Corrado Chisari

Application of a Translational Tuned Mass Damper Designed by Means of Genetic Algorithms on a Multistory Cross-Laminated Timber Building

AbstractThis paper presents a numerical study conducted on a seven-story timber building made of cross-laminated (X-lam) panels, equipped with a linear translational tuned mass damper (TMD). The TMD is placed on the top of the building as a technique for reducing the notoriously high drifts and seismic accelerations of these types of structures. TMD parameters (mass, stiffness, and damping) were designed using a genetic algorithm (GA) technique by optimizing the structural response under seven recorded earthquake ground motions compatible, on average, with a predefined elastic spectrum. Time-history dynamic analyses were carried out on a simplified two-degree-of-freedom system equivalent to the multistory building, while a detailed model of the entire building using two-dimensional elastic shell elements and elastic springs for modeling connections was used as a verification of the evaluated solution. Several comparisons between the response of the structure with and without TMD subjected to medium- and h...

Tolerance-based Pareto optimality for structural identification accounting for uncertainty

Structural parameter identification often requires an estimate, at least in a qualitative fashion, of the uncertainty of the solution. This uncertainty quantification should account for the sensitivity of the response to the sought parameters, the error in the measurement and the repeatability of the test. In this paper, repeatability is taken into account into a multi-objective framework, while a non-standard definition of Pareto dominance based on a given tolerance in the objective satisfaction allows one to consider uncertainty in the experimental data. The solution of the identification is not given as a single value, but a region of the parameter space which is compatible with the data and accounts for uncertainties and response sensitivity to model parameters. The procedure is applied to an experimental test on a masonry panel, showing its effectiveness in discriminating identifiable parameters from those affected by higher uncertainty.

Pushdown Tests on Masonry Infilled Frames for Assessment of Building Robustness

AbstractThe research presented in this paper addresses the influence of nonstructural masonry infill on the resistance of multistory buildings to progressive collapse under sudden column loss scena...

Comparison of Hysteretic Models for Steel Beams Calibrated by Means of Multi-Objective Optimisation

Phenomenological models are often used to model post-elastic behaviour of steel members in the framework of concentrated-plasticity approach. Many of them can simulate degradation phenomena occurring during cyclic loading, but are dependent on model parameters without clear physical meaning. To overcome this issue, parameter calibration should be performed by curve fitting of experimental responses. In this work, several numerical models implemented in widely used software packages are calibrated against the results provided by an experimental programme involving cyclic and monotonic tests on open and closed cross-section profiles, according a multi-objective methodology recently developed by the authors. The extensive calibration analyses carried out show that the most reliable model among those investigated is the Sivalselvan-Reinhorn model, which is able to provide accurate simulation of both monotonic and cyclic responses. Extension of the calibration procedure is proposed, with an additional objective related to the envelope curve of the cyclic response, and it is shown that this improvement adds robustness to the results.