| The construction of super tall buildings is subject to enormous challenges owing to the difficulty in structural design and the complexity of the construction process. In the construction stage, the probability of risk and failure of the whole building can be increased greatly due to the incompleteness of the structural resistance system and the complexity of external loads. In the long-term service stage, factors such as the aging and fatigue of materials, typhoons and earthquakes can lead to the accumulation of structural damage and reduction of structural resistance. Therefore, it is of gr eat significance to combine the structural health monitoring(SHM) and finite element model(FEM) for the reliable and efficient evaluation of the structural deformation and stress state of the buildings. Besides, the results are of great use for the optim ization the constructional scheme, thereby assuring the structural safety and improving the construction efficiency.This thesis presents a combined study of structural health monitoring and numerical simulation of Ping An Financial Center(PAFC) which wil l be the tallest building in China upon completion. The optimization of the construction scheme that advancing the construction of the core tube to the external frame and deferring the installation of the outrigger-bracing are investigated to improve the s tructural performance. The main contents discussed in the thesis are as follows:Finite element models of PAFC at different construction stages are established and the influences of construction progress and time-dependent effects of building materials are considered in the whole construction process analysis. The trend of the vertical deformation of the tower and the stress distribution in key structural components are studied. Besides, the effect of concrete's shrinkage and creep, and the construction procedures are investigated.The results indicate that, the vertical deformation suggests a “fish-bellied” curve and the compressive stress on the key structural members gradually decrease with the increase of structural height. The shrinkage and creep of con crete and the construction process have significant effect on the vertical deformation and compressive stress of this building. Therefore, these factors are worthy to be considered in the structural design phase for super tall buildings. Moreover, analysis of the action of reduced wind and seismic load on PAFC during construction provides a further proof that PAFC is in a safe and stable state.The effect of construction speed, the advance construction layers of the core tube and the deferred installation of the outrigger-brace are discussed. The results indicate that the construction speed has little influence on the vertical deformation, the vertical differential deformation and the stress of structure. The advance construction of the core tube by a height of 25-floor is safe and stable for the structure during the construction stage. However, the lower part of the building should adopt a larger advance layer and the middle-upper part should take a smaller value to reduce the vertical differential deformation. At last, the optimization of outrigger-brace installation schedule, taking the additional stress as the control objective, is proposed and verified by a numerical example.The simulation results and the measured data are in good agreement, which confirms the rationality of the combination of SHM and finite element analysis for the monitoring of super tall buildings during construction. This thesis provides valuable information regarding the estimation the reliability of PAFC during various construction stages. Furthermore, it can be very helpful for the design and construction of similar projects in the future as well. |
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