My research activity is focused on various subjects of Seismic Engineering. The major topics investigated include: seismic response and design of 3D building structures with coupled lateral-torsional response (design criteria for new buildings and methods of analysis for seismic assessment of existing structures), design criteria for steel frames formulated and calibrated to fulfil the performance objectives of the European seismic code (moment resisting frames, concentrically braced frames, eccentrically braced frames and frames with buckling restrained braces), nonlinear static methods for seismic assessment of existing buildings (identification of the field of application of conventional methods and formulation of new improved variants), seismic upgrading of existing RC buildings by sustainable and low-disturbance techniques, performance based design, and seismic codes. Currently, my research activity is oriented towards the development of analysis/design tools for innovative and conventional structural types applied for seismic protection of new and existing buildings, thus promoting a disaster-resilient society.
Seismic upgrading of buildings with RC structure by sustainable and low-disturbance techniques
Italy and other European countries are in seismically-active areas. In spite of this, the building stock of these countries is often vulnerable to the earthquake. In Italy, 3.5 million residential buildings were built between the seventies and eighties of the twentieth century with RC framed structure. They were designed without considering seismic excitation, because they were built before the enforcement of seismic codes or in areas not considered seismically active yet. Because of this these countries are exposed to high seismic risk and significant losses in terms of human lives, damage to buildings and interruption of economic/social activities are likely to occur in the event of earthquake. It is therefore crucial to implement extensive seismic upgrading of buildings that, by reducing the vulnerability of the built environment, could improve the resilience of our society. Unfortunately, the application of traditional techniques often requires high implementation costs and time, produces high disturbance to the occupants which can also result in a temporary stop of the building activity. This inhibits seismic upgrading of buildings and represents an almost formidable barrier on the road that leads to a seismically resilient society. This line of research is contextualized within this framework and is aimed to formulate and validate new seismic upgrading techniques and related design methods. The common root of the techniques under investigation is represented by (1) use of eco-compatible materials, to ensure sustainable structural solutions from an environmental point of view, (2) use of engineered products, to minimize the time required for their implementation and (3) execution of the intervention from the outside of the building to minimize the disturbance to occupants.
Promoting innovative technologies into the European practice for seismic protection of buildings
In the last decades, the scientific community has generated a vigorous research activity devoted to the development of new technologies for seismic protection of buildings. Many devices/systems have been invented, their features and limitations have been investigated by experimental and theoretical studies, and their effectiveness in seismic protection of buildings has been proved. Structural designers are the main vehicle to transfer these technologies from Labs to real applications. Nevertheless, they often do not use these technologies, because specific provisions for their design are missing in seismic codes. Based on this consideration, this line of research aims at developing of design tools for building structures protected from earthquakes by innovative technologies. These design tools are formulated to be consistent with the framework of EC8, thus promoting the use of the innovative technologies for seismic protection of building structures in Europe.
Towards a reliable seismic assessment of building structures by nonlinear static analysis
A reliable seismic assessment of existing structures is essential to detect their structural deficiencies, to quantify their capacity, and eventually to select and design the seismic upgrading intervention to fill the gap between the expected and the code-required seismic performance. Out of the available (linear and nonlinear) methods of analysis, the nonlinear static method of analysis is considered a fair compromise between simplicity in application and effectiveness of seismic response prediction. Hence, the use of the nonlinear static method of analysis is allowed by most seismic codes. However, the nonlinear static methods provided in seismic codes, for instance Eurocode 8, are suitable only for planar structures that vibrate predominantly in a single mode. Hence, this research task is devoted to the formulation of improved variants of the nonlinear static method that account for the effects of higher modes of vibration, consider the gradual variation of the dynamic properties of the structure because of yielding, and are able to predict properly the effect of deck rotation on the response of 3D building structures.
Simplifying and improving design criteria for conventional structural types
Conventional structural types are still a valid solution to provide buildings with seismic resistance. These structural types are widely used by structural designers for many reasons: the knowledge of advantages achievable by each structural type acquired over decades of use, the experience with numerical models and methods of analysis used for design, and the know-how of the construction workers for their realization. This research task aims at proposing improvements in the design methods of these structural types. These improvements are intended to simplify the design procedures, to relax the requirements for their application, and to recalibrate the design parameters (e.g. the behaviour factor) based on refined numerical models and performance objectives stipulated in current seismic codes. Also, this research task aims at proposing novel structural types obtained by coupling conventional ones.