Dr. Maureira-Carsalade, Nelson

A novel energy dissipation device is proposed to protect structures against dynamic loads. A conceptual model of the device is presented, describing the fundamental components of its operation. This model has a linear elastic element and a frictional damper. The equilibrium equations that lead to the relationship that governs its behavior are proposed. A functional model of the device was built on a 3D printer with PLA filament. Experimental trials were carried out to characterize its elastic component and the coefficient of friction of the damping parts. Proofs of concept load-unload tests were also carried out on the device, subjecting it to cyclical movement sequences. The results of the first two types of tests allowed the parameters of the previously developed analytical model to be calibrated. The results of the load-unload tests were compared with the predictions of the analytical model using the calibrated parameters. Consistency was observed between the experimental and analytical results, demonstrating the basic attributes of the device: self-centering capacity, dissipation capacity and force proportional to the displacement demand. It is concluded that the proposed device has the potential to be used effectively in the protection of structures under dynamic loads.

A proposal of a semi-rigid self-centering connection for the seismic protection of wooden structures is studied. An analytical model for the characterization of the response of the connection is developed. Quasi-static tests of a wooden column with the proposed connection allowed to validate the model and calibrate its parameters, obtaining errors smaller than 6% between analytical prediction and experimental results. The self-centering capacity and the effectiveness of the connection to limit the loads transmitted to the connected elements were evidenced. Damped free vibration tests evidenced the capacity of the connection to reduce structural vibrations. It was verified that the resistance and dissipation capacity of the connection can be modified by two design parameters that can be adjusted at the assembly. The proposed connection has desirable characteristics for its use in the protection of structural wooden frames, is versatile, and its design is simple, with explicit physical parameters.