Robustness is the ability of a structural system to resist progressive collapse. While research on evaluating structural robustness has been ongoing for a while, many critical questions still remain unanswered. What are the sources of collapse resistance? Can structural robustness be quantified, and if so, how? Can simple design modifications, such as seismic-resistant detailing, provide increased collapse resistance, particularly at the system level? To address these open issues, special-purpose connection macromodels will be developed to enable collapse simulations of RC and steel moment frames. The calibration and validation of the simulation models will be accomplished in two ways: through comparison with unique experimental data on large-scale testing of connections and through comparison with high fidelity analyses. Several quantitative measures of structural robustness will be developed to assess local and global collapse potential of typical steel and RC building structures. The research results will then be synthesized into a probabilistic framework that can be used as a basis for defining the probability of structural collapse for a given damage scenario. The intellectual merit of the proposed work lies in the unprecedented opportunity to leverage unique large-scale test data to answer a number of critical questions that have long concerned the structural engineering community.
The findings from this project will result in a significantly improved understanding of collapse resistance of building structures. In addition, the developed models and the framework for assessment of structural robustness will form the basis of a more general methodology that can be extended to other structural systems. At a broader scale, the proposed research will provide critical information needed to support the development of a new generation of design codes that attempt to explicitly quantify collapse risk. The new structural robustness indices that will be developed are expected to lead to a better understanding of reserve capacity in structures following the damage or failure of one or more critical structural elements. These benefits directly translate into saved lives and reduced injuries and suffering in the aftermath of unexpected loads on buildings. The project will also provide advanced training to graduate students by involving them in all phases of the research activity.
