A. Orbe

Innovation evaluation model for macro-construction sector companies: A study in Spain

The innovativeness of the traditional construction sector, composed of construction companies or contractors, is not one of its strong points. Likewise, its poor productivity in comparison with other sectors, such as manufacturing, has historically been criticized. Similar features are found in the Spanish traditional construction sector, which it has been described as not very innovative. However, certain characteristics of the sector may explain this behavior; the companies invest in R+D less than in other sectors and release fewer patents, so traditional innovation evaluation indicators do not reflect the true extent of its innovative activity. While previous research has focused on general innovation evaluation models, limited research has been done regarding innovation evaluation in the macro-construction sector, which includes, apart from the traditional construction companies or contractors, all companies related to the infrastructure life-cycle. Therefore, in this research an innovation evaluation model has been developed for macro-construction sector companies and is applied in the Spanish case. The model may be applied to the macro-construction sector companies in other countries, requiring the adaption of the model to the specific characteristics of the sector in that country, in consultation with a panel of experts at a national level.

Study of historical developments in the use of fire resistant steels

Abstract This paper presents a review of the most relevant articles on fire-resistant (FR) steels, as part of a research project at the University of the Basque Country (UPV/EHU) on the FR properties of steelstructures. An important characteristic of FR steels is that they maintain their mechanical properties at high temperatures better than the more widely used structural steels, mainly due to their special chemical composition and the thermal treatment used in their manufacture. The available information on FR steel tests has been analysed. All the data allow us to study the evolution of mechanical properties at different temperatures. We have, in particular, conducted a comparative evolution of the yield stress (YE) and the yield stress ratio (Ra) at different temperatures. A summary is also presented of the most important elements in their composition and the different manufacturing treatments of these steels and their influence on the initial YE and RA at different temperatures. For example, molybdenum and niobium improve the YE considerably at elevated temperatures. The alloy Cr–Mo–V–Nb is considered effective in FR steels and the use of boron is recommended, if an FR steelstructure is required to withstand temperatures higher than 700°C and to decrease the percentage of carbon. In view of the temperatures associated with manufacturing treatments, it should be recalled that although accelerated cooling, such as quenching, increases YE at room temperature and at high temperatures, it reduces the Ra of these steels. The most effective thermal treatment is air cooling, although special attention should be paid to the influence of slab reheating and the finish rolling temperature.