Seismic analysis of tall buildings through an enriched equivalent beam model: Application to Grenoble City Hall

The seismic assessment of multi-story buildings at city scale requires robust but simplified modeling techniques to reduce the computational resources and time. This paper presents an equivalent beam model (EBM), issued from homogenization, capable of describing the seismic response of real tall buildings. The EBM is a generalization of the Timoshenko beam model. It integrates shear, global bending, and inner bending mechanisms, which are identified to control the response of reticulated structures such as buildings, foams, honeycombs, or lattice structures. The parameters of the EBM are obtained through the static analysis of a single building story. This work uses a new finite element formulation of the EBM to estimate the dynamic properties of buildings (i.e., eigenfrequencies and eigenmodes) and perform time history analyses with natural seismic records. This approach is validated through a real case study. The Grenoble City Hall corresponds to a regular 13-story reinforced concrete building located in Grenoble-France. The inner bending significantly influences its behavior, whereas usual beam models do not include this mechanism. The results obtained via this 1D simplified EBM match those obtained with a fully 3D finite element simulation, which are also very close to experimental data.