Evaluating damage potential in buildings affected by excavations

Predicting building damage due to ground movements caused by excavations is an important design consideration when building in a congested urban environment. Current predictive approaches range from empirical methods to detailed finite element calculations. Limitations inherent in the simpler of these models preclude them from accurately predicting damage in cases where important assumptions are invalid. A new simple model for representing buildings is presented to allow a designer to make realistic simplifications to a building system that is consistent with major features of the structure so that the response to ground movements can be adequately represented. This model assumes that the floors restrain bending deformations and the walls, whether load bearing or in-fill between columns, resist shear deformations. Closed-form equations are presented that relate bending and shear stiffness to normalized deflection ratios. The proposed model is shown to adequately represent the response of a three-story framed structure which was affected by an adjacent deep excavation. The proposed model represents a reasonable compromise between overly simplistic empirical methods and complex, burdensome detailed analyses.