GEODETIC ASSESSMENT OF STRUCTURAL DEFLECTIONS IN A HIGH-RISE BUILDING UNDERGOING CONTROLLED DEMOLITION USING TOTAL STATION MEASUREMENTS

Abstract

Geodetic monitoring via Total Station (TS) surveying provides a model-independent framework for characterizing quasi-static structural displacement in high-rise reinforced concrete buildings undergoing controlled deconstruction; hence, augmenting vibration-based methods that are constrained in addressing gradually accumulating deformation. This paper presents a systematic, six-campaign TS displacement analysis conducted over 47 days on a 14-storey RC study building undergoing NDT-informed controlled deconstruction in Lagos, Nigeria. Taking multiple floor-level measurements on bother both left and right sides with 24 prism targets on Floors 2–13. The baseline displacement profile for the right face followed a second-order polynomial distribution that depended on height with R² = 0.933. The highest observed displacement was 15.53 mm at Floor 2. The active penthouse deconstruction caused a statistically significant increase in displacement with cumulative right-face displacements reaching 31.08 mm representing 102% increase over baseline. The average growth rates were 0.46 mm/day on the right face and 0.29 mm/day on the left face, with the highest rate being 0.74 mm/day on Floor 2. The global tilt at Floor 2 went up from 222.4 to 445.2 millidegrees and remained constant after week 4. The maximum displacement was 31.1% of the 100 mm safety threshold, which was the highest. The validated geodetic dataset can be used as the principal reference for cross-validation with associated vibration sensor and differential GNSS measurements in further studies.