Construction settlement monitoring and thermal actions monitoring of supertall structures

Abstract

Recent decades many supertall buildings over 600 m have been and are being constructed for serving the needs of society and economic development. Numerical analysis and scaled laboratory experiments have been conducted in structural design. However, the actual external loading and environmental parameters of the supertall structures are different from those employed in the numerical models and laboratory experiments. Moreover, the structural system during the construction can be more critical than the service, because the structural configuration and boundary conditions during the construction stage are significantly different from those during the service stage. The structural performance under the real construction and service conditions has not been fully understood due to the storage of first-hand information, which poses challenges for the safety and serviceability of these structures in the construction and service phases. The sophisticated long-term structural health monitoring systems in the 632 m high Shanghai Tower and the 600 m high Canton Tower serve as the test-beds for this PhD research. The first part of the thesis proposes an integrated construction settlement monitoring method integrating the Kalman Filtering approach and the finite element forward construction stage analysis, and applies it to the Shanghai Tower. With the Kalman Filtering method, the modeling errors and the measurement noise are filtered out. The updated results consider both the construction load effects and various uncertainties. Consequently, the results are more realistic and accurate for studying the floors{174} pre-determined height of supertall buildings. The densely distributed thermal sensors in the Canton Tower are used to monitor the temperature actions of this supertall structure. Based on the long-term monitoring data of the Canton Tower over seven years from 2008 to 2014 during the construction and service stages of the structure, the temperature difference between the inner and outer tubes, and the temperature difference between different facades of structure are investigated. The last part of the thesis integrates field monitoring and numerical simulation to study the temperature actions of the Canton Tower, including temperature-induced displacement and stresses. The simulated results are verified through a comparison with the measurements. The temperature model can be used as the reference in design and construction of similar supertall structures in future. Moreover, the results are compared with the typhoon-induced counterparts. The present study offers the first-hand investigation on the structural settlement during the construction stage and thermal actions during the service stage. It will assist practitioners to better understand the structural performance in the real world. With more such monitoring exercises implemented in more practical high-rise structures, the accumulated experience will improve the relevant design/construction standards.