Resumen de MetodologÍa para la evaluación y seguimiento de procedimientos constructivos de forma sostenible e integrada
This doctoral thesis defines a new methodology for evaluating and comparing different construction projects in an objective and systematic manner. It is innovative by incorporating issues as diverse as cost, occupational risks, environmental impact, and social impact. The methodology enables public administrations or other entities, during the construction tender stage, to quantify and compare the impact of the different construction options, to prioritise them, and to select the best based on a multi-criteria analysis. The proposed methodology can assess the impact of actual work during construction and contrast it with the impact predicted at the design stage, enabling corrective measures to be proposed timeously. The methodology is based on the multi-attribute utility theory, which was found to be the most appropriate theory among all multi-criteria decision aid methods reviewed. An occupational risk index (ORI) that allows the quantification of occupational risks in construction work is defined. The ORI is based solely on a given project's design and its resulting construction process and a project's ORI is a function of the total amount of work to be devoted to each risk activity. Occupational risks in construction work - and the activities in which the risks are present - have been categorised and, for each risk activity, the probability of occurrence and the most probable consequence have been determined. The ORI allows the prioritisation of the construction processes in terms of occupational risks and the selection of the least occupationally-risky construction process. It also enables the detection of the most risky activities and the introduction of improvements. Prior to the ORI, no similar index specific to construction work existed. A construction project has environmental impacts not only during the construction work stage but also during the preceding stages (extraction, manufacturing and transport of construction materials). The environmental impacts of the different stages in construction projects have been studied and different ways for measuring them have been defined according to data availability. The thesis includes average values of energy consumption and greenhouse gas emissions obtained from databases and from calculations in the thesis. This data can be used for the environmental impact calculations in cases where more accurate local data is not available. The methodology is sensitive to material consumption, reuse and recycling, energy saving, greenhouse gas and air pollutant emissions, waste generation, effects on sensitive environments and suchlike. The methodology enables the prioritisation of the construction projects, the selection of the best alternative and the introduction of improvements in terms of environmental impact. Social impacts due to construction work, especially in urban areas, (effects on transport, pedestrians, shops, noise and others) are very complex to analyse and the hitherto least studied and regulated type of impact. The different types of social impacts produced during construction work are identified and classified. An objective and systematic manner of measuring each one of these impacts is defined. The ability to quantify these social impacts is considered to be one of the main innovations of the thesis. This enables the prioritisation of the construction projects, the selection of the best alternative and the introduction of improvements in terms of social impact. Another significant contribution of the methodology is the incorporation of the different types of impacts, including the cost, in the same evaluation. Furthermore, it enables the incorporation of the interests of the different stakeholders: developers, people affected during construction work, constructors, etc. The methodology has been successfully applied in field trials: to four construction projects built by Imperial College London students in the UK and to two emergency shafts of a tunnel in Barcelona.
