Analysis of lateral load transfer from intermediate floor to shear walls in multi-story timber modular buildings

Abstract

Multi-story timber modular buildings (MSTMBs) are prefabricated volumetric modules that are connected to each other in-situ. In the absence of an additional lateral load resisting system, wind and other lateral load must be safely transferred through intermediate floor and shear walls down to the foundations. In this Master´s thesis, a 2D FEM is proposed and its application for the lateral load distribution analysis in MSTMBs is demonstrated. The 2D FEM is based on modelling the discontinuous semirigid intermediate floors supported by the shear walls and simulating the lateral load transfer in every story of MSTMB. The 2D FEM is validated by conducting load distribution analysis in a reference project. The results obtained by using the 2D FEM are compared with the results from a reference 3D FEM as well as with simplified methods that are commonly used in MSTMBs projects. The developed 2D FEM shows a broad agreement with the results from the reference 3D DEM. Furthermore, individual parameters that determine the load distribution are studied by the 2D FEM. The influence of the inter-module connections as well as the stiffness of the plates forming the intermediate floor are identified to be relevant for structural design. Additionally, the effects of the stiffness and geometrical variations of the shear walls are expressed. Eventually, a comparison of different building layouts is made in order to evaluate how the positions of the shear walls play a role in the load transfer. It is shown that even small modifications in a floor plan may considerably change the load distribution. Overall, in the thesis, the 2D FEM is introduced and the results of the parametric analysis are reported and discussed. Finally, the possibilities of using the 2D FEM for optimizing MSTMBs are presented.