Iwona Rybka

Risk of Alterations to Project Documentation on an Example of Environmental Engineering Construction

Abstract Investor bears responsibility for proper preparation of the investment process. One of his tasks is to prepare the project documentation and obtaina building permit. Frequently, during his work, there are situations and events whose im pact interferes with the design solutions. Regardless of reasons, alterations to a project constitute a source of cost risk. In each case, the Investor should be prepared for this type of a risk. Exposure to risk should be taken into account in the planning stage of the investment. Also, a model of investment execution should be chosen at this stage. The type of model is associated with the distribution of risk throughout the project. The aim of this paper is to identify events that generate risk related to alterations to Project Documentation in the context of the selection of the investment executionmodel.

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

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.