MANAGING UNCERTAINTY IN THE SUSTAINABLE DESIGN OF CONCRETE STRUCTURES

Abstract

In 2008 came into force the current version of the Spanish structural concrete Code (EHE), which provides a tool for assessing structural sustainability, using a specific index for that purpose (“Índice de Contribución de la Estructura a la Sostenibilidad”: ICES). The EHE does not take into account the uncertainty about the final design and specifications of the structure (and therefore, its potential ICES), existing in the phases of the project prior to structural completion. This paper suggests two mathematical models to manage that uncertainty and summarizes the works currently under development for building the corresponding computer tools. Both are based on the MIVES method (Integrated Value Method for Sustainability Assessment), used in the EHE, which is based in the value analysis technique, and that can use the Analytic Hierarchy Process (AHP) as part of the model. The first new model combines MIVES with Monte Carlo simulation. In this way, the designer, instead of estimating a specific ICES level (A, B, C, D or E), will obtain a cumulative probability curve, to determine the probability of achieving the different ICES levels. The second model combines MIVES with fuzzy mathematics. Here some inputs to the model, and its output, are fuzzy numbers. Keywords: structural concrete; sustainability; Spanish EHE Code; uncertainty; Monte Carlo simulation; fuzzy mathematics