Economic analysis of safety risks in construction

Abstract

The objective of this study revolves around the analysis of the safety risks involved within a large construction project, and the respective economic effects. This analysis is fundamental for the safety management and cost reduction of accidents. The case study is the result of the safety coordination of systems, and of the harmonization between the project owner, the safety coordinator and the contractor. The result of this collaboration is and adequate strategy to prevent the risks during the construction of a large hydro-electric dam in the north of Portugal. The project is part of a governmental plan to invest in the energy obtained from hydraulic sources. The dam in the north of Portugal is located in a river and near the confluence with the river Douro. It will have a capacity of storage that will be strategic to the electricity generation in the country. It has two storage-pumped plants equipped with reversible units. The construction volume covers around 700000 m 3 of concrete, 600000 m 3 of excavation and an installed power of 170 MW. This dam presents a strategic value since it will increase the water supply reserves for domestic and industrial use. It will be the largest reserve of water in Portugal. The safety risk evaluation on this construction project was carried out using simulation tools of the different phases of construction according to the tasks of the program plan. This overall analysis of the risks related with the planned tasks provides a sequence of risks over the duration of the project. The simulation allows the analysis to identify peaks and levels of high risks that are identified. The method proposes a scale to classify risks that is compatible with probability of occurrence and gravity of the consequences. There is also a systematic evaluation of risks to each type of the construction task. These conclusions allow the scheduling of additional proposals to prevent accidents and to reduce risks. These preventive measures will contribute to reduce the high risks and consequently, lead to a flattening effect of the project global risk chart. These measures consist in on-site measures and in an integrated implementation of working safety policies. Of course these measures contribute to the risk reduction and rarely to eliminate the risks. The implementation of these prevention systems and working safety policies implies additional costs but when costs are associated to the possible accidents it is concluded that safety has lower costs than a lack of prevention. © 2011 WIT Press.