Modélisation de la transmission des charges dans les travaux d'étaiement et de ré-étaiement de bâtiments multi-étages en béton armé

Abstract

The prediction of load transfer during the construction of reinforced concrete multi-story buildings is crucial to prevent both structural collapses during the construction phase and the alteration of the building's serviceability. During the construction phase, the loads applied to the slabs occur before they have reached their characteristic strength. Furthermore, depending on the construction sequences and the construction system, these loads can exceed the building's service load. These two factors, combined with the creep properties of concrete, can lead to significant deflections, compromising the structure's serviceability. In this thesis, a finite element modeling method is developed for load transfer during the construction phase in order to analyze the deflections caused until the application of the maximum service load. The methodology of this research project is specifically designed for constructions using the shoring/reshoring system and includes the consideration of the stiffness of this system, the time-dependent properties of concrete, and creep. The methodology is implemented in the finite element modeling software SAP 2000. To validate the developed modeling method, it was applied to two real case studies from literature: a 28-story building construction project in Edmonton, Canada and a seven-story building project in Cardington, England. The consistency between the finite element model results and the data collected on-site allowed to conclude the effectiveness of the proposed method. Finally, the model was applied to a typical building to study the influence of various parameters, including the stiffness of the shoring system, the number of reshored levels, and the construction loads. It was found that considering the stiffness of current formwork systems is essential for evaluating deflections during the construction phase, while the number of reshored levels had less influence. Additionally, the study highlights the importance of considering creep and loading/unloading cycles during the construction phase in the calculation of deflections of reinforced concrete two-way slabs in multi-story buildings.

Date	14 Feb 2025
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Georges El-Saikaly (Supervisor) & Ahmad Abo El Ezz (Co-supervisor)