Assessment of building damage due to excavation-induced displacements: The GIBV method

Abstract

This paper presents an original methodology for the rapid assessment of “potential” building damage caused by an excavation. The combination of the Ground-work Impact (GI), in terms of induced greenfield displacements, and the Building Vulnerability (BV) form the basis for the GIBV damage assessment method. Both short- and long-term displacements are considered in the impact evaluation. In addition to short-term displacement due to undrained shear deformations, groundwater drawdown can result in significant consolidation settlements at considerable distance from the excavation site. In the proposed method for soft soil ground conditions, the short-term excavation-induced settlement is derived using empirical expressions and long-term displacement is estimated by coupling empirically-derived relationships for excavation-induced groundwater drawdown with a soil stratification model and consolidation theory. The building vulnerability is assessed by considering different physical characteristics and conditions of the buildings. The GIBV method has been implemented in a GIS tool to predict damage classes for buildings exposed to excavation-induced settlements. Two different case studies in Norway were used to test the reliability of the predictions of the tool and validate the methodology. A comparison between the predicted damage classes with the back-calculated ones shows a relatively high accuracy of the methodology. Moreover, the coupled model, which considers both impact and vulnerability for the damage assessment of buildings, has a higher accuracy and lower overestimation rate compared to the results obtained by just considering the impact.