Monitoring and time-dependent analysis of vertical deformations of the tallest building in China

Ping-An Finance Center (PAFC) in Shenzhen, with a structural height of 597 m and a total height of 660 m, is currently the second tallest building in the world and the tallest in China. In this paper, based on the outputs of a structural health monitoring system installed in PAFC, a combined study of both on-site measurements and numerical analysis of the vertical deformations (axial shortenings) of the super tall building during its various construction stages is carried out. It is worth noting that a novel strategy to adjust the elevation of each floor of PAFC was implemented in the design and construction of the super tall building, in which the floor-to-floor height is modestly increased to compensate for the axial shortenings of gravity load bearing elements during the construction process and in-service stage. This design strategy is referred to as elevation reservation, and its effectiveness is verified through the field measurements of the vertical deformations in this study. A good agreement is found between the numerical results and the field measurements, which validates the finite element models of PAFC at different construction stages. The finite element models are further used to investigate the time-dependent effects due to the construction sequence and the shrinkage and creep of concrete on the vertical deformations. The numerical results show that the vertical deformations would be seriously underestimated without consideration of the time-dependent effects. The outcomes of this study would be of interest and practical use for engineers and researchers involved in the structural design, construction, and structural health monitoring of super tall buildings.