Tilt and Settlement Monitoring of High-Rise Buildings Using GNSS Precise Point Positioning and Seasonal Ground Deformation

This paper introduces a method which utilizes global navigation satellite system (GNSS) based precision point positioning (PPP) for conducting long-term tilt and settlement monitoring of high-rise buildings in North China. Two-year continuous GNSS observations from two high-rise buildings near a deep foundation pit in Beijing are used for the case study. The method comprises four steps: ① Calculating the geocentric coordinates (XYZ) of the GNSS antenna with respect to a global reference frame (e.g., IGS08) with the PPP method; ② transforming the geocentric coordinates to a regional reference frame-the North China reference frame (NChina16); ③ converting the geocentric XYZ coordinates to a station-centric East -North-Up (ENU) coordinates; ④ removing seasonal ground-surface deformation from the ENU time series and restoring the true displacements (tilt and settlement) of the building. Experimental result indicates that the PPP method is able to achieve 2-3 mm horizontal accuracy(root mean square error) and 6-9 mm vertical accuracy (root mean square error)for 24-hour continuous observations in North China. The combination of PPP, NChina16, and the North China seasonal ground deformation model can perform millimeter-accuracy, near-real time, and long term static structural health monitoring of high-rise buildings and other large-scale infrastructure projects in North China.