Photogrammetry Assisted Measurement of Interstory Drift for Rapid Post-disaster Building Damage Reconnaissance

Abstract

Timely and accurate evaluation of damage sustained by buildings after seismic events such as earthquakes or blasts is critical to determine the buildings’ safety and suitability for their future occupancy. Time used in conducting the evaluations substantially affects the duration for which the potentially damaged buildings remain unusable. The elapsed time may lead to direct economic losses to both public and private owners, and society at large. The presented research investigates the application of close-range photogrammetry surveying techniques and Augmented Reality (AR) visualization to design a semi-automated method for rapidly measuring structural damage induced in tall buildings by seismic events such as earthquakes or explosions. Close-range photogrammetry algorithms were designed to extract spatial information from photographic image data, and geometrically measure the horizontal drift (also called interstory drift) sustained at key floors along the edge of a damaged building. The measured drift can then be used to compute damage indices that correlate the drift to the building’s structural integrity and safety. In this research, the measurement accuracy of the calculated drift using photogrammetry principles is particularly studied. The experimental results achieved an acceptable and usable accuracy level of 5 mm using a consumer grade digital SLR camera, demonstrating the potential of photogrammetry assisted rapid measurement of earthquake-induced building damage. It is expected that in the future, as advances in optical-sensing and positioning technologies continue to make high-end cameras and measurement systems (GPS, compass) more affordable, higher accuracy will be practically achievable for further improvement in measurements using the proposed method.