The construction process begins with the formulation of an idea for the project and finishes with the final commissioning. This consists of many stages, the most important of which is the construction of the buildings for the facility. This results from the specific features of the construction project, such as its long duration, its uniqueness, the seasonality of the work, dependence on weather con-ditions, and the necessity of interfering with the environment. There are many more factors, and when we consider the construction of a treatment works plus the sewerage system itself, we must also take into account any special requirements connected with their function in the local water and sewage management system. All these factors generate the risk exposure. Such risks should be included in the initial project-costing, schedule planning, and establishing the duration of the work. Events which can occur during the building of the sewage treatment works and the sewerage system have been detailed in this paper. Such events can lead to cost overruns and the prolonging of the construction phase. The method known as expert interview was used to establish whether the pre-prepared list contained the most important sources of risk. The specialists, all with long ...
Surveys, documentation reviews and direct observation on the building sites point to a number of "exposures", which can have a negative influence on the sewerage's projects completion. Such exposure occur at every stage of the project. The most important among them are errors in the construction project, materials' defects and damages and disadvantageous meteorological conditions. They cause a high level of quality, schedule and cost risk. Risk response development can lower the level of risk. In this paper a risk response matrix was used to achieve this purpose. This technique is used in a risk management plan. The activities, which allow the achievement of a lower frequency of risk and reduction in their consequence have to be determined by this technique. This paper indicates that activities based on risk avoidance and mitigation have their best application in sewerage's projects. These include: tightening contractor selection's criteria, a detailed contract and contingency reserves. Analysis of risk response development indicates that to lower levels of quality, schedule and cost risk throughout a project suitable action should be taken as early as at the planning phase and the contract stage.
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Construction works in the open air, in particular laying sewage systems, are susceptible to weather conditions. Weather conditions, such as very high or low emperatures, strong winds, intense and prolonged precipitation, interfere with work and they can even lead to cessation of construction. In consequence, the construction work lasts longer than originally assumed. On the other hand, it is impossible to alter weather. Therefore, it is vital to conduct a thorough identification of threats related to adverse weather conditions. This work makes an attempt to determine basic relationship between adverse weather conditions and the possibility of completing construction work according to a schedule. This analysis is a part of Schedule Risk Assessment. The findings show that the frequency of adverse weather occurrence is high and it affects schedule risk with special regard to air temperatures below -5°C and above 25°C. Thus, before starting construction, the probability of adverse weather conditions should be considered. Accurate identification of weather factors during the planning phase may help in accumulation of adequate reserves. Therefore, any unavoidable circumstances that are forced by adverse weather seem to be allowed in the schedule. This work focuses on air temperature, precipitation and wind because of their ...
Occurence of minus air temperature, precipitation and wind worsen tech-nical conditions of the performance of maintenance works and it also has an impact on the occupational safety. Some of the results of considered weather events are the delays in the performance of particular works and an increase of their costs in a result of additional works. Potential financial loss that may influence enterprise in a result of unfavourable weather conditions is determined as the weather risk. In the following research the level of the risk in maintenance works in watercourses was assessed. The analysis of the weather forms was conducted in Wrocław between 2000 and 2011 for that purpose. Three weather conditions such as the air temperature below 0, rainfall, snowfall and the velocity of the wind were considered. Analysis was conducted basing on the data obtained from the Wroclaw Airport station. It was performed for the period recommended for the performance of maintenance works in watercourses from the 1st to the 31st of December. Frequency of the days occurence while weather conditions constituted an obstacle was determined basing on the obtained data. The analysis revealed that unfavourable weather conditions occurred often in realization of the works in the considered ...
