Case History of the Use of Electronic Survey Techniques to Assess Planar Distortions in Building Facades

Abstract

The occurrence of distortions within facade elements in the form of leaning, bowed and vertically displaced wall construction is common in older structures. Quite often these conditions are identified by building owners and serve as the primary focus of investigations to assess their significance. Quantifying the severity and extent of these displacements is integral to these evaluations. Various surveying methods are available to assist the investigator in determining planar distortions, ranging from simple plumb bob and level surveys to digital electronic surveying techniques. This paper focuses on the use of electronic surveying techniques as a diagnostic tool in assessing planar distortions and displacement in three dimensions on building facades. A case study is presented as a typical application where planar displacements within a building facade needed to be assessed. To provide context for selection, use, and interpretation of various survey techniques, a project is reviewed in detail from initial identification of displacements, review/selection of an appropriate survey technique, manipulation, and interpretation of survey data, assessing the significance of the data relative to the case study building, and review of repair program parameters.