction sites completed in the last 5 years in southwestern Poland. In each case, these were linear road projects, executed by different contractors, according to conditions in the contract set out in the Yellow Book FIDIC. In the study, other documents relating events that according to contractors entitled them to claim were also analysed. They included among others: project documentation, terms of reference, construction log, reports and correspondence under the contract. The events constituting the reason for contractors` claims were classified according to their sources. 8 areas of potential threats were distinguished. They were presented in the form of a block diagram. Most events initiating the claims were reported in the following group - adverse actions of third parties, while the fewest were recorded in the group – the lack of access to the construction site. Based on calculated similarity indicators it was found that considered construction sites were diversified in terms of the number of the events occurrence that generated the claim and their sources. In recent years, many road projects are completed behind the schedule and their initially planned budgets are significantly exceeded. Conducted research indicated that data derived from the analysis of documents connected with claims can be applied to identify and classify both cost and schedule risk factors. Obtained data can also be useful at the stage of risk control because early diagnosis of threats in relation to technical and organizational aspects is necessary to take effective action.

Identification of the interference in the investment process during the realization of a shopping centre - a case study

Abstract During the planning and controlling of the construction process, most attention is focused on risk analysis, especially in the context of final costs and deadlines of the investment. In this analysis, the primary and most significant concern is the proper identification and quantification of events, which on a certain level of probability may affect the development process. This paper presents the result of a risk analysis for a particular building object, made after completion of the investment and accepting it for use. Knowledge of the planned values and the actual investment process allowed for the identification of the events and their effects that in this case have significantly disrupted the investment process. The limited total cost of the investment project in question had a considerable impact on the progress of the project execution. Despite three transitions of administrative procedures, the opening date of the shopping centre was delayed by only three weeks.

Optimization Model for the Design of Multi-layered Permeable Reactive Barriers

Permeable reactive barriers (PRBs) are employed as in situ groundwater remediation technology. The installation of PRBs is usually a major investment, where one of the biggest cost drivers are material costs. PRBs are barriers against contaminants moving under the natural gradient, however not against groundwater contaminants. The most common construction of a PRB is a single barrier, but in the case of contaminant mixtures a multi-layered construction, i.e. a combination of different reactive materials and removal processes, is required. The most important parameters for PRB design are dimensions. The barrier must be long enough to treat the entire width of the plume (dimension perpendicular to groundwater flow) and should extend to and be keyed into an impermeable layer. The problem is to determine the optimal thickness of a PRB, which should provide a residence time appropriate for reducing the concentration of contaminants to the desired effluent concentration. In PRBs, design is accomplished using numerical methods or simulators, which are useful to predict the scenarios and evaluate the resulting groundwater flow systems to specific site conditions. On the other hand, numerical methods are complicated and may have significant errors if the discretization is too coarse or is incorrectly aligned. This paper deals with a simple, conceptual model of a one-approach optimization method for multi-layered PRB design. Based on literature and laboratory test results (residence time, density and hydraulic coefficient), a selection of layers of reactive materials was determined. Considering the lowest cost of the reactive materials, the required thicknesses of activated carbon, zeolite and zero valent iron were calculated using two different algorithms. The simple model may be used for preliminary barrier design and cost calculations. Using the optimization model in a preliminary design stage, it is possible to reject the PRB concept and avoid losing time for the complicated analysis.

Causes and effects of adverse events during water supply and sewerage system constructions

Abstract This paper identifies the adverse events occurring during the execution of water supply and sewerage systems construction. The basis for this paper is research conducted in 2010-2014 on the construction sites of water supply and sewerage systems located in the provinces of Lower Silesia and Opole. The research consisted of direct observations of construction sites and review of construction documentation. It showed that work stoppages on the examined construction sites were frequent. They were caused by violations of work discipline by the production employees, adverse weather conditions, and defects in the project documentation. The study demonstrated that in almost every case, these bad an adverse effect on the completion date and budget of the investment. The analyses show that in such important and expensive investments as water supply and sewerage systems, organizational structures in which a special role is assigned to middle-rank personnel should be adopted.

Application of the work breakdown structure in determining cost buffers in construction schedules

Abstract The paper presents methods of determining the location of cost buffers and corresponding contingency costs in the CPM schedule based on its work breakdown structure. Application of correctly located cost buffers with appropriately established reserve costs is justified by the common overrunning of scheduled costs in construction projects. Interpolated cost buffers (CB) as separate tasks have been combined with relevant summary tasks by the start–to–start (SS) relationship, whereas the time of their execution has been dynamically connected with the time of accomplishment of particular summary tasks using the “paste connection” option. Besides cost buffers linked with the group of tasks assigned to summary tasks, a definition of the cost buffer for the entire project (PCB) has been proposed, i.e. as one initial task of the entire project. Contingency costs corresponding to these buffers, depending on the data that the planner has at his disposal, can be determined using different methods, but always depend on the costs of all tasks protected by each buffer. The paper presents an exemplary schedule for a facility and the method of determining locations and cost for buffers CB and PCB, as well as their influence on the course of the curve illustrating the budgeted cost of work scheduled (BCWS). The proposed solution has been adjusted and presented with consideration of the possibilities created by the scheduling software MS Project, though its general assumptions may be implemented with application of other similar specialist tools.