  Several studies exist which use scientific literature for comparing
scientific activities (e.g., productivity, and collaboration). In this study,
using co-authorship data over the last 40 years, we present the evolutionary
dynamics of multi level (i.e., individual, institutional and national)
collaboration networks for exploring the emergence of collaborations in the
research field of "steel structures". The collaboration network of scientists
in the field has been analyzed using author affiliations extracted from Scopus
between 1970 and 2009. We have studied collaboration distribution networks at
the micro-, meso- and macro-levels for the 40 years. We compared and analyzed a
number of properties of these networks (i.e., density, centrality measures, the
giant component and clustering coefficient) for presenting a longitudinal
analysis and statistical validation of the evolutionary dynamics of "steel
structures" collaboration networks. At all levels, the scientific
collaborations network structures were central considering the closeness
centralization while betweenness and degree centralization were much lower. In
general networks density, connectedness, centralization and clustering
coefficient were highest in marco-level and decreasing as the network size grow
to the lowest in micro-level. We also find that the average distance between
countries about two and institutes five and for authors eight meaning that only
about eight steps are necessary to get from one randomly chosen author to
another.
